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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-10-13 07:28:54 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-10-13 16:05:07 -0400 |
| commit | 87fb4b7b533073eeeaed0b6bf7c2328995f6c075 (patch) | |
| tree | be4b37f08d7fe2d018ae68bae4577b1b2bafd0fc /net/core/sock.c | |
| parent | 97ba0eb64ca690165f945a83e609102fcefa99cb (diff) | |
| download | blackbird-op-linux-87fb4b7b533073eeeaed0b6bf7c2328995f6c075.tar.gz blackbird-op-linux-87fb4b7b533073eeeaed0b6bf7c2328995f6c075.zip | |
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/core/sock.c')
| -rw-r--r-- | net/core/sock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index 83c462d3f451..5a087626bb3a 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -207,7 +207,7 @@ static struct lock_class_key af_callback_keys[AF_MAX]; * not depend upon such differences. */ #define _SK_MEM_PACKETS 256 -#define _SK_MEM_OVERHEAD (sizeof(struct sk_buff) + 256) +#define _SK_MEM_OVERHEAD SKB_TRUESIZE(256) #define SK_WMEM_MAX (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS) #define SK_RMEM_MAX (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS) |
