This matches the map_kernel_range_noflush API. Also change to pass a size
instead of the end, similar to the noflush version.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-15-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These have non-static aliases called map_kernel_range_noflush and
unmap_kernel_range_noflush that just differ slightly in the calling
conventions that pass addr + size instead of an end.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-14-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ever use of addr in vb_free casts to unsigned long first, and the caller
has an unsigned long version of the address available anyway. Just pass
that and avoid all the casts.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-13-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows to unexport map_vm_area and unmap_kernel_range, which are
rather deep internal and should not be available to modules, as they for
example allow fine grained control of mapping permissions, and also
allow splitting the setup of a vmalloc area and the actual mapping and
thus expose vmalloc internals.
zsmalloc is typically built-in and continues to work (just like the
percpu-vm code using a similar patter), while modular zsmalloc also
continues to work, but must use copies.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-12-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These helpers are only used for remapping the ISA I/O base. Replace the
mapping side with a remap_isa_range helper in isa-bridge.c that hard codes
all the known arguments, and just remove __iounmap_at in favour of open
coding it in the only caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-8-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Factor code shared between pci_64 and electra_cf into a ioremap_pbh helper
that follows the normal ioremap semantics, and returns a useful __iomem
pointer. Note that it opencodes __ioremap_at as we know from the callers
the slab is available. Switch pci_64 to also store the result as __iomem
pointer, and unmap the result using iounmap instead of force casting and
using vmalloc APIs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace the open coded instance of vmap with the actual function. In
the non-contiguous (IOMMU) case this requires an extra find_vm_area,
but given that this isn't a fast path function that is a small price
to pay.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vm_map_ram can keep mappings around after the vm_unmap_ram. Using that
with non-PAGE_KERNEL mappings can lead to all kinds of aliasing issues.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-4-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "decruft the vmalloc API", v2.
Peter noticed that with some dumb luck you can toast the kernel address
space with exported vmalloc symbols.
I used this as an opportunity to decruft the vmalloc.c API and make it
much more systematic. This also removes any chance to create vmalloc
mappings outside the designated areas or using executable permissions
from modules. Besides that it removes more than 300 lines of code.
This patch (of 29):
Use the designated helper for allocating executable kernel memory, and
remove the now unused PAGE_KERNEL_RX define.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200414131348.444715-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200414131348.444715-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some processes dont't want to be killed early, but in "Action Required"
case, those also may be killed by BUS_MCEERR_AO when sharing memory with
other which is accessing the fail memory. And sending SIGBUS with
BUS_MCEERR_AO for action required error is strange, so ignore the
non-current processes here.
Suggested-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Wetp Zhang <wetp.zy@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/1590817116-21281-1-git-send-email-wetp.zy@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 25b2995a35 ("mm: remove MEMORY_DEVICE_PUBLIC support"),
the assignment to 'page' for pte_devmap case has been unnecessary.
Let's remove it.
[willy@infradead.org: changelog]
Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/1587349685-31712-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The page table entry is passed in the 'val' argument to note_page(),
however this was previously an "unsigned long" which is fine on 64-bit
platforms. But for 32 bit x86 it is not always big enough to contain a
page table entry which may be 64 bits.
Change the type to u64 to ensure that it is always big enough.
[akpm@linux-foundation.org: fix riscv]
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200521152308.33096-3-steven.price@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Fix W+X debug feature on x86"
Jan alerted me[1] that the W+X detection debug feature was broken in x86
by my change[2] to switch x86 to use the generic ptdump infrastructure.
Fundamentally the approach of trying to move the calculation of
effective permissions into note_page() was broken because note_page() is
only called for 'leaf' entries and the effective permissions are passed
down via the internal nodes of the page tree. The solution I've taken
here is to create a new (optional) callback which is called for all
nodes of the page tree and therefore can calculate the effective
permissions.
Secondly on some configurations (32 bit with PAE) "unsigned long" is not
large enough to store the table entries. The fix here is simple - let's
just use a u64.
[1] https://lore.kernel.org/lkml/d573dc7e-e742-84de-473d-f971142fa319@suse.com/
[2] 2ae27137b2 ("x86: mm: convert dump_pagetables to use walk_page_range")
This patch (of 2):
By switching the x86 page table dump code to use the generic code the
effective permissions are no longer calculated correctly because the
note_page() function is only called for *leaf* entries. To calculate
the actual effective permissions it is necessary to observe the full
hierarchy of the page tree.
