Linus Torvalds 8e3e076c5a BKL: revert back to the old spinlock implementation ... The generic semaphore rewrite had a huge performance regression on AIM7 (and potentially other BKL-heavy benchmarks) because the generic semaphores had been rewritten to be simple to understand and fair. The latter, in particular, turns a semaphore-based BKL implementation into a mess of scheduling. The attempt to fix the performance regression failed miserably (see the previous commit 00b41ec261 'Revert "semaphore: fix"'), and so for now the simple and sane approach is to instead just go back to the old spinlock-based BKL implementation that never had any issues like this. This patch also has the advantage of being reported to fix the regression completely according to Yanmin Zhang, unlike the semaphore hack which still left a couple percentage point regression. As a spinlock, the BKL obviously has the potential to be a latency issue, but it's not really any different from any other spinlock in that respect. We do want to get rid of the BKL asap, but that has been the plan for several years. These days, the biggest users are in the tty layer (open/release in particular) and Alan holds out some hope: "tty release is probably a few months away from getting cured - I'm afraid it will almost certainly be the very last user of the BKL in tty to get fixed as it depends on everything else being sanely locked." so while we're not there yet, we do have a plan of action. Tested-by: Yanmin Zhang <yanmin_zhang@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Andi Kleen <andi@firstfloor.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Alexander Viro <viro@ftp.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2008-05-10 20:58:02 -07:00
..
lzo	lzo: fix typo in decompressor	2008-04-10 15:34:05 -07:00
reed_solomon	lib: Remove unnecessary inclusions of asm/semaphore.h	2008-04-18 22:17:17 -04:00
zlib_deflate	lib/: Spelling fixes	2008-02-03 17:48:52 +02:00
zlib_inflate	[ZLIB]: Fix external builds of zlib_inflate code.	2007-10-11 22:17:20 -07:00
.gitignore	Add some basic .gitignore files	2005-10-18 08:26:15 -07:00
argv_split.c	LIB: Replace inappropriate include of <linux/bug.h>	2007-10-20 00:26:10 +02:00
audit.c	[PATCH] audit signal recipients	2007-05-11 05:38:25 -04:00
bitmap.c	mempolicy: add bitmap_onto() and bitmap_fold() operations	2008-04-28 08:58:19 -07:00
bitrev.c	[PATCH] add MODULE_* attributes to bit reversal library	2006-12-10 10:07:52 -08:00
bug.c	generic bug: use show_regs() instead of dump_stack()	2007-07-16 09:05:51 -07:00
bust_spinlocks.c	handle recursive calls to bust_spinlocks()	2007-10-17 08:42:56 -07:00
check_signature.c	uninline check_signature()	2007-07-16 09:05:50 -07:00
cmdline.c	[PATCH] Numerous fixes to kernel-doc info in source files.	2007-02-11 10:51:32 -08:00
cpumask.c	Safer nr_node_ids and nr_node_ids determination and initial values	2007-05-07 12:12:51 -07:00
crc7.c	CRC7 support	2007-07-17 10:23:04 -07:00
crc16.c	[PATCH] kernel-doc for lib/crc*.c	2006-06-25 10:01:20 -07:00
crc32.c	lib/: Spelling fixes	2008-02-03 17:48:52 +02:00
crc32defs.h
crc-ccitt.c	[PATCH] kernel-doc for lib/crc*.c	2006-06-25 10:01:20 -07:00
crc-itu-t.c	CRC ITU-T V.41	2007-05-10 18:24:13 +02:00
ctype.c
debug_locks.c	[PATCH] lockdep: better lock debugging	2006-07-03 15:27:01 -07:00
debugobjects.c	infrastructure to debug (dynamic) objects	2008-04-30 08:29:53 -07:00
dec_and_lock.c	[PATCH] atomic: dec_and_lock use atomic primitives	2006-01-08 20:13:48 -08:00
devres.c	[POWERPC] devres: Add devm_ioremap_prot()	2008-05-05 16:47:14 +10:00
div64.c	rename div64_64 to div64_u64	2008-05-01 08:03:58 -07:00
dump_stack.c
extable.c	lib/extable.c: remove an expensive integer divide in search_extable()	2008-02-06 10:41:08 -08:00
fault-inject.c	libfs: allow error return from simple attributes	2008-02-08 09:22:34 -08:00
find_next_bit.c	bitops: remove "optimizations"	2008-04-29 08:11:16 -07:00
gen_crc32table.c
genalloc.c	Slab allocators: Replace explicit zeroing with __GFP_ZERO	2007-07-17 10:23:02 -07:00
halfmd4.c
hexdump.c	hexdump: don't print bytes with bit 7 set	2007-11-29 09:24:53 -08:00
hweight.c	remove asm/bitops.h includes	2007-10-19 11:53:41 -07:00
idr.c	idr: fix idr_remove()	2008-05-01 08:04:00 -07:00
inflate.c	lib/inflate.c: handle failed malloc()	2008-04-29 08:06:02 -07:00
int_sqrt.c	[PATCH] lib: Fix bug in int_sqrt() for 64 bit longs	2006-02-03 08:32:08 -08:00
iomap_copy.c	[PATCH] add __iowrite64_copy	2006-06-20 20:24:58 -07:00
