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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A67CEC433EF for ; Mon, 4 Oct 2021 12:09:15 +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 560C96128A for ; Mon, 4 Oct 2021 12:09:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 560C96128A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:35428 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mXMmQ-0002DO-Do for qemu-devel@archiver.kernel.org; Mon, 04 Oct 2021 08:09:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44164) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXMgV-0001uy-4P for qemu-devel@nongnu.org; Mon, 04 Oct 2021 08:03:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:45097) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXMgT-0006LZ-7M for qemu-devel@nongnu.org; Mon, 04 Oct 2021 08:03:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633348984; 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=e29Gggx2QJ++Sey6LRiwKPCe4BhS91CgAJ0+aKHqpRE=; b=I9mr4XJyaIU6uo+eD3ggphbv329T8JQETiZsQeBmukmJbZcB3IwnpzQZJtBiYs/QhPRKbw LXUIwdqw0sjk0EclWSWXG7QBFfWxfhBpGx5EIQishDvUx6wjvoxYIKDzy1GgJ4D1zhwlmN 0SYn/KMtIYuiaMCPytUurc9wcjTEMJo= 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-479-jhAdaFcbOjSOoCYE-7GDHQ-1; Mon, 04 Oct 2021 08:02:59 -0400 X-MC-Unique: jhAdaFcbOjSOoCYE-7GDHQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0A2B15721F; Mon, 4 Oct 2021 12:02:58 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.194.159]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4C06019C59; Mon, 4 Oct 2021 12:02:54 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v4 6/7] util/oslib-posix: Support concurrent os_mem_prealloc() invocation Date: Mon, 4 Oct 2021 14:02:07 +0200 Message-Id: <20211004120208.7409-7-david@redhat.com> In-Reply-To: <20211004120208.7409-1-david@redhat.com> References: <20211004120208.7409-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.066, 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_H2=-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 , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Michael S. Tsirkin" , David Hildenbrand , "Dr . David Alan Gilbert" , Pankaj Gupta , Igor Mammedov , Paolo Bonzini 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 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