linux-kernel - Re: [PATCH] use round_jiffies() for slow work thread pool's 5 second cull timer

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Date:	Sun, 10 May 2009 12:38:46 -0700
From:	Chris Peterson <cpeterso@...terso.com>
To:	Richard Kennedy <richard@....demon.co.uk>
Cc:	dhowells@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] use round_jiffies() for slow work thread pool's 5 second 
	cull timer

Yes, you are correct. I misread how round_jiffies_relative() worked.

chris


On Sun, May 10, 2009 at 7:23 AM, Richard Kennedy
<richard@....demon.co.uk> wrote:
> Chris Peterson wrote:
>> The slow work thread pool culls its idle threads after 5 seconds without any work requests. Also, the slow work thread pool waits 5 seconds before starting new threads after OOM.
>>
>> This patch uses round_jiffies() to round these 5 second timers to whole seconds. In this case, the actual timer wait would be between 4.75 and 5.75 seconds (because round_jiffies() rounds < 0.25 seconds down and > 0.25 seconds up). This patch also refactors the mod_timer() logic into a separate helper function.
>>
>> Signed-off-by: Chris Peterson <cpeterso@...terso.com>
>> ---
>> diff --git a/kernel/slow-work.c b/kernel/slow-work.c
>> index b28d191..9bfcb53 100644
>> --- a/kernel/slow-work.c
>> +++ b/kernel/slow-work.c
>> @@ -318,6 +318,12 @@ cant_get_ref:
>>  }
>>  EXPORT_SYMBOL(slow_work_enqueue);
>>
>> +static void slow_work_defer_cull_time(void)
>> +{
>> +     mod_timer(&slow_work_cull_timer,
>> +                       round_jiffies_relative(SLOW_WORK_CULL_TIMEOUT));
>> +}
>> +
> Hi Chris,
>
> Doesn't mod_timer take an absolute time not a relative one?
>
> So I think this should be
>
>        mod_timer(&timer,round_jiffies(jiffies + TIMEOUT) );
>
> regards
>
> Richard
>
>
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