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authorEric Dumazet <eric.dumazet@gmail.com>2011-10-13 07:28:54 +0000
committerDavid S. Miller <davem@davemloft.net>2011-10-13 16:05:07 -0400
commit87fb4b7b533073eeeaed0b6bf7c2328995f6c075 (patch)
treebe4b37f08d7fe2d018ae68bae4577b1b2bafd0fc /net/sctp
parent97ba0eb64ca690165f945a83e609102fcefa99cb (diff)
net: more accurate skb truesize
skb truesize currently accounts for sk_buff struct and part of skb head. kmalloc() roundings are also ignored. Considering that skb_shared_info is larger than sk_buff, its time to take it into account for better memory accounting. This patch introduces SKB_TRUESIZE(X) macro to centralize various assumptions into a single place. At skb alloc phase, we put skb_shared_info struct at the exact end of skb head, to allow a better use of memory (lowering number of reallocations), since kmalloc() gives us power-of-two memory blocks. Unless SLUB/SLUB debug is active, both skb->head and skb_shared_info are aligned to cache lines, as before. Note: This patch might trigger performance regressions because of misconfigured protocol stacks, hitting per socket or global memory limits that were previously not reached. But its a necessary step for a more accurate memory accounting. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Andi Kleen <ak@linux.intel.com> CC: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/protocol.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 91784f44a2e..61b9fca5a17 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1299,7 +1299,7 @@ SCTP_STATIC __init int sctp_init(void)
max_share = min(4UL*1024*1024, limit);
sysctl_sctp_rmem[0] = SK_MEM_QUANTUM; /* give each asoc 1 page min */
- sysctl_sctp_rmem[1] = (1500 *(sizeof(struct sk_buff) + 1));
+ sysctl_sctp_rmem[1] = 1500 * SKB_TRUESIZE(1);
sysctl_sctp_rmem[2] = max(sysctl_sctp_rmem[1], max_share);
sysctl_sctp_wmem[0] = SK_MEM_QUANTUM;