Introduce a new callback for ptdump which is called for every entry and
can therefore update the prot_levels array correctly. note_page() can
then simply access the appropriate element in the array.
[steven.price@arm.com: make the assignment conditional on val != 0]
Link: http://lkml.kernel.org/r/430c8ab4-e7cd-6933-dde6-087fac6db872@arm.com
Fixes: 2ae27137b2 ("x86: mm: convert dump_pagetables to use walk_page_range")
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200521152308.33096-1-steven.price@arm.com
Link: http://lkml.kernel.org/r/20200521152308.33096-2-steven.price@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While trying to use remote memcg charging in an out-of-tree kernel
module I found it's not working, because the current thread is a
workqueue thread.
As we will probably encounter this issue in the future as the users of
memalloc_use_memcg() grow, and it's nothing wrong for this usage, it's
better we fix it now.
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Link: http://lkml.kernel.org/r/1d202a12-26fe-0012-ea14-f025ddcd044a@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a memory.swap.high knob, which can be used to protect the system
from SWAP exhaustion. The mechanism used for penalizing is similar to
memory.high penalty (sleep on return to user space).
That is not to say that the knob itself is equivalent to memory.high.
The objective is more to protect the system from potentially buggy tasks
consuming a lot of swap and impacting other tasks, or even bringing the
whole system to stand still with complete SWAP exhaustion. Hopefully
without the need to find per-task hard limits.
Slowing misbehaving tasks down gradually allows user space oom killers
or other protection mechanisms to react. oomd and earlyoom already do
killing based on swap exhaustion, and memory.swap.high protection will
help implement such userspace oom policies more reliably.
We can use one counter for number of pages allocated under pressure to
save struct task space and avoid two separate hierarchy walks on the hot
path. The exact overage is calculated on return to user space, anyway.
Take the new high limit into account when determining if swap is "full".
Borrowing the explanation from Johannes:
The idea behind "swap full" is that as long as the workload has plenty
of swap space available and it's not changing its memory contents, it
makes sense to generously hold on to copies of data in the swap device,
even after the swapin. A later reclaim cycle can drop the page without
any IO. Trading disk space for IO.
But the only two ways to reclaim a swap slot is when they're faulted
in and the references go away, or by scanning the virtual address space
like swapoff does - which is very expensive (one could argue it's too
expensive even for swapoff, it's often more practical to just reboot).
So at some point in the fill level, we have to start freeing up swap
slots on fault/swapin. Otherwise we could eventually run out of swap
slots while they're filled with copies of data that is also in RAM.
We don't want to OOM a workload because its available swap space is
filled with redundant cache.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Chris Down <chris@chrisdown.name>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200527195846.102707-5-kuba@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
High memory limit is currently recorded directly in struct mem_cgroup.
We are about to add a high limit for swap, move the field to struct
page_counter and add some helpers.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Down <chris@chrisdown.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200527195846.102707-4-kuba@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We will want to call calculate_high_delay() twice - once for memory and
once for swap, and we should apply the clamp value to sum of the
penalties. Clamping has to be applied outside of calculate_high_delay().
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Down <chris@chrisdown.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200527195846.102707-3-kuba@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "memcg: Slow down swap allocation as the available space
gets depleted", v6.
Tejun describes the problem as follows:
When swap runs out, there's an abrupt change in system behavior - the
anonymous memory suddenly becomes unmanageable which readily breaks any
sort of memory isolation and can bring down the whole system. To avoid
that, oomd [1] monitors free swap space and triggers kills when it drops
below the specific threshold (e.g. 15%).
While this works, it's far from ideal:
- Depending on IO performance and total swap size, a given
headroom might not be enough or too much.
- oomd has to monitor swap depletion in addition to the usual
pressure metrics and it currently doesn't consider memory.swap.max.
Solve this by adapting parts of the approach that memory.high uses -
slow down allocation as the resource gets depleted turning the depletion
behavior from abrupt cliff one to gradual degradation observable through
memory pressure metric.
