Messages in this thread | | | Subject | Re: [PATCH] sched: remove rcu_read_lock from wake_affine | From | Peter Zijlstra <> | Date | Tue, 07 Jun 2011 12:26:51 +0200 |
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On Tue, 2011-06-07 at 15:43 +0530, Nikunj A. Dadhania wrote: > wake_affine is called from one path: select_task_rq_fair, which already has > rcu read lock held. > > Signed-off-by: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com> > --- > kernel/sched_fair.c | 3 +-- > 1 files changed, 1 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c > index 354e26b..0bfec93 100644 > --- a/kernel/sched_fair.c > +++ b/kernel/sched_fair.c > @@ -1461,6 +1461,7 @@ static inline unsigned long effective_load(struct task_group *tg, int cpu, > > #endif > > +/* Assumes rcu_read_lock is held */
Not a big fan of such comments, esp with CONFIG_PROVE_RCU its better to use those facilities, which is to say: if we're missing a rcu_read_lock() the thing will yell bloody murder.
> static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) > { > s64 this_load, load; > @@ -1481,7 +1482,6 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) > * effect of the currently running task from the load > * of the current CPU: > */ > - rcu_read_lock(); > if (sync) { > tg = task_group(current); > weight = current->se.load.weight; > @@ -1517,7 +1517,6 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) > balanced = this_eff_load <= prev_eff_load; > } else > balanced = true; > - rcu_read_unlock(); > > /* > * If the currently running task will sleep within >
OK, took the patch and removed the comment, thanks!
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