From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nick Piggin <nickpiggin@yahoo.com.au>
Subject: Re: [PATCH 03/33] mm: slub: add knowledge of reserve pages
Date: Wed, 31 Oct 2007 14:37:28 +1100
Message-ID: <200710311437.28630.nickpiggin@yahoo.com.au>
References: <20071030160401.296770000@chello.nl> <20071030160910.813944000@chello.nl>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	netdev@vger.kernel.org, trond.myklebust@fys.uio.no
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
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On Wednesday 31 October 2007 03:04, Peter Zijlstra wrote:
> Restrict objects from reserve slabs (ALLOC_NO_WATERMARKS) to allocation
> contexts that are entitled to it.
>
> Care is taken to only touch the SLUB slow path.
>
> This is done to ensure reserve pages don't leak out and get consumed.

I think this is generally a good idea (to prevent slab allocators
from stealing reserve). However I naively think the implementation
is a bit overengineered and thus has a few holes.

Humour me, what was the problem with failing the slab allocation
(actually, not fail but just call into the page allocator to do
correct waiting  / reclaim) in the slowpath if the process fails the
watermark checks?