diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2012-04-03 05:28:28 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-04-03 16:43:18 -0400 |
| commit | eb6a24816b247c0be6b2e97e68933072874bbe54 (patch) | |
| tree | c815981e955e9e32d1b9bd279bd18a358038e031 /net/unix | |
| parent | edbc0bb3fb72ec4645a242520cf1d0b9b6b02261 (diff) | |
| download | lwn-eb6a24816b247c0be6b2e97e68933072874bbe54.tar.gz lwn-eb6a24816b247c0be6b2e97e68933072874bbe54.zip | |
af_unix: reduce high order page allocations
unix_dgram_sendmsg() currently builds linear skbs, and this can stress
page allocator with high order page allocations. When memory gets
fragmented, this can eventually fail.
We can try to use order-2 allocations for skb head (SKB_MAX_ALLOC) plus
up to 16 page fragments to lower pressure on buddy allocator.
This patch has no effect on messages of less than 16064 bytes.
(on 64bit arches with PAGE_SIZE=4096)
For bigger messages (from 16065 to 81600 bytes), this patch brings
reliability at the expense of performance penalty because of extra pages
allocations.
netperf -t DG_STREAM -T 0,2 -- -m 16064 -s 200000
->4086040 Messages / 10s
netperf -t DG_STREAM -T 0,2 -- -m 16068 -s 200000
->3901747 Messages / 10s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/unix')
| -rw-r--r-- | net/unix/af_unix.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index d510353ef431..eadb9020cd64 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1442,6 +1442,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, long timeo; struct scm_cookie tmp_scm; int max_level; + int data_len = 0; if (NULL == siocb->scm) siocb->scm = &tmp_scm; @@ -1475,7 +1476,13 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, if (len > sk->sk_sndbuf - 32) goto out; - skb = sock_alloc_send_skb(sk, len, msg->msg_flags&MSG_DONTWAIT, &err); + if (len > SKB_MAX_ALLOC) + data_len = min_t(size_t, + len - SKB_MAX_ALLOC, + MAX_SKB_FRAGS * PAGE_SIZE); + + skb = sock_alloc_send_pskb(sk, len - data_len, data_len, + msg->msg_flags & MSG_DONTWAIT, &err); if (skb == NULL) goto out; @@ -1485,8 +1492,10 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, max_level = err + 1; unix_get_secdata(siocb->scm, skb); - skb_reset_transport_header(skb); - err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len); + skb_put(skb, len - data_len); + skb->data_len = data_len; + skb->len = len; + err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, len); if (err) goto out_free; |