Change tcp_mem initialization function. The fraction of total memory is now a continuous function of memory size, and independent of page size. Signed-off-by: John Heffner --- commit a4461a36efb376bf01399cfd6f1ad15dc89a8794 tree 23b2fb9da52b45de8008fc7ea6bb8c10e3a3724b parent 8b9909ded6922c33c221b105b26917780cfa497d author John Heffner Wed, 14 Mar 2007 17:15:06 -0400 committer John Heffner Wed, 14 Mar 2007 17:15:06 -0400 net/ipv4/tcp.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 74c4d10..3834b10 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2458,11 +2458,18 @@ void __init tcp_init(void) sysctl_max_syn_backlog = 128; } - /* Allow no more than 3/4 kernel memory (usually less) allocated to TCP */ - sysctl_tcp_mem[0] = (1536 / sizeof (struct inet_bind_hashbucket)) << order; - sysctl_tcp_mem[1] = sysctl_tcp_mem[0] * 4 / 3; + /* Set the pressure threshold to be a fraction of global memory that + * is up to 1/2 at 256 MB, decreasing toward zero with the amount of + * memory, with a floor of 128 pages. + */ + limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); + limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); + 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; + /* Set per-socket limits to no more than 1/128 the pressure threshold */ limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7); max_share = min(4UL*1024*1024, limit);