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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 C8E3AC07E9A for ; Wed, 14 Jul 2021 11:25:27 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 79CAD613AF for ; Wed, 14 Jul 2021 11:25:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 79CAD613AF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33350 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m3d14-0003xz-Na for qemu-devel@archiver.kernel.org; Wed, 14 Jul 2021 07:25:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59354) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m3czN-0001GN-IK for qemu-devel@nongnu.org; Wed, 14 Jul 2021 07:23:41 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:56077) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m3czL-0007zb-SD for qemu-devel@nongnu.org; Wed, 14 Jul 2021 07:23:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626261819; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=d8Ju46ooO+LpOYtWfQ0zrbry10jP0PKilFnn/DoA13E=; b=gqggPKPJ9vLqdPYfWTnHJZPNTI/u/BHZy53K6Y3vjaAlxzWnj3mj09gV2wbRB4fwUAY11R DAgg54pU7Oy60h/9qq2y0OTl0R7JY5GJMMqknNd7IuOYDCbW+2410Jm7M+DcecHJEvhLmc IBnIQoDV5z63kXyPbJLvnXJSgek8pGI= 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-376-mxaYE6vXNtWTWARBu8ZaSg-1; Wed, 14 Jul 2021 07:23:36 -0400 X-MC-Unique: mxaYE6vXNtWTWARBu8ZaSg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 15C47100CF6E; Wed, 14 Jul 2021 11:23:35 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-63.ams2.redhat.com [10.36.114.63]) by smtp.corp.redhat.com (Postfix) with ESMTP id CD2561001281; Wed, 14 Jul 2021 11:23:25 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v1 3/3] util/oslib-posix: Support concurrent os_mem_prealloc() invocation Date: Wed, 14 Jul 2021 13:23:06 +0200 Message-Id: <20210714112306.67793-4-david@redhat.com> In-Reply-To: <20210714112306.67793-1-david@redhat.com> References: <20210714112306.67793-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.699, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Pankaj Gupta , Eduardo Habkost , "Michael S. Tsirkin" , David Hildenbrand , "Dr . David Alan Gilbert" , Igor Mammedov , Paolo Bonzini , Marek Kedzierski Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Add a mutext to protect the SIGBUS case, as we cannot mess concurrently with the sigbus handler and we have to manage the global variable sigbus_memset_context. The MADV_POPULATE_WRITE path can run concurrently. Note that page_mutex and page_cond are shared between concurrent invocations, which shouldn't be a problem. This is a preparation for future virtio-mem prealloc code, which will call os_mem_prealloc() asynchronously from an iothread when handling guest requests. Signed-off-by: David Hildenbrand --- util/oslib-posix.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 60d1da2d6c..181f6bbf1a 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -94,6 +94,7 @@ typedef struct MemsetThread MemsetThread; /* used by sigbus_handler() */ static MemsetContext *sigbus_memset_context; +static QemuMutex sigbus_mutex; static QemuMutex page_mutex; static QemuCond page_cond; @@ -605,12 +606,17 @@ static bool madv_populate_write_possible(char *area, size_t pagesize) void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, Error **errp) { + static gsize initialized; int ret; struct sigaction act, oldact; size_t hpagesize = qemu_fd_getpagesize(fd); size_t numpages = DIV_ROUND_UP(memory, hpagesize); bool use_madv_populate_write; + if (g_once_init_enter(&initialized)) { + qemu_mutex_init(&sigbus_mutex); + } + /* * Sense on every invocation, as MADV_POPULATE_WRITE cannot be used for * some special mappings, such as mapping /dev/mem. @@ -620,6 +626,7 @@ void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, } if (!use_madv_populate_write) { + qemu_mutex_lock(&sigbus_mutex); memset(&act, 0, sizeof(act)); act.sa_handler = &sigbus_handler; act.sa_flags = 0; @@ -646,6 +653,7 @@ void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, perror("os_mem_prealloc: failed to reinstall signal handler"); exit(1); } + qemu_mutex_unlock(&sigbus_mutex); } } -- 2.31.1