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93aaae2e01
linux/include
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Eric Dumazet 93aaae2e01 filter: optimize sk_run_filter 
Remove pc variable to avoid arithmetic to compute fentry at each filter
instruction. Jumps directly manipulate fentry pointer.

As the last instruction of filter[] is guaranteed to be a RETURN, and
all jumps are before the last instruction, we dont need to check filter
bounds (number of instructions in filter array) at each iteration, so we
remove it from sk_run_filter() params.

On x86_32 remove f_k var introduced in commit 57fe93b374
(filter: make sure filters dont read uninitialized memory)

Note : We could use a CONFIG_ARCH_HAS_{FEW|MANY}_REGISTERS in order to
avoid too many ifdefs in this code.

This helps compiler to use cpu registers to hold fentry and A
accumulator.

On x86_32, this saves 401 bytes, and more important, sk_run_filter()
runs much faster because less register pressure (One less conditional
branch per BPF instruction)

# size net/core/filter.o net/core/filter_pre.o
   text    data     bss     dec     hex filename
   2948       0       0    2948     b84 net/core/filter.o
   3349       0       0    3349     d15 net/core/filter_pre.o

on x86_64 :
# size net/core/filter.o net/core/filter_pre.o
   text    data     bss     dec     hex filename
   5173       0       0    5173    1435 net/core/filter.o
   5224       0       0    5224    1468 net/core/filter_pre.o

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-19 09:49:59 -08:00
..
acpi Merge branch 'misc' into release 2010-10-26 14:51:00 -04:00
asm-generic asm-generic/stat.h: support 64-bit file time_t for stat() 2010-11-01 15:31:29 -04:00
crypto Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
drm drm/ttm: Be consistent on ttm_bo_init() failures 2010-11-10 11:52:19 +10:00
keys
linux filter: optimize sk_run_filter 2010-11-19 09:49:59 -08:00
math-emu
media Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2010-10-28 09:35:11 -07:00
mtd mtd: Define MLC Flash as a different flash type 2010-10-25 00:50:20 +01:00
net net: use the macros defined for the members of flowi 2010-11-17 12:27:45 -08:00
pcmcia pcmcia: IOCARD is also required for using IRQs 2010-10-22 08:46:36 +02:00
rdma IB/core: Add VLAN support for IBoE 2010-10-25 10:20:39 -07:00
rxrpc
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2010-10-31 20:43:12 -04:00
sound Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6 2010-10-25 08:32:05 -07:00
trace ext4: Add new ext4 inode tracepoints 2010-11-08 13:51:33 -05:00
video Merge master.kernel.org:/pub/scm/linux/kernel/git/lethal/genesis-2.6 into devel-stable 2010-10-28 20:14:38 +01:00
xen Merge branch 'stable/xen-pcifront-0.8.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2010-10-28 17:11:17 -07:00
Kbuild