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authorEric Dumazet <edumazet@google.com>2015-04-22 07:33:36 -0700
committerDavid S. Miller <davem@davemloft.net>2015-04-22 16:24:59 -0400
commit79930f5892e134c6da1254389577fffb8bd72c66 (patch)
tree6a6b4cf89527383ae541fdd797d90dfc2e07c69f
parent26349c71b4323e62f8de0fe45f2f06c4df535b9b (diff)
downloadlinux-79930f5892e134c6da1254389577fffb8bd72c66.tar.gz
net: do not deplete pfmemalloc reserve
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>
-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 d1967dab9cc6..456ead534e10 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -311,7 +311,11 @@ 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;
@@ -348,7 +352,8 @@ static struct page *__page_frag_refill(struct netdev_alloc_cache *nc,
gfp_t gfp = gfp_mask;
if (order) {
- gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY;
+ gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
+ __GFP_NOMEMALLOC;
page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, order);
nc->frag.size = PAGE_SIZE << (page ? order : 0);
}