From d810156278d9b5fe9b1034da3fce1a28219ab9ee Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 22 Apr 2015 07:33:36 -0700 Subject: net: do not deplete pfmemalloc reserve [ Upstream commit 79930f5892e134c6da1254389577fffb8bd72c66 ] build_skb() should look at the page pfmemalloc status. If set, this means page allocator allocated this page in the expectation it would help to free other pages. Networking stack can do that only if skb->pfmemalloc is also set. Also, we must refrain using high order pages from the pfmemalloc reserve, so __page_frag_refill() must also use __GFP_NOMEMALLOC for them. Under memory pressure, using order-0 pages is probably the best strategy. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/skbuff.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index e2b1bba69882..8334c7048bbd 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -309,7 +309,11 @@ struct sk_buff *build_skb(void *data, unsigned int frag_size) memset(skb, 0, offsetof(struct sk_buff, tail)); skb->truesize = SKB_TRUESIZE(size); - skb->head_frag = frag_size != 0; + if (frag_size) { + skb->head_frag = 1; + if (virt_to_head_page(data)->pfmemalloc) + skb->pfmemalloc = 1; + } atomic_set(&skb->users, 1); skb->head = data; skb->data = data; @@ -352,7 +356,8 @@ refill: gfp_t gfp = gfp_mask; if (order) - gfp |= __GFP_COMP | __GFP_NOWARN; + gfp |= __GFP_COMP | __GFP_NOWARN | + __GFP_NOMEMALLOC; nc->frag.page = alloc_pages(gfp, order); if (likely(nc->frag.page)) break; -- cgit v1.2.3