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mm, x86, pat: rework linear pfn-mmap tracking 

Replace the generic vma-flag VM_PFN_AT_MMAP with x86-only VM_PAT.

We can toss mapping address from remap_pfn_range() into
track_pfn_vma_new(), and collect all PAT-related logic together in
arch/x86/.

This patch also restores orignal frustration-free is_cow_mapping() check
in remap_pfn_range(), as it was before commit v2.6.28-rc8-88-g3c8bb73
("x86: PAT: store vm_pgoff for all linear_over_vma_region mappings - v3")

is_linear_pfn_mapping() checks can be removed from mm/huge_memory.c,
because it already handled by VM_PFNMAP in VM_NO_THP bit-mask.

[suresh.b.siddha@intel.com: Reset the VM_PAT flag as part of untrack_pfn_vma()]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Konstantin Khlebnikov 2012-10-08 16:28:34 -07:00 committed by Linus Torvalds
parent 5180da410d
commit b3b9c2932c
5 changed files with 30 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
arch/x86/mm/pat.c
View File

@ -677,7 +677,7 @@ int track_pfn_copy(struct vm_area_struct *vma)
unsigned long vma_size = vma->vm_end - vma->vm_start;
pgprot_t pgprot;
if (is_linear_pfn_mapping(vma)) {
if (vma->vm_flags & VM_PAT) {
/*
* reserve the whole chunk covered by vma. We need the
* starting address and protection from pte.
@ -699,14 +699,20 @@ int track_pfn_copy(struct vm_area_struct *vma)
* single reserve_pfn_range call.
*/
int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
unsigned long pfn, unsigned long size)
unsigned long pfn, unsigned long addr, unsigned long size)
{
resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT;
unsigned long flags;
/* reserve the whole chunk starting from paddr */
if (is_linear_pfn_mapping(vma))
return reserve_pfn_range(paddr, size, prot, 0);
if (addr == vma->vm_start && size == (vma->vm_end - vma->vm_start)) {
int ret;
ret = reserve_pfn_range(paddr, size, prot, 0);
if (!ret)
vma->vm_flags |= VM_PAT;
return ret;
}
if (!pat_enabled)
return 0;
@ -758,7 +764,7 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
resource_size_t paddr;
unsigned long prot;
if (!is_linear_pfn_mapping(vma))
if (!(vma->vm_flags & VM_PAT))
return;
/* free the chunk starting from pfn or the whole chunk */
@ -772,6 +778,7 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
size = vma->vm_end - vma->vm_start;
}
free_pfn_range(paddr, size);
vma->vm_flags &= ~VM_PAT;
}
pgprot_t pgprot_writecombine(pgprot_t prot)

6
include/asm-generic/pgtable.h
View File

@ -391,7 +391,8 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm,
* by remap_pfn_range() for physical range indicated by pfn and size.
*/
static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
unsigned long pfn, unsigned long size)
unsigned long pfn, unsigned long addr,
unsigned long size)
{
return 0;
}
@ -426,7 +427,8 @@ static inline void untrack_pfn(struct vm_area_struct *vma,
}
#else
extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
unsigned long pfn, unsigned long size);
unsigned long pfn, unsigned long addr,
unsigned long size);
extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
unsigned long pfn);
extern int track_pfn_copy(struct vm_area_struct *vma);

20
include/linux/mm.h
View File

@ -117,7 +117,7 @@ extern unsigned int kobjsize(const void *objp);
#define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */
#define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */
#define VM_SAO 0x20000000 /* Strong Access Ordering (powerpc) */
#define VM_PFN_AT_MMAP 0x40000000 /* PFNMAP vma that is fully mapped at mmap time */
#define VM_PAT 0x40000000 /* PAT reserves whole VMA at once (x86) */
#define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */
/* Bits set in the VMA until the stack is in its final location */
@ -158,24 +158,6 @@ extern pgprot_t protection_map[16];
#define FAULT_FLAG_RETRY_NOWAIT 0x10 /* Don't drop mmap_sem and wait when retrying */
#define FAULT_FLAG_KILLABLE 0x20 /* The fault task is in SIGKILL killable region */
/*
* This interface is used by x86 PAT code to identify a pfn mapping that is
* linear over entire vma. This is to optimize PAT code that deals with
* marking the physical region with a particular prot. This is not for generic
* mm use. Note also that this check will not work if the pfn mapping is
* linear for a vma starting at physical address 0. In which case PAT code
* falls back to slow path of reserving physical range page by page.
*/
static inline int is_linear_pfn_mapping(struct vm_area_struct *vma)
{
return !!(vma->vm_flags & VM_PFN_AT_MMAP);
}
static inline int is_pfn_mapping(struct vm_area_struct *vma)
{
return !!(vma->vm_flags & VM_PFNMAP);
}
/*
* vm_fault is filled by the the pagefault handler and passed to the vma's
* ->fault function. The vma's ->fault is responsible for returning a bitmask

