Currently, faultaround code produces young pte. This can screw up
vmscan behaviour[1], as it makes vmscan think that these pages are hot
and not push them out on first round.
During sparse file access faultaround gets more pages mapped and all of
them are young. Under memory pressure, this makes vmscan swap out anon
pages instead, or to drop other page cache pages which otherwise stay
resident.
Modify faultaround to produce old ptes, so they can easily be reclaimed
under memory pressure.
This can to some extend defeat the purpose of faultaround on machines
without hardware accessed bit as it will not help us with reducing the
number of minor page faults.
We may want to disable faultaround on such machines altogether, but
that's subject for separate patchset.
Minchan:
"I tested 512M mmap sequential word read test on non-HW access bit
system (i.e., ARM) and confirmed it doesn't increase minor fault any
more.
old: 4096 fault_around
minor fault: 131291
elapsed time: 6747645 usec
new: 65536 fault_around
minor fault: 131291
elapsed time: 6709263 usec
0.56% benefit"
[1] https://lkml.kernel.org/r/1460992636-711-1-git-send-email-vinmenon@codeaurora.org
Link: http://lkml.kernel.org/r/1463488366-47723-1-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Tested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 92923ca3aa ("mm: meminit: only set page reserved in the
memblock region") the reserved bit is set on reserved memblock regions.
However start and end address are passed as unsigned long. This is only
32bit on i386, so it can end up marking the wrong pages reserved for
ranges at 4GB and above.
This was observed on a 32bit Xen dom0 which was booted with initial
memory set to a value below 4G but allowing to balloon in memory
(dom0_mem=1024M for example). This would define a reserved bootmem
region for the additional memory (for example on a 8GB system there was
a reverved region covering the 4GB-8GB range). But since the addresses
were passed on as unsigned long, this was actually marking all pages
from 0 to 4GB as reserved.
Fixes: 92923ca3aa ("mm: meminit: only set page reserved in the memblock region")
Link: http://lkml.kernel.org/r/1463491221-10573-1-git-send-email-stefan.bader@canonical.com
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Cc: <stable@vger.kernel.org> [4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
compound_mapcount() is only called after PageCompound() has already been
checked by the caller, so there's no point to check it again. Gcc may
optimize it away too because it's inline but this will remove the
runtime check for sure and add it'll add an assert instead.
Link: http://lkml.kernel.org/r/1462547040-1737-3-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make is_vmalloc_addr() return bool to improve readability due to this
particular function only using either one or zero as its return value.
Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many developers already know that field for reference count of the
struct page is _count and atomic type. They would try to handle it
directly and this could break the purpose of page reference count
tracepoint. To prevent direct _count modification, this patch rename it
to _refcount and add warning message on the code. After that, developer
who need to handle reference count will find that field should not be
accessed directly.
[akpm@linux-foundation.org: fix comments, per Vlastimil]
[akpm@linux-foundation.org: Documentation/vm/transhuge.txt too]
[sfr@canb.auug.org.au: sync ethernet driver changes]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sunil Goutham <sgoutham@cavium.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Manish Chopra <manish.chopra@qlogic.com>
Cc: Yuval Mintz <yuval.mintz@qlogic.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When doing cow faults, we cannot directly fill in PTE as we do for other
faults as we rely on generic code to do proper accounting of the cowed page.
We also have no page to lock to protect against races with truncate as
other faults have and we need the protection to extend until the moment
generic code inserts cowed page into PTE thus at that point we have no
protection of fs-specific i_mmap_sem. So far we relied on using
i_mmap_lock for the protection however that is completely special to cow
faults. To make fault locking more uniform use DAX entry lock instead.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
- virt_to_page/page_address optimisations
- Support for NUMA systems described using device-tree
- Support for hibernate/suspend-to-disk
- Proper support for maxcpus= command line parameter
- Detection and graceful handling of AArch64-only CPUs
- Miscellaneous cleanups and non-critical fixes
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABCgAGBQJXNbgkAAoJELescNyEwWM0PtcIAK11xaOMmSqXz8fcTeNLw4dS
taaPWhjCYus8EhJyvTetfwk74+qVApdvKXKNKgODJXQEjeQx2brdUfbQZb31DTGT
798UYCAyEYCWkXspqi+/dpZEgUGPYH7uGOu2eDd19+PhTeX/EQSRX3fC9k0BNhvh
PN9pOgRcKAlIExZ6QYmT0g56VLtbCfFShN41mQ8HdpShl6pPJuhQ+kDDzudmRjuD
11/oYuOaVTnwbPuXn+sjOrWvMkfINHI70BAQnnBs0v+5c45mzpqEMsy0dYo2Pl2m
ar5lUFVIZggQkiqcOzqBzEgF+4gNw4LUu1DgK6cNKNMtL6k8E9zeOZMWeSVr0lg=
=bT5E
-----END PGP SIGNATURE-----
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
- virt_to_page/page_address optimisations
- support for NUMA systems described using device-tree
- support for hibernate/suspend-to-disk
- proper support for maxcpus= command line parameter
- detection and graceful handling of AArch64-only CPUs
- miscellaneous cleanups and non-critical fixes
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (92 commits)
arm64: do not enforce strict 16 byte alignment to stack pointer
arm64: kernel: Fix incorrect brk randomization
arm64: cpuinfo: Missing NULL terminator in compat_hwcap_str
arm64: secondary_start_kernel: Remove unnecessary barrier
arm64: Ensure pmd_present() returns false after pmd_mknotpresent()
arm64: Replace hard-coded values in the pmd/pud_bad() macros
arm64: Implement pmdp_set_access_flags() for hardware AF/DBM
arm64: Fix typo in the pmdp_huge_get_and_clear() definition
arm64: mm: remove unnecessary EXPORT_SYMBOL_GPL
arm64: always use STRICT_MM_TYPECHECKS
arm64: kvm: Fix kvm teardown for systems using the extended idmap
arm64: kaslr: increase randomization granularity
arm64: kconfig: drop CONFIG_RTC_LIB dependency
arm64: make ARCH_SUPPORTS_DEBUG_PAGEALLOC depend on !HIBERNATION
arm64: hibernate: Refuse to hibernate if the boot cpu is offline
arm64: kernel: Add support for hibernate/suspend-to-disk
PM / Hibernate: Call flush_icache_range() on pages restored in-place
arm64: Add new asm macro copy_page
arm64: Promote KERNEL_START/KERNEL_END definitions to a header file
arm64: kernel: Include _AC definition in page.h
...
This will provide fully accuracy to the mapcount calculation in the
write protect faults, so page pinning will not get broken by false
positive copy-on-writes.
total_mapcount() isn't the right calculation needed in
reuse_swap_page(), so this introduces a page_trans_huge_mapcount()
that is effectively the full accurate return value for page_mapcount()
if dealing with Transparent Hugepages, however we only use the
page_trans_huge_mapcount() during COW faults where it strictly needed,
due to its higher runtime cost.
This also provide at practical zero cost the total_mapcount
information which is needed to know if we can still relocate the page
anon_vma to the local vma. If page_trans_huge_mapcount() returns 1 we
can reuse the page no matter if it's a pte or a pmd_trans_huge
triggering the fault, but we can only relocate the page anon_vma to
the local vma->anon_vma if we're sure it's only this "vma" mapping the
whole THP physical range.
Kirill A. Shutemov discovered the problem with moving the page
anon_vma to the local vma->anon_vma in a previous version of this
patch and another problem in the way page_move_anon_rmap() was called.
Andrew Morton discovered that CONFIG_SWAP=n wouldn't build in a
previous version, because reuse_swap_page must be a macro to call
page_trans_huge_mapcount from swap.h, so this uses a macro again
instead of an inline function. With this change at least it's a less
dangerous usage than it was before, because "page" is used only once
now, while with the previous code reuse_swap_page(page++) would have
called page_mapcount on page+1 and it would have increased page twice
instead of just once.
Dean Luick noticed an uninitialized variable that could result in a
rmap inefficiency for the non-THP case in a previous version.
Mike Marciniszyn said:
: Our RDMA tests are seeing an issue with memory locking that bisects to
: commit 61f5d698cc ("mm: re-enable THP")
:
: The test program registers two rather large MRs (512M) and RDMA
: writes data to a passive peer using the first and RDMA reads it back
: into the second MR and compares that data. The sizes are chosen randomly
: between 0 and 1024 bytes.
:
: The test will get through a few (<= 4 iterations) and then gets a
: compare error.
:
: Tracing indicates the kernel logical addresses associated with the individual
: pages at registration ARE correct , the data in the "RDMA read response only"
: packets ARE correct.
:
: The "corruption" occurs when the packet crosse two pages that are not physically
: contiguous. The second page reads back as zero in the program.
:
: It looks like the user VA at the point of the compare error no longer points to
: the same physical address as was registered.
:
: This patch totally resolves the issue!
Link: http://lkml.kernel.org/r/1462547040-1737-2-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Tested-by: Josh Collier <josh.d.collier@intel.com>
Cc: Marc Haber <mh+linux-kernel@zugschlus.de>
Cc: <stable@vger.kernel.org> [4.5]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In gather_pte_stats() a THP pmd is cast into a pte, which is wrong
because the layouts may differ depending on the architecture. On s390
this will lead to inaccurate numa_maps accounting in /proc because of
misguided pte_present() and pte_dirty() checks on the fake pte.
On other architectures pte_present() and pte_dirty() may work by chance,
but there may be an issue with direct-access (dax) mappings w/o
underlying struct pages when HAVE_PTE_SPECIAL is set and THP is
available. In vm_normal_page() the fake pte will be checked with
pte_special() and because there is no "special" bit in a pmd, this will
always return false and the VM_PFNMAP | VM_MIXEDMAP checking will be
skipped. On dax mappings w/o struct pages, an invalid struct page
pointer would then be returned that can crash the kernel.
This patch fixes the numa_maps THP handling by introducing new "_pmd"
variants of the can_gather_numa_stats() and vm_normal_page() functions.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> [4.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
HugeTLB pages cannot be split, so we use the compound_mapcount to track
rmaps.
Currently page_mapped() will check the compound_mapcount, but will also
go through the constituent pages of a THP compound page and query the
individual _mapcount's too.
Unfortunately, page_mapped() does not distinguish between HugeTLB and
THP compound pages and assumes that a compound page always needs to have
HPAGE_PMD_NR pages querying.
For most cases when dealing with HugeTLB this is just inefficient, but
for scenarios where the HugeTLB page size is less than the pmd block
size (e.g. when using contiguous bit on ARM) this can lead to crashes.
