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Commit cdc4e86b authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 993db4b4

kernel/sched/cputime.c

+4 −6
Original line number Diff line number Diff line
@@ -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));

}