19
mm/huge_memory.c
View File

@ -1655,11 +1655,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
if (vma->vm_ops)
/* khugepaged not yet working on file or special mappings */
return 0;
/*
* If is_pfn_mapping() is true is_learn_pfn_mapping() must be
* true too, verify it here.
*/
VM_BUG_ON(is_linear_pfn_mapping(vma) || vma->vm_flags & VM_NO_THP);
VM_BUG_ON(vma->vm_flags & VM_NO_THP);
hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
hend = vma->vm_end & HPAGE_PMD_MASK;
if (hstart < hend)
@ -1912,11 +1908,7 @@ static void collapse_huge_page(struct mm_struct *mm,
goto out;
if (is_vma_temporary_stack(vma))
goto out;
/*
* If is_pfn_mapping() is true is_learn_pfn_mapping() must be
* true too, verify it here.
*/
VM_BUG_ON(is_linear_pfn_mapping(vma) || vma->vm_flags & VM_NO_THP);
VM_BUG_ON(vma->vm_flags & VM_NO_THP);
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
@ -2154,12 +2146,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
goto skip;
if (is_vma_temporary_stack(vma))
goto skip;
/*
* If is_pfn_mapping() is true is_learn_pfn_mapping()
* must be true too, verify it here.
*/
VM_BUG_ON(is_linear_pfn_mapping(vma) ||
vma->vm_flags & VM_NO_THP);
VM_BUG_ON(vma->vm_flags & VM_NO_THP);
hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
hend = vma->vm_end & HPAGE_PMD_MASK;

26
mm/memory.c
View File

@ -1055,7 +1055,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
if (is_vm_hugetlb_page(vma))
return copy_hugetlb_page_range(dst_mm, src_mm, vma);
if (unlikely(is_pfn_mapping(vma))) {
if (unlikely(vma->vm_flags & VM_PFNMAP)) {
/*
* We do not free on error cases below as remove_vma
* gets called on error from higher level routine
@ -1327,7 +1327,7 @@ static void unmap_single_vma(struct mmu_gather *tlb,
if (vma->vm_file)
uprobe_munmap(vma, start, end);
if (unlikely(is_pfn_mapping(vma)))
if (unlikely(vma->vm_flags & VM_PFNMAP))
untrack_pfn(vma, 0, 0);
if (start != end) {
@ -2299,26 +2299,20 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
* There's a horrible special case to handle copy-on-write
* behaviour that some programs depend on. We mark the "original"
* un-COW'ed pages by matching them up with "vma->vm_pgoff".
* See vm_normal_page() for details.
*/
if (addr == vma->vm_start && end == vma->vm_end) {
if (is_cow_mapping(vma->vm_flags)) {
if (addr != vma->vm_start || end != vma->vm_end)
return -EINVAL;
vma->vm_pgoff = pfn;
vma->vm_flags |= VM_PFN_AT_MMAP;
} else if (is_cow_mapping(vma->vm_flags))
}
err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
if (err)
return -EINVAL;
vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
err = track_pfn_remap(vma, &prot, pfn, PAGE_ALIGN(size));
if (err) {
/*
* To indicate that track_pfn related cleanup is not
* needed from higher level routine calling unmap_vmas
*/
vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
vma->vm_flags &= ~VM_PFN_AT_MMAP;
return -EINVAL;
}
BUG_ON(addr >= end);
pfn -= addr >> PAGE_SHIFT;
pgd = pgd_offset(mm, addr);