This patch adjusts the page_mapped function such that we skip the
unnecessary THP reference checks for HugeTLB pages.
Fixes: e1534ae950 ("mm: differentiate page_mapped() from page_mapcount() for compound pages")
Signed-off-by: Steve Capper <steve.capper@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The open coded conversion from struct page address to virtual address in
lowmem_page_address() involves an intermediate conversion step to pfn
number/physical address. Since the placement of the struct page array
relative to the linear mapping may be completely independent from the
placement of physical RAM (as is that case for arm64 after commit
dfd55ad85e 'arm64: vmemmap: use virtual projection of linear region'),
the conversion to physical address and back again should factor out of
the equation, but unfortunately, the shifting and pointer arithmetic
involved prevent this from happening, and the resulting calculation
essentially subtracts the address of the start of physical memory and
adds it back again, in a way that prevents the compiler from optimizing
it away.
Since the start of physical memory is not a build time constant on arm64,
the resulting conversion involves an unnecessary memory access, which
we would like to get rid of. So replace the open coded conversion with
a call to page_to_virt(), and use the open coded conversion as its
default definition, to be overriden by the architecture, if desired.
The existing arch specific definitions of page_to_virt are all equivalent
to this default definition, so by itself this patch is a no-op.
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Pull mm gup cleanup from Ingo Molnar:
"This removes the ugly get-user-pages API hack, now that all upstream
code has been migrated to it"
("ugly" is putting it mildly. But it worked.. - Linus)
* 'mm-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
mm/gup: Remove the macro overload API migration helpers from the get_user*() APIs
The pkeys changes brought about a truly hideous set of macros in:
cde70140fe ("mm/gup: Overload get_user_pages() functions")
... which macros are (ab-)using the fact that __VA_ARGS__ can be used
to shift parameter positions in macro arguments without breaking the
build and so can be used to call separate C functions depending on
the number of arguments of the macro.
This allowed easy migration of these 3 GUP APIs, as both these variants
worked at the C level:
old:
ret = get_user_pages(current, current->mm, address, 1, 1, 0, &page, NULL);
new:
ret = get_user_pages(address, 1, 1, 0, &page, NULL);
... while we also generated a (functionally harmless but noticeable) build
time warning if the old API was used. As there are over 300 uses of these
APIs, this trick eased the migration of the API and avoided excessive
migration pain in linux-next.
Now, with its work done, get rid of all of that complication and ugliness:
3 files changed, 16 insertions(+), 140 deletions(-)
... where the linecount of the migration hack was further inflated by the
fact that there are NOMMU variants of these GUP APIs as well.
Much of the conversion was done in linux-next over the past couple of months,
and Linus recently removed all remaining old API uses from the upstream tree
in the following upstrea commit:
cb107161df ("Convert straggling drivers to new six-argument get_user_pages()")
There was one more old-API usage in mm/gup.c, in the CONFIG_HAVE_GENERIC_RCU_GUP
code path that ARM, ARM64 and PowerPC uses.
After this commit any old API usage will break the build.
[ Also fixed a PowerPC/HAVE_GENERIC_RCU_GUP warning reported by Stephen Rothwell. ]
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Mostly direct substitution with occasional adjustment or removing
outdated comments.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch (of 5):
This is based on the idea from Mel Gorman discussed during LSFMM 2015
and independently brought up by Oleg Nesterov.
The OOM killer currently allows to kill only a single task in a good
hope that the task will terminate in a reasonable time and frees up its
memory. Such a task (oom victim) will get an access to memory reserves
via mark_oom_victim to allow a forward progress should there be a need
for additional memory during exit path.
It has been shown (e.g. by Tetsuo Handa) that it is not that hard to
construct workloads which break the core assumption mentioned above and
the OOM victim might take unbounded amount of time to exit because it
might be blocked in the uninterruptible state waiting for an event (e.g.
lock) which is blocked by another task looping in the page allocator.
This patch reduces the probability of such a lockup by introducing a
specialized kernel thread (oom_reaper) which tries to reclaim additional
memory by preemptively reaping the anonymous or swapped out memory owned
by the oom victim under an assumption that such a memory won't be needed
when its owner is killed and kicked from the userspace anyway. There is
one notable exception to this, though, if the OOM victim was in the
process of coredumping the result would be incomplete. This is
considered a reasonable constrain because the overall system health is
more important than debugability of a particular application.
A kernel thread has been chosen because we need a reliable way of
invocation so workqueue context is not appropriate because all the
workers might be busy (e.g. allocating memory). Kswapd which sounds
like another good fit is not appropriate as well because it might get
blocked on locks during reclaim as well.
oom_reaper has to take mmap_sem on the target task for reading so the
solution is not 100% because the semaphore might be held or blocked for
write but the probability is reduced considerably wrt. basically any
lock blocking forward progress as described above. In order to prevent
from blocking on the lock without any forward progress we are using only
a trylock and retry 10 times with a short sleep in between. Users of
mmap_sem which need it for write should be carefully reviewed to use
_killable waiting as much as possible and reduce allocations requests
done with the lock held to absolute minimum to reduce the risk even
further.
The API between oom killer and oom reaper is quite trivial.
wake_oom_reaper updates mm_to_reap with cmpxchg to guarantee only
NULL->mm transition and oom_reaper clear this atomically once it is done
with the work. This means that only a single mm_struct can be reaped at
the time. As the operation is potentially disruptive we are trying to
limit it to the ncessary minimum and the reaper blocks any updates while
it operates on an mm. mm_struct is pinned by mm_count to allow parallel
exit_mmap and a race is detected by atomic_inc_not_zero(mm_users).
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Mel Gorman <mgorman@suse.de>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Argangeli <andrea@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 protection key support from Ingo Molnar:
"This tree adds support for a new memory protection hardware feature
that is available in upcoming Intel CPUs: 'protection keys' (pkeys).
There's a background article at LWN.net:
https://lwn.net/Articles/643797/
The gist is that protection keys allow the encoding of
user-controllable permission masks in the pte. So instead of having a
fixed protection mask in the pte (which needs a system call to change
and works on a per page basis), the user can map a (handful of)
protection mask variants and can change the masks runtime relatively
cheaply, without having to change every single page in the affected
virtual memory range.
This allows the dynamic switching of the protection bits of large
amounts of virtual memory, via user-space instructions. It also
allows more precise control of MMU permission bits: for example the
executable bit is separate from the read bit (see more about that
below).
This tree adds the MM infrastructure and low level x86 glue needed for
that, plus it adds a high level API to make use of protection keys -
if a user-space application calls:
mmap(..., PROT_EXEC);
or
mprotect(ptr, sz, PROT_EXEC);
(note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice
this special case, and will set a special protection key on this
memory range. It also sets the appropriate bits in the Protection
Keys User Rights (PKRU) register so that the memory becomes unreadable
and unwritable.
So using protection keys the kernel is able to implement 'true'
PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies
PROT_READ as well. Unreadable executable mappings have security
advantages: they cannot be read via information leaks to figure out
ASLR details, nor can they be scanned for ROP gadgets - and they
cannot be used by exploits for data purposes either.
We know about no user-space code that relies on pure PROT_EXEC
mappings today, but binary loaders could start making use of this new
feature to map binaries and libraries in a more secure fashion.
There is other pending pkeys work that offers more high level system
call APIs to manage protection keys - but those are not part of this
pull request.
Right now there's a Kconfig that controls this feature
(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled
(like most x86 CPU feature enablement code that has no runtime
overhead), but it's not user-configurable at the moment. If there's
any serious problem with this then we can make it configurable and/or
flip the default"
* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
x86/mm/pkeys: Fix mismerge of protection keys CPUID bits
mm/pkeys: Fix siginfo ABI breakage caused by new u64 field
x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA
mm/core, x86/mm/pkeys: Add execute-only protection keys support
x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags
x86/mm/pkeys: Allow kernel to modify user pkey rights register
x86/fpu: Allow setting of XSAVE state
x86/mm: Factor out LDT init from context init
mm/core, x86/mm/pkeys: Add arch_validate_pkey()
mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits()
x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU
x86/mm/pkeys: Add Kconfig prompt to existing config option
x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps
x86/mm/pkeys: Dump PKRU with other kernel registers
mm/core, x86/mm/pkeys: Differentiate instruction fetches
x86/mm/pkeys: Optimize fault handling in access_error()
mm/core: Do not enforce PKEY permissions on remote mm access
um, pkeys: Add UML arch_*_access_permitted() methods
mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys
x86/mm/gup: Simplify get_user_pages() PTE bit handling
...
The define has a comment from Nick Piggin from 2007:
/* For backwards compat. Remove me quickly. */
I guess 9 years should not be too hurried sense of 'quickly' even for
kernel measures.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The success of CMA allocation largely depends on the success of
migration and key factor of it is page reference count. Until now, page
reference is manipulated by direct calling atomic functions so we cannot
follow up who and where manipulate it. Then, it is hard to find actual
reason of CMA allocation failure. CMA allocation should be guaranteed
to succeed so finding offending place is really important.
In this patch, call sites where page reference is manipulated are
converted to introduced wrapper function. This is preparation step to
add tracepoint to each page reference manipulation function. With this
facility, we can easily find reason of CMA allocation failure. There is
no functional change in this patch.
In addition, this patch also converts reference read sites. It will
help a second step that renames page._count to something else and
prevents later attempt to direct access to it (Suggested by Andrew).
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In machines with 140G of memory and enterprise flash storage, we have
seen read and write bursts routinely exceed the kswapd watermarks and
cause thundering herds in direct reclaim. Unfortunately, the only way
to tune kswapd aggressiveness is through adjusting min_free_kbytes - the
system's emergency reserves - which is entirely unrelated to the
system's latency requirements. In order to get kswapd to maintain a
250M buffer of free memory, the emergency reserves need to be set to 1G.
That is a lot of memory wasted for no good reason.
On the other hand, it's reasonable to assume that allocation bursts and
overall allocation concurrency scale with memory capacity, so it makes
sense to make kswapd aggressiveness a function of that as well.
Change the kswapd watermark scale factor from the currently fixed 25% of
the tunable emergency reserve to a tunable 0.1% of memory.
Beyond 1G of memory, this will produce bigger watermark steps than the
current formula in default settings. Ensure that the new formula never
chooses steps smaller than that, i.e. 25% of the emergency reserve.
On a 140G machine, this raises the default watermark steps - the
distance between min and low, and low and high - from 16M to 143M.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are few things about *pte_alloc*() helpers worth cleaning up:
- 'vma' argument is unused, let's drop it;
- most __pte_alloc() callers do speculative check for pmd_none(),
before taking ptl: let's introduce pte_alloc() macro which does
the check.
