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cputime: Remove irqsave from seqlock readers

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The reader side code has no requirement to disable interrupts while
sampling data. The sequence counter is enough to ensure consistency.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner 2013-02-15 23:47:07 +01:00 committed by Ingo Molnar
parent 993db4b45f
commit cdc4e86b58
1 changed files with 4 additions and 6 deletions
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10
kernel/sched/cputime.c
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@ -729,18 +729,17 @@ void vtime_init_idle(struct task_struct *t)
cputime_t task_gtime(struct task_struct *t) cputime_t task_gtime(struct task_struct *t)
{ {
unsigned long flags;
unsigned int seq; unsigned int seq;
cputime_t gtime; cputime_t gtime;
do { do {
seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags); seq = read_seqbegin(&t->vtime_seqlock);
gtime = t->gtime; gtime = t->gtime;
if (t->flags & PF_VCPU) if (t->flags & PF_VCPU)
gtime += vtime_delta(t); gtime += vtime_delta(t);
} while (read_seqretry_irqrestore(&t->vtime_seqlock, seq, flags)); } while (read_seqretry(&t->vtime_seqlock, seq));
return gtime; return gtime;
} }
@ -756,7 +755,6 @@ fetch_task_cputime(struct task_struct *t,
cputime_t *u_src, cputime_t *s_src, cputime_t *u_src, cputime_t *s_src,
cputime_t *udelta, cputime_t *sdelta) cputime_t *udelta, cputime_t *sdelta)
{ {
unsigned long flags;
unsigned int seq; unsigned int seq;
unsigned long long delta; unsigned long long delta;
@ -764,7 +762,7 @@ fetch_task_cputime(struct task_struct *t,
*udelta = 0; *udelta = 0;
*sdelta = 0; *sdelta = 0;
seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags); seq = read_seqbegin(&t->vtime_seqlock);
if (u_dst) if (u_dst)
*u_dst = *u_src; *u_dst = *u_src;
@ -788,7 +786,7 @@ fetch_task_cputime(struct task_struct *t,
if (t->vtime_snap_whence == VTIME_SYS) if (t->vtime_snap_whence == VTIME_SYS)
*sdelta = delta; *sdelta = delta;
} }
} while (read_seqretry_irqrestore(&t->vtime_seqlock, seq, flags)); } while (read_seqretry(&t->vtime_seqlock, seq));
} }