[1] https://github.com/facebookincubator/oomd
This patch (of 4):
Slice the memory overage calculation logic a little bit so we can reuse
it to apply a similar penalty to the swap. The logic which accesses the
memory-specific fields (use and high values) has to be taken out of
calculate_high_delay().
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200527195846.102707-1-kuba@kernel.org
Link: http://lkml.kernel.org/r/20200527195846.102707-2-kuba@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
One way to measure the efficiency of memory reclaim is to look at the
ratio (pgscan+pfrefill)/pgsteal. However at the moment these stats are
not updated consistently at the system level and the ratio of these are
not very meaningful. The pgsteal and pgscan are updated for only global
reclaim while pgrefill gets updated for global as well as cgroup
reclaim.
Please note that this difference is only for system level vmstats. The
cgroup stats returned by memory.stat are actually consistent. The
cgroup's pgsteal contains number of reclaimed pages for global as well
as cgroup reclaim. So, one way to get the system level stats is to get
these stats from root's memory.stat, so, expose memory.stat for the root
cgroup.
From Johannes Weiner:
There are subtle differences between /proc/vmstat and
memory.stat, and cgroup-aware code that wants to watch the full
hierarchy currently has to know about these intricacies and
translate semantics back and forth.
Generally having the fully recursive memory.stat at the root
level could help a broader range of usecases.
Why not fix the stats by including both the global and cgroup reclaim
activity instead of exposing root cgroup's memory.stat? The reason is
the benefit of having metrics exposing the activity that happens purely
due to machine capacity rather than localized activity that happens due
to the limits throughout the cgroup tree. Additionally there are
userspace tools like sysstat(sar) which reads these stats to inform
about the system level reclaim activity. So, we should not break such
use-cases.
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200508170630.94406-1-shakeelb@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the variables count and limit have the same value(count == limit),
the result of min(margin, limit - count) statement should be 0 and the
variable margin is set to 0. So in this case, the min() statement is
not necessary and we can directly set the variable margin to 0.
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Link: http://lkml.kernel.org/r/1587479661-27237-1-git-send-email-kaixuxia@tencent.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There's a new workingset counter introduced in commit 1899ad18c6 ("mm:
workingset: tell cache transitions from workingset thrashing"). With
the help of this counter we can know the workingset is transitioning or
thrashing. To leverage the benifit of this counter to memcg, we should
introduce it into memory.stat. Then we could know the workingset of the
workload inside a memcg better.
Bellow is the verification of this new counter in memory.stat. Read a
file into the memory and then read it again to make these pages be
active. The size of this file is 1G. (memory.max is greater than file
size) The counters in memory.stat will be
inactive_file 0
active_file 1073639424
workingset_refault 0
workingset_activate 0
workingset_restore 0
workingset_nodereclaim 0
Trigger the memcg reclaim by setting a lower value to memory.high, and
then some pages will be demoted into inactive list, and then some pages
in the inactive list will be evicted into the storage.
inactive_file 498094080
active_file 310063104
workingset_refault 0
workingset_activate 0
workingset_restore 0
workingset_nodereclaim 0
Then recover the memory.high and read the file into memory again. As a
result of it, the transitioning will occur. Bellow is the result of
this transitioning,
inactive_file 498094080
active_file 575397888
workingset_refault 64746
workingset_activate 64746
workingset_restore 64746
workingset_nodereclaim 0
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Link: http://lkml.kernel.org/r/20200504153522.11553-1-laoar.shao@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 8d93b41c09 ("mm: Convert add_to_swap_cache to XArray"),
__add_to_swap_cache and add_to_swap_cache are combined into one
function. There is no __add_to_swap_cache() anymore.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Link: http://lkml.kernel.org/r/1590810326-2493-1-git-send-email-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the heading and Size/Used/Priority field alignments in /proc/swaps.
If the Size and/or Used value is >= 10000000 (8 bytes), then the
alignment by using tab characters is broken.
This patch maintains the use of tabs for alignment. If spaces are
preferred, we can just use a Field Width specifier for the bytes and
inuse fields. That way those fields don't have to be a multiple of 8
bytes in width. E.g., with a field width of 12, both Size and Used
would always fit on the first line of an 80-column wide terminal (only
Priority would be on the second line).
