lkml.org 
[lkml]   [2012]   [Aug]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 4/7] workqueue: single pass rebind_workers
On 08/28/2012 03:04 AM, Tejun Heo wrote:
> Hello, Lai.
>
> On Tue, Aug 28, 2012 at 01:58:24AM +0800, Lai Jiangshan wrote:
>> busy_worker_rebind_fn() can't return until all idle workers are rebound,
>> the code of busy_worker_rebind_fn() ensure this.
>>
>> So we can change the order of the code of rebind_workers(),
>> and make it a single pass do the rebind_workers().
>>
>> It makes the code much clean and better readability.
>
> I can't see how this could be correct.

Could you elaborate more why it is not correct.

> What prevents busy worker from
> grabbing manager_mutex before idle one?
>

busy worker still has WORKER_REBIND when it enter busy_worker_rebind_fn(),
so it can sleep(include grab the manager_mutex). When this mutex_lock()
returns, it means rebind_workers() are done which means all idle are rebound
and can be locally woken up. So busy worker can return from busy_worker_rebind_fn()
and handle other possible-sleeping items.

If the CPU is offline again, the busy worker has WORKER_UNBOUND, it is also correct
when it returns from busy_worker_rebind_fn().


\
 
 \ /
  Last update: 2012-08-29 05:01    [W:0.119 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site