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| author |  Waiman Long <Waiman.Long@hpe.com>
| 2015-11-09 19:09:23 -0500 |
|---|---|---|
| committer |  Ingo Molnar <mingo@kernel.org>
| 2015-11-23 10:02:00 +0100 |
| commit | aa68744f80bfb6f26fbe7f10e42876066f7dac1b (patch) | |
| tree | 1346f724cd714045744db3c49c6b859b10c3b1a3 /kernel/locking/qspinlock_paravirt.h | |
| parent | locking/qspinlock: Prefetch the next node cacheline (diff) | |
| download | linux-aa68744f80bfb6f26fbe7f10e42876066f7dac1b.tar.gz linux-aa68744f80bfb6f26fbe7f10e42876066f7dac1b.tar.bz2 linux-aa68744f80bfb6f26fbe7f10e42876066f7dac1b.zip | |
locking/qspinlock: Avoid redundant read of next pointer
With optimistic prefetch of the next node cacheline, the next pointer
may have been properly inititalized. As a result, the reading
of node->next in the contended path may be redundant. This patch
eliminates the redundant read if the next pointer value is not NULL.
Signed-off-by: Waiman Long <Waiman.Long@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1447114167-47185-4-git-send-email-Waiman.Long@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/qspinlock_paravirt.h')
0 files changed, 0 insertions, 0 deletions