There are actually 2 problems: heading alignment and field width. On an
xterm, if Used is 7 bytes in length, the tab does nothing, and the
display is like this, with no space/tab between the Used and Priority
fields. (ugh)
Filename Type Size Used Priority
/dev/sda8 partition 16779260 2023012-1
To be clear, if one does 'cat /proc/swaps >/tmp/proc.swaps', it does look
different, like so:
Filename Type Size Used Priority
/dev/sda8 partition 16779260 2086988 -1
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/c0ffb41a-81ac-ddfa-d452-a9229ecc0387@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In some swap scalability test, it is found that there are heavy lock
contention on swap cache even if we have split one swap cache radix tree
per swap device to one swap cache radix tree every 64 MB trunk in commit
4b3ef9daa4 ("mm/swap: split swap cache into 64MB trunks").
The reason is as follow. After the swap device becomes fragmented so
that there's no free swap cluster, the swap device will be scanned
linearly to find the free swap slots. swap_info_struct->cluster_next is
the next scanning base that is shared by all CPUs. So nearby free swap
slots will be allocated for different CPUs. The probability for
multiple CPUs to operate on the same 64 MB trunk is high. This causes
the lock contention on the swap cache.
To solve the issue, in this patch, for SSD swap device, a percpu version
next scanning base (cluster_next_cpu) is added. Every CPU will use its
own per-cpu next scanning base. And after finishing scanning a 64MB
trunk, the per-cpu scanning base will be changed to the beginning of
another randomly selected 64MB trunk. In this way, the probability for
multiple CPUs to operate on the same 64 MB trunk is reduced greatly.
Thus the lock contention is reduced too. For HDD, because sequential
access is more important for IO performance, the original shared next
scanning base is used.
To test the patch, we have run 16-process pmbench memory benchmark on a
2-socket server machine with 48 cores. One ram disk is configured as the
swap device per socket. The pmbench working-set size is much larger than
the available memory so that swapping is triggered. The memory read/write
ratio is 80/20 and the accessing pattern is random. In the original
implementation, the lock contention on the swap cache is heavy. The perf
profiling data of the lock contention code path is as following,
_raw_spin_lock_irq.add_to_swap_cache.add_to_swap.shrink_page_list: 7.91
_raw_spin_lock_irqsave.__remove_mapping.shrink_page_list: 7.11
_raw_spin_lock.swapcache_free_entries.free_swap_slot.__swap_entry_free: 2.51
_raw_spin_lock_irqsave.swap_cgroup_record.mem_cgroup_uncharge_swap: 1.66
_raw_spin_lock_irq.shrink_inactive_list.shrink_lruvec.shrink_node: 1.29
_raw_spin_lock.free_pcppages_bulk.drain_pages_zone.drain_pages: 1.03
_raw_spin_lock_irq.shrink_active_list.shrink_lruvec.shrink_node: 0.93
After applying this patch, it becomes,
_raw_spin_lock.swapcache_free_entries.free_swap_slot.__swap_entry_free: 3.58
_raw_spin_lock_irq.shrink_inactive_list.shrink_lruvec.shrink_node: 2.3
_raw_spin_lock_irqsave.swap_cgroup_record.mem_cgroup_uncharge_swap: 2.26
_raw_spin_lock_irq.shrink_active_list.shrink_lruvec.shrink_node: 1.8
_raw_spin_lock.free_pcppages_bulk.drain_pages_zone.drain_pages: 1.19
The lock contention on the swap cache is almost eliminated.
And the pmbench score increases 18.5%. The swapin throughput increases
18.7% from 2.96 GB/s to 3.51 GB/s. While the swapout throughput increases
18.5% from 2.99 GB/s to 3.54 GB/s.
We need really fast disk to show the benefit. I have tried this on 2
Intel P3600 NVMe disks. The performance improvement is only about 1%.
The improvement should be better on the faster disks, such as Intel Optane
disk.
[ying.huang@intel.com: fix cluster_next_cpu allocation and freeing, per Daniel]
Link: http://lkml.kernel.org/r/20200525002648.336325-1-ying.huang@intel.com
[ying.huang@intel.com: v4]
Link: http://lkml.kernel.org/r/20200529010840.928819-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200520031502.175659-1-ying.huang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To improve the code readability and take advantage of the common
implementation.
