linux-kernel - Re: GFP_NOWAIT and GFP

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Message-ID: <20090929143729.5af8e1f8@infradead.org>
Date:	Tue, 29 Sep 2009 14:37:29 +0200
From:	Arjan van de Ven <arjan@...radead.org>
To:	"Leonidas ." <leonidas137@...il.com>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: GFP_NOWAIT and GFP_NOMEMALLOC

On Tue, 29 Sep 2009 17:46:35 +0530
"Leonidas ." <leonidas137@...il.com> wrote:
> 
> The module is going to be a profiling module and the user module which
> is under profiling
> will call the apis which I am exporting. My apis will collect certain
> data from point

(I assume you are aware of 'perf' and such)


> But frankly, I am not very familiar with Linux kernel apis yet hence
> have resorted to
> using a tree data structure for the first cut where I allocate memory
> as needed depending on the context I am executing in. To optimize a
> bit, I do not free my memory
> till some threshold is reached.
> 
> Some questions here:
> 
> 1. GFP_NOWAIT as in kmalloc(size, GFP_KERNEL | GFPNOWAIT)?
> 
> or
> 
> kmalloc(size, GFP_NOWAIT), I know this one is a dumb one.

don't do GFP_KERNEL |

because that makes it basically equivalent to GFP_KERNEL, which is a
sleeping version.

> 
> 2. Any reference for the mempool kind of implementation mentioned
> above?

there's mm/mempool.c..

as a general suggestion I would say "look at perf, and see if you can
build on that, or borrow from it"...


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
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