Messages in this thread |  | | Subject | Re: [PATCH 1/3] sched, timer: Remove usages of ACCESS_ONCE in the scheduler | From | Jason Low <> | Date | Wed, 15 Apr 2015 19:29:01 -0700 |
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On Tue, 2015-04-14 at 22:40 -0400, Steven Rostedt wrote: > You are correct. Now I'm thinking that the WRITE_ONCE() is not needed, > and just a: > > p->mm->numa_scan_seq = READ_ONCE(p->numa_scan_seq) + 1;
Just to confirm, is this a typo? Because there really is a numa_scan_seq in the task_struct itself too :)
p->mm->numa_scan_seq is read in task_numa_placement() with ACCESS_ONCE(), and so the benefit that I do see with it is that it makes it consistent by doing the updates with ACCESS_ONCE too (for documentation purposes).
If that's really the case:
WRITE_ONCE(p->mm->numa_scan_seq, p->mm->numa_scan_seq + 1)
should be enough for that.
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