Date: Sun, 1 Nov 2009 08:35:27 +0100
From: Pavel Machek <pavel@ucw.cz>
To: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>,
       Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mel@csn.ul.ie>,
       stable@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
       Frans Pop <elendil@planet.nl>, Jiri Kosina <jkosina@suse.cz>,
       Sven Geggus <lists@fuchsschwanzdomain.de>,
       Karol Lewandowski <karol.k.lewandowski@gmail.com>,
       Tobias Oetiker <tobi@oetiker.ch>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Pekka Enberg <penberg@cs.helsinki.fi>,
       Christoph Lameter <cl@linux-foundation.org>,
       Stephan von Krawczynski <skraw@ithnet.com>,
       kernel-testers@vger.kernel.org
Subject: Re: [PATCH 2/3] page allocator: Do not allow interrupts to use
 ALLOC_HARDER
Message-ID: <20091101073527.GB32720@elf.ucw.cz>
References: <1256650833-15516-1-git-send-email-mel@csn.ul.ie>
 <1256650833-15516-3-git-send-email-mel@csn.ul.ie>
 <20091027130924.fa903f5a.akpm@linux-foundation.org>
 <alpine.DEB.2.00.0910271411530.9183@chino.kir.corp.google.com>
 <20091031184054.GB1475@ucw.cz>
 <alpine.DEB.2.00.0910311248490.13829@chino.kir.corp.google.com>
 <20091031201158.GB29536@elf.ucw.cz>
 <alpine.DEB.2.00.0910311413160.25524@chino.kir.corp.google.com>
 <20091031222905.GA32720@elf.ucw.cz>
 <4AECC04B.9060808@redhat.com>
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> > I believe it would be better to simply remove it.
> 
> You are against trying to give the realtime tasks a best effort
> advantage at memory allocation?

Yes. Those memory reserves were for kernel, GPF_ATOMIC and stuff. Now
realtime tasks are allowed to eat into them. That feels wrong.

"realtime" tasks are not automatically "more important".

> Realtime apps often *have* to allocate memory on the kernel side,
> because they use network system calls, etc...

So what? As soon as they do that, they lose any guarantees, anyway.
									Pavel
-- 
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