Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756817Ab0HPVGw (ORCPT ); Mon, 16 Aug 2010 17:06:52 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:57516 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756757Ab0HPVGv convert rfc822-to-8bit (ORCPT ); Mon, 16 Aug 2010 17:06:51 -0400 Subject: Re: [PATCH] Fixed a mismatch between the users of radix_tree and the implementation. From: Peter Zijlstra To: Salman Qazi Cc: paulmck@us.ibm.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, adurbin@google.com In-Reply-To: References: <20100816182834.3541.42317.stgit@bumblebee1.mtv.corp.google.com> <1281987236.1926.1895.camel@laptop> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Mon, 16 Aug 2010 23:06:41 +0200 Message-ID: <1281992801.1926.2019.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1487 Lines: 37 (html damaged email alert) On Mon, 2010-08-16 at 13:59 -0700, Salman Qazi wrote: > On Mon, Aug 16, 2010 at 12:33 PM, Peter Zijlstra wrote: > On Mon, 2010-08-16 at 11:30 -0700, Salman Qazi wrote: > > For the delete case, > > we no longer shrink the tree back to being just the root containing the > > only remaining object. For the insert case, we no longer store the > > first object in the root, rather allocating a node structure for it. The > > reason that this works is that deleting (or inserting) intermediate nodes > > does not make a difference to a reader holding a slot. > > > Ah, I through that was what it did. So you basically increase the memory > footprint for tiny files.. have you done any measurements on that? > > You raise a valid concern. I haven't. What would you recommend as a > benchmark/metric to measure this? One thing you could try is something like the below on a freshly booted machine, once without and once with the patch: cd /usr/src/linux-2.6 echo 1 > /proc/sys/vm/drop_caches grep radix /proc/slabinfo make bzImage echo 1 > /proc/sys/vm/drop_caches grep radix /proc/slabinfo -- 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/