android_kernel_oneplus_msm8998/arch
Michel Lespinasse a31a369b07 x86 rwsem: avoid taking slow path when stealing write lock
modify __down_write[_nested] and __down_write_trylock to grab the write
lock whenever the active count is 0, even if there are queued waiters
(they must be writers pending wakeup, since the active count is 0).

Note that this is an optimization only; architectures without this
optimization will still work fine:

- __down_write() would take the slow path which would take the wait_lock
  and then try stealing the lock (as in the spinlocked rwsem implementation)

- __down_write_trylock() would fail, but callers must be ready to deal
  with that - since there are some writers pending wakeup, they could
  have raced with us and obtained the lock before we steal it.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-07 07:20:17 -07:00
..
alpha alpha: irq: remove deprecated use of IRQF_DISABLED 2013-04-07 12:59:30 -07:00
arc ARC: Add implicit compiler barrier to raw_local_irq* functions 2013-04-08 16:10:26 -07:00
arm ARM: arm-soc fixes for 3.9 2013-04-27 13:58:36 -07:00
arm64 Fix IS_ENABLED() usage typo (missing CONFIG_ prefix). 2013-03-28 13:45:49 -07:00
avr32 avr32: fix build error in atstk1006_defconfig 2013-04-17 16:10:44 -07:00
blackfin Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
c6x add memory barrier to arch_local_irq_restore 2013-04-09 15:35:46 -04:00
cris Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
frv Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
h8300 Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
hexagon Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
ia64 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-04-09 12:22:49 -07:00
m32r UAPI: fix endianness conditionals in M32R's asm/stat.h 2013-03-13 15:21:49 -07:00
m68k m68k: define a local gpio_request_one() function 2013-04-09 15:15:31 +10:00
metag metag: Inhibit NUMA balancing. 2013-03-04 10:29:19 +00:00
microblaze Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
mips Revert "MIPS: page.h: Provide more readable definition for PAGE_MASK." 2013-04-22 18:09:35 +02:00
mn10300 Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
openrisc openrisc: remove HAVE_VIRT_TO_BUS 2013-03-13 06:12:39 +01:00
parisc parisc: use spin_lock_irqsave/spin_unlock_irqrestore for PTE updates 2013-04-25 22:37:00 +02:00
powerpc Merge git://git.kernel.org/pub/scm/virt/kvm/kvm 2013-04-16 19:46:14 -07:00
s390 s390: move dummy io_remap_pfn_range() to asm/pgtable.h 2013-04-17 08:46:19 -07:00
score Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
sh hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sparc sparc64: Fix missing put_cpu_var() in tlb_batch_add_one() when not batching. 2013-04-24 16:52:18 -07:00
tile tile: comment assumption about __insn_mtspr for <asm/irqflags.h> 2013-04-09 10:08:14 -07:00
um um: Use tty_port in SIGWINCH handler 2013-03-11 10:08:04 +01:00
unicore32 Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
x86 x86 rwsem: avoid taking slow path when stealing write lock 2013-05-07 07:20:17 -07:00
xtensa Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00
.gitignore
Kconfig Select VIRT_TO_BUS directly where needed 2013-03-12 11:16:40 -07:00