The only direct user of __pte_alloc left is userfaultfd, which has
different expectation about atomicity wrt pmd.
- pte_alloc_map() and pte_alloc_map_lock() are redefined using
pte_alloc().
[sudeep.holla@arm.com: fix build for arm64 hugetlbpage]
[sfr@canb.auug.org.au: fix arch/arm/mm/mmu.c some more]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new field, VIRTIO_BALLOON_S_AVAIL, to virtio_balloon memory
statistics protocol, corresponding to 'Available' in /proc/meminfo.
It indicates to the hypervisor how big the balloon can be inflated
without pushing the guest system to swap. This metric would be very
useful in VM orchestration software to improve memory management of
different VMs under overcommit.
This patch (of 2):
Factor out calculation of the available memory counter into a separate
exportable function, in order to be able to use it in other parts of the
kernel.
In particular, it appears a relevant metric to report to the hypervisor
via virtio-balloon statistics interface (in a followup patch).
Signed-off-by: Igor Redko <redkoi@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Get list of VMA flags up-to-date and sort it to match VM_* definition
order.
[vbabka@suse.cz: add a note above vmaflag definitions to update the names when changing]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
max_map_count sysctl unrelated to scheduler. Move its bits from
include/linux/sched/sysctl.h to include/linux/mm.h.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge first patch-bomb from Andrew Morton:
- some misc things
- ofs2 updates
- about half of MM
- checkpatch updates
- autofs4 update
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (120 commits)
autofs4: fix string.h include in auto_dev-ioctl.h
autofs4: use pr_xxx() macros directly for logging
autofs4: change log print macros to not insert newline
autofs4: make autofs log prints consistent
autofs4: fix some white space errors
autofs4: fix invalid ioctl return in autofs4_root_ioctl_unlocked()
autofs4: fix coding style line length in autofs4_wait()
autofs4: fix coding style problem in autofs4_get_set_timeout()
autofs4: coding style fixes
autofs: show pipe inode in mount options
kallsyms: add support for relative offsets in kallsyms address table
kallsyms: don't overload absolute symbol type for percpu symbols
x86: kallsyms: disable absolute percpu symbols on !SMP
checkpatch: fix another left brace warning
checkpatch: improve UNSPECIFIED_INT test for bare signed/unsigned uses
checkpatch: warn on bare unsigned or signed declarations without int
checkpatch: exclude asm volatile from complex macro check
mm: memcontrol: drop unnecessary lru locking from mem_cgroup_migrate()
mm: migrate: consolidate mem_cgroup_migrate() calls
mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous
...
Now that migration doesn't clear page->mem_cgroup of live pages anymore,
it's safe to make lock_page_memcg() and the memcg stat functions take
pages, and spare the callers from memcg objects.
[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Changing a page's memcg association complicates dealing with the page,
so we want to limit this as much as possible. Page migration e.g. does
not have to do that. Just like page cache replacement, it can forcibly
charge a replacement page, and then uncharge the old page when it gets
freed. Temporarily overcharging the cgroup by a single page is not an
issue in practice, and charging is so cheap nowadays that this is much
preferrable to the headache of messing with live pages.
The only place that still changes the page->mem_cgroup binding of live
pages is when pages move along with a task to another cgroup. But that
path isolates the page from the LRU, takes the page lock, and the move
lock (lock_page_memcg()). That means page->mem_cgroup is always stable
in callers that have the page isolated from the LRU or locked. Lighter
unlocked paths, like writeback accounting, can use lock_page_memcg().
[akpm@linux-foundation.org: fix build]
[vdavydov@virtuozzo.com: fix lockdep splat]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By default, page poisoning uses a poison value (0xaa) on free. If this
is changed to 0, the page is not only sanitized but zeroing on alloc
with __GFP_ZERO can be skipped as well. The tradeoff is that detecting
corruption from the poisoning is harder to detect. This feature also
cannot be used with hibernation since pages are not guaranteed to be
zeroed after hibernation.
Credit to Grsecurity/PaX team for inspiring this work
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Page poisoning is currently set up as a feature if architectures don't
have architecture debug page_alloc to allow unmapping of pages. It has
uses apart from that though. Clearing of the pages on free provides an
increase in security as it helps to limit the risk of information leaks.
Allow page poisoning to be enabled as a separate option independent of
kernel_map pages since the two features do separate work. Because of
how hiberanation is implemented, the checks on alloc cannot occur if
hibernation is enabled. The runtime alloc checks can also be enabled
with an option when !HIBERNATION.
Credit to Grsecurity/PaX team for inspiring this work
Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, open code for checking DEBUG_PAGEALLOC cache is spread to
some sites. It makes code unreadable and hard to change.
This patch cleans up this code. The following patch will change the
criteria for DEBUG_PAGEALLOC cache so this clean-up will help it, too.
[akpm@linux-foundation.org: fix build with CONFIG_DEBUG_PAGEALLOC=n]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 asm updates from Ingo Molnar:
"This is another big update. Main changes are:
- lots of x86 system call (and other traps/exceptions) entry code
enhancements. In particular the complex parts of the 64-bit entry
code have been migrated to C code as well, and a number of dusty
corners have been refreshed. (Andy Lutomirski)
- vDSO special mapping robustification and general cleanups (Andy
Lutomirski)
- cpufeature refactoring, cleanups and speedups (Borislav Petkov)
- lots of other changes ..."
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
x86/cpufeature: Enable new AVX-512 features
x86/entry/traps: Show unhandled signal for i386 in do_trap()
x86/entry: Call enter_from_user_mode() with IRQs off
x86/entry/32: Change INT80 to be an interrupt gate
x86/entry: Improve system call entry comments
x86/entry: Remove TIF_SINGLESTEP entry work
x86/entry/32: Add and check a stack canary for the SYSENTER stack
x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup
x86/entry: Only allocate space for tss_struct::SYSENTER_stack if needed
x86/entry: Vastly simplify SYSENTER TF (single-step) handling
x86/entry/traps: Clear DR6 early in do_debug() and improve the comment
x86/entry/traps: Clear TIF_BLOCKSTEP on all debug exceptions
x86/entry/32: Restore FLAGS on SYSEXIT
x86/entry/32: Filter NT and speed up AC filtering in SYSENTER
x86/entry/compat: In SYSENTER, sink AC clearing below the existing FLAGS test
selftests/x86: In syscall_nt, test NT|TF as well
x86/asm-offsets: Remove PARAVIRT_enabled
x86/entry/32: Introduce and use X86_BUG_ESPFIX instead of paravirt_enabled
uprobes: __create_xol_area() must nullify xol_mapping.fault
x86/cpufeature: Create a new synthetic cpu capability for machine check recovery
...
As discussed earlier, we attempt to enforce protection keys in
software.
However, the code checks all faults to ensure that they are not
violating protection key permissions. It was assumed that all
faults are either write faults where we check PKRU[key].WD (write
disable) or read faults where we check the AD (access disable)
bit.
But, there is a third category of faults for protection keys:
instruction faults. Instruction faults never run afoul of
protection keys because they do not affect instruction fetches.
So, plumb the PF_INSTR bit down in to the
arch_vma_access_permitted() function where we do the protection
key checks.
We also add a new FAULT_FLAG_INSTRUCTION. This is because
handle_mm_fault() is not passed the architecture-specific
error_code where we keep PF_INSTR, so we need to encode the
instruction fetch information in to the arch-generic fault
flags.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210224.96928009@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We try to enforce protection keys in software the same way that we
do in hardware. (See long example below).
But, we only want to do this when accessing our *own* process's
memory. If GDB set PKRU[6].AD=1 (disable access to PKEY 6), then
tried to PTRACE_POKE a target process which just happened to have
some mprotect_pkey(pkey=6) memory, we do *not* want to deny the
debugger access to that memory. PKRU is fundamentally a
thread-local structure and we do not want to enforce it on access
to _another_ thread's data.
This gets especially tricky when we have workqueues or other
delayed-work mechanisms that might run in a random process's context.
We can check that we only enforce pkeys when operating on our *own* mm,
but delayed work gets performed when a random user context is active.
We might end up with a situation where a delayed-work gup fails when
running randomly under its "own" task but succeeds when running under
another process. We want to avoid that.
To avoid that, we use the new GUP flag: FOLL_REMOTE and add a
fault flag: FAULT_FLAG_REMOTE. They indicate that we are
walking an mm which is not guranteed to be the same as
current->mm and should not be subject to protection key
enforcement.
Thanks to Jerome Glisse for pointing out this scenario.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Dominik Vogt <vogt@linux.vnet.ibm.com>
Cc: Eric B Munson <emunson@akamai.com>
Cc: Geliang Tang <geliangtang@163.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Low <jason.low2@hp.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Shachar Raindel <raindel@mellanox.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Lots of things seem to do:
vma->vm_page_prot = vm_get_page_prot(flags);
and the ptes get created right from things we pull out
of ->vm_page_prot. So it is very convenient if we can
store the protection key in flags and vm_page_prot, just
like the existing permission bits (_PAGE_RW/PRESENT). It
greatly reduces the amount of plumbing and arch-specific
hacking we have to do in generic code.
This also takes the new PROT_PKEY{0,1,2,3} flags and
turns *those* in to VM_ flags for vma->vm_flags.
The protection key values are stored in 4 places:
1. "prot" argument to system calls
2. vma->vm_flags, filled from the mmap "prot"
3. vma->vm_page prot, filled from vma->vm_flags
4. the PTE itself.
The pseudocode for these for steps are as follows:
mmap(PROT_PKEY*)
vma->vm_flags = ... | arch_calc_vm_prot_bits(mmap_prot);
vma->vm_page_prot = ... | arch_vm_get_page_prot(vma->vm_flags);
pte = pfn | vma->vm_page_prot
Note that this provides a new definitions for x86:
arch_vm_get_page_prot()
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210210.FE483A42@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
vma->vm_flags is an 'unsigned long', so has space for 32 flags
on 32-bit architectures. The high 32 bits are unused on 64-bit
platforms. We've steered away from using the unused high VMA
bits for things because we would have difficulty supporting it
on 32-bit.
Protection Keys are not available in 32-bit mode, so there is
no concern about supporting this feature in 32-bit mode or on
32-bit CPUs.
This patch carves out 4 bits from the high half of
vma->vm_flags and allows architectures to set config option
to make them available.
Sparse complains about these constants unless we explicitly
call them "UL".
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210208.81AF00D5@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The concept here was a suggestion from Ingo. The implementation
horrors are all mine.
