From c93bdd0e03e848555d144eb44a1f275b871a8dd5 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 31 Jul 2012 16:44:19 -0700 Subject: netvm: allow skb allocation to use PFMEMALLOC reserves Change the skb allocation API to indicate RX usage and use this to fall back to the PFMEMALLOC reserve when needed. SKBs allocated from the reserve are tagged in skb->pfmemalloc. If an SKB is allocated from the reserve and the socket is later found to be unrelated to page reclaim, the packet is dropped so that the memory remains available for page reclaim. Network protocols are expected to recover from this packet loss. [a.p.zijlstra@chello.nl: Ideas taken from various patches] [davem@davemloft.net: Use static branches, coding style corrections] [sebastian@breakpoint.cc: Avoid unnecessary cast, fix !CONFIG_NET build] Signed-off-by: Mel Gorman Acked-by: David S. Miller Cc: Neil Brown Cc: Peter Zijlstra Cc: Mike Christie Cc: Eric B Munson Cc: Eric Dumazet Cc: Sebastian Andrzej Siewior Cc: Mel Gorman Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- net/core/sock.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index 3617f65..c8c5816 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -271,6 +271,9 @@ __u32 sysctl_rmem_default __read_mostly = SK_RMEM_MAX; int sysctl_optmem_max __read_mostly = sizeof(unsigned long)*(2*UIO_MAXIOV+512); EXPORT_SYMBOL(sysctl_optmem_max); +struct static_key memalloc_socks = STATIC_KEY_INIT_FALSE; +EXPORT_SYMBOL_GPL(memalloc_socks); + /** * sk_set_memalloc - sets %SOCK_MEMALLOC * @sk: socket to set it on @@ -283,6 +286,7 @@ void sk_set_memalloc(struct sock *sk) { sock_set_flag(sk, SOCK_MEMALLOC); sk->sk_allocation |= __GFP_MEMALLOC; + static_key_slow_inc(&memalloc_socks); } EXPORT_SYMBOL_GPL(sk_set_memalloc); @@ -290,6 +294,7 @@ void sk_clear_memalloc(struct sock *sk) { sock_reset_flag(sk, SOCK_MEMALLOC); sk->sk_allocation &= ~__GFP_MEMALLOC; + static_key_slow_dec(&memalloc_socks); } EXPORT_SYMBOL_GPL(sk_clear_memalloc); -- cgit v1.1