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| author | Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> | 2016-06-14 14:37:27 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-27 11:37:41 +0200 |
| commit | 0dceeaf599e6d9b8bd908ba4bd3dfee84aa26be2 (patch) | |
| tree | 901f7641d6bc6ed48fdffaee6f85f155e0fb8a07 | |
| parent | ebff09a6ff164aec2b33bf1f9a488c45ac108413 (diff) | |
| download | linux-0dceeaf599e6d9b8bd908ba4bd3dfee84aa26be2.tar.bz2 | |
locking/qspinlock: Use __this_cpu_dec() instead of full-blown this_cpu_dec()
queued_spin_lock_slowpath() should not worry about another
queued_spin_lock_slowpath() running in interrupt context and
changing node->count by accident, because node->count keeps
the same value every time we enter/leave queued_spin_lock_slowpath().
On some architectures this_cpu_dec() will save/restore irq flags,
which has high overhead. Use the much cheaper __this_cpu_dec() instead.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hpe.com
Link: http://lkml.kernel.org/r/1465886247-3773-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
[ Rewrote changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/locking/qspinlock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 730655533440..b2caec7315af 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -619,7 +619,7 @@ release: /* * release the node */ - this_cpu_dec(mcs_nodes[0].count); + __this_cpu_dec(mcs_nodes[0].count); } EXPORT_SYMBOL(queued_spin_lock_slowpath); |