This allows get_user_pages(), get_user_pages_unlocked(), and
get_user_pages_locked() to be called with or without the
leading tsk/mm arguments. We will give a compile-time warning
about the old style being __deprecated and we will also
WARN_ON() if the non-remote version is used for a remote-style
access.
Doing this, folks will get nice warnings and will not break the
build. This should be nice for -next and will hopefully let
developers fix up their own code instead of maintainers needing
to do it at merge time.
The way we do this is hideous. It uses the __VA_ARGS__ macro
functionality to call different functions based on the number
of arguments passed to the macro.
There's an additional hack to ensure that our EXPORT_SYMBOL()
of the deprecated symbols doesn't trigger a warning.
We should be able to remove this mess as soon as -rc1 hits in
the release after this is merged.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Geliang Tang <geliangtang@163.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Leon Romanovsky <leon@leon.nu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210155.73222EE1@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For protection keys, we need to understand whether protections
should be enforced in software or not. In general, we enforce
protections when working on our own task, but not when on others.
We call these "current" and "remote" operations.
This patch introduces a new get_user_pages() variant:
get_user_pages_remote()
Which is a replacement for when get_user_pages() is called on
non-current tsk/mm.
We also introduce a new gup flag: FOLL_REMOTE which can be used
for the "__" gup variants to get this new behavior.
The uprobes is_trap_at_addr() location holds mmap_sem and
calls get_user_pages(current->mm) on an instruction address. This
makes it a pretty unique gup caller. Being an instruction access
and also really originating from the kernel (vs. the app), I opted
to consider this a 'remote' access where protection keys will not
be enforced.
Without protection keys, this patch should not change any behavior.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: jack@suse.cz
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210154.3F0E51EA@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
* add VM_STACK as alias for VM_GROWSUP/DOWN depending on architecture
* always account VMAs with flag VM_STACK as stack (as it was before)
* cleanup classifying helpers
* update comments and documentation
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Tested-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit b76437579d ("procfs: mark thread stack correctly in
proc/<pid>/maps") added [stack:TID] annotation to /proc/<pid>/maps.
Finding the task of a stack VMA requires walking the entire thread list,
turning this into quadratic behavior: a thousand threads means a
thousand stacks, so the rendering of /proc/<pid>/maps needs to look at a
million combinations.
The cost is not in proportion to the usefulness as described in the
patch.
Drop the [stack:TID] annotation to make /proc/<pid>/maps (and
/proc/<pid>/numa_maps) usable again for higher thread counts.
The [stack] annotation inside /proc/<pid>/task/<tid>/maps is retained, as
identifying the stack VMA there is an O(1) operation.
Siddesh said:
"The end users needed a way to identify thread stacks programmatically and
there wasn't a way to do that. I'm afraid I no longer remember (or have
access to the resources that would aid my memory since I changed
employers) the details of their requirement. However, I did do this on my
own time because I thought it was an interesting project for me and nobody
really gave any feedback then as to its utility, so as far as I am
concerned you could roll back the main thread maps information since the
information is available in the thread-specific files"
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Cc: Shaohua Li <shli@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change region_intersects() to identify a target with @flags and
@desc, instead of @name with strcmp().
Change the callers of region_intersects(), memremap() and
devm_memremap(), to set IORESOURCE_SYSTEM_RAM in @flags and
IORES_DESC_NONE in @desc when searching System RAM.
Also, export region_intersects() so that the ACPI EINJ error
injection driver can call this function in a later patch.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jakub Sitnicki <jsitnicki@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>
Link: http://lkml.kernel.org/r/1453841853-11383-13-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since can_do_mlock only return 1 or 0, so make it boolean.
No functional change.
[akpm@linux-foundation.org: update declaration in mm.h]
Signed-off-by: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During Jason's work with postcopy migration support for s390 a problem
regarding gmap faults was discovered.
The gmap code will call fixup_user_fault which will end up always in
handle_mm_fault. Till now we never cared about retries, but as the
userfaultfd code kind of relies on it. this needs some fix.
This patchset does not take care of the futex code. I will now look
closer at this.
This patch (of 2):
With the introduction of userfaultfd, kvm on s390 needs fixup_user_fault
to pass in FAULT_FLAG_ALLOW_RETRY and give feedback if during the
faulting we ever unlocked mmap_sem.
This patch brings in the logic to handle retries as well as it cleans up
the current documentation. fixup_user_fault was not having the same
semantics as filemap_fault. It never indicated if a retry happened and
so a caller wasn't able to handle that case. So we now changed the
behaviour to always retry a locked mmap_sem.
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Jason J. Herne" <jjherne@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric B Munson <emunson@akamai.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A dax mapping establishes a pte with _PAGE_DEVMAP set when the driver
has established a devm_memremap_pages() mapping, i.e. when the pfn_t
return from ->direct_access() has PFN_DEV and PFN_MAP set. Later, when
encountering _PAGE_DEVMAP during a page table walk we lookup and pin a
struct dev_pagemap instance to keep the result of pfn_to_page() valid
until put_page().
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A dax-huge-page mapping while it uses some thp helpers is ultimately not
a transparent huge page. The distinction is especially important in the
get_user_pages() path. pmd_devmap() is used to distinguish dax-pmds
from pmd_huge() and pmd_trans_huge() which have slightly different
semantics.
Explicitly mark the pmd_trans_huge() helpers that dax needs by adding
pmd_devmap() checks.
[kirill.shutemov@linux.intel.com: fix regression in handling mlocked pages in __split_huge_pmd()]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert the raw unsigned long 'pfn' argument to pfn_t for the purpose of
evaluating the PFN_MAP and PFN_DEV flags. When both are set it triggers
_PAGE_DEVMAP to be set in the resulting pte.
There are no functional changes to the gpu drivers as a result of this
conversion.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In support of providing struct page for large persistent memory
capacities, use struct vmem_altmap to change the default policy for
allocating memory for the memmap array. The default vmemmap_populate()
allocates page table storage area from the page allocator. Given
persistent memory capacities relative to DRAM it may not be feasible to
store the memmap in 'System Memory'. Instead vmem_altmap represents
pre-allocated "device pages" to satisfy vmemmap_alloc_block_buf()
requests.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Prevent userspace from trying and failing to online ZONE_DEVICE pages
which are meant to never be onlined.
For example on platforms with a udev rule like the following:
SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", ATTR{state}="online"
...will generate futile attempts to online the ZONE_DEVICE sections.
Example kernel messages:
Built 1 zonelists in Node order, mobility grouping on. Total pages: 1004747
Policy zone: Normal
online_pages [mem 0x248000000-0x24fffffff] failed
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Both page_referenced() and page_idle_clear_pte_refs_one() assume that
THP can only be mapped with PMD, so there's no reason to look on PTEs
for PageTransHuge() pages. That's no true anymore: THP can be mapped
with PTEs too.
The patch removes PageTransHuge() test from the functions and opencode
page table check.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we don't split huge page on partial unmap. It's not an ideal
situation. It can lead to memory overhead.
Furtunately, we can detect partial unmap on page_remove_rmap(). But we
cannot call split_huge_page() from there due to locking context.
It's also counterproductive to do directly from munmap() codepath: in
many cases we will hit this from exit(2) and splitting the huge page
just to free it up in small pages is not what we really want.
The patch introduce deferred_split_huge_page() which put the huge page
into queue for splitting. The splitting itself will happen when we get
memory pressure via shrinker interface. The page will be dropped from
list on freeing through compound page destructor.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some mm-related BUG_ON()s could trigger from hwpoison code due to recent
changes in thp refcounting rule. This patch fixes them up.
In the new refcounting, we no longer use tail->_mapcount to keep tail's
refcount, and thereby we can simplify get/put_hwpoison_page().
And another change is that tail's refcount is not transferred to the raw
page during thp split (more precisely, in new rule we don't take
refcount on tail page any more.) So when we need thp split, we have to
transfer the refcount properly to the 4kB soft-offlined page before
migration.
thp split code goes into core code only when precheck
(total_mapcount(head) == page_count(head) - 1) passes to avoid useless
split, where we assume that one refcount is held by the caller of thp
split and the others are taken via mapping. To meet this assumption,
this patch moves thp split part in soft_offline_page() after
get_any_page().
[akpm@linux-foundation.org: remove unneeded #define, per Kirill]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's define page_mapped() to be true for compound pages if any
sub-pages of the compound page is mapped (with PMD or PTE).
On other hand page_mapcount() return mapcount for this particular small
page.
This will make cases like page_get_anon_vma() behave correctly once we
allow huge pages to be mapped with PTE.
Most users outside core-mm should use page_mapcount() instead of
page_mapped().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We're going to allow mapping of individual 4k pages of THP compound. It
means we need to track mapcount on per small page basis.
Straight-forward approach is to use ->_mapcount in all subpages to track
how many time this subpage is mapped with PMDs or PTEs combined. But
this is rather expensive: mapping or unmapping of a THP page with PMD
would require HPAGE_PMD_NR atomic operations instead of single we have
now.
The idea is to store separately how many times the page was mapped as
whole -- compound_mapcount. This frees up ->_mapcount in subpages to
track PTE mapcount.
We use the same approach as with compound page destructor and compound
order to store compound_mapcount: use space in first tail page,
->mapping this time.
Any time we map/unmap whole compound page (THP or hugetlb) -- we
increment/decrement compound_mapcount. When we map part of compound
page with PTE we operate on ->_mapcount of the subpage.
page_mapcount() counts both: PTE and PMD mappings of the page.
Basically, we have mapcount for a subpage spread over two counters. It
makes tricky to detect when last mapcount for a page goes away.
We introduced PageDoubleMap() for this. When we split THP PMD for the
first time and there's other PMD mapping left we offset up ->_mapcount
in all subpages by one and set PG_double_map on the compound page.
These additional references go away with last compound_mapcount.
This approach provides a way to detect when last mapcount goes away on
per small page basis without introducing new overhead for most common
cases.
[akpm@linux-foundation.org: fix typo in comment]
[mhocko@suse.com: ignore partial THP when moving task]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are going to use migration entries to stabilize page counts. It
means we don't need compound_lock() for that.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tail page refcounting is utterly complicated and painful to support.
It uses ->_mapcount on tail pages to store how many times this page is
pinned. get_page() bumps ->_mapcount on tail page in addition to
->_count on head. This information is required by split_huge_page() to
be able to distribute pins from head of compound page to tails during
the split.
We will need ->_mapcount to account PTE mappings of subpages of the
compound page. We eliminate need in current meaning of ->_mapcount in
tail pages by forbidding split entirely if the page is pinned.
The only user of tail page refcounting is THP which is marked BROKEN for
now.
