From: Linus Torvalds <torvalds@osdl.org>
To: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] might_sleep() improvements
Date: Tue, 02 Sep 2003 01:36:51 -0700 [thread overview]
Message-ID: <bj1kr3$a2g$1@build.pdx.osdl.net> (raw)
In-Reply-To: 3F545175.1080505@cyberone.com.au
Nick Piggin wrote:
>
> I think these should be pushed down to where the sleeping
> actually happens if possible.
No, that ends up doing the wrong thing for most of the really common cases.
In particular, most of the memory allocation functions very seldom actually
sleep. After all, they'll find plenty of free memory (or easily freeable
memory) without having to wait for any pageouts or anything like that.
Yet the bug is there - the call _could_ have slept.
So "might_sleep()" really does what the name suggests: it is used to say
that a particular case _may_ sleep, even if it ends up being unlikely.
Because what we're after is not a bug actually happening, but a latent bug
that has been hidden by the fact that it happens so rarely in practice.
This is why "might_sleep()" should happen as early as possible, and not
get pushed down.
Linus
next prev parent reply other threads:[~2003-09-02 8:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-02 7:51 [PATCH] might_sleep() improvements Mitchell Blank Jr
2003-09-02 8:14 ` Nick Piggin
2003-09-02 8:32 ` Mitchell Blank Jr
2003-09-02 8:39 ` Nick Piggin
2003-09-02 8:36 ` Linus Torvalds [this message]
2003-09-02 8:44 ` Nick Piggin
2003-09-02 13:55 ` Robert Love
2003-09-02 18:39 ` Mitchell Blank Jr
2003-09-09 3:10 ` Rob Landley
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='bj1kr3$a2g$1@build.pdx.osdl.net' \
--to=torvalds@osdl.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).