Re: [Bugme-new] [Bug 38032] New: default values of /proc/sys/net/ipv4/udp_mem does not consider huge page allocation
From: Eric Dumazet <hidden>
Date: 2011-07-07 04:38:19
Also in:
linux-mm
Subsystem:
networking [general], networking [tcp], sctp protocol, the rest, user datagram protocol (udp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Marcelo Ricardo Leitner, Xin Long, Linus Torvalds, Willem de Bruijn
Lets use following patch ?
[PATCH] 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 <redacted>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eric Dumazet <redacted>
---
net/ipv4/tcp.c | 10 ++--------
net/ipv4/udp.c | 10 ++--------
net/sctp/protocol.c | 11 +----------
3 files changed, 5 insertions(+), 26 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 054a59d..46febca 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c@@ -3220,7 +3220,7 @@ __setup("thash_entries=", set_thash_entries); void __init tcp_init(void) { struct sk_buff *skb = NULL; - unsigned long nr_pages, limit; + unsigned long limit; int i, max_share, cnt; unsigned long jiffy = jiffies;
@@ -3277,13 +3277,7 @@ void __init tcp_init(void) sysctl_tcp_max_orphans = cnt / 2; sysctl_max_syn_backlog = max(128, cnt / 256); - /* 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. - */ - 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_tcp_mem[0] = limit / 4 * 3; sysctl_tcp_mem[1] = limit;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 48cd88e..198f75b 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c@@ -2209,16 +2209,10 @@ void __init udp_table_init(struct udp_table *table, const char *name) void __init udp_init(void) { - unsigned long nr_pages, limit; + unsigned long limit; udp_table_init(&udp_table, "UDP"); - /* Set the pressure threshold up by the same strategy of TCP. It is 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. - */ - 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_udp_mem[0] = limit / 4 * 3; sysctl_udp_mem[1] = limit;
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 @@ SCTP_STATIC __init int sctp_init(void) int status = -EINVAL; unsigned long goal; unsigned long limit; - unsigned long nr_pages; int max_share; int order;
@@ -1148,15 +1147,7 @@ SCTP_STATIC __init int sctp_init(void) /* 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; --
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