Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755787Ab0KLSrB (ORCPT ); Fri, 12 Nov 2010 13:47:01 -0500 Received: from smtp-out.google.com ([74.125.121.35]:45243 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810Ab0KLSrA (ORCPT ); Fri, 12 Nov 2010 13:47:00 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version:content-type; b=iCnkmk/UNL6fcMMIsnaChbFJp4S3D4d/8h++PjPCo/KJILUvfrY9Dtxrlx89UhrfNH l2xRa1p8y+vcGA6VAbbw== Date: Fri, 12 Nov 2010 10:46:51 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Richard Kennedy cc: Pekka Enberg , Christoph Lameter , lkml , linux-mm Subject: Re: [PATCH/RFC] MM slub: add a sysfs entry to show the calculated number of fallback slabs In-Reply-To: <1289561309.1972.30.camel@castor.rsk> Message-ID: References: <1289561309.1972.30.camel@castor.rsk> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1190 Lines: 25 On Fri, 12 Nov 2010, Richard Kennedy wrote: > Add a slub sysfs entry to show the calculated number of fallback slabs. > > Using the information already available it is straightforward to > calculate the number of fallback & full size slabs. We can then track > which slabs are particularly effected by memory fragmentation and how > long they take to recover. > > There is no change to the mainline code, the calculation is only > performed on request, and the value is available without having to > enable CONFIG_SLUB_STATS. > I don't see why this information is generally useful unless debugging an issue where statistics are already needed such as ALLOC_SLOWPATH and ALLOC_SLAB, so it CONFIG_SLUB_STATS can be enabled to also track ORDER_FALLBACK. All stats can be cleared by writing a '0' to its sysfs stats file so you can collect statistics for various workloads without rebooting (after doing a forced shrink, for example). -- 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/