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200512081013.520201-1-ying.huang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
swap_info_struct->swap_map[] encodes some flag and count. And to
do some condition check, it also introduces some special values.
Currently those macros are defined with some magic order, which makes
audience hard to understand the exact meaning.
This patch split those macros into three categories:
flag
special value for first swap_map
special value for continued swap_map
May this help audiences a little.
[akpm@linux-foundation.org: tweak capitalization in comments]
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200501015259.32237-1-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, the scalability of swap code will drop much when the swap device
becomes fragmented, because the swap slots allocation batching stops
working. To solve the problem, in this patch, we will try to scan a
little more swap slots with restricted effort to batch the swap slots
allocation even if the swap device is fragmented. Test shows that the
benchmark score can increase up to 37.1% with the patch. Details are as
follows.
The swap code has a per-cpu cache of swap slots. These batch swap space
allocations to improve swap subsystem scaling. In the following code
path,
add_to_swap()
get_swap_page()
refill_swap_slots_cache()
get_swap_pages()
scan_swap_map_slots()
scan_swap_map_slots() and get_swap_pages() can return multiple swap
slots for each call. These slots will be cached in the per-CPU swap
slots cache, so that several following swap slot requests will be
fulfilled there to avoid the lock contention in the lower level swap
space allocation/freeing code path.
But this only works when there are free swap clusters. If a swap device
becomes so fragmented that there's no free swap clusters,
scan_swap_map_slots() and get_swap_pages() will return only one swap
slot for each call in the above code path. Effectively, this falls back
to the situation before the swap slots cache was introduced, the heavy
lock contention on the swap related locks kills the scalability.
Why does it work in this way? Because the swap device could be large,
and the free swap slot scanning could be quite time consuming, to avoid
taking too much time to scanning free swap slots, the conservative
method was used.
In fact, this can be improved via scanning a little more free slots with
strictly restricted effort. Which is implemented in this patch. In
scan_swap_map_slots(), after the first free swap slot is gotten, we will
try to scan a little more, but only if we haven't scanned too many slots
(< LATENCY_LIMIT). That is, the added scanning latency is strictly
restricted.
To test the patch, we have run 16-process pmbench memory benchmark on a
2-socket server machine with 48 cores. Multiple ram disks are
configured as the swap devices. The pmbench working-set size is much
larger than the available memory so that swapping is triggered. The
memory read/write ratio is 80/20 and the accessing pattern is random, so
the swap space becomes highly fragmented during the test. In the
original implementation, the lock contention on swap related locks is
very heavy. The perf profiling data of the lock contention code path is
as following,
_raw_spin_lock.get_swap_pages.get_swap_page.add_to_swap: 21.03
_raw_spin_lock_irq.shrink_inactive_list.shrink_lruvec.shrink_node: 1.92
_raw_spin_lock_irq.shrink_active_list.shrink_lruvec.shrink_node: 1.72
_raw_spin_lock.free_pcppages_bulk.drain_pages_zone.drain_pages: 0.69
While after applying this patch, it becomes,
_raw_spin_lock_irq.shrink_inactive_list.shrink_lruvec.shrink_node: 4.89
_raw_spin_lock_irq.shrink_active_list.shrink_lruvec.shrink_node: 3.85
_raw_spin_lock.free_pcppages_bulk.drain_pages_zone.drain_pages: 1.1
_raw_spin_lock_irqsave.pagevec_lru_move_fn.__lru_cache_add.do_swap_page: 0.88
That is, the lock contention on the swap locks is eliminated.
And the pmbench score increases 37.1%. The swapin throughput increases
45.7% from 2.02 GB/s to 2.94 GB/s. While the swapout throughput increases
45.3% from 2.04 GB/s to 2.97 GB/s.
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200427030023.264780-1-ying.huang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are two duplicate code to handle the case when there is no available
swap entry. To avoid this, we can compare tmp and max first and let the
second guard do its job.
No functional change is expected.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200421213824.8099-3-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If tmp is bigger or equal to max, we would jump to new_cluster.
Return true directly.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200421213824.8099-2-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is not necessary to use the variable found_free to record the status.
Just check tmp and max is enough.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200421213824.8099-1-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
scan_swap_map_slots() is only called by scan_swap_map() and
get_swap_pages(). Both ensure nr would not exceed SWAP_BATCH.
