net: refine {udp|tcp|sctp}_mem limits
Current tcp/udp/sctp global memory limits are not taking into account
hugepages allocations, and allow 50% of ram to be used by buffers of a
single protocol [ not counting space used by sockets / inodes ...]
Lets use nr_free_buffer_pages() and allow a default of 1/8 of kernel ram
per protocol, and a minimum of 128 pages.
Heavy duty machines sysadmins probably need to tweak limits anyway.
References: https://bugzilla.stlinux.com/show_bug.cgi?id=38032
Reported-by: starlight <starlight@binnacle.cx>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 67380a2..207175b 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1058,7 +1058,6 @@
int status = -EINVAL;
unsigned long goal;
unsigned long limit;
- unsigned long nr_pages;
int max_share;
int order;
@@ -1148,15 +1147,7 @@
/* Initialize handle used for association ids. */
idr_init(&sctp_assocs_id);
- /* 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.
- * Note this initializes the data in sctpv6_prot too
- * Unabashedly stolen from tcp_init
- */
- nr_pages = totalram_pages - totalhigh_pages;
- limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
- limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
+ limit = nr_free_buffer_pages() / 8;
limit = max(limit, 128UL);
sysctl_sctp_mem[0] = limit / 4 * 3;
sysctl_sctp_mem[1] = limit;