Let's drop all this mess. It makes get_page() and put_page() much
simpler.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which
testing the RLIMIT_DATA value to figure out if we're allowed to assign
new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been
commited that RLIMIT_DATA in a form it's implemented now doesn't do
anything useful because most of user-space libraries use mmap() syscall
for dynamic memory allocations.
Linus suggested to convert RLIMIT_DATA rlimit into something suitable
for anonymous memory accounting. But in this patch we go further, and
the changes are bundled together as:
* keep vma counting if CONFIG_PROC_FS=n, will be used for limits
* replace mm->shared_vm with better defined mm->data_vm
* account anonymous executable areas as executable
* account file-backed growsdown/up areas as stack
* drop struct file* argument from vm_stat_account
* enforce RLIMIT_DATA for size of data areas
This way code looks cleaner: now code/stack/data classification depends
only on vm_flags state:
VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc)
VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk)
VM_WRITE & ~VM_SHARED & !stack -> data (VmData)
The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called
"shared", but that might be strange beast like readonly-private or VM_IO
area.
- RLIMIT_AS limits whole address space "VmSize"
- RLIMIT_STACK limits stack "VmStk" (but each vma individually)
- RLIMIT_DATA now limits "VmData"
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Kees Cook <keescook@google.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page_cache_read has been historically using page_cache_alloc_cold to
allocate a new page. This means that mapping_gfp_mask is used as the
base for the gfp_mask. Many filesystems are setting this mask to
GFP_NOFS to prevent from fs recursion issues. page_cache_read is called
from the vm_operations_struct::fault() context during the page fault.
This context doesn't need the reclaim protection normally.
ceph and ocfs2 which call filemap_fault from their fault handlers seem
to be OK because they are not taking any fs lock before invoking generic
implementation. xfs which takes XFS_MMAPLOCK_SHARED is safe from the
reclaim recursion POV because this lock serializes truncate and punch
hole with the page faults and it doesn't get involved in the reclaim.
There is simply no reason to deliberately use a weaker allocation
context when a __GFP_FS | __GFP_IO can be used. The GFP_NOFS protection
might be even harmful. There is a push to fail GFP_NOFS allocations
rather than loop within allocator indefinitely with a very limited
reclaim ability. Once we start failing those requests the OOM killer
might be triggered prematurely because the page cache allocation failure
is propagated up the page fault path and end up in
pagefault_out_of_memory.
We cannot play with mapping_gfp_mask directly because that would be racy
wrt. parallel page faults and it might interfere with other users who
really rely on NOFS semantic from the stored gfp_mask. The mask is also
inode proper so it would even be a layering violation. What we can do
instead is to push the gfp_mask into struct vm_fault and allow fs layer
to overwrite it should the callback need to be called with a different
allocation context.
Initialize the default to (mapping_gfp_mask | __GFP_FS | __GFP_IO)
because this should be safe from the page fault path normally. Why do
we care about mapping_gfp_mask at all then? Because this doesn't hold
only reclaim protection flags but it also might contain zone and
movability restrictions (GFP_DMA32, __GFP_MOVABLE and others) so we have
to respect those.
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Jan Kara <jack@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Address Space Layout Randomization (ASLR) provides a barrier to
exploitation of user-space processes in the presence of security
vulnerabilities by making it more difficult to find desired code/data
which could help an attack. This is done by adding a random offset to
the location of regions in the process address space, with a greater
range of potential offset values corresponding to better protection/a
larger search-space for brute force, but also to greater potential for
fragmentation.
The offset added to the mmap_base address, which provides the basis for
the majority of the mappings for a process, is set once on process exec
in arch_pick_mmap_layout() and is done via hard-coded per-arch values,
which reflect, hopefully, the best compromise for all systems. The
trade-off between increased entropy in the offset value generation and
the corresponding increased variability in address space fragmentation
is not absolute, however, and some platforms may tolerate higher amounts
of entropy. This patch introduces both new Kconfig values and a sysctl
interface which may be used to change the amount of entropy used for
offset generation on a system.
The direct motivation for this change was in response to the
libstagefright vulnerabilities that affected Android, specifically to
information provided by Google's project zero at:
http://googleprojectzero.blogspot.com/2015/09/stagefrightened.html
The attack presented therein, by Google's project zero, specifically
targeted the limited randomness used to generate the offset added to the
mmap_base address in order to craft a brute-force-based attack.
Concretely, the attack was against the mediaserver process, which was
limited to respawning every 5 seconds, on an arm device. The hard-coded
8 bits used resulted in an average expected success rate of defeating
the mmap ASLR after just over 10 minutes (128 tries at 5 seconds a
piece). With this patch, and an accompanying increase in the entropy
value to 16 bits, the same attack would take an average expected time of
over 45 hours (32768 tries), which makes it both less feasible and more
likely to be noticed.
The introduced Kconfig and sysctl options are limited by per-arch
minimum and maximum values, the minimum of which was chosen to match the
current hard-coded value and the maximum of which was chosen so as to
give the greatest flexibility without generating an invalid mmap_base
address, generally a 3-4 bits less than the number of bits in the
user-space accessible virtual address space.
When decided whether or not to change the default value, a system
developer should consider that mmap_base address could be placed
anywhere up to 2^(value) bits away from the non-randomized location,
which would introduce variable-sized areas above and below the mmap_base
address such that the maximum vm_area_struct size may be reduced,
preventing very large allocations.
This patch (of 4):
ASLR only uses as few as 8 bits to generate the random offset for the
mmap base address on 32 bit architectures. This value was chosen to
prevent a poorly chosen value from dividing the address space in such a
way as to prevent large allocations. This may not be an issue on all
platforms. Allow the specification of a minimum number of bits so that
platforms desiring greater ASLR protection may determine where to place
the trade-off.
Signed-off-by: Daniel Cashman <dcashman@google.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hector Marco-Gisbert <hecmargi@upv.es>
Cc: Borislav Petkov <bp@suse.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently looking at /proc/<pid>/status or statm, there is no way to
distinguish shmem pages from pages mapped to a regular file (shmem pages
are mapped to /dev/zero), even though their implication in actual memory
use is quite different.
The internal accounting currently counts shmem pages together with
regular files. As a preparation to extend the userspace interfaces,
this patch adds MM_SHMEMPAGES counter to mm_rss_stat to account for
shmem pages separately from MM_FILEPAGES. The next patch will expose it
to userspace - this patch doesn't change the exported values yet, by
adding up MM_SHMEMPAGES to MM_FILEPAGES at places where MM_FILEPAGES was
used before. The only user-visible change after this patch is the OOM
killer message that separates the reported "shmem-rss" from "file-rss".
[vbabka@suse.cz: forward-porting, tweak changelog]
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The x86 vvar vma contains pages with differing cacheability
flags. x86 currently implements this by manually inserting all
the ptes using (io_)remap_pfn_range when the vma is set up.
x86 wants to move to using .fault with VM_FAULT_NOPAGE to set up
the mappings as needed. The correct API to use to insert a pfn
in .fault is vm_insert_pfn(), but vm_insert_pfn() can't override the
vma's cache mode, and the HPET page in particular needs to be
uncached despite the fact that the rest of the VMA is cached.
Add vm_insert_pfn_prot() to support varying cacheability within
the same non-COW VMA in a more sane manner.
x86 could alternatively use multiple VMAs, but that's messy,
would break CRIU, and would create unnecessary VMAs that would
waste memory.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/d2938d1eb37be7a5e4f86182db646551f11e45aa.1451446564.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Let's try to be consistent about data type of page order.
[sfr@canb.auug.org.au: fix build (type of pageblock_order)]
[hughd@google.com: some configs end up with MAX_ORDER and pageblock_order having different types]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh has pointed that compound_head() call can be unsafe in some
context. There's one example:
CPU0 CPU1
isolate_migratepages_block()
page_count()
compound_head()
!!PageTail() == true
put_page()
tail->first_page = NULL
head = tail->first_page
alloc_pages(__GFP_COMP)
prep_compound_page()
tail->first_page = head
__SetPageTail(p);
!!PageTail() == true
<head == NULL dereferencing>
The race is pure theoretical. I don't it's possible to trigger it in
practice. But who knows.
We can fix the race by changing how encode PageTail() and compound_head()
within struct page to be able to update them in one shot.
The patch introduces page->compound_head into third double word block in
front of compound_dtor and compound_order. Bit 0 encodes PageTail() and
the rest bits are pointer to head page if bit zero is set.
The patch moves page->pmd_huge_pte out of word, just in case if an
architecture defines pgtable_t into something what can have the bit 0
set.
hugetlb_cgroup uses page->lru.next in the second tail page to store
pointer struct hugetlb_cgroup. The patch switch it to use page->private
in the second tail page instead. The space is free since ->first_page is
removed from the union.
The patch also opens possibility to remove HUGETLB_CGROUP_MIN_ORDER
limitation, since there's now space in first tail page to store struct
hugetlb_cgroup pointer. But that's out of scope of the patch.
That means page->compound_head shares storage space with:
- page->lru.next;
- page->next;
- page->rcu_head.next;
That's too long list to be absolutely sure, but looks like nobody uses
bit 0 of the word.
page->rcu_head.next guaranteed[1] to have bit 0 clean as long as we use
call_rcu(), call_rcu_bh(), call_rcu_sched(), or call_srcu(). But future
call_rcu_lazy() is not allowed as it makes use of the bit and we can
get false positive PageTail().
[1] http://lkml.kernel.org/g/20150827163634.GD4029@linux.vnet.ibm.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patch halves space occupied by compound_dtor and compound_order in
struct page.
For compound_order, it's trivial long -> short conversion.
For get_compound_page_dtor(), we now use hardcoded table for destructor
lookup and store its index in the struct page instead of direct pointer
to destructor. It shouldn't be a big trouble to maintain the table: we
have only two destructor and NULL currently.
This patch free up one word in tail pages for reuse. This is preparation
for the next patch.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The cost of faulting in all memory to be locked can be very high when
working with large mappings. If only portions of the mapping will be used
this can incur a high penalty for locking.
For the example of a large file, this is the usage pattern for a large
statical language model (probably applies to other statical or graphical
models as well). For the security example, any application transacting in
data that cannot be swapped out (credit card data, medical records, etc).
This patch introduces the ability to request that pages are not
pre-faulted, but are placed on the unevictable LRU when they are finally
faulted in. The VM_LOCKONFAULT flag will be used together with VM_LOCKED
and has no effect when set without VM_LOCKED. Setting the VM_LOCKONFAULT
flag for a VMA will cause pages faulted into that VMA to be added to the
unevictable LRU when they are faulted or if they are already present, but
will not cause any missing pages to be faulted in.
