From: Catalin Marinas <catalin.marinas@arm.com>
To: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Further copy_from_user() discussion.
Date: Fri, 15 Apr 2005 11:14:28 +0100 [thread overview]
Message-ID: <tnx64yobb3v.fsf@arm.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0504141001580.5403@shell2.speakeasy.net> (Vadim Lobanov's message of "Thu, 14 Apr 2005 10:04:33 -0700 (PDT)")
Vadim Lobanov <vlobanov@speakeasy.net> wrote:
> I think I misspoke a bit in my email above. The intent was not to
> eliminate all might_sleep() calls from the copy_from_user() code path;
> but rather juggle the source around a bit so there is only one
> might_sleep() call per each code path. Currently, in the default case,
> it calls it twice.
>
> By the way, is the following still true about might_sleep()?
> http://kerneltrap.org/node/3440/10103
With Ingo's realtime-preempt patch, might_sleep() expands to
might_resched(). The latter expands to cond_resched() only if
CONFIG_PREEMPT_VOLUNTARY is enabled (for CONFIG_PREEMPT_RT this is not
needed since the kernel is involuntarily preemptible). In this case it
might be useful to have might_sleep() only called before memset().
--
Catalin
next prev parent reply other threads:[~2005-04-15 10:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-13 20:52 Further copy_from_user() discussion Vadim Lobanov
2005-04-14 9:36 ` Catalin Marinas
2005-04-14 17:04 ` Vadim Lobanov
2005-04-15 10:14 ` Catalin Marinas [this message]
2005-04-15 15:55 ` Vadim Lobanov
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