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authorEric Dumazet <edumazet@google.com>2015-05-15 12:39:30 -0700
committerDavid S. Miller <davem@davemloft.net>2015-05-17 22:45:49 -0400
commitb66e91ccbc34ebd5a2f90f9e1bc1597e2924a500 (patch)
tree13db6cdf2a7ff4f841f3ec44b5700a8e9af1b361 /net/ipv4/tcp.c
parent76dfa6082032b5c179864816fa508879421678eb (diff)
tcp: halves tcp_mem[] limits
Allowing tcp to use ~19% of physical memory is way too much, and allowed bugs to be hidden. Add to this that some drivers use a full page per incoming frame, so real cost can be twice the advertized one. Reduce tcp_mem by 50 % as a first step to sanity. tcp_mem[0,1,2] defaults are now 4.68%, 6.25%, 9.37% of physical memory. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
-rw-r--r--net/ipv4/tcp.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9eabfd3e0925..c724195e5862 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3068,11 +3068,12 @@ __setup("thash_entries=", set_thash_entries);
static void __init tcp_init_mem(void)
{
- unsigned long limit = nr_free_buffer_pages() / 8;
+ unsigned long limit = nr_free_buffer_pages() / 16;
+
limit = max(limit, 128UL);
- sysctl_tcp_mem[0] = limit / 4 * 3;
- sysctl_tcp_mem[1] = limit;
- sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
+ sysctl_tcp_mem[0] = limit / 4 * 3; /* 4.68 % */
+ sysctl_tcp_mem[1] = limit; /* 6.25 % */
+ sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; /* 9.37 % */
}
void __init tcp_init(void)