* [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits
@ 2012-02-02 10:07 Jason Wang
2012-02-02 10:39 ` Glauber Costa
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Jason Wang @ 2012-02-02 10:07 UTC (permalink / raw)
To: netdev, jasowang, davem, linux-kernel, glommer; +Cc: mst
Commit 4acb4190 tries to fix the using uninitialized value
introduced by commit 3dc43e3, but it would make the
per-socket memory limits too small.
This patch fixes this and also remove the redundant codes
introduced in 4acb4190.
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
net/ipv4/sysctl_net_ipv4.c | 5 -----
net/ipv4/tcp.c | 4 ++--
2 files changed, 2 insertions(+), 7 deletions(-)
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 4cb9cd2..1eb8caa 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -815,11 +815,6 @@ static __net_init int ipv4_sysctl_init_net(struct net *net)
net->ipv4.sysctl_rt_cache_rebuild_count = 4;
tcp_init_mem(net);
- limit = nr_free_buffer_pages() / 8;
- limit = max(limit, 128UL);
- net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
- net->ipv4.sysctl_tcp_mem[1] = limit;
- net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
net->ipv4.ipv4_hdr = register_net_sysctl_table(net,
net_ipv4_ctl_path, table);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 06373b4..3a7514b 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3218,7 +3218,6 @@ __setup("thash_entries=", set_thash_entries);
void tcp_init_mem(struct net *net)
{
- /* Set per-socket limits to no more than 1/128 the pressure threshold */
unsigned long limit = nr_free_buffer_pages() / 8;
limit = max(limit, 128UL);
net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
@@ -3287,7 +3286,8 @@ void __init tcp_init(void)
sysctl_max_syn_backlog = max(128, cnt / 256);
tcp_init_mem(&init_net);
- limit = nr_free_buffer_pages() / 8;
+ /* Set per-socket limits to no more than 1/128 the pressure threshold */
+ limit = nr_free_buffer_pages() << (PAGE_SHIFT - 10);
limit = max(limit, 128UL);
max_share = min(4UL*1024*1024, limit);
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits
2012-02-02 10:07 [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits Jason Wang
@ 2012-02-02 10:39 ` Glauber Costa
2012-02-02 19:27 ` David Miller
2012-02-03 3:26 ` Jason Wang
2 siblings, 0 replies; 4+ messages in thread
From: Glauber Costa @ 2012-02-02 10:39 UTC (permalink / raw)
To: Jason Wang; +Cc: netdev, davem, linux-kernel, mst
On 02/02/2012 02:07 PM, Jason Wang wrote:
> Commit 4acb4190 tries to fix the using uninitialized value
> introduced by commit 3dc43e3, but it would make the
> per-socket memory limits too small.
>
> This patch fixes this and also remove the redundant codes
> introduced in 4acb4190.
>
> Signed-off-by: Jason Wang<jasowang@redhat.com>
Acked-by: Glauber Costa <glommer@parallels.com>
> ---
> net/ipv4/sysctl_net_ipv4.c | 5 -----
> net/ipv4/tcp.c | 4 ++--
> 2 files changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
> index 4cb9cd2..1eb8caa 100644
> --- a/net/ipv4/sysctl_net_ipv4.c
> +++ b/net/ipv4/sysctl_net_ipv4.c
> @@ -815,11 +815,6 @@ static __net_init int ipv4_sysctl_init_net(struct net *net)
> net->ipv4.sysctl_rt_cache_rebuild_count = 4;
>
> tcp_init_mem(net);
> - limit = nr_free_buffer_pages() / 8;
> - limit = max(limit, 128UL);
> - net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
> - net->ipv4.sysctl_tcp_mem[1] = limit;
> - net->ipv4.sysctl_tcp_mem[2] = net->ipv4.sysctl_tcp_mem[0] * 2;
>
> net->ipv4.ipv4_hdr = register_net_sysctl_table(net,
> net_ipv4_ctl_path, table);
Ok, this is indeed a good change, since we avoid initializing it twice.
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 06373b4..3a7514b 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -3218,7 +3218,6 @@ __setup("thash_entries=", set_thash_entries);
>
> void tcp_init_mem(struct net *net)
> {
> - /* Set per-socket limits to no more than 1/128 the pressure threshold */
> unsigned long limit = nr_free_buffer_pages() / 8;
> limit = max(limit, 128UL);
> net->ipv4.sysctl_tcp_mem[0] = limit / 4 * 3;
> @@ -3287,7 +3286,8 @@ void __init tcp_init(void)
> sysctl_max_syn_backlog = max(128, cnt / 256);
>
> tcp_init_mem(&init_net);
> - limit = nr_free_buffer_pages() / 8;
> + /* Set per-socket limits to no more than 1/128 the pressure threshold */
> + limit = nr_free_buffer_pages()<< (PAGE_SHIFT - 10);
> limit = max(limit, 128UL);
> max_share = min(4UL*1024*1024, limit);
Indeed, this ends up influencing the value of max_share used below to
initialize the other fields.
I like your change because now the limit variable is being set
independently between the global (now per-cgroup) and the per-socket
limits. (it previously was limit = sysctl_tcp_mem[1] << (PAGE_SHIFT-7))
So in the end, I personally think this is even clearer than what we had
before.
Acked-by: Glauber Costa <glommer@parallels.com>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits
2012-02-02 10:07 [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits Jason Wang
2012-02-02 10:39 ` Glauber Costa
@ 2012-02-02 19:27 ` David Miller
2012-02-03 3:26 ` Jason Wang
2 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2012-02-02 19:27 UTC (permalink / raw)
To: jasowang; +Cc: netdev, linux-kernel, glommer, mst
From: Jason Wang <jasowang@redhat.com>
Date: Thu, 02 Feb 2012 18:07:00 +0800
> Commit 4acb4190 tries to fix the using uninitialized value
> introduced by commit 3dc43e3, but it would make the
> per-socket memory limits too small.
>
> This patch fixes this and also remove the redundant codes
> introduced in 4acb4190.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Applied.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits
2012-02-02 10:07 [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits Jason Wang
2012-02-02 10:39 ` Glauber Costa
2012-02-02 19:27 ` David Miller
@ 2012-02-03 3:26 ` Jason Wang
2 siblings, 0 replies; 4+ messages in thread
From: Jason Wang @ 2012-02-03 3:26 UTC (permalink / raw)
To: Jason Wang; +Cc: netdev, davem, linux-kernel, glommer, mst
On 02/02/2012 06:07 PM, Jason Wang wrote:
> Commit 4acb4190 tries to fix the using uninitialized value
> introduced by commit 3dc43e3, but it would make the
> per-socket memory limits too small.
>
> This patch fixes this and also remove the redundant codes
> introduced in 4acb4190.
>
> Signed-off-by: Jason Wang<jasowang@redhat.com>
> ---
Just FYI, this fix the tcp performance regression, I test the virtio-net
tcp performance:
without this patch:
[root@amd-6168-8-1 net-next]# netperf -H 192.168.100.4 -t TCP_MAERTS
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.100.4
(192.168.100.4) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 10.00 5997.95
with this patch:
[root@amd-6168-8-1 net-next]# netperf -H 192.168.100.4 -t TCP_MAERTS
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.100.4
(192.168.100.4) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 10.00 9670.98
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-02-03 3:26 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-02-02 10:07 [v3.3-rc2+ PATCH] tcp: properly initialize tcp memory limits Jason Wang
2012-02-02 10:39 ` Glauber Costa
2012-02-02 19:27 ` David Miller
2012-02-03 3:26 ` Jason Wang
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).