Introduce pagefault_{disable,enable}() and use these where previously we did
manual preempt increments/decrements to make the pagefault handler do the
atomic thing.
Currently they still rely on the increased preempt count, but do not rely on
the disabled preemption, this might go away in the future.
(NOTE: the extra barrier() in pagefault_disable might fix some holes on
machines which have too many registers for their own good)
[heiko.carstens@de.ibm.com: s390 fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a version of __get_user() which is safe to call inside mmap_sem.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use the x86 cache-bypassing copy instructions for copy_from_user().
Some performance data are
Total of GLOBAL_POWER_EVENTS (CPU cycle samples)
2.6.12.4.orig 1921587
2.6.12.4.nt 1599424
1599424/1921587=83.23% (16.77% reduction)
BSQ_CACHE_REFERENCE (L3 cache miss)
2.6.12.4.orig 57427
2.6.12.4.nt 20858
20858/57427=36.32% (63.7% reduction)
L3 cache miss reduction of __copy_from_user_ll
samples %
37408 65.1412 vmlinux __copy_from_user_ll
23 0.1103 vmlinux __copy_user_zeroing_intel_nocache
23/37408=0.061% (99.94% reduction)
Top 5 of 2.6.12.4.nt
Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000
samples % app name symbol name
128392 8.0274 vmlinux __copy_user_zeroing_intel_nocache
64206 4.0143 vmlinux journal_add_journal_head
59746 3.7355 vmlinux do_get_write_access
47674 2.9807 vmlinux journal_put_journal_head
46021 2.8774 vmlinux journal_dirty_metadata
pattern9-0-cpu4-0-09011728/summary.out
Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x3f (multiple flags) count 3000
samples % app name symbol name
69755 4.2861 vmlinux __copy_user_zeroing_intel_nocache
55685 3.4215 vmlinux journal_add_journal_head
52371 3.2179 vmlinux __find_get_block
45504 2.7960 vmlinux journal_put_journal_head
36005 2.2123 vmlinux journal_stop
pattern9-0-cpu4-0-09011744/summary.out
Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x200 (read 3rd level cache miss) count 3000
samples % app name symbol name
1147 5.4994 vmlinux journal_add_journal_head
881 4.2240 vmlinux journal_dirty_data
872 4.1809 vmlinux blk_rq_map_sg
734 3.5192 vmlinux journal_commit_transaction
617 2.9582 vmlinux radix_tree_delete
pattern9-0-cpu4-0-09011731/summary.out
iozone results are
original 2.6.12.4 CPU time = 207.768 sec
cache aware CPU time = 184.783 sec
(three times run)
184.783/207.768=88.94% (11.06% reduction)
original:
pattern9-0-cpu4-0-08191720/iozone.out: CPU Utilization: Wall time 45.997 CPU time 64.527 CPU utilization 140.28 %
pattern9-0-cpu4-0-08191741/iozone.out: CPU Utilization: Wall time 46.878 CPU time 71.933 CPU utilization 153.45 %
pattern9-0-cpu4-0-08191743/iozone.out: CPU Utilization: Wall time 45.152 CPU time 71.308 CPU utilization 157.93 %
cache awre:
pattern9-0-cpu4-0-09011728/iozone.out: CPU Utilization: Wall time 44.842 CPU time 62.465 CPU utilization 139.30 %
pattern9-0-cpu4-0-09011731/iozone.out: CPU Utilization: Wall time 44.718 CPU time 59.273 CPU utilization 132.55 %
pattern9-0-cpu4-0-09011744/iozone.out: CPU Utilization: Wall time 44.367 CPU time 63.045 CPU utilization 142.10 %
Signed-off-by: Hiro Yoshioka <hyoshiok@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Peter Zijlstra