From patchwork Fri Dec 13 13:19:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 1209135 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="fjcyhzf/"; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 47ZBB30B9Lz9sPc for ; Sat, 14 Dec 2019 00:20:42 +1100 (AEDT) Received: from localhost ([::1]:49176 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifks2-0007TR-Ro for incoming@patchwork.ozlabs.org; Fri, 13 Dec 2019 08:20:38 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46677) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifkrJ-0007Ss-0N for qemu-devel@nongnu.org; Fri, 13 Dec 2019 08:19:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifkrH-0003Vl-H3 for qemu-devel@nongnu.org; Fri, 13 Dec 2019 08:19:52 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:38125 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ifkrA-0003PE-56 for qemu-devel@nongnu.org; Fri, 13 Dec 2019 08:19:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576243183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wZYL7F6gvK4pRsIDqosx/JqqT5tyk+i8zgLBy3ZPN04=; b=fjcyhzf/BxxrEcpZLddHPuyBmWvyPK3qalr+bCcdle17qP1ivg1jiYVHWtn6Ro/LXaKSa7 r+1RZgofrDwEE0JupjXQmiDPZQKk3i6HwDczH4OkTCm2o2J1rlb1H+S4kZh1wpDaxwbBEP 5P9n2+gwQnXvl6/JZqziPN2ok/3nmGo= 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-126-wEqf63WfMPe_sin7gSsXQw-1; Fri, 13 Dec 2019 08:19:38 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9EC6918552A8; Fri, 13 Dec 2019 13:19:37 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.36.117.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9F3ED60C05; Fri, 13 Dec 2019 13:19:36 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, pbonzini@redhat.com, cota@braap.org, rkagan@virtuozzo.com Subject: [PATCH 2/2] qsp: Use WITH_RCU_READ_LOCK_GUARD Date: Fri, 13 Dec 2019 13:19:31 +0000 Message-Id: <20191213131931.143878-3-dgilbert@redhat.com> In-Reply-To: <20191213131931.143878-1-dgilbert@redhat.com> References: <20191213131931.143878-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: wEqf63WfMPe_sin7gSsXQw-1 X-Mimecast-Spam-Score: 0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: "Dr. David Alan Gilbert" The automatic rcu read lock maintenance works quite nicely in this case where it previously relied on a comment to delimit the lifetime and now has a block. Signed-off-by: Dr. David Alan Gilbert --- util/qsