net: sk_free_datagram() should use sk_mem_reclaim_partial()
commit270acefafeb74ce2fe93d35b75733870bf1e11e7
authorEric Dumazet <dada1@cosmosbay.com>
Wed, 5 Nov 2008 09:38:06 +0000 (5 01:38 -0800)
committerDavid S. Miller <davem@davemloft.net>
Wed, 5 Nov 2008 09:38:06 +0000 (5 01:38 -0800)
tree9368122a53b2834d2cd7894a1a316a9fde5d19ca
parentd99a7bd210a14001007fc5233597c78877f0a11c
net: sk_free_datagram() should use sk_mem_reclaim_partial()

I noticed a contention on udp_memory_allocated on regular UDP applications.

While tcp_memory_allocated is seldom used, it appears each incoming UDP frame
is currently touching udp_memory_allocated when queued, and when received by
application.

One possible solution is to use sk_mem_reclaim_partial() instead of
sk_mem_reclaim(), so that we keep a small reserve (less than one page)
of memory for each UDP socket.

We did something very similar on TCP side in commit
9993e7d313e80bdc005d09c7def91903e0068f07
([TCP]: Do not purge sk_forward_alloc entirely in tcp_delack_timer())

A more complex solution would need to convert prot->memory_allocated to
use a percpu_counter with batches of 64 or 128 pages.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/datagram.c