lkml.org 
[lkml]   [2015]   [Jun]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 08/14] hrtimer: Allow hrtimer::function() to free the timer
On 06/08, Oleg Nesterov wrote:
>
> And I simply can not understand the complication in hrtimer_active(),
> please help!

Sorry for another off-topic email, but I don't even understand the
usage of hrtimer_active().

Say, do_nanosleep()

hrtimer_start_expires(&t->timer, mode);
if (!hrtimer_active(&t->timer))
t->task = NULL;

why? Assuming that hrtimer_active() is correct, it can only return
false if t->task was already cleared by hrtimer_wakeup().


OTOH. perf_cpu_hrtimer_restart() does

if (hrtimer_active(hr))
return;

if (!hrtimer_callback_running(hr))
__hrtimer_start_range_ns(...);

why it can't simply do

if (!hrtimer_active(hr)) // implies !hrtimer_callback_running()
__hrtimer_start_range_ns(...);


Confused.

Oleg.



\
 
 \ /
  Last update: 2015-06-08 01:21    [W:0.270 / U:0.124 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site