From: Mitchell Blank Jr <mitch@sfgoth.com>
To: Nick Piggin <piggin@cyberone.com.au>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] might_sleep() improvements
Date: Tue, 2 Sep 2003 01:32:56 -0700 [thread overview]
Message-ID: <20030902083256.GA52644@gaz.sfgoth.com> (raw)
In-Reply-To: <3F545175.1080505@cyberone.com.au>
Nick Piggin wrote:
> >Andrew - I thought this might be appropriate for -mm kernels.
> >
> >This patch makes the following improvements to might_sleep():
> >
> >o Add a "might_sleep_if()" macro for when we might sleep only if some
> > condition is met. I think this is a bit better than the currently used
> > "if (cond) might_sleep();" since it's clearer that the test won't be
> > compiled in if spinlock sleep debugging is turned off. (Obviously
> > gcc is smart enough to omit simple conditions in that case) It also
> > looks cleaner, IMO. Think of it as analogous to BUG()/BUG_ON().
> >
>
> I think these should be pushed down to where the sleeping
> actually happens if possible.
No, you want to generate the warning as early as possible in case the
sleeping case happens very infrequently. For instance:
newskb = skb_unshare(skb, GFP_KERNEL);
might not even need to do any allocation (much less a sleep) in 99.9% of
cases, but it's still a bug if it's called in atomic context and we want
spinlock sleep debugging to catch that for us.
-Mitch
next prev parent reply other threads:[~2003-09-02 8:25 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-02 7:51 [PATCH] might_sleep() improvements Mitchell Blank Jr
2003-09-02 8:14 ` Nick Piggin
2003-09-02 8:32 ` Mitchell Blank Jr [this message]
2003-09-02 8:39 ` Nick Piggin
2003-09-02 8:36 ` Linus Torvalds
2003-09-02 8:44 ` Nick Piggin
2003-09-02 13:55 ` Robert Love
2003-09-02 18:39 ` Mitchell Blank Jr
2003-09-09 3:10 ` Rob Landley
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