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=-17.2 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,URIBL_BLOCKED, 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 8718EC4338F for ; Tue, 27 Jul 2021 05:35:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D06E610D2 for ; Tue, 27 Jul 2021 05:35:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235523AbhG0Fe6 (ORCPT ); Tue, 27 Jul 2021 01:34:58 -0400 Received: from relay.sw.ru ([185.231.240.75]:40352 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235417AbhG0FeQ (ORCPT ); Tue, 27 Jul 2021 01:34:16 -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=fzoFoDaPrywkHjs/msWPtHPRzT9tQ7zWHa/Zk4Ahhwk=; b=nKtcynS6hfZJpSCIigQ ARbmJkMFzuqHPG+MoSXEwrH/q54YaaHRU5okecX15OW365YE563YcX+XYj6zE16YspHAUyW5wZk/8 rPtY8T8RaHr2b3+i+ac5prJPyvW0vKdcuxa7cfgG9rCcovFIMtp7o+ev+T9+RPTtyeEWPi7ET/M=; Received: from [10.93.0.56] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1m8FjL-005LZ2-1V; Tue, 27 Jul 2021 08:34:15 +0300 From: Vasily Averin Subject: [PATCH v7 09/10] memcg: enable accounting for tty-related objects To: Andrew Morton Cc: cgroups@vger.kernel.org, Michal Hocko , Shakeel Butt , Johannes Weiner , Vladimir Davydov , Roman Gushchin , Greg Kroah-Hartman , Jiri Slaby , linux-kernel@vger.kernel.org References: <6f21a0e0-bd36-b6be-1ffa-0dc86c06c470@virtuozzo.com> Message-ID: Date: Tue, 27 Jul 2021 08:34:14 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: 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 At each login the user forces the kernel to create a new terminal and allocate up to ~1Kb memory for the tty-related structures. By default it's allowed to create up to 4096 ptys with 1024 reserve for initial mount namespace only and the settings are controlled by host admin. Though this default is not enough for hosters with thousands of containers per node. Host admin can be forced to increase it up to NR_UNIX98_PTY_MAX = 1<<20. By default container is restricted by pty mount_opt.max = 1024, but admin inside container can change it via remount. As a result, one container can consume almost all allowed ptys and allocate up to 1Gb of unaccounted memory. It is not enough per-se to trigger OOM on host, however anyway, it allows to significantly exceed the assigned memcg limit and leads to troubles on the over-committed node. It makes sense to account for them to restrict the host's memory consumption from inside the memcg-limited container. Signed-off-by: Vasily Averin Acked-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 26debec..e787f6f 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1493,7 +1493,7 @@ void tty_save_termios(struct tty_struct *tty) /* Stash the termios data */ tp = tty->driver->termios[idx]; if (tp == NULL) { - tp = kmalloc(sizeof(*tp), GFP_KERNEL); + tp = kmalloc(sizeof(*tp), GFP_KERNEL_ACCOUNT); if (tp == NULL) return; tty->driver->termios[idx] = tp; @@ -3119,7 +3119,7 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) { struct tty_struct *tty; - tty = kzalloc(sizeof(*tty), GFP_KERNEL); + tty = kzalloc(sizeof(*tty), GFP_KERNEL_ACCOUNT); if (!tty) return NULL; -- 1.8.3.1