Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754630Ab0F0JR4 (ORCPT ); Sun, 27 Jun 2010 05:17:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5314 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752701Ab0F0JRz (ORCPT ); Sun, 27 Jun 2010 05:17:55 -0400 Message-ID: <4C271736.5010102@redhat.com> Date: Sun, 27 Jun 2010 12:17:42 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-3.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Nick Piggin CC: linux-kernel , KVM list , Andrew Morton Subject: Re: Slow vmalloc in 2.6.35-rc3 References: <4C232324.7070305@redhat.com> <20100624151427.GH10441@laptop> In-Reply-To: <20100624151427.GH10441@laptop> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1049 Lines: 32 On 06/24/2010 06:14 PM, Nick Piggin wrote: > On Thu, Jun 24, 2010 at 12:19:32PM +0300, Avi Kivity wrote: > >> I see really slow vmalloc performance on 2.6.35-rc3: >> > Can you try this patch? > http://userweb.kernel.org/~akpm/mmotm/broken-out/mm-vmap-area-cache.patch > The patch completely eliminates the problem. >> >> It seems completely wrong - iterating 8 levels of a binary tree >> shouldn't take half a millisecond. >> > It's not iterating down the tree, it's iterating through the > nodes to find a free area. Slows down because lazy vunmap means > that quite a lot of little areas build up right at the start of > our search start address. The vmap cache should hopefully fix > it up. > I see, thanks. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/