From: Eric Dumazet Date: Wed, 22 Apr 2015 14:33:36 +0000 (-0700) Subject: net: do not deplete pfmemalloc reserve X-Git-Tag: v3.16.35~2295 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=dff9eb052112ca49c872f48d38a0aec7e6b2f3ed;p=thirdparty%2Fkernel%2Fstable.git net: do not deplete pfmemalloc reserve commit 79930f5892e134c6da1254389577fffb8bd72c66 upstream. 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 [ luis: backported to 3.16: used davem's backport to 3.14 ] Signed-off-by: Luis Henriques --- diff --git a/net/core/skbuff.c b/net/core/skbuff.c index fe07faaed2561..0f27eae2ccc10 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;