From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 08 May 2001 15:54:05 +0100 From: Alex Bligh - linux-kernel Reply-To: Alex Bligh - linux-kernel Subject: Re: [PATCH] allocation looping + kswapd CPU cycles Message-ID: <2523472481.989337245@[192.168.199.16]> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: Mark Hemment , Linus Torvalds Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Alex Bligh - linux-kernel List-ID: > The real fix is to measure fragmentation and the progress of kswapd, but > that is too drastic for 2.4.x. I suspect the real fix might, in general, be a) to reduce use of kmalloc() etc. which gives physically contiguous memory, where virtually contiguous memory will do (and is, presumably, far easier to come by). (or perhaps add some flag to kmalloc to allocate out of virtual rather than physical memory). b) to bias flush or swap out routines to create physically contiguous higher order blocks. Many heuristics will give you that ability. Disclaimer: I haven't looked at this for issue for years, but Linux seems to fail on >4k allocations now, and fragment memory far more, than it did on much smaller systems doing lots of nasty (8k, thus 3 pages including header) NFS stuff back in 94. -- Alex Bligh -- 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.eu.org/Linux-MM/