>From 691a961bb401c5815ed741dac63591efbc6027e3 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Date: Fri, 29 Jan 2016 15:06:17 +0300
Subject: [PATCH 2/2] 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.
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@xxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 14 +++++---------
1 file 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;
}
--
2.7.0.rc3
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