From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 9 Mar 2007 14:00:05 +0000 (GMT) From: Mel Gorman Subject: Re: [SLUB 0/3] SLUB: The unqueued slab allocator V4 In-Reply-To: Message-ID: References: <20070307023502.19658.39217.sendpatchset@schroedinger.engr.sgi.com> <20070308174004.GB12958@skynet.ie> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: akpm@osdl.org, Marcelo Tosatti , Linux Kernel Mailing List , Linux Memory Management List , mpm@selenic.com, Manfred Spraul List-ID: On Thu, 8 Mar 2007, Christoph Lameter wrote: > Note that I am amazed that the kernbench even worked. On small machine How small? The machines I am testing on aren't "big" but they aren't misterable either. > I > seem to be getting into trouble with order 1 allocations. That in itself is pretty incredible. From what I see, allocations up to 3 generally work unless they are atomic even with the vanilla kernel. That said, it could be because slab is holding onto the high order pages for itself. > SLAB seems to be > able to avoid the situation by keeping higher order pages on a freelist > and reduce the alloc/frees of higher order pages that the page allocator > has to deal with. Maybe we need per order queues in the page allocator? > I'm not sure what you mean by per-order queues. The buddy allocator already has per-order lists. > There must be something fundamentally wrong in the page allocator if the > SLAB queues fix this issue. I was able to fix the issue in V5 by forcing > SLUB to keep a mininum number of objects around regardless of the fit to > a page order page. Pass through is deadly since the crappy page allocator > cannot handle it. > > Higher order page allocation failures can be avoided by using kmalloc. > Yuck! Hopefully your patches fix that fundamental problem. > One way to find out for sure. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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