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authorJohn Heffner <jheffner@psc.edu>2007-04-17 14:44:06 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2007-05-01 17:05:58 -0700
commit3300bb14330a902331bcdfd0f69d9b0945585c51 (patch)
tree397559e112690338579d82e55da2e91f343271cc
parent979a764e6449e9f9b73d7a9fa84d8e2e5bc65729 (diff)
Fix errors in tcp_mem[] calculations.
In 2.6.18 a change was made to the tcp_mem[] calculations, but this causes regressions for some folks up to 2.6.20 The following fix to smooth out the calculation from the pending 2.6.21 tree by John Heffner fixes the problem for these folks. [TCP]: Fix tcp_mem[] initialization. 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 <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/ipv4/tcp.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ebe9d0d238fd..4a71b310f9a6 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2457,11 +2457,18 @@ 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);