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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 549A1C11F67 for ; Tue, 29 Jun 2021 15:05:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27B2361DC4 for ; Tue, 29 Jun 2021 15:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234595AbhF2PHf (ORCPT ); Tue, 29 Jun 2021 11:07:35 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:34656 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232521AbhF2PHb (ORCPT ); Tue, 29 Jun 2021 11:07:31 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lyFIN-008dtP-NA; Tue, 29 Jun 2021 09:05:03 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95]:58984 helo=email.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lyFIM-001WCn-AL; Tue, 29 Jun 2021 09:05:03 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Linus Torvalds Cc: Alexey Gladkov , Linux Kernel Mailing List , Linux Containers References: <87fsx1vcr9.fsf@disp2133> Date: Tue, 29 Jun 2021 10:04:19 -0500 In-Reply-To: (Linus Torvalds's message of "Mon, 28 Jun 2021 20:47:12 -0700") Message-ID: <87r1gku2z0.fsf@disp2133> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1lyFIM-001WCn-AL;;;mid=<87r1gku2z0.fsf@disp2133>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX192t3ZGKJh38+xv4Fmewi8hlGXzg4wt6Nc= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [GIT PULL] ucounts: Count rlimits in each user namespace X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds writes: > On Mon, Jun 28, 2021 at 3:35 PM Eric W. Biederman wrote: >> >> This is the work mainly by Alexey Gladkov to limit rlimits to the >> rlimits of the user that created a user namespace, and to allow users to >> have stricter limits on the resources created within a user namespace. > > I guess all the performance issues got sorted, since I haven't seen > any reports from the test robots. Yes. The structure was made to not change anything unnecessarily (such as the ordering in sigqueue_alloc) and the performances differences went away. With the code in linux-next the entire cycle I think that is a reliable result. There are probably some things we could do to further optimize things but we did not need them to avoid regressions. > I do end up with two questions, mainly because of looking at the > result of the conflict resolution. > > In particular, in __sigqueue_alloc(), two oddities.. > > Why the "sigpending < LONG_MAX" test in that > > if (override_rlimit || (sigpending < LONG_MAX && sigpending <= > task_rlimit(t, RLIMIT_SIGPENDING))) { > > thing? > And why test for "ucounts" being non-NULL in > > if (ucounts && dec_rlimit_ucounts(ucounts, > UCOUNT_RLIMIT_SIGPENDING, 1)) > put_ucounts(ucounts); > > when afaik both of those should be happy with a NULL 'ucounts' pointer > (if it was NULL, we certainly already used it for the reverse > operations for get_ucounts() and inc_rlimit_ucounts()..) > > Hmm? Yes. I suspect that those tests are left over from a previous version of the change. Alex do you remember why those tests are there? > And somebody should verify that I didn't screw anything up in my merge > resolution. It all looked very straightforward, but mistakes happen.. Just reading through the resolution looks correct. Eric