Exposing this new lock state means that we cannot overload the meaning of
the FOLL_POPULATE flag any longer. Prior to this patch it was used to
mean that the VMA for a fault was locked. This means we need the new
FOLL_MLOCK flag to communicate the locked state of a VMA. FOLL_POPULATE
will now only control if the VMA should be populated and in the case of
VM_LOCKONFAULT, it will not be set.
Signed-off-by: Eric B Munson <emunson@akamai.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If ALLOC_SPLIT_PTLOCKS is defined, ptlock_init may fail, in which case we
shouldn't increment NR_PAGETABLE.
Since small allocations, such as ptlock, normally do not fail (currently
they can fail if kmemcg is used though), this patch does not really fix
anything and should be considered as a code cleanup.
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Maximal readahead size is limited now by two values:
1) by global 2Mb constant (MAX_READAHEAD in max_sane_readahead())
2) by configurable per-device value* (bdi->ra_pages)
There are devices, which require custom readahead limit.
For instance, for RAIDs it's calculated as number of devices
multiplied by chunk size times 2.
Readahead size can never be larger than bdi->ra_pages * 2 value
(POSIX_FADV_SEQUNTIAL doubles readahead size).
If so, why do we need two limits?
I suggest to completely remove this max_sane_readahead() stuff and
use per-device readahead limit everywhere.
Also, using right readahead size for RAID disks can significantly
increase i/o performance:
before:
dd if=/dev/md2 of=/dev/null bs=100M count=100
100+0 records in
100+0 records out
10485760000 bytes (10 GB) copied, 12.9741 s, 808 MB/s
after:
$ dd if=/dev/md2 of=/dev/null bs=100M count=100
100+0 records in
100+0 records out
10485760000 bytes (10 GB) copied, 8.91317 s, 1.2 GB/s
(It's an 8-disks RAID5 storage).
This patch doesn't change sys_readahead and madvise(MADV_WILLNEED)
behavior introduced by 6d2be915e5 ("mm/readahead.c: fix readahead
failure for memoryless NUMA nodes and limit readahead pages").
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: onstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The problem starts with a file backed dirty page which is charged to a
memcg. Then page migration is used to move oldpage to newpage.
Migration:
- copies the oldpage's data to newpage
- clears oldpage.PG_dirty
- sets newpage.PG_dirty
- uncharges oldpage from memcg
- charges newpage to memcg
Clearing oldpage.PG_dirty decrements the charged memcg's dirty page
count.
However, because newpage is not yet charged, setting newpage.PG_dirty
does not increment the memcg's dirty page count. After migration
completes newpage.PG_dirty is eventually cleared, often in
account_page_cleaned(). At this time newpage is charged to a memcg so
the memcg's dirty page count is decremented which causes underflow
because the count was not previously incremented by migration. This
underflow causes balance_dirty_pages() to see a very large unsigned
number of dirty memcg pages which leads to aggressive throttling of
buffered writes by processes in non root memcg.
This issue:
- can harm performance of non root memcg buffered writes.
- can report too small (even negative) values in
memory.stat[(total_)dirty] counters of all memcg, including the root.
To avoid polluting migrate.c with #ifdef CONFIG_MEMCG checks, introduce
page_memcg() and set_page_memcg() helpers.
Test:
0) setup and enter limited memcg
mkdir /sys/fs/cgroup/test
echo 1G > /sys/fs/cgroup/test/memory.limit_in_bytes
echo $$ > /sys/fs/cgroup/test/cgroup.procs
1) buffered writes baseline
dd if=/dev/zero of=/data/tmp/foo bs=1M count=1k
sync
grep ^dirty /sys/fs/cgroup/test/memory.stat
2) buffered writes with compaction antagonist to induce migration
yes 1 > /proc/sys/vm/compact_memory &
rm -rf /data/tmp/foo
dd if=/dev/zero of=/data/tmp/foo bs=1M count=1k
kill %
sync
grep ^dirty /sys/fs/cgroup/test/memory.stat
3) buffered writes without antagonist, should match baseline
rm -rf /data/tmp/foo
dd if=/dev/zero of=/data/tmp/foo bs=1M count=1k
sync
grep ^dirty /sys/fs/cgroup/test/memory.stat
(speed, dirty residue)
unpatched patched
1) 841 MB/s 0 dirty pages 886 MB/s 0 dirty pages
2) 611 MB/s -33427456 dirty pages 793 MB/s 0 dirty pages
3) 114 MB/s -33427456 dirty pages 891 MB/s 0 dirty pages
Notice that unpatched baseline performance (1) fell after
migration (3): 841 -> 114 MB/s. In the patched kernel, post
migration performance matches baseline.
Fixes: c4843a7593 ("memcg: add per cgroup dirty page accounting")
Signed-off-by: Greg Thelen <gthelen@google.com>
Reported-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org> [4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=TEFw
-----END PGP SIGNATURE-----
Merge tag 'media/v4.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab:
"A series of patches that move part of the code used to allocate memory
from the media subsystem to the mm subsystem"
[ The mm parts have been acked by VM people, and the series was
apparently in -mm for a while - Linus ]
* tag 'media/v4.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] drm/exynos: Convert g2d_userptr_get_dma_addr() to use get_vaddr_frames()
[media] media: vb2: Remove unused functions
[media] media: vb2: Convert vb2_dc_get_userptr() to use frame vector
[media] media: vb2: Convert vb2_vmalloc_get_userptr() to use frame vector
[media] media: vb2: Convert vb2_dma_sg_get_userptr() to use frame vector
[media] vb2: Provide helpers for mapping virtual addresses
[media] media: omap_vout: Convert omap_vout_uservirt_to_phys() to use get_vaddr_pfns()
[media] mm: Provide new get_vaddr_frames() helper
[media] vb2: Push mmap_sem down to memops
Add the additional "vm_flags_t vm_flags" argument to do_mmap_pgoff(),
rename it to do_mmap(), and re-introduce do_mmap_pgoff() as a simple
wrapper on top of do_mmap(). Perhaps we should update the callers of
do_mmap_pgoff() and kill it later.
This way mpx_mmap() can simply call do_mmap(vm_flags => VM_MPX) and do not
play with vm internals.
After this change mmap_region() has a single user outside of mmap.c,
arch/tile/mm/elf.c:arch_setup_additional_pages(). It would be nice to
change arch/tile/ and unexport mmap_region().
[kirill@shutemov.name: fix build]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge second patch-bomb from Andrew Morton:
"Almost all of the rest of MM. There was an unusually large amount of
MM material this time"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (141 commits)
zpool: remove no-op module init/exit
mm: zbud: constify the zbud_ops
mm: zpool: constify the zpool_ops
mm: swap: zswap: maybe_preload & refactoring
zram: unify error reporting
zsmalloc: remove null check from destroy_handle_cache()
zsmalloc: do not take class lock in zs_shrinker_count()
zsmalloc: use class->pages_per_zspage
zsmalloc: consider ZS_ALMOST_FULL as migrate source
zsmalloc: partial page ordering within a fullness_list
zsmalloc: use shrinker to trigger auto-compaction
zsmalloc: account the number of compacted pages
zsmalloc/zram: introduce zs_pool_stats api
zsmalloc: cosmetic compaction code adjustments
zsmalloc: introduce zs_can_compact() function
zsmalloc: always keep per-class stats
zsmalloc: drop unused variable `nr_to_migrate'
mm/memblock.c: fix comment in __next_mem_range()
mm/page_alloc.c: fix type information of memoryless node
memory-hotplug: fix comments in zone_spanned_pages_in_node() and zone_spanned_pages_in_node()
...
Introduce put_hwpoison_page to put refcount for memory error handling.
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The pair of get/set_freepage_migratetype() functions are used to cache
pageblock migratetype for a page put on a pcplist, so that it does not
have to be retrieved again when the page is put on a free list (e.g.
when pcplists become full). Historically it was also assumed that the
value is accurate for pages on freelists (as the functions' names
unfortunately suggest), but that cannot be guaranteed without affecting
various allocator fast paths. It is in fact not needed and all such
uses have been removed.
The last remaining (but pointless) usage related to pages of freelists
is in move_freepages(), which this patch removes.
To prevent further confusion, rename the functions to
get/set_pcppage_migratetype() and expand their description. Since all
the users are now in mm/page_alloc.c, move the functions there from the
shared header.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Seungho Park <seungho1.park@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It has no callers.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow non-anonymous VMAs to provide huge pages in response to a page fault.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
special_mapping_fault() is absolutely broken. It seems it was always
wrong, but this didn't matter until vdso/vvar started to use more than
one page.
And after this change vma_is_anonymous() becomes really trivial, it
simply checks vm_ops == NULL. However, I do think the helper makes
sense. There are a lot of ->vm_ops != NULL checks, the helper makes the
caller's code more understandable (self-documented) and this is more
grep-friendly.
This patch (of 3):
Preparation. Add the new simple helper, vma_is_anonymous(vma), and change
handle_pte_fault() to use it. It will have more users.
The name is not accurate, say a hpet_mmap()'ed vma is not anonymous.
Perhaps it should be named vma_has_fault() instead. But it matches the
logic in mmap.c/memory.c (see next changes). "True" just means that a
page fault will use do_anonymous_page().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1/ Introduce ZONE_DEVICE and devm_memremap_pages() as a generic
mechanism for adding device-driver-discovered memory regions to the
kernel's direct map. This facility is used by the pmem driver to
enable pfn_to_page() operations on the page frames returned by DAX
('direct_access' in 'struct block_device_operations'). For now, the
'memmap' allocation for these "device" pages comes from "System
RAM". Support for allocating the memmap from device memory will
arrive in a later kernel.
2/ Introduce memremap() to replace usages of ioremap_cache() and
ioremap_wt(). memremap() drops the __iomem annotation for these
mappings to memory that do not have i/o side effects. The
replacement of ioremap_cache() with memremap() is limited to the
pmem driver to ease merging the api change in v4.3. Completion of
the conversion is targeted for v4.4.
3/ Similar to the usage of memcpy_to_pmem() + wmb_pmem() in the pmem
driver, update the VFS DAX implementation and PMEM api to provide
persistence guarantees for kernel operations on a DAX mapping.
4/ Convert the ACPI NFIT 'BLK' driver to map the block apertures as
cacheable to improve performance.
