linux-kernel - Re: [PATCH] leak less memory in failure paths of alloc_rt_sched

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Date:	Mon, 3 Mar 2008 00:29:19 +0100
From:	"Jesper Juhl" <jesper.juhl@...il.com>
To:	"Peter Zijlstra" <a.p.zijlstra@...llo.nl>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	"Linus Torvalds" <torvalds@...ux-foundation.org>,
	linux-mm@...ck.org, "Ingo Molnar" <mingo@...e.hu>
Subject: Re: [PATCH] leak less memory in failure paths of alloc_rt_sched_group()

On 03/03/2008, Peter Zijlstra <a.p.zijlstra@...llo.nl> wrote:
>
>  On Mon, 2008-03-03 at 00:09 +0100, Jesper Juhl wrote:
>  > In kernel/sched.c b/kernel/sched.c::alloc_rt_sched_group() we currently do
>  > some paired memory allocations, and if one fails we bail out without
>  > freeing the previous one.
>  >
>  > If we fail inside the loop we should proably roll the whole thing back.
>  > This patch does not do that, it simply frees the first member of the
>  > paired alloc if the second fails. This is not perfect, but it's a simple
>  > change that will, at least, result in us leaking a little less than we
>  > currently do when an allocation fails.
>  >
>  > So, not perfect, but better than what we currently have.
>  > Please consider applying.
>
>
> Doesn't the following handle that:
>
>  sched_create_group()
>  {
>  ...
>         if (!alloc_rt_sched_group())
>                 goto err;
>  ...
>
>  err:
>         free_sched_group();
>  }
>
>
>  free_sched_group()
>  {
>  ...
>         free_rt_sched_group();
>  ...
>  }
>
>  free_rt_sched_group()
>  {
>         free all relevant stuff
>  }
>

Hmmm, it might. I must admit I only looked at alloc_rt_sched_group()
isolated, and what I saw looked like leaks. It seems I need to do a
more thorough reading of the code to be dead sure.

-- 
Jesper Juhl <jesper.juhl@...il.com>
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