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sched/cputime: Convert vtime_seqlock to seqcount

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The cputime can only be updated by the current task itself, even in
vtime case. So we can safely use seqcount instead of seqlock as there
is no writer concurrency involved.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1447948054-28668-8-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Frederic Weisbecker
2015-11-19 16:47:34 +01:00
committed by Ingo Molnar
parent e592539466
commit b7ce2277f0
4 changed files with 27 additions and 25 deletions
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2
include/linux/sched.h
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@@ -1519,7 +1519,7 @@ struct task_struct {
cputime_t gtime;
struct prev_cputime prev_cputime;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
seqlock_t vtime_seqlock;
seqcount_t vtime_seqcount;
unsigned long long vtime_snap;
enum {
/* Task is sleeping or running in a CPU with VTIME inactive */