Just remove it.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200325220309.9803-2-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use min3() to simplify the comparison and make it more self-explaining.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200325220309.9803-1-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now we can see there is redundant goto for SSD case. In these two places,
we can just let the code walk through to the correct tag instead of
explicitly jump to it.
Let's remove them for better readability.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20200328060520.31449-4-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code shows if this is ssd, it will jump to specific tag and skip the
following code for non-ssd.
Let's use "else if" to explicitly show the mutually exclusion for
ssd/non-ssd to reduce ambiguity.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20200328060520.31449-3-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
scan_swap_map_slots() is used to iterate swap_map[] array for an
available swap entry. While after several optimizations, e.g. for ssd
case, the logic of this function is a little not easy to catch.
This patchset tries to clean up the logic a little:
* shows the ssd/non-ssd case is handled mutually exclusively
* remove some unnecessary goto for ssd case
This patch (of 3):
When si->cluster_nr is zero, function would reach done and return. The
increased offset would not be used any more. This means we can move the
offset increment into the if clause.
This brings a further code cleanup possibility.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20200328060520.31449-1-richard.weiyang@gmail.com
Link: http://lkml.kernel.org/r/20200328060520.31449-2-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In unuse_pte_range() we blindly swap-in pages without checking if the
swap entry is already present in the swap cache.
By doing this, the hit/miss ratio used by the swap readahead heuristic
is not properly updated and this leads to non-optimal performance during
swapoff.
Tracing the distribution of the readahead size returned by the swap
readahead heuristic during swapoff shows that a small readahead size is
used most of the time as if we had only misses (this happens both with
cluster and vma readahead), for example:
r::swapin_nr_pages(unsigned long offset):unsigned long:$retval
COUNT EVENT
36948 $retval = 8
44151 $retval = 4
49290 $retval = 1
527771 $retval = 2
Checking if the swap entry is present in the swap cache, instead, allows
to properly update the readahead statistics and the heuristic behaves in a
better way during swapoff, selecting a bigger readahead size:
r::swapin_nr_pages(unsigned long offset):unsigned long:$retval
COUNT EVENT
1618 $retval = 1
4960 $retval = 2
41315 $retval = 4
103521 $retval = 8
In terms of swapoff performance the result is the following:
Testing environment
===================
- Host:
CPU: 1.8GHz Intel Core i7-8565U (quad-core, 8MB cache)
HDD: PC401 NVMe SK hynix 512GB
MEM: 16GB
- Guest (kvm):
8GB of RAM
virtio block driver
16GB swap file on ext4 (/swapfile)
Test case
=========
- allocate 85% of memory
- `systemctl hibernate` to force all the pages to be swapped-out to the
swap file
- resume the system
- measure the time that swapoff takes to complete:
# /usr/bin/time swapoff /swapfile
Result (swapoff time)
======
5.6 vanilla 5.6 w/ this patch
----------- -----------------
cluster-readahead 22.09s 12.19s
vma-readahead 18.20s 15.33s
Conclusion
==========
The specific use case this patch is addressing is to improve swapoff
performance in cloud environments when a VM has been hibernated, resumed
and all the memory needs to be forced back to RAM by disabling swap.
This change allows to better exploits the advantages of the readahead
heuristic during swapoff and this improvement allows to to speed up the
resume process of such VMs.
