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>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9eabfd3..c724195 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3068,11 +3068,12 @@
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)