5/ Miscellaneous updates and fixes to libnvdimm including support
for issuing "address range scrub" commands, clarifying the optimal
'sector size' of pmem devices, a clarification of the usage of the
ACPI '_STA' (status) property for DIMM devices, and other minor
fixes.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=o57/
-----END PGP SIGNATURE-----
Merge tag 'libnvdimm-for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"This update has successfully completed a 0day-kbuild run and has
appeared in a linux-next release. The changes outside of the typical
drivers/nvdimm/ and drivers/acpi/nfit.[ch] paths are related to the
removal of IORESOURCE_CACHEABLE, the introduction of memremap(), and
the introduction of ZONE_DEVICE + devm_memremap_pages().
Summary:
- Introduce ZONE_DEVICE and devm_memremap_pages() as a generic
mechanism for adding device-driver-discovered memory regions to the
kernel's direct map.
This facility is used by the pmem driver to enable pfn_to_page()
operations on the page frames returned by DAX ('direct_access' in
'struct block_device_operations').
For now, the 'memmap' allocation for these "device" pages comes
from "System RAM". Support for allocating the memmap from device
memory will arrive in a later kernel.
- Introduce memremap() to replace usages of ioremap_cache() and
ioremap_wt(). memremap() drops the __iomem annotation for these
mappings to memory that do not have i/o side effects. The
replacement of ioremap_cache() with memremap() is limited to the
pmem driver to ease merging the api change in v4.3.
Completion of the conversion is targeted for v4.4.
- Similar to the usage of memcpy_to_pmem() + wmb_pmem() in the pmem
driver, update the VFS DAX implementation and PMEM api to provide
persistence guarantees for kernel operations on a DAX mapping.
- Convert the ACPI NFIT 'BLK' driver to map the block apertures as
cacheable to improve performance.
- Miscellaneous updates and fixes to libnvdimm including support for
issuing "address range scrub" commands, clarifying the optimal
'sector size' of pmem devices, a clarification of the usage of the
ACPI '_STA' (status) property for DIMM devices, and other minor
fixes"
* tag 'libnvdimm-for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (34 commits)
libnvdimm, pmem: direct map legacy pmem by default
libnvdimm, pmem: 'struct page' for pmem
libnvdimm, pfn: 'struct page' provider infrastructure
x86, pmem: clarify that ARCH_HAS_PMEM_API implies PMEM mapped WB
add devm_memremap_pages
mm: ZONE_DEVICE for "device memory"
mm: move __phys_to_pfn and __pfn_to_phys to asm/generic/memory_model.h
dax: drop size parameter to ->direct_access()
nd_blk: change aperture mapping from WC to WB
nvdimm: change to use generic kvfree()
pmem, dax: have direct_access use __pmem annotation
dax: update I/O path to do proper PMEM flushing
pmem: add copy_from_iter_pmem() and clear_pmem()
pmem, x86: clean up conditional pmem includes
pmem: remove layer when calling arch_has_wmb_pmem()
pmem, x86: move x86 PMEM API to new pmem.h header
libnvdimm, e820: make CONFIG_X86_PMEM_LEGACY a tristate option
pmem: switch to devm_ allocations
devres: add devm_memremap
libnvdimm, btt: write and validate parent_uuid
...
vma->vm_ops->mremap() looks more natural and clean in move_vma(), and this
way ->mremap() can have more users. Say, vdso.
While at it, s/aio_ring_remap/aio_ring_mremap/.
Note: this is the minimal change before ->mremap() finds another user in
file_operations; this method should have more arguments, and it can be
used to kill arch_remap().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge
must be aware about so that we can merge vmas back like they were
originally before arming the userfaultfd on some memory range.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Cc: zhang.zhanghailiang@huawei.com
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These two flags gets set in vma->vm_flags to tell the VM common code
if the userfaultfd is armed and in which mode (only tracking missing
faults, only tracking wrprotect faults or both). If neither flags is
set it means the userfaultfd is not armed on the vma.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Cc: zhang.zhanghailiang@huawei.com
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit c48a11c7ad ("netvm: propagate page->pfmemalloc to skb") added
checks for page->pfmemalloc to __skb_fill_page_desc():
if (page->pfmemalloc && !page->mapping)
skb->pfmemalloc = true;
It assumes page->mapping == NULL implies that page->pfmemalloc can be
trusted. However, __delete_from_page_cache() can set set page->mapping
to NULL and leave page->index value alone. Due to being in union, a
non-zero page->index will be interpreted as true page->pfmemalloc.
So the assumption is invalid if the networking code can see such a page.
And it seems it can. We have encountered this with a NFS over loopback
setup when such a page is attached to a new skbuf. There is no copying
going on in this case so the page confuses __skb_fill_page_desc which
interprets the index as pfmemalloc flag and the network stack drops
packets that have been allocated using the reserves unless they are to
be queued on sockets handling the swapping which is the case here and
that leads to hangs when the nfs client waits for a response from the
server which has been dropped and thus never arrive.
The struct page is already heavily packed so rather than finding another
hole to put it in, let's do a trick instead. We can reuse the index
again but define it to an impossible value (-1UL). This is the page
index so it should never see the value that large. Replace all direct
users of page->pfmemalloc by page_is_pfmemalloc which will hide this
nastiness from unspoiled eyes.
The information will get lost if somebody wants to use page->index
obviously but that was the case before and the original code expected
that the information should be persisted somewhere else if that is
really needed (e.g. what SLAB and SLUB do).
[akpm@linux-foundation.org: fix blooper in slub]
Fixes: c48a11c7ad ("netvm: propagate page->pfmemalloc to skb")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Debugged-by: Vlastimil Babka <vbabka@suse.com>
Debugged-by: Jiri Bohac <jbohac@suse.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org> [3.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide new function get_vaddr_frames(). This function maps virtual
addresses from given start and fills given array with page frame numbers of
the corresponding pages. If given start belongs to a normal vma, the function
grabs reference to each of the pages to pin them in memory. If start
belongs to VM_IO | VM_PFNMAP vma, we don't touch page structures. Caller
must make sure pfns aren't reused for anything else while he is using
them.
This function is created for various drivers to simplify handling of
their buffers.
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
region_is_ram() is used to prevent the establishment of aliased mappings
to physical "System RAM" with incompatible cache settings. However, it
uses "-1" to indicate both "unknown" memory ranges (ranges not described
by platform firmware) and "mixed" ranges (where the parameters describe
a range that partially overlaps "System RAM").
Fix this up by explicitly tracking the "unknown" vs "mixed" resource
cases and returning REGION_INTERSECTS, REGION_MIXED, or REGION_DISJOINT.
This re-write also adds support for detecting when the requested region
completely eclipses all of a resource. Note, the implementation treats
overlaps between "unknown" and the requested memory type as
REGION_INTERSECTS.
Finally, other memory types can be passed in by name, for now the only
usage "System RAM".
Suggested-by: Luis R. Rodriguez <mcgrof@suse.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
__early_pfn_to_nid() use static variables to cache recent lookups as
memblock lookups are very expensive but it assumes that memory
initialisation is single-threaded. Parallel initialisation of struct
pages will break that assumption so this patch makes __early_pfn_to_nid()
SMP-safe by requiring the caller to cache recent search information.
early_pfn_to_nid() keeps the same interface but is only safe to use early
in boot due to the use of a global static variable. meminit_pfn_in_nid()
is an SMP-safe version that callers must maintain their own state for.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently each page struct is set as reserved upon initialization. This
patch leaves the reserved bit clear and only sets the reserved bit when it
is known the memory was allocated by the bootmem allocator. This makes it
easier to distinguish between uninitialised struct pages and reserved
struct pages in later patches.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull cgroup writeback support from Jens Axboe:
"This is the big pull request for adding cgroup writeback support.
This code has been in development for a long time, and it has been
simmering in for-next for a good chunk of this cycle too. This is one
of those problems that has been talked about for at least half a
decade, finally there's a solution and code to go with it.
Also see last weeks writeup on LWN:
http://lwn.net/Articles/648292/"
* 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits)
writeback, blkio: add documentation for cgroup writeback support
vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB
writeback: do foreign inode detection iff cgroup writeback is enabled
v9fs: fix error handling in v9fs_session_init()
bdi: fix wrong error return value in cgwb_create()
buffer: remove unusued 'ret' variable
writeback: disassociate inodes from dying bdi_writebacks
writeback: implement foreign cgroup inode bdi_writeback switching
writeback: add lockdep annotation to inode_to_wb()
writeback: use unlocked_inode_to_wb transaction in inode_congested()
writeback: implement unlocked_inode_to_wb transaction and use it for stat updates
writeback: implement [locked_]inode_to_wb_and_lock_list()
writeback: implement foreign cgroup inode detection
writeback: make writeback_control track the inode being written back
writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use
writeback: implement memcg writeback domain based throttling
writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes
writeback: implement memcg wb_domain
writeback: update wb_over_bg_thresh() to use wb_domain aware operations
...
Change type of action_result's param 3 to enum for type consistency,
and rename mf_outcome to mf_result for clearly.
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Export 'outcome' and 'action_page_type' to mm.h, so we could use
this emnus outside.
This patch is preparation for adding trace events for memory-failure
recovery action.
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memory_failure() can run in 2 different mode (specified by
MF_COUNT_INCREASED) in page refcount perspective. When
MF_COUNT_INCREASED is set, memory_failure() assumes that the caller
takes a refcount of the target page. And if cleared, memory_failure()
takes it in it's own.
In current code, however, refcounting is done differently in each caller.
For example, madvise_hwpoison() uses get_user_pages_fast() and
hwpoison_inject() uses get_page_unless_zero(). So this inconsistent
refcounting causes refcount failure especially for thp tail pages.
Typical user visible effects are like memory leak or
VM_BUG_ON_PAGE(!page_count(page)) in isolate_lru_page().
To fix this refcounting issue, this patch introduces get_hwpoison_page()
to handle thp tail pages in the same manner for each caller of hwpoison
code.
memory_failure() might fail to split thp and in such case it returns
without completing page isolation. This is not good because PageHWPoison
on the thp is still set and there's no easy way to unpoison such thps. So
this patch try to roll back any action to the thp in "non anonymous thp"
case and "thp split failed" case, expecting an MCE(SRAR) generated by
later access afterward will properly free such thps.
[akpm@linux-foundation.org: fix CONFIG_HWPOISON_INJECT=m]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reintroduce 8d63d99a5d ("mm: avoid tail page refcounting on non-THP
compound pages") after removing bogus VM_BUG_ON_PAGE() in
put_unrefcounted_compound_page().
THP uses tail page refcounting to be able to split huge pages at any time.
Tail page refcounting is not needed for other users of compound pages and
it's harmful because of overhead.
We try to exclude non-THP pages from tail page refcounting using
__compound_tail_refcounted() check. It excludes most common non-THP
compound pages: SL*B and hugetlb, but it doesn't catch rest of __GFP_COMP
users -- drivers.
