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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-02-05 15:36:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-02-05 18:10:40 -0800
commit77bf45e78050790d8f7fc30b87a0ca674bf6265a (patch)
treea1f4de8b8eac57e9ba35f71d69aa0ae0e67dd277 /mm
parent564e81a57f9788b1475127012e0fd44e9049e342 (diff)
downloadlinux-linaro-stable-77bf45e78050790d8f7fc30b87a0ca674bf6265a.tar.gz
mempolicy: do not try to queue pages from !vma_migratable()
Maybe I miss some point, but I don't see a reason why we try to queue pages from non migratable VMAs. This testcase steps on VM_BUG_ON_PAGE() in isolate_lru_page(): #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <sys/mman.h> #include <numaif.h> #define SIZE 0x2000 int foo; int main() { int fd; char *p; unsigned long mask = 2; fd = open("/dev/sg0", O_RDWR); p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); /* Faultin pages */ foo = p[0] + p[0x1000]; mbind(p, SIZE, MPOL_BIND, &mask, 4, MPOL_MF_MOVE | MPOL_MF_STRICT); return 0; } The only case when we can queue pages from such VMA is MPOL_MF_STRICT plus MPOL_MF_MOVE or MPOL_MF_MOVE_ALL for VMA which has pages on LRU, but gfp mask is not sutable for migaration (see mapping_gfp_mask() check in vma_migratable()). That's looks like a bug to me. Let's filter out non-migratable vma at start of queue_pages_test_walk() and go to queue_pages_pte_range() only if MPOL_MF_MOVE or MPOL_MF_MOVE_ALL flag is set. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mempolicy.c14
1 files changed, 5 insertions, 9 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 27d135408a22..4c4187c0e1de 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -548,8 +548,7 @@ retry:
goto retry;
}
- if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
- migrate_page_add(page, qp->pagelist, flags);
+ migrate_page_add(page, qp->pagelist, flags);
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
@@ -625,7 +624,7 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
unsigned long endvma = vma->vm_end;
unsigned long flags = qp->flags;
- if (vma->vm_flags & VM_PFNMAP)
+ if (!vma_migratable(vma))
return 1;
if (endvma > end)
@@ -644,16 +643,13 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
if (flags & MPOL_MF_LAZY) {
/* Similar to task_numa_work, skip inaccessible VMAs */
- if (vma_migratable(vma) &&
- vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
+ if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
change_prot_numa(vma, start, endvma);
return 1;
}
- if ((flags & MPOL_MF_STRICT) ||
- ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
- vma_migratable(vma)))
- /* queue pages from current vma */
+ /* queue pages from current vma */
+ if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
return 0;
return 1;
}