From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752266AbdFNJoX convert rfc822-to-8bit (ORCPT ); Wed, 14 Jun 2017 05:44:23 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:37004 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751889AbdFNJoU (ORCPT ); Wed, 14 Jun 2017 05:44:20 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Ian Kent Cc: Andrei Vagin , Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Linux Containers References: <20170512070838.5037-1-avagin@openvz.org> <1497405190.2595.3.camel@themaw.net> Date: Wed, 14 Jun 2017 04:37:19 -0500 In-Reply-To: <1497405190.2595.3.camel@themaw.net> (Ian Kent's message of "Wed, 14 Jun 2017 09:53:10 +0800") Message-ID: <87wp8ec3lc.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-XM-SPF: eid=1dL4qT-0000OD-DT;;;mid=<87wp8ec3lc.fsf@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=67.3.213.87;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18BYmiTseiaq0Y+mvDUjmILqAFlJOSBCiU= X-SA-Exim-Connect-IP: 67.3.213.87 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 TVD_RCVD_IP Message was received from an IP address * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4994] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa05 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject * 0.0 T_TooManySym_02 5+ unique symbols in subject X-Spam-DCC: XMission; sa05 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Ian Kent X-Spam-Relay-Country: X-Spam-Timing: total 5111 ms - load_scoreonly_sql: 0.06 (0.0%), signal_user_changed: 3.8 (0.1%), b_tie_ro: 2.7 (0.1%), parse: 1.41 (0.0%), extract_message_metadata: 17 (0.3%), get_uri_detail_list: 1.82 (0.0%), tests_pri_-1000: 7 (0.1%), tests_pri_-950: 1.67 (0.0%), tests_pri_-900: 1.33 (0.0%), tests_pri_-400: 22 (0.4%), check_bayes: 20 (0.4%), b_tokenize: 7 (0.1%), b_tok_get_all: 6 (0.1%), b_comp_prob: 2.6 (0.1%), b_tok_touch_all: 2.8 (0.1%), b_finish: 0.79 (0.0%), tests_pri_0: 271 (5.3%), check_dkim_signature: 0.74 (0.0%), check_dkim_adsp: 4.1 (0.1%), tests_pri_500: 4781 (93.5%), poll_dns_idle: 4776 (93.4%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH RFC] mnt: umount mounts one by one in umount_tree() X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ian Kent writes: > On Fri, 2017-05-12 at 00:08 -0700, Andrei Vagin wrote: >> With this patch, we don't try to umount all mounts of a tree together. >> Instead of this we umount them one by one. In this case, we see a significant >> improvement in performance for the worsе case. > > Indeed, umount has been very slow for a while now. > Even a moderately large number of mounts (~10000) become painfully slow. > > Re you still perusing this? > Anything I can do to help? > > Eric, what are your thoughts on this latest attempt? I have something slightly more recent. Please checkout my for-next branch of my userns tree: git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git for-next There is one open area of semantics that I looking at with Ram Pai in the hopes we can drive consensus before we take any patches for better checkpoint-restart support. Eric