From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH 0/5] make slab gfp fair From: Peter Zijlstra In-Reply-To: References: <20070514131904.440041502@chello.nl> <20070514161224.GC11115@waste.org> Content-Type: text/plain Date: Mon, 14 May 2007 19:40:52 +0200 Message-Id: <1179164453.2942.26.camel@lappy> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Matt Mackall , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Thomas Graf , David Miller , Andrew Morton , Daniel Phillips , Pekka Enberg List-ID: On Mon, 2007-05-14 at 09:29 -0700, Christoph Lameter wrote: > On Mon, 14 May 2007, Matt Mackall wrote: > > > privileged thread unprivileged greedy process > > kmem_cache_alloc(...) > > adds new slab page from lowmem pool > > Yes but it returns an object for the privileged thread. Is that not > enough? No, because we reserved memory for n objects, and like matt illustrates most of those that will be eaten by the greedy process. We could reserve 1 page per object but that rather bloats the reserve. > > do_io() > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > ... > > eats it all > > kmem_cache_alloc(...) -> ENOMEM > > who ate my donuts?! > > > > But I think this solution is somehow overkill. If we only care about > > this issue in the OOM avoidance case, then our rank reduces to a > > boolean. I tried to slim it down to a two state affair; but last time I tried performance runs that actually slowed it down some. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org