tcp: properly initialize tcp memory limits

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 4cb9cd2f2c390fc14289f918da8098af0549f5f2..7a7724da9bff61eb51cb2ad70f8a92c135f1dcfa 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -778,7 +778,6 @@ EXPORT_SYMBOL_GPL(net_ipv4_ctl_path);
 static __net_init int ipv4_sysctl_init_net(struct net *net)
 {
        struct ctl_table *table;
-       unsigned long limit;
 
        table = ipv4_net_table;
        if (!net_eq(net, &init_net)) {
@@ -815,11 +814,6 @@ 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 a34f5cfdd44c25bcfd7dfc8af4037454c65c946d..37755ccc0e96d8da1b36e0c43e695b0f0a6431e4 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3229,7 +3229,6 @@ __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;
@@ -3298,7 +3297,8 @@ 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);