From patchwork Tue Mar 23 08:14:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 12157165 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=-21.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 95241C433E4 for ; Tue, 23 Mar 2021 08:15:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53337619C8 for ; Tue, 23 Mar 2021 08:15:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229979AbhCWIPV (ORCPT ); Tue, 23 Mar 2021 04:15:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:31080 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229898AbhCWIPQ (ORCPT ); Tue, 23 Mar 2021 04:15:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616487315; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=x1wm+AvHpyrvrTAF75kQjdToXkB8LXKooRb8yh3T4dk=; b=SEeF/x01HDKjmjdUe06xa5wEWtLfIenNJjtOyG1/KnFXp9nOTz01mcs3zfMJ8Nt+QgXhg2 SES4Tvdk3OpugzVs1tYLH1ylRCgUIlTsTVSf4OkTjVFUyVNHoHFM1QBWMzBcwza3nrsMy3 fSKlL8QrlDBJy1R4Zjmr9ocrEJsqHYs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-43-xruTtytLPLmq_cDyFLQDkQ-1; Tue, 23 Mar 2021 04:15:10 -0400 X-MC-Unique: xruTtytLPLmq_cDyFLQDkQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9DF47100746C; Tue, 23 Mar 2021 08:15:09 +0000 (UTC) Received: from localhost (ovpn-13-171.pek2.redhat.com [10.72.13.171]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2E074171E2; Tue, 23 Mar 2021 08:15:02 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , linux-kernel@vger.kernel.org, Ming Lei Subject: [PATCH 2/2] blktrace: limit allowed total trace buffer size Date: Tue, 23 Mar 2021 16:14:40 +0800 Message-Id: <20210323081440.81343-3-ming.lei@redhat.com> In-Reply-To: <20210323081440.81343-1-ming.lei@redhat.com> References: <20210323081440.81343-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On some ARCHs, such as aarch64, page size may be 64K, meantime there may be lots of CPU cores. relay_open() needs to allocate pages on each CPU blktrace, so easily too many pages are taken by blktrace. For example, on one ARM64 server: 224 CPU cores, 16G RAM, blktrace finally got allocated 7GB in case of 'blktrace -b 8192' which is used by device-mapper test suite[1]. This way could cause OOM easily. Fix the issue by limiting max allowed pages to be 1/8 of totalram_pages(). [1] https://github.com/jthornber/device-mapper-test-suite.git Signed-off-by: Ming Lei --- kernel/trace/blktrace.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index c221e4c3f625..8403ff19d533 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -466,6 +466,35 @@ static void blk_trace_setup_lba(struct blk_trace *bt, } } +/* limit total allocated buffer size is <= 1/8 of total pages */ +static void validate_and_adjust_buf(struct blk_user_trace_setup *buts) +{ + unsigned buf_size = buts->buf_size; + unsigned buf_nr = buts->buf_nr; + unsigned long max_allowed_pages = totalram_pages() >> 3; + unsigned long req_pages = PAGE_ALIGN(buf_size * buf_nr) >> PAGE_SHIFT; + + if (req_pages * num_online_cpus() <= max_allowed_pages) + return; + + req_pages = DIV_ROUND_UP(max_allowed_pages, num_online_cpus()); + + if (req_pages == 0) { + buf_size = PAGE_SIZE; + buf_nr = 1; + } else { + buf_size = req_pages << PAGE_SHIFT / buf_nr; + if (buf_size < PAGE_SIZE) + buf_size = PAGE_SIZE; + buf_nr = req_pages << PAGE_SHIFT / buf_size; + if (buf_nr == 0) + buf_nr = 1; + } + + buts->buf_size = min_t(unsigned, buf_size, buts->buf_size); + buts->buf_nr = min_t(unsigned, buf_nr, buts->buf_nr); +} + /* * Setup everything required to start tracing */ @@ -482,6 +511,9 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, if (!buts->buf_size || !buts->buf_nr) return -EINVAL; + /* make sure not allocate too much for userspace */ + validate_and_adjust_buf(buts); + strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';