From: Ralf Baechle <ralf@linux-mips.org>
To: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: linux-mips@linux-mips.org
Subject: Re: copy_from_user_page/copy_to_user_page fix
Date: Wed, 9 Feb 2005 19:10:44 +0100 [thread overview]
Message-ID: <20050209181044.GA5740@linux-mips.org> (raw)
In-Reply-To: <20050209.225256.92587183.anemo@mba.ocn.ne.jp>
On Wed, Feb 09, 2005 at 10:52:56PM +0900, Atsushi Nemoto wrote:
> ralf> I'm going to apply this because it's a correct fix; the
> ralf> temporary mapping strategy as we've discussed for the dup_mmap
> ralf> problem would be preferable.
>
> Thank you. I agree that the temporary mapping will be more efficient
> though I chose a simple fix. I suppose a performance requirement for
> ptrace() would be less than the dup_mmap (fork()).
People have come up with creative abuses for ptrace which actually make
it a performance critical path. Especially UML should be mentioned in
this cathegory. And we're talkign about a few thousand cycles differences
per ptrace invocation.
Ralf
prev parent reply other threads:[~2005-02-09 18:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-09 9:49 copy_from_user_page/copy_to_user_page fix Atsushi Nemoto
2005-02-09 12:51 ` Ralf Baechle
2005-02-09 13:52 ` Atsushi Nemoto
2005-02-09 18:10 ` Ralf Baechle [this message]
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