From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B28DFC3A59C for ; Fri, 16 Aug 2019 02:49:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 87EBF2089E for ; Fri, 16 Aug 2019 02:49:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726477AbfHPCtr (ORCPT ); Thu, 15 Aug 2019 22:49:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39252 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726279AbfHPCtq (ORCPT ); Thu, 15 Aug 2019 22:49:46 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A2DA43082DDD; Fri, 16 Aug 2019 02:49:46 +0000 (UTC) Received: from ming.t460p (ovpn-8-25.pek2.redhat.com [10.72.8.25]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E9CE8841FD; Fri, 16 Aug 2019 02:49:40 +0000 (UTC) Date: Fri, 16 Aug 2019 10:49:35 +0800 From: Ming Lei To: "Ray, Mark C (Global Solutions Engineering (GSE))" Cc: Greg KH , Jens Axboe , "linux-block@vger.kernel.org" , "stable@vger.kernel.org" Subject: Re: [PATCH] blk-mq: avoid sysfs buffer overflow by too many CPU cores Message-ID: <20190816024934.GA27844@ming.t460p> References: <20190815121518.16675-1-ming.lei@redhat.com> <20190815122419.GA31891@kroah.com> <20190815122909.GA28032@ming.t460p> <20190815123535.GA29217@kroah.com> <20190815124321.GB28032@ming.t460p> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Fri, 16 Aug 2019 02:49:46 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Aug 15, 2019 at 11:10:35PM +0000, Ray, Mark C (Global Solutions Engineering (GSE)) wrote: > Hi Ming, > > In the customer case, the cpu_list file was not needed. It was just part of a SAP Hana script to collect all the block device data (similar to sosreport). So they were just dumping everything, and it picks up the mq-related files. > > I know with IRQs, we have bitmaps/mask, and can represent the list such as "0-27", without listing every CPU. I'm sure there's lots of options to address this, and getting rid of the cpu_list is one of them. Indeed, same with several attributes under /sys/devices/system/cpu/, actually we can use cpumap_print_to_pagebuf() to print the CPUs. Thanks, Ming