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linux-2.6
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linux-2.6/drivers/isdn
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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
..
act2000 isdn: Free irq_data namespace 2010-10-04 11:00:55 +02:00
capi convert get_sb_single() users 2010-10-29 04:16:28 -04:00
divert isdn: potential buffer overflows 2010-09-06 18:29:18 -07:00
gigaset isdn/gigaset: improve bas_gigaset USB error reporting 2010-10-01 00:33:37 -07:00
hardware drivers/isdn: Remove unnecessary semicolons 2010-11-15 11:06:17 -08:00
hisax drivers/isdn/hisax: Add printf format/argument verification and fix fallout 2010-11-17 10:58:22 -08:00
hysdn drivers: isdn: remove custom strtoul() 2010-07-15 19:05:25 -07:00
i4l filter: optimize sk_run_filter 2010-11-19 09:49:59 -08:00
icn include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
isdnloop include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
mISDN drivers/isdn/mISDN: Use printf extension %pV 2010-11-16 10:22:58 -08:00
pcbit drivers/isdn: Use static const char * const where possible 2010-09-14 20:22:02 -07:00
sc isdn: strcpy() => strlcpy() 2010-10-08 10:21:22 -07:00
Kconfig isdn: fix a few Kconfig imperfections 2010-02-22 15:45:53 -08:00
Makefile mISDN fix main ISDN Makefile 2008-08-02 16:28:20 +02:00