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net: attempt high order allocations in sock_alloc_send_pskb()

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Adding paged frags skbs to af_unix sockets introduced a performance
regression on large sends because of additional page allocations, even
if each skb could carry at least 100% more payload than before.

We can instruct sock_alloc_send_pskb() to attempt high order
allocations.

Most of the time, it does a single page allocation instead of 8.

I added an additional parameter to sock_alloc_send_pskb() to
let other users to opt-in for this new feature on followup patches.

Tested:

Before patch :

$ netperf -t STREAM_STREAM
STREAM STREAM TEST
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 2304  212992  212992    10.00    46861.15

After patch :

$ netperf -t STREAM_STREAM
STREAM STREAM TEST
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 2304  212992  212992    10.00    57981.11

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2013-08-08 14:38:47 -07:00 committed by David S. Miller
parent e370a72363
commit 28d6427109
6 changed files with 61 additions and 56 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/macvtap.c
View File

@ -524,7 +524,7 @@ static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
linear = len;
skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
err);
err, 0);
if (!skb)
return NULL;

2
drivers/net/tun.c
View File

@ -949,7 +949,7 @@ static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
linear = len;
skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
&err);
&err, 0);
if (!skb)
return ERR_PTR(err);

3
include/net/sock.h
View File

@ -1539,7 +1539,8 @@ extern struct sk_buff *sock_alloc_send_pskb(struct sock *sk,
unsigned long header_len,
unsigned long data_len,
int noblock,
int *errcode);
int *errcode,
int max_page_order);
extern void *sock_kmalloc(struct sock *sk, int size,
gfp_t priority);
extern void sock_kfree_s(struct sock *sk, void *mem, int size);

102
net/core/sock.c
View File

@ -1741,24 +1741,23 @@ static long sock_wait_for_wmem(struct sock *sk, long timeo)
struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
unsigned long data_len, int noblock,
int *errcode)
int *errcode, int max_page_order)
{
struct sk_buff *skb;
struct sk_buff *skb = NULL;
unsigned long chunk;
gfp_t gfp_mask;
long timeo;
int err;
int npages = (data_len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
struct page *page;
int i;
err = -EMSGSIZE;
if (npages > MAX_SKB_FRAGS)
goto failure;
gfp_mask = sk->sk_allocation;
if (gfp_mask & __GFP_WAIT)
gfp_mask |= __GFP_REPEAT;
timeo = sock_sndtimeo(sk, noblock);
while (1) {
while (!skb) {
err = sock_error(sk);
if (err != 0)
goto failure;
@ -1767,50 +1766,52 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
if (sk->sk_shutdown & SEND_SHUTDOWN)
goto failure;
if (atomic_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) {
skb = alloc_skb(header_len, gfp_mask);
if (skb) {
int i;
/* No pages, we're done... */
if (!data_len)
break;
skb->truesize += data_len;
skb_shinfo(skb)->nr_frags = npages;
for (i = 0; i < npages; i++) {
struct page *page;
page = alloc_pages(sk->sk_allocation, 0);
if (!page) {
err = -ENOBUFS;
skb_shinfo(skb)->nr_frags = i;
kfree_skb(skb);
goto failure;
}
__skb_fill_page_desc(skb, i,
page, 0,
(data_len >= PAGE_SIZE ?
PAGE_SIZE :
data_len));
data_len -= PAGE_SIZE;
}
/* Full success... */
break;
}
err = -ENOBUFS;
goto failure;
if (atomic_read(&sk->sk_wmem_alloc) >= sk->sk_sndbuf) {
set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
err = -EAGAIN;
if (!timeo)
goto failure;
if (signal_pending(current))
goto interrupted;
timeo = sock_wait_for_wmem(sk, timeo);
continue;
}
set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
err = -EAGAIN;
if (!timeo)
err = -ENOBUFS;
gfp_mask = sk->sk_allocation;
if (gfp_mask & __GFP_WAIT)
gfp_mask |= __GFP_REPEAT;
skb = alloc_skb(header_len, gfp_mask);
if (!skb)
goto failure;
if (signal_pending(current))
goto interrupted;
timeo = sock_wait_for_wmem(sk, timeo);
skb->truesize += data_len;
for (i = 0; npages > 0; i++) {
int order = max_page_order;
while (order) {
if (npages >= 1 << order) {
page = alloc_pages(sk->sk_allocation |
__GFP_COMP | __GFP_NOWARN,
order);
if (page)
goto fill_page;
}
order--;
}
page = alloc_page(sk->sk_allocation);
if (!page)
goto failure;
fill_page:
chunk = min_t(unsigned long, data_len,
PAGE_SIZE << order);
skb_fill_page_desc(skb, i, page, 0, chunk);
data_len -= chunk;
npages -= 1 << order;
}
}
skb_set_owner_w(skb, sk);
@ -1819,6 +1820,7 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
interrupted:
err = sock_intr_errno(timeo);
failure:
kfree_skb(skb);
*errcode = err;
return NULL;
}
@ -1827,7 +1829,7 @@ EXPORT_SYMBOL(sock_alloc_send_pskb);
struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
int noblock, int *errcode)
{
return sock_alloc_send_pskb(sk, size, 0, noblock, errcode);
return sock_alloc_send_pskb(sk, size, 0, noblock, errcode, 0);
}
EXPORT_SYMBOL(sock_alloc_send_skb);

2
net/packet/af_packet.c
View File

@ -2181,7 +2181,7 @@ static struct sk_buff *packet_alloc_skb(struct sock *sk, size_t prepad,
linear = len;
skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
err);
err, 0);
if (!skb)
return NULL;

6
net/unix/af_unix.c
View File

@ -1479,7 +1479,8 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
MAX_SKB_FRAGS * PAGE_SIZE);
skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
msg->msg_flags & MSG_DONTWAIT, &err);
msg->msg_flags & MSG_DONTWAIT, &err,
PAGE_ALLOC_COSTLY_ORDER);
if (skb == NULL)
goto out;
@ -1651,7 +1652,8 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
msg->msg_flags & MSG_DONTWAIT, &err);
msg->msg_flags & MSG_DONTWAIT, &err,
get_order(UNIX_SKB_FRAGS_SZ));
if (!skb)
goto out_err;