From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Peng Tao <bergwolf@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Oleg Drokin <oleg.drokin@intel.com>,
Andreas Dilger <andreas.dilger@intel.com>
Subject: Re: [PATCH RFC] sched: introduce add_wait_queue_exclusive_head
Date: Tue, 18 Mar 2014 16:47:24 +0100 [thread overview]
Message-ID: <20140318154724.GA5669@redhat.com> (raw)
In-Reply-To: <20140318140504.GD23193@laptop.programming.kicks-ass.net>
On 03/18, Peter Zijlstra wrote:
>
> I think we can avoid the entire function if we add
> WQ_FLAG_LIFO and make prepare_to_wait_event() DTRT.
Agreed, this looks very natural.
prepare_to_wait_event(WQ_FLAG_LIFO) should probably skip all "flags == 0"
entries before list_add(). Given that it is supposed that the users won't
mix exclusive and !exclusive, perhaps the additional list_for_each() won't
hurt?
> Then we only need to teach ___wait() about this; and I suppose we could
> make .exclusive=-1 be the LIFO flag.
Or we can change ___wait_event()
- if (exclusive) \
- __wait.flags = WQ_FLAG_EXCLUSIVE; \
- else \
- __wait.flags = 0; \
+ __wait.flags = exclusive; \
and obviously change the callers. Perhaps this argument should be renamed
then.
But I am fine either way, just I like the idea to extend the current
interface.
Oleg.
next prev parent reply other threads:[~2014-03-18 15:48 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-18 13:10 [PATCH RFC] sched: introduce add_wait_queue_exclusive_head Peng Tao
2014-03-18 13:33 ` Peter Zijlstra
2014-03-18 13:51 ` Peng Tao
2014-03-18 14:05 ` Peter Zijlstra
2014-03-18 14:44 ` Peng Tao
2014-03-18 16:23 ` Oleg Nesterov
2014-03-19 2:22 ` Peng Tao
2014-03-19 17:33 ` Oleg Nesterov
2014-03-19 19:44 ` Dilger, Andreas
2014-03-19 19:55 ` Peter Zijlstra
2014-03-20 7:06 ` Dilger, Andreas
2014-03-20 18:49 ` Oleg Nesterov
2014-03-18 15:47 ` Oleg Nesterov [this message]
2014-03-19 2:17 ` Peng Tao
[not found] ` <20140319164907.GA10113@redhat.com>
2014-03-19 16:57 ` Peter Zijlstra
2014-03-19 17:19 ` Oleg Nesterov
2014-03-20 17:51 ` [PATCH 0/2] wait: introduce WQ_FLAG_EXCLUSIVE_HEAD Oleg Nesterov
2014-03-20 17:51 ` [PATCH 1/2] wait: turn "bool exclusive" arg of __wait_event() into wflags Oleg Nesterov
2014-03-20 17:51 ` [PATCH 2/2] wait: introduce WQ_FLAG_EXCLUSIVE_HEAD Oleg Nesterov
2014-03-21 2:45 ` [PATCH 0/2] " Dilger, Andreas
2014-03-21 18:49 ` Oleg Nesterov
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