[andrea.righi@canonical.com: update changelog]
Link: http://lkml.kernel.org/r/20200418084705.GA147642@xps-13
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Anchal Agarwal <anchalag@amazon.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Vineeth Remanan Pillai <vpillai@digitalocean.com>
Cc: Kelley Nielsen <kelleynnn@gmail.com>
Link: http://lkml.kernel.org/r/20200416180132.GB3352@xps-13
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
"prev_offset" is a static variable in swapin_nr_pages() that can be
accessed concurrently with only mmap_sem held in read mode as noticed by
KCSAN,
BUG: KCSAN: data-race in swap_cluster_readahead / swap_cluster_readahead
write to 0xffffffff92763830 of 8 bytes by task 14795 on cpu 17:
swap_cluster_readahead+0x2a6/0x5e0
swapin_readahead+0x92/0x8dc
do_swap_page+0x49b/0xf20
__handle_mm_fault+0xcfb/0xd70
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x715
page_fault+0x34/0x40
1 lock held by (dnf)/14795:
#0: ffff897bd2e98858 (&mm->mmap_sem#2){++++}-{3:3}, at: do_page_fault+0x143/0x715
do_user_addr_fault at arch/x86/mm/fault.c:1405
(inlined by) do_page_fault at arch/x86/mm/fault.c:1535
irq event stamp: 83493
count_memcg_event_mm+0x1a6/0x270
count_memcg_event_mm+0x119/0x270
__do_softirq+0x365/0x589
irq_exit+0xa2/0xc0
read to 0xffffffff92763830 of 8 bytes by task 1 on cpu 22:
swap_cluster_readahead+0xfd/0x5e0
swapin_readahead+0x92/0x8dc
do_swap_page+0x49b/0xf20
__handle_mm_fault+0xcfb/0xd70
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x715
page_fault+0x34/0x40
1 lock held by systemd/1:
#0: ffff897c38f14858 (&mm->mmap_sem#2){++++}-{3:3}, at: do_page_fault+0x143/0x715
irq event stamp: 43530289
count_memcg_event_mm+0x1a6/0x270
count_memcg_event_mm+0x119/0x270
__do_softirq+0x365/0x589
irq_exit+0xa2/0xc0
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200402213748.2237-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use list_{prev,next}_entry() instead of list_entry() for better
code readability.
Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Baoquan He <bhe@redhat.com>
Link: http://lkml.kernel.org/r/1586599916-15456-2-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This code was using get_user_pages*(), in a "Case 2" scenario
(DMA/RDMA), using the categorization from [1]. That means that it's
time to convert the get_user_pages*() + put_page() calls to
pin_user_pages*() + unpin_user_pages() calls.
There is some helpful background in [2]: basically, this is a small part
of fixing a long-standing disconnect between pinning pages, and file
systems' use of those pages.
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: http://lkml.kernel.org/r/20200518012157.1178336-3-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce pin_user_pages_unlocked(), which is nearly identical to the
get_user_pages_unlocked() that it wraps, except that it sets FOLL_PIN
and rejects FOLL_GET.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: http://lkml.kernel.org/r/20200518012157.1178336-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is an attempt to update the documentation.
- Add/ remove extra * based on type of function static/global.
- Add description for functions and their input arguments.
[akpm@linux-foundation.org: s@/*@/**@]
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1588013630-4497-1-git-send-email-jrdr.linux@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After an NFS page has been written it is considered "unstable" until a
COMMIT request succeeds. If the COMMIT fails, the page will be
re-written.
These "unstable" pages are currently accounted as "reclaimable", either
in WB_RECLAIMABLE, or in NR_UNSTABLE_NFS which is included in a
'reclaimable' count. This might have made sense when sending the COMMIT
required a separate action by the VFS/MM (e.g. releasepage() used to
send a COMMIT). However now that all writes generated by ->writepages()
will automatically be followed by a COMMIT (since commit 919e3bd9a8
("NFS: Ensure we commit after writeback is complete")) it makes more
sense to treat them as writeback pages.
So this patch removes NR_UNSTABLE_NFS and accounts unstable pages in
NR_WRITEBACK and WB_WRITEBACK.
A particular effect of this change is that when
wb_check_background_flush() calls wb_over_bg_threshold(), the latter
will report 'true' a lot less often as the 'unstable' pages are no
longer considered 'dirty' (as there is nothing that writeback can do
about them anyway).
Currently wb_check_background_flush() will trigger writeback to NFS even
when there are relatively few dirty pages (if there are lots of unstable
pages), this can result in small writes going to the server (10s of
Kilobytes rather than a Megabyte) which hurts throughput. With this
patch, there are fewer writes which are each larger on average.
Where the NR_UNSTABLE_NFS count was included in statistics
virtual-files, the entry is retained, but the value is hard-coded as
zero. static trace points and warning printks which mentioned this
counter no longer report it.
[akpm@linux-foundation.org: re-layout comment]
[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: Michal Hocko <mhocko@suse.com> [mm]
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Link: http://lkml.kernel.org/r/87d06j7gqa.fsf@notabene.neil.brown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Christoph Hellwig