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authorMel Gorman <mgorman@suse.de>2012-07-31 16:44:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 18:42:46 -0700
commitc48a11c7ad2623b99bbd6859b0b4234e7f11176f (patch)
tree5937aa7e5679761d516431de3be4cb9c4f81f350 /include
parentc93bdd0e03e848555d144eb44a1f275b871a8dd5 (diff)
netvm: propagate page->pfmemalloc to skb
The skb->pfmemalloc flag gets set to true iff during the slab allocation of data in __alloc_skb that the the PFMEMALLOC reserves were used. If the packet is fragmented, it is possible that pages will be allocated from the PFMEMALLOC reserve without propagating this information to the skb. This patch propagates page->pfmemalloc from pages allocated for fragments to the skb. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: David S. Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/skbuff.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0336f02e366..b814bb8fd5a 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1247,6 +1247,17 @@ static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
{
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ /*
+ * Propagate page->pfmemalloc to the skb if we can. The problem is
+ * that not all callers have unique ownership of the page. If
+ * pfmemalloc is set, we check the mapping as a mapping implies
+ * page->index is set (index and pfmemalloc share space).
+ * If it's a valid mapping, we cannot use page->pfmemalloc but we
+ * do not lose pfmemalloc information as the pages would not be
+ * allocated using __GFP_MEMALLOC.
+ */
+ if (page->pfmemalloc && !page->mapping)
+ skb->pfmemalloc = true;
frag->page.p = page;
frag->page_offset = off;
skb_frag_size_set(frag, size);