[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <alpine.LFD.2.11.1505090910060.1671@ja.home.ssi.bg>
Date: Sat, 9 May 2015 11:49:01 +0300 (EEST)
From: Julian Anastasov <ja@....bg>
To: Peter Zijlstra <peterz@...radead.org>
cc: Ingo Molnar <mingo@...nel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Oleg Nesterov <oleg@...hat.com>, linux-kernel@...r.kernel.org,
neilb@...e.de
Subject: Re: [PATCH] sched: Introduce TASK_NOLOAD and TASK_IDLE
Hello,
On Fri, 8 May 2015, Peter Zijlstra wrote:
> Subject: sched: Introduce TASK_NOLOAD and TASK_IDLE
> From: Peter Zijlstra <peterz@...radead.org>
> Date: Fri May 8 14:23:45 CEST 2015
>
> Currently people use TASK_INTERRUPTIBLE to idle kthreads and wait for
> 'work' because TASK_UNINTERRUPTIBLE contributes to the loadavg. Having
> all idle kthreads contribute to the loadavg is somewhat silly.
>
> Now mostly this works OK, because kthreads have all their signals
> masked. However there's a few sites where this is causing problems and
> TASK_UNINTERRUPTIBLE should be used, except for that loadavg issue.
>
> This patch adds TASK_NOLOAD which, when combined with
> TASK_UNINTERRUPTIBLE avoids the loadavg accounting.
>
> As most of imagined usage sites are loops where a thread wants to
> idle, waiting for work, a helper TASK_IDLE is introduced.
After checking our code in net/netfilter/ipvs/ip_vs_sync.c,
sync_thread_master(), we may also need some wrappers:
- schedule_timeout_idle (instead of schedule_timeout call):
__set_current_state(TASK_IDLE);
return schedule_timeout(timeout);
- we here are really idle, so "N" looks ok
- pair of __wait_event_idle(wq, condition) and
wait_event_idle(wq, condition) macros
- we here are write-blocked for socket, not sure
if this blocked vs idle difference is useful to
represent, in new bit for this blocked state "B"=2048,
with 2 TASK_NOLOAD variants: N(idle) and B(blocked,
2|1024|2048, eg. for read-blocked or write-blocked).
It will need additional argument 'state'/'blocked' for
*wait_event_idle().
Regards
--
Julian Anastasov <ja@....bg>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists