From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 11 Apr 2003 01:25:04 +1000 From: Anton Blanchard Subject: Re: [PATCH] bootmem speedup from the IA64 tree Message-ID: <20030410152504.GA18082@krispykreme> References: <20030410122421.A17889@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030410122421.A17889@lst.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Hellwig Cc: akpm@zip.com.au, davidm@napali.hpl.hp.com, linux-mm@kvack.org List-ID: > This is a performance speed up and some minor indendation fixups. > > The problem is that the bootmem code is (a) hugely slow and (b) has > execution that grow quadratically with the size of the bootmap bitmap. > This causes noticable slowdowns, especially on machines with (relatively) > large holes in the physical memory map. Issue (b) is addressed by > maintaining the "last_success" cache, so that we start the next search > from the place where we last found some memory (this part of the patch > could stand additional reviewing/testing). Issue (a) is addressed by > using find_next_zero_bit() instead of the slow bit-by-bit testing. FYI I have some ppc64 machines with a memory layout of 1GB MEM 3GB IO 63GB MEM And see the same problem. Anton -- 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: aart@kvack.org