From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 83DC98D0001 for ; Fri, 12 Nov 2010 13:47:03 -0500 (EST) Received: from hpaq2.eem.corp.google.com (hpaq2.eem.corp.google.com [172.25.149.2]) by smtp-out.google.com with ESMTP id oACIl074019877 for ; Fri, 12 Nov 2010 10:47:00 -0800 Received: from pzk33 (pzk33.prod.google.com [10.243.19.161]) by hpaq2.eem.corp.google.com with ESMTP id oACIkc3c008521 for ; Fri, 12 Nov 2010 10:46:59 -0800 Received: by pzk33 with SMTP id 33so539658pzk.38 for ; Fri, 12 Nov 2010 10:46:54 -0800 (PST) Date: Fri, 12 Nov 2010 10:46:51 -0800 (PST) From: David Rientjes 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Richard Kennedy Cc: Pekka Enberg , Christoph Lameter , lkml , linux-mm List-ID: 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, 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org