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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 9CD08C433EF for ; Fri, 17 Dec 2021 13:57:50 +0000 (UTC) Received: from localhost ([::1]:59804 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1myDk5-00040W-Lf for qemu-devel@archiver.kernel.org; Fri, 17 Dec 2021 08:57:49 -0500 Received: from eggs.gnu.org ([209.51.188.92]:54176) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1myDa1-0005vw-9z for qemu-devel@nongnu.org; Fri, 17 Dec 2021 08:47:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:20993) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1myDZy-0008Oc-PC for qemu-devel@nongnu.org; Fri, 17 Dec 2021 08:47:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639748832; 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=oK7N/JLH1vH5Wlk2zn5oWnKUC7prf7gO4iOXi3lsnLg=; b=SiO7qe3aHVgcTcrNRqArdHYLUaGdkbPTumPqO7LsuHxieE3TWHKY5CYzU4xj8ZqzSl5VVA gj1wZcwa5WX4Wn3gGuYjZwut5E5rRSYgM5MTMzZnQyleDTMyUFw0qrgSxcwFjTXFfHtqSU 5BTWawGoNKJGDq//qkN439wiiLOC8Yg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-27-7maYqgKIP9i_3hik0-w_Aw-1; Fri, 17 Dec 2021 08:47:09 -0500 X-MC-Unique: 7maYqgKIP9i_3hik0-w_Aw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D433E101F7A1; Fri, 17 Dec 2021 13:47:07 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.204]) by smtp.corp.redhat.com (Postfix) with ESMTP id D054A5E482; Fri, 17 Dec 2021 13:47:04 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v2 6/8] util/oslib-posix: Support concurrent os_mem_prealloc() invocation Date: Fri, 17 Dec 2021 14:46:09 +0100 Message-Id: <20211217134611.31172-7-david@redhat.com> In-Reply-To: <20211217134611.31172-1-david@redhat.com> References: <20211217134611.31172-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; 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=-0.718, 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_H3=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Pankaj Gupta , Gavin Shan , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Michael S. Tsirkin" , =?UTF-8?q?Michal=20Pr=C3=ADvozn=C3=ADk?= , David Hildenbrand , "Dr . David Alan Gilbert" , Pankaj Gupta , Sebastien Boeuf , Igor Mammedov , Paolo Bonzini , Hui Zhu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Add a mutex 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. Reviewed-by: Pankaj Gupta Reviewed-by: Daniel P. Berrangé Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand --- util/oslib-posix.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/util/oslib-posix.c b/util/oslib-posix.c index efa4f96d56..9829149e4b 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -95,6 +95,7 @@ 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; @@ -625,6 +626,7 @@ 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); @@ -638,6 +640,12 @@ void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus, use_madv_populate_write = madv_populate_write_possible(area, hpagesize); if (!use_madv_populate_write) { + if (g_once_init_enter(&initialized)) { + qemu_mutex_init(&sigbus_mutex); + g_once_init_leave(&initialized, 1); + } + + qemu_mutex_lock(&sigbus_mutex); memset(&act, 0, sizeof(act)); act.sa_handler = &sigbus_handler; act.sa_flags = 0; @@ -665,6 +673,7 @@ 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