And it's not only about overhead.
Drivers might want to use compound pages to get refcounting semantics
suitable for mapping high-order pages to userspace. But tail page
refcounting breaks it.
Tail page refcounting uses ->_mapcount in tail pages to store GUP pins on
them. It means GUP pins would affect page_mapcount() for tail pages.
It's not a problem for THP, because it never maps tail pages. But unlike
THP, drivers map parts of compound pages with PTEs and it makes
page_mapcount() be called for tail pages.
In particular, GUP pins would shift PSS up and affect /proc/kpagecount for
such pages. But, I'm not aware about anything which can lead to crash or
other serious misbehaviour.
Since currently all THP pages are anonymous and all drivers pages are not,
we can fix the __compound_tail_refcounted() check by requiring PageAnon()
to enable tail page refcounting.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The mechanism for detecting whether an inode should switch its wb
(bdi_writeback) association is now in place. This patch build the
framework for the actual switching.
This patch adds a new inode flag I_WB_SWITCHING, which has two
functions. First, the easy one, it ensures that there's only one
switching in progress for a give inode. Second, it's used as a
mechanism to synchronize wb stat updates.
The two stats, WB_RECLAIMABLE and WB_WRITEBACK, aren't event counters
but track the current number of dirty pages and pages under writeback
respectively. As such, when an inode is moved from one wb to another,
the inode's portion of those stats have to be transferred together;
unfortunately, this is a bit tricky as those stat updates are percpu
operations which are performed without holding any lock in some
places.
This patch solves the problem in a similar way as memcg. Each such
lockless stat updates are wrapped in transaction surrounded by
unlocked_inode_to_wb_begin/end(). During normal operation, they map
to rcu_read_lock/unlock(); however, if I_WB_SWITCHING is asserted,
mapping->tree_lock is grabbed across the transaction.
In turn, the switching path sets I_WB_SWITCHING and waits for a RCU
grace period to pass before actually starting to switch, which
guarantees that all stat update paths are synchronizing against
mapping->tree_lock.
This patch still doesn't implement the actual switching.
v3: Updated on top of the recent cancel_dirty_page() updates.
unlocked_inode_to_wb_begin() now nests inside
mem_cgroup_begin_page_stat() to match the locking order.
v2: The i_wb access transaction will be used for !stat accesses too.
Function names and comments updated accordingly.
s/inode_wb_stat_unlocked_{begin|end}/unlocked_inode_to_wb_{begin|end}/
s/switch_wb/switch_wbs/
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When modifying PG_Dirty on cached file pages, update the new
MEM_CGROUP_STAT_DIRTY counter. This is done in the same places where
global NR_FILE_DIRTY is managed. The new memcg stat is visible in the
per memcg memory.stat cgroupfs file. The most recent past attempt at
this was http://thread.gmane.org/gmane.linux.kernel.cgroups/8632
The new accounting supports future efforts to add per cgroup dirty
page throttling and writeback. It also helps an administrator break
down a container's memory usage and provides evidence to understand
memcg oom kills (the new dirty count is included in memcg oom kill
messages).
The ability to move page accounting between memcg
(memory.move_charge_at_immigrate) makes this accounting more
complicated than the global counter. The existing
mem_cgroup_{begin,end}_page_stat() lock is used to serialize move
accounting with stat updates.
Typical update operation:
memcg = mem_cgroup_begin_page_stat(page)
if (TestSetPageDirty()) {
[...]
mem_cgroup_update_page_stat(memcg)
}
mem_cgroup_end_page_stat(memcg)
Summary of mem_cgroup_end_page_stat() overhead:
- Without CONFIG_MEMCG it's a no-op
- With CONFIG_MEMCG and no inter memcg task movement, it's just
rcu_read_lock()
- With CONFIG_MEMCG and inter memcg task movement, it's
rcu_read_lock() + spin_lock_irqsave()
A memcg parameter is added to several routines because their callers
now grab mem_cgroup_begin_page_stat() which returns the memcg later
needed by for mem_cgroup_update_page_stat().
Because mem_cgroup_begin_page_stat() may disable interrupts, some
adjustments are needed:
- move __mark_inode_dirty() from __set_page_dirty() to its caller.
__mark_inode_dirty() locking does not want interrupts disabled.
- use spin_lock_irqsave(tree_lock) rather than spin_lock_irq() in
__delete_from_page_cache(), replace_page_cache_page(),
invalidate_complete_page2(), and __remove_mapping().
text data bss dec hex filename
8925147 1774832 1785856 12485835 be84cb vmlinux-!CONFIG_MEMCG-before
8925339 1774832 1785856 12486027 be858b vmlinux-!CONFIG_MEMCG-after
+192 text bytes
8965977 1784992 1785856 12536825 bf4bf9 vmlinux-CONFIG_MEMCG-before
8966750 1784992 1785856 12537598 bf4efe vmlinux-CONFIG_MEMCG-after
+773 text bytes
Performance tests run on v4.0-rc1-36-g4f671fe2f952. Lower is better for
all metrics, they're all wall clock or cycle counts. The read and write
fault benchmarks just measure fault time, they do not include I/O time.
* CONFIG_MEMCG not set:
baseline patched
kbuild 1m25.030000(+-0.088% 3 samples) 1m25.426667(+-0.120% 3 samples)
dd write 100 MiB 0.859211561 +-15.10% 0.874162885 +-15.03%
dd write 200 MiB 1.670653105 +-17.87% 1.669384764 +-11.99%
dd write 1000 MiB 8.434691190 +-14.15% 8.474733215 +-14.77%
read fault cycles 254.0(+-0.000% 10 samples) 253.0(+-0.000% 10 samples)
write fault cycles 2021.2(+-3.070% 10 samples) 1984.5(+-1.036% 10 samples)
* CONFIG_MEMCG=y root_memcg:
baseline patched
kbuild 1m25.716667(+-0.105% 3 samples) 1m25.686667(+-0.153% 3 samples)
dd write 100 MiB 0.855650830 +-14.90% 0.887557919 +-14.90%
dd write 200 MiB 1.688322953 +-12.72% 1.667682724 +-13.33%
dd write 1000 MiB 8.418601605 +-14.30% 8.673532299 +-15.00%
read fault cycles 266.0(+-0.000% 10 samples) 266.0(+-0.000% 10 samples)
write fault cycles 2051.7(+-1.349% 10 samples) 2049.6(+-1.686% 10 samples)
* CONFIG_MEMCG=y non-root_memcg:
baseline patched
kbuild 1m26.120000(+-0.273% 3 samples) 1m25.763333(+-0.127% 3 samples)
dd write 100 MiB 0.861723964 +-15.25% 0.818129350 +-14.82%
dd write 200 MiB 1.669887569 +-13.30% 1.698645885 +-13.27%
dd write 1000 MiB 8.383191730 +-14.65% 8.351742280 +-14.52%
read fault cycles 265.7(+-0.172% 10 samples) 267.0(+-0.000% 10 samples)
write fault cycles 2070.6(+-1.512% 10 samples) 2084.4(+-2.148% 10 samples)
As expected anon page faults are not affected by this patch.
tj: Updated to apply on top of the recent cancel_dirty_page() changes.
Signed-off-by: Sha Zhengju <handai.szj@gmail.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
cancel_dirty_page() had some issues and b9ea25152e ("page_writeback:
clean up mess around cancel_dirty_page()") replaced it with
account_page_cleaned() which makes the caller responsible for clearing
the dirty bit; unfortunately, the planned changes for cgroup writeback
support requires synchronization between dirty bit manipulation and
stat updates. While we can open-code such synchronization in each
account_page_cleaned() callsite, that's gonna be unnecessarily awkward
and verbose.
This patch revives cancel_dirty_page() but in a more restricted form.
All it does is TestClearPageDirty() followed by account_page_cleaned()
invocation if the page was dirty. This helper covers all
account_page_cleaned() usages except for __delete_from_page_cache()
which is a special case anyway and left alone. As this leaves no
module user for account_page_cleaned(), EXPORT_SYMBOL() is dropped
from it.
This patch just revives cancel_dirty_page() as a trivial wrapper to
replace equivalent usages and doesn't introduce any functional
changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jens Axboe <axboe@fb.com>
This will allow FS that uses VM_PFNMAP | VM_MIXEDMAP (no page structs) to
get notified when access is a write to a read-only PFN.
This can happen if we mmap() a file then first mmap-read from it to
page-in a read-only PFN, than we mmap-write to the same page.
We need this functionality to fix a DAX bug, where in the scenario above
we fail to set ctime/mtime though we modified the file. An xfstest is
attached to this patchset that shows the failure and the fix. (A DAX
patch will follow)
This functionality is extra important for us, because upon dirtying of a
pmem page we also want to RDMA the page to a remote cluster node.
We define a new pfn_mkwrite and do not reuse page_mkwrite because
1 - The name ;-)
2 - But mainly because it would take a very long and tedious
audit of all page_mkwrite functions of VM_MIXEDMAP/VM_PFNMAP
users. To make sure they do not now CRASH. For example current
DAX code (which this is for) would crash.
If we would want to reuse page_mkwrite, We will need to first
patch all users, so to not-crash-on-no-page. Then enable this
patch. But even if I did that I would not sleep so well at night.
Adding a new vector is the safest thing to do, and is not that
expensive. an extra pointer at a static function vector per driver.
Also the new vector is better for performance, because else we
Will call all current Kernel vectors, so to:
check-ha-no-page-do-nothing and return.
No need to call it from do_shared_fault because do_wp_page is called to
change pte permissions anyway.
Signed-off-by: Yigal Korman <yigal@plexistor.com>
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Most-used page->mapping helper -- page_mapping() -- has already uninlined.
Let's uninline also page_rmapping() and page_anon_vma(). It saves us
depending on configuration around 400 bytes in text:
text data bss dec hex filename
660318 99254 410000 1169572 11d8a4 mm/built-in.o-before
659854 99254 410000 1169108 11d6d4 mm/built-in.o
I also tried to make code a bit more clean.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Flip the flag test so that it is the simplest. No functional change, just
a small readability improvement:
No code changed:
# arch/x86/kernel/sys_x86_64.o:
text data bss dec hex filename
1551 24 0 1575 627 sys_x86_64.o.before
1551 24 0 1575 627 sys_x86_64.o.after
md5:
70708d1b1ad35cc891118a69dc1a63f9 sys_x86_64.o.before.asm
70708d1b1ad35cc891118a69dc1a63f9 sys_x86_64.o.after.asm
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kirill A. Shutemov