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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 679BDC433F5 for ; Sat, 11 Sep 2021 07:40:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 42C8761206 for ; Sat, 11 Sep 2021 07:40:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235396AbhIKHlZ (ORCPT ); Sat, 11 Sep 2021 03:41:25 -0400 Received: from relay.sw.ru ([185.231.240.75]:43196 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235384AbhIKHlY (ORCPT ); Sat, 11 Sep 2021 03:41:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Content-Type:MIME-Version:Date:Message-ID:Subject :From; bh=Sj1B4dxxEgCYUObVr5tn3EBz2yvfW+//sFIcOOUDc5U=; b=SUiOHBCKVqMzFtBCHuo +yEezW7VXZzWxFfxvZosB5l1ohptlc/j68xDJ/3kIXPlYJhoBSeNVe4QD0JhinidYSrsN4t7/7h5P gb8CBcZz1ZoSDepWoa+IZWpsc2wLZd0Mj3DFK0TK2g3mhmgH48DiFhaiJVGWM9v6VZ4Nt1uMKUs=; Received: from [10.93.0.56] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1mOxcP-001awD-Ot; Sat, 11 Sep 2021 10:40:09 +0300 From: Vasily Averin Subject: [PATCH] ipc: remove memcg accounting for sops objects in do_semtimedop() To: Andrew Morton Cc: Linus Torvalds , Shakeel Butt , linux-kernel@vger.kernel.org, Michal Hocko , Johannes Weiner , kernel@openvz.org, cgroups@vger.kernel.org Message-ID: <90e254df-0dfe-f080-011e-b7c53ee7fd20@virtuozzo.com> Date: Sat, 11 Sep 2021 10:40:08 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus proposes to revert an accounting for sops objects in do_semtimedop() because it's really just a temporary buffer for a single semtimedop() system call. This object can consume up to 2 pages, syscall is sleeping one, size and duration can be controlled by user, and this allocation can be repeated by many thread at the same time. However Shakeel Butt pointed that there are much more popular objects with the same life time and similar memory consumption, the accounting of which was decided to be rejected for performance reasons. In addition, any usual task consumes much more accounted memory, so 2 pages of this temporal buffer can be safely ignored. Link: https://patchwork.kernel.org/project/linux-fsdevel/patch/20171005222144.123797-1-shakeelb@google.com/ Fixes: 18319498fdd4 ("memcg: enable accounting of ipc resources") Signed-off-by: Vasily Averin --- ipc/sem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/ipc/sem.c b/ipc/sem.c index f833238df1ce..6693daf4fe11 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -2238,7 +2238,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, return -EINVAL; if (nsops > SEMOPM_FAST) { - sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL_ACCOUNT); + sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); if (sops == NULL) return -ENOMEM; } -- 2.25.1