linux/kernel/locking
Davidlohr Bueso d269a8b8c5 kernel/locking: Compute 'current' directly
This patch effectively replaces the tsk pointer dereference
(which is obviously == current), to directly use get_current()
macro. This is to make the removal of setting foreign task
states smoother and painfully obvious. Performance win on some
archs such as x86-64 and ppc64. On a microbenchmark that calls
set_task_state() vs set_current_state() and an inode rwsem
pounding benchmark doing unlink:

== 1. x86-64 ==

Avg runtime set_task_state():    601 msecs
Avg runtime set_current_state(): 552 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      36089.26 (  0.00%)    38977.33 (  8.00%)
Hmean    unlink1-processes-5      28555.01 (  0.00%)    29832.55 (  4.28%)
Hmean    unlink1-processes-8      37323.75 (  0.00%)    44974.57 ( 20.50%)
Hmean    unlink1-processes-12     43571.88 (  0.00%)    44283.01 (  1.63%)
Hmean    unlink1-processes-21     34431.52 (  0.00%)    38284.45 ( 11.19%)
Hmean    unlink1-processes-30     34813.26 (  0.00%)    37975.17 (  9.08%)
Hmean    unlink1-processes-48     37048.90 (  0.00%)    39862.78 (  7.59%)
Hmean    unlink1-processes-79     35630.01 (  0.00%)    36855.30 (  3.44%)
Hmean    unlink1-processes-110    36115.85 (  0.00%)    39843.91 ( 10.32%)
Hmean    unlink1-processes-141    32546.96 (  0.00%)    35418.52 (  8.82%)
Hmean    unlink1-processes-172    34674.79 (  0.00%)    36899.21 (  6.42%)
Hmean    unlink1-processes-203    37303.11 (  0.00%)    36393.04 ( -2.44%)
Hmean    unlink1-processes-224    35712.13 (  0.00%)    36685.96 (  2.73%)

== 2. ppc64le ==

Avg runtime set_task_state():  938 msecs
Avg runtime set_current_state: 940 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      19269.19 (  0.00%)    30704.50 ( 59.35%)
Hmean    unlink1-processes-5      20106.15 (  0.00%)    21804.15 (  8.45%)
Hmean    unlink1-processes-8      17496.97 (  0.00%)    17243.28 ( -1.45%)
Hmean    unlink1-processes-12     14224.15 (  0.00%)    17240.21 ( 21.20%)
Hmean    unlink1-processes-21     14155.66 (  0.00%)    15681.23 ( 10.78%)
Hmean    unlink1-processes-30     14450.70 (  0.00%)    15995.83 ( 10.69%)
Hmean    unlink1-processes-48     16945.57 (  0.00%)    16370.42 ( -3.39%)
Hmean    unlink1-processes-79     15788.39 (  0.00%)    14639.27 ( -7.28%)
Hmean    unlink1-processes-110    14268.48 (  0.00%)    14377.40 (  0.76%)
Hmean    unlink1-processes-141    14023.65 (  0.00%)    16271.69 ( 16.03%)
Hmean    unlink1-processes-172    13417.62 (  0.00%)    16067.55 ( 19.75%)
Hmean    unlink1-processes-203    15293.08 (  0.00%)    15440.40 (  0.96%)
Hmean    unlink1-processes-234    13719.32 (  0.00%)    16190.74 ( 18.01%)
Hmean    unlink1-processes-265    16400.97 (  0.00%)    16115.22 ( -1.74%)
Hmean    unlink1-processes-296    14388.60 (  0.00%)    16216.13 ( 12.70%)
Hmean    unlink1-processes-320    15771.85 (  0.00%)    15905.96 (  0.85%)

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-4-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-14 11:14:14 +01:00
..
lockdep_internals.h lockdep: Limit static allocations if PROVE_LOCKING_SMALL is defined 2016-11-18 11:33:19 -08:00
lockdep_proc.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
lockdep_states.h locking: Move the lockdep code to kernel/locking/ 2013-11-06 07:55:08 +01:00
lockdep.c xfs: updates for 4.10-rc1 2016-12-14 21:35:31 -08:00
locktorture.c lcoking/locktorture: Simplify the torture_runnable computation 2016-04-28 10:57:51 +02:00
Makefile locking/lglock: Remove lglock implementation 2016-09-22 15:25:56 +02:00
mcs_spinlock.h locking/core: Remove cpu_relax_lowlatency() users 2016-11-16 10:15:10 +01:00
mutex-debug.c locking/mutex: Rework mutex::owner 2016-10-25 11:31:50 +02:00
mutex-debug.h locking/mutex: Rework mutex::owner 2016-10-25 11:31:50 +02:00
mutex.c kernel/locking: Compute 'current' directly 2017-01-14 11:14:14 +01:00
mutex.h locking/mutex: Rework mutex::owner 2016-10-25 11:31:50 +02:00
osq_lock.c locking/osq: Break out of spin-wait busy waiting loop for a preempted vCPU in osq_lock() 2016-11-22 12:48:10 +01:00
percpu-rwsem.c locking/percpu-rwsem: Optimize readers and reduce global impact 2016-08-10 14:34:01 +02:00
qrwlock.c locking/core: Remove cpu_relax_lowlatency() users 2016-11-16 10:15:10 +01:00
qspinlock_paravirt.h locking/pvqspinlock: Don't wait if vCPU is preempted 2017-01-12 09:35:57 +01:00
qspinlock_stat.h don't open-code file_inode() 2016-12-04 18:29:28 -05:00
qspinlock.c locking/qspinlock: Use __this_cpu_dec() instead of full-blown this_cpu_dec() 2016-06-27 11:37:41 +02:00
rtmutex_common.h locking/rtmutex: Get rid of RT_MUTEX_OWNER_MASKALL 2016-12-02 11:13:57 +01:00
rtmutex-debug.c rtmutex: Cleanup deadlock detector debug logic 2014-06-21 22:05:30 +02:00
rtmutex-debug.h rtmutex: Cleanup deadlock detector debug logic 2014-06-21 22:05:30 +02:00
rtmutex.c locking/rtmutex: Explain locking rules for rt_mutex_proxy_unlock()/init_proxy_locked() 2016-12-02 11:13:57 +01:00
rtmutex.h rtmutex: Cleanup deadlock detector debug logic 2014-06-21 22:05:30 +02:00
rwsem-spinlock.c kernel/locking: Compute 'current' directly 2017-01-14 11:14:14 +01:00
rwsem-xadd.c kernel/locking: Compute 'current' directly 2017-01-14 11:14:14 +01:00
rwsem.c locking/rwsem: Add reader-owned state to the owner field 2016-06-08 15:16:59 +02:00
rwsem.h locking/rwsem: Protect all writes to owner by WRITE_ONCE() 2016-06-08 15:16:59 +02:00
semaphore.c kernel/locking: Compute 'current' directly 2017-01-14 11:14:14 +01:00
spinlock_debug.c locking: Move the spinlock code to kernel/locking/ 2013-11-06 07:55:21 +01:00
spinlock.c locking/spinlocks: Remove the unused spin_lock_bh_nested() API 2017-01-12 09:33:39 +01:00