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authorEric Dumazet <edumazet@google.com>2015-04-22 07:33:36 -0700
committerJiri Slaby <jslaby@suse.cz>2015-04-30 13:28:09 +0200
commitbdcfb6f23733c64c4514ae0820899a7866700659 (patch)
treee1bd8559285009dada2cf4cb329b6c7e875ff778 /net
parent90a176dc03dc495e17a34edb12bade9ce481d238 (diff)
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 <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 17313d17a923..d354bb277539 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -308,7 +308,11 @@ 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;
@@ -351,7 +355,8 @@ 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;