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authorLee Schermerhorn <lee.schermerhorn@hp.com>2012-10-25 16:16:30 +0400
committerMel Gorman <mgorman@suse.de>2012-12-11 18:42:41 +0400
commit771fb4d806a92bf6c988fcfbd286ae40a9374332 (patch)
treeda0070fcf99959e9519ad810133ecacc45d3a096 /include/linux
parentd3a710337b0590f43fd236d5e6518439afc7410a (diff)
downloadlinux-771fb4d806a92bf6c988fcfbd286ae40a9374332.tar.xz
mm: mempolicy: Check for misplaced page
This patch provides a new function to test whether a page resides on a node that is appropriate for the mempolicy for the vma and address where the page is supposed to be mapped. This involves looking up the node where the page belongs. So, the function returns that node so that it may be used to allocated the page without consulting the policy again. A subsequent patch will call this function from the fault path. Because of this, I don't want to go ahead and allocate the page, e.g., via alloc_page_vma() only to have to free it if it has the correct policy. So, I just mimic the alloc_page_vma() node computation logic--sort of. Note: we could use this function to implement a MPOL_MF_STRICT behavior when migrating pages to match mbind() mempolicy--e.g., to ensure that pages in an interleaved range are reinterleaved rather than left where they are when they reside on any page in the interleave nodemask. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> [ Added MPOL_F_LAZY to trigger migrate-on-fault; simplified code now that we don't have to bother with special crap for interleaved ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Mel Gorman <mgorman@suse.de>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/mempolicy.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index e5ccb9ddd90e..c511e2523560 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -198,6 +198,8 @@ static inline int vma_migratable(struct vm_area_struct *vma)
return 1;
}
+extern int mpol_misplaced(struct page *, struct vm_area_struct *, unsigned long);
+
#else
struct mempolicy {};
@@ -323,5 +325,11 @@ static inline int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol,
return 0;
}
+static inline int mpol_misplaced(struct page *page, struct vm_area_struct *vma,
+ unsigned long address)
+{
+ return -1; /* no node preference */
+}
+
#endif /* CONFIG_NUMA */
#endif