From: Andrew Morton <akpm@osdl.org>
To: Paul Jackson <pj@sgi.com>
Cc: torvalds@osdl.org, Simon.Derr@bull.net, pj@sgi.com,
linux-kernel@vger.kernel.org, nikita@clusterfs.com
Subject: Re: [PATCH] cpuset semaphore depth check optimize
Date: Mon, 12 Sep 2005 04:39:43 -0700 [thread overview]
Message-ID: <20050912043943.5795d8f8.akpm@osdl.org> (raw)
In-Reply-To: <20050912113030.15934.9433.sendpatchset@jackhammer.engr.sgi.com>
Paul Jackson <pj@sgi.com> wrote:
>
> +static struct task_struct *cpuset_sem_owner;
> +static int cpuset_sem_depth;
>
> /*
> * The global cpuset semaphore cpuset_sem can be needed by the
> @@ -200,16 +202,19 @@ static DECLARE_MUTEX(cpuset_sem);
>
> static inline void cpuset_down(struct semaphore *psem)
> {
> - if (current->cpuset_sem_nest_depth == 0)
> + if (cpuset_sem_owner != current) {
> down(psem);
> - current->cpuset_sem_nest_depth++;
> + cpuset_sem_owner = current;
> + }
> + cpuset_sem_depth++;
> }
Better, but still hacky. The rest of the kernel manages to avoid the need
for nestable semaphores by getting the locking design sorted out. Can
cpusets do that sometime?
next prev parent reply other threads:[~2005-09-12 11:41 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-12 11:30 Paul Jackson
2005-09-12 11:39 ` Andrew Morton [this message]
2005-09-12 14:38 ` Linus Torvalds
2005-09-12 15:32 ` Paul Jackson
[not found] ` <17189.39100.862561.865802@gargle.gargle.HOWL>
2005-09-12 15:38 ` Paul Jackson
2005-09-13 7:04 ` Ingo Molnar
2005-09-13 22:21 ` Paul Jackson
2005-09-12 14:51 ` Paul Jackson
2005-09-12 17:07 ` Roman Zippel
[not found] ` <20050912153135.3812d8e2.pj@sgi.com>
2005-09-13 11:42 ` Roman Zippel
2005-09-13 17:37 ` Paul Jackson
2005-09-14 6:01 ` Paul Jackson
2005-09-14 15:56 ` Roman Zippel
2005-09-14 19:46 ` Paul Jackson
2005-09-15 10:51 ` Roman Zippel
2005-09-15 17:45 ` Paul Jackson
2005-09-15 19:18 ` Paul Jackson
2005-09-17 2:06 ` Roman Zippel
2005-09-17 2:27 ` Roman Zippel
2005-09-20 7:57 ` Paul Jackson
2005-09-20 12:05 ` Robin Holt
2005-09-20 12:21 ` Robin Holt
2005-09-20 13:10 ` Simon Derr
2005-09-20 14:22 ` Paul Jackson
2005-09-20 14:54 ` Robin Holt
2005-09-20 15:07 ` Linus Torvalds
2005-09-20 15:14 ` Paul Jackson
2005-09-20 15:17 ` Simon Derr
2005-09-12 11:48 ` Nikita Danilov
2005-09-12 13:25 ` Paul Jackson
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