lkml.org 
[lkml]   [2017]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] sched/swait: allow swake_up() to return
On Fri, Nov 10, 2017 at 03:10:17PM +0800, Peter Xu wrote:
> I came to this when reading kvm_vcpu_wake_up(), so that only affects
> some statistic which may not be that critical. However I don't know
> whether there would be any other real use case that we would like to
> know exactly whether a call to [s]wake_up() has really done something
> or just returned with a NOP.
>
> Anyway, please let me know if you think the same change to wake_up()
> would be meaningful, otherwise I can drop this patch and post another
> KVM-only one to clean up the redundant callers of swait_active(),
> since even if we dropped that list check in 35a2897c2a30, we'll do
> that again in swake_up_locked().

See commits:

8cd641e3c7cb ("sched/wait: Add swq_has_sleeper()")
5e0018b3e39e ("kvm: Serialize wq active checks in kvm_vcpu_wake_up()")


In any case, I don't think we want the change you propose. The numbers
don't mean much and there's no point in making all the callers in the
kernel slower for it.

\
 
 \ /
  Last update: 2017-11-10 09:06    [W:0.043 / U:0.376 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site