Date: Sat, 6 Nov 2004 16:29:03 +0100
From: Andrea Arcangeli <andrea@novell.com>
To: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <piggin@cyberone.com.au>, Jesse Barnes <jbarnes@sgi.com>,
       Marcelo Tosatti <marcelo.tosatti@cyclades.com>,
       Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org
Subject: Re: [PATCH] Remove OOM killer from try_to_free_pages / all_unreclaimable braindamage
Message-ID: <20041106152903.GA3851@dualathlon.random>
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On Sat, Nov 06, 2004 at 09:47:56AM +0000, Hugh Dickins wrote:
> Problematic, yes: don't overlook that GFP_REPEAT and GFP_NOFAIL _can_
> fail, returning NULL: when the process is being OOM-killed (PF_MEMDIE).

that looks weird, why that? The oom killer must be robust against a task
not going anyway regardless of this (task can be stuck in nfs or
similar). If a fail path ever existed, __GFP_NOFAIL should not have been
used in the first place. I don't see many valid excuses to use
__GFP_NOFAIL if we can return NULL without the caller running into an
infinite loop.

btw, PF_MEMDIE has always been racy in the way it's being set, so it can
corrupt the p->flags, but the race window is very small to trigger it
(and even if it triggers, it probably wouldn't be fatal). That's why I
don't use PF_MEMDIE in 2.4-aa.
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