From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [patch 0/9] Critical Mempools From: Pekka Enberg In-Reply-To: <43DABDBF.7010006@us.ibm.com> References: <1138217992.2092.0.camel@localhost.localdomain> <43D954D8.2050305@us.ibm.com> <43D95BFE.4010705@us.ibm.com> <20060127000304.GG10409@kvack.org> <43D968E4.5020300@us.ibm.com> <84144f020601262335g49c21b62qaa729732e9275c0@mail.gmail.com> <20060127021050.f50d358d.pj@sgi.com> <84144f020601270307t7266a4ccs5071d4b288a9257f@mail.gmail.com> <43DABDBF.7010006@us.ibm.com> Date: Sat, 28 Jan 2006 12:21:51 +0200 Message-Id: <1138443711.8657.16.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Matthew Dobson Cc: Paul Jackson , bcrl@kvack.org, clameter@engr.sgi.com, linux-kernel@vger.kernel.org, sri@us.ibm.com, andrea@suse.de, pavel@suse.cz, linux-mm@kvack.org List-ID: Hi, On Fri, 2006-01-27 at 16:41 -0800, Matthew Dobson wrote: > Now, a few pages of memory could be incredibly crucial, since > we're discussing an emergency (presumably) low-mem situation, but if > we're going to be getting several requests for the same > slab/kmalloc-size then we're probably better of giving a whole page to > the slab allocator. This is pure speculation, of course... :) Yeah but even then there's no guarantee that the critical allocations will be serviced first. The slab allocator can as well be giving away bits of the fresh page to non-critical allocations. For the exact same reason, I don't think it's enough that you pass a subsystem-specific page pool to the slab allocator. Sorry if this has been explained before but why aren't mempools sufficient for your purposes? Also one more alternative would be to create a separate object cache for each subsystem-specific critical allocation and implement a internal "page pool" for the slab allocator so that you could specify for the number of pages an object cache guarantees to always hold on to. Pekka -- 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