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authorMel Gorman <mgorman@suse.de>2012-07-31 16:44:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 18:42:46 -0700
commitc93bdd0e03e848555d144eb44a1f275b871a8dd5 (patch)
tree8aff3bc2b9ff9f32e51040a7652bfb31257db626 /net/core/sock.c
parent7cb0240492caea2f6467f827313478f41877e6ef (diff)
downloadblackbird-op-linux-c93bdd0e03e848555d144eb44a1f275b871a8dd5.tar.gz
blackbird-op-linux-c93bdd0e03e848555d144eb44a1f275b871a8dd5.zip
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 <mgorman@suse.de> Acked-by: David S. Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net/core/sock.c')
-rw-r--r--net/core/sock.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 3617f652f6b0..c8c5816289fe 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);
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