From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 20 Aug 2007 12:26:09 -0700 (PDT) From: Christoph Lameter Subject: Re: [PATCH 04/10] mm: slub: add knowledge of reserve pages In-Reply-To: <84144f020708200228v1af5248cx6f6da4a7a35400f3@mail.gmail.com> Message-ID: References: <20070806102922.907530000@chello.nl> <20070806103658.603735000@chello.nl> <1187595513.6114.176.camel@twins> <1187601455.6114.189.camel@twins> <84144f020708200228v1af5248cx6f6da4a7a35400f3@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Pekka Enberg Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Miller , Andrew Morton , Daniel Phillips , Matt Mackall , Lee Schermerhorn , Steve Dickson List-ID: On Mon, 20 Aug 2007, Pekka Enberg wrote: > Hi Peter, > > On Mon, 2007-08-20 at 12:12 +0300, Pekka J Enberg wrote: > > > Any reason why the callers that are actually interested in this don't do > > > page->reserve on their own? > > On 8/20/07, Peter Zijlstra wrote: > > because new_slab() destroys the content? > > Right. So maybe we could move the initialization parts of new_slab() > to __new_slab() so that the callers that are actually interested in > 'reserve' could do allocate_slab(), store page->reserve and do rest of > the initialization with it? I am still not convinced about this approach and there seems to be agreement that this is not working on large NUMA. So #ifdef it out? !CONFIG_NUMA? Some more general approach that does not rely on a single slab being a reserve? The object is to check the alloc flags when having allocated a reserve slab right? Adding another flag SlabReserve and keying off on that one may be the easiest solution. I have pending patches here that add per cpu structures. Those will make that job easier. > As for the __GFP_WAIT handling, I *think* we can move the interrupt > enable/disable to allocate_slab()... Christoph? The reason the enable/disable is in new_slab is to minimize interrupt holdoff time. If we move it to allocate slab then the slab preparation is done with interrupts disabled. -- 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