android_kernel_motorola_sm6225/net/iucv
Eric Dumazet 87fb4b7b53 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>
2011-10-13 16:05:07 -04:00
..
af_iucv.c net: more accurate skb truesize 2011-10-13 16:05:07 -04:00
iucv.c iucv: introduce loadable iucv interface 2011-08-13 01:10:15 -07:00
Kconfig iucv: kernel option for z/VM IUCV and HiperSockets 2011-08-13 01:10:16 -07:00
Makefile [S390]: Add AF_IUCV socket support 2007-02-08 13:51:54 -08:00