lkml.org 
[lkml]   [2015]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/5] sched/deadline: Remove cpu_active_mask from cpudl_find()
On Mon, Jan 19, 2015 at 04:49:37AM +0000, Xunlei Pang wrote:
> cpu_active_mask is rarely changeable, so remove this operation
> to gain a little performance.
>
> If there is a change in cpu_active_mask, rq_online_dl() and
> rq_offline_dl() should take care of it normally, so cpudl::
> free_cpus carries enough information for us.
>
> For the rare case(causing a task put onto a dying cpu) which
> rq_offline_dl() can't handle timely, then it can be handled
> through _cpu_down()->...->multi_cpu_stop()->migration_call()
> ->migrate_tasks(), preventing the task from hanging on the
> dead cpu.

Maybe; I'll need to go crawl through the long and twisted history of
active_mask here :/


\
 
 \ /
  Last update: 2015-01-27 16:21    [W:0.128 / U:1.956 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site