cputime: Remove irqsave from seqlock readers

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>

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index ccff275..9857329 100644 (file)
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -729,18 +729,17 @@ void vtime_init_idle(struct task_struct *t)
 
 cputime_t task_gtime(struct task_struct *t)
 {
-       unsigned long flags;
        unsigned int seq;
        cputime_t gtime;
 
        do {
-               seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags);
+               seq = read_seqbegin(&t->vtime_seqlock);
 
                gtime = t->gtime;
                if (t->flags & PF_VCPU)
                        gtime += vtime_delta(t);
 
-       } while (read_seqretry_irqrestore(&t->vtime_seqlock, seq, flags));
+       } while (read_seqretry(&t->vtime_seqlock, seq));
 
        return gtime;
 }
@@ -756,7 +755,6 @@ fetch_task_cputime(struct task_struct *t,
                   cputime_t *u_src, cputime_t *s_src,
                   cputime_t *udelta, cputime_t *sdelta)
 {
-       unsigned long flags;
        unsigned int seq;
        unsigned long long delta;
 
@@ -764,7 +762,7 @@ fetch_task_cputime(struct task_struct *t,
                *udelta = 0;
                *sdelta = 0;
 
-               seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags);
+               seq = read_seqbegin(&t->vtime_seqlock);
 
                if (u_dst)
                        *u_dst = *u_src;
@@ -788,7 +786,7 @@ fetch_task_cputime(struct task_struct *t,
                        if (t->vtime_snap_whence == VTIME_SYS)
                                *sdelta = delta;
                }
-       } while (read_seqretry_irqrestore(&t->vtime_seqlock, seq, flags));
+       } while (read_seqretry(&t->vtime_seqlock, seq));
 }