iomap.c	iomap: fix 64 bits resources on 32 bits	2008-04-29 08:06:02 -07:00
iommu-helper.c	iommu: export iommu_is_span_boundary helper function	2008-03-04 16:35:17 -08:00
ioremap.c	lib/ioremap.c should #include <linux/io.h>	2007-10-17 08:42:50 -07:00
irq_regs.c	[PATCH] irq_reqs: export __irq_regs	2006-10-06 08:53:40 -07:00
kasprintf.c	lib: move kasprintf to a separate file	2007-07-31 15:39:39 -07:00
Kconfig	x86, bitops: select the generic bitmap search functions	2008-04-26 19:21:17 +02:00
Kconfig.debug	debugobjects: add timer specific object debugging code	2008-04-30 08:29:53 -07:00
Kconfig.kgdb	kgdb: kconfig fix xconfig/menuconfig element	2008-05-05 07:13:21 -05:00
kernel_lock.c	BKL: revert back to the old spinlock implementation	2008-05-10 20:58:02 -07:00
klist.c	klist: fix coding style errors in klist.h and klist.c	2008-04-30 16:52:58 -07:00
kobject_uevent.c	lib: replace remaining __FUNCTION__ occurrences	2008-04-30 08:29:54 -07:00
kobject.c	kobject: do not copy vargs, just pass them around	2008-04-30 16:52:48 -07:00
kref.c	kref: add kref_set()	2008-01-24 20:40:05 -08:00
libcrc32c.c	[LIB] crc32c: Keep intermediate crc state in cpu order	2007-11-08 21:34:09 +08:00
list_debug.c	[PATCH] More list debugging context	2006-12-07 08:39:35 -08:00
lmb.c	[POWERPC] Provide walk_memory_resource() for powerpc	2008-04-29 15:57:53 +10:00
locking-selftest-hardirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-mutex.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-rlock-hardirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-rlock-softirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-rlock.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-rsem.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-softirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-spin-hardirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-spin-softirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-spin.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-wlock-hardirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-wlock-softirq.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-wlock.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest-wsem.h	[PATCH] lockdep: locking API self tests	2006-07-03 15:27:03 -07:00
locking-selftest.c	[PATCH] lockdep: show more details about self-test failures	2006-12-07 08:39:43 -08:00
Makefile	infrastructure to debug (dynamic) objects	2008-04-30 08:29:53 -07:00
parser.c	[AFS]: Make the match_*() functions take const options.	2007-05-03 03:10:39 -07:00
percpu_counter.c	mm: bdi: export BDI attributes in sysfs	2008-04-30 08:29:49 -07:00
plist.c	[PATCH] pi-futex: add plist implementation	2006-06-27 17:32:46 -07:00
prio_heap.c	Fix cpusets update_cpumask	2007-10-19 11:53:41 -07:00
prio_tree.c
proportions.c	mm: bdi: allow setting a maximum for the bdi dirty limit	2008-04-30 08:29:50 -07:00
radix-tree.c	Remove set_migrateflags()	2008-04-28 08:58:17 -07:00
random32.c	[NET]: srandom32 fixes for networking v2	2008-04-03 14:07:02 -07:00
ratelimit.c	isolate ratelimit from printk.c for other use	2008-04-29 08:06:06 -07:00
rbtree.c	[PATCH] rbtree: fixed reversed RB_EMPTY_NODE and rb_next/prev	2006-09-30 20:26:56 +02:00
reciprocal_div.c	[PATCH] SLAB: use a multiply instead of a divide in obj_to_index()	2006-12-13 09:05:49 -08:00
rwsem-spinlock.c	lib: remove fastcall from lib/*	2008-02-08 09:22:31 -08:00
rwsem.c	x86: fix UML and -regparm=3	2008-01-30 13:33:00 +01:00
scatterlist.c	[SCSI] block: add sg buffer copy helper functions	2008-04-07 12:15:45 -05:00
sha1.c	[PATCH] Numerous fixes to kernel-doc info in source files.	2007-02-11 10:51:32 -08:00
smp_processor_id.c	debug_smp_processor_id() fixlets	2008-02-06 10:41:09 -08:00
sort.c	lib/sort.c optimization	2007-10-17 08:42:52 -07:00
spinlock_debug.c	Use helpers to obtain task pid in printks	2007-10-19 11:53:43 -07:00
string.c	Add a new sysfs_streq() string comparison function	2008-05-01 08:03:59 -07:00
swiotlb.c	dma/ia64: update ia64 machvecs, swiotlb.c	2008-04-29 08:06:12 -07:00
textsearch.c	[TEXTSEARCH]: Do not allow zero length patterns in the textsearch infrastructure	2007-12-01 00:03:52 +11:00
ts_bm.c	[TEXTSEARCH]: Fix Boyer Moore initialization bug	2006-08-22 14:33:58 -07:00
ts_fsm.c	[PATCH] lib/ts_fsm.c: constify structs	2006-09-29 09:18:23 -07:00
ts_kmp.c	Remove obsolete #include <linux/config.h>	2006-06-30 19:25:36 +02:00
vsprintf.c	lib/vsprintf.c: fix bug omitting minus sign of numbers (module_param)	2008-02-23 17:12:14 -08:00