net: do not deplete pfmemalloc reserve
authorEric Dumazet <edumazet@google.com>
Wed, 22 Apr 2015 14:33:36 +0000 (07:33 -0700)
committerDavid S. Miller <davem@davemloft.net>
Wed, 22 Apr 2015 20:24:59 +0000 (16:24 -0400)
commit79930f5892e134c6da1254389577fffb8bd72c66
tree6a6b4cf89527383ae541fdd797d90dfc2e07c69f
parent26349c71b4323e62f8de0fe45f2f06c4df535b9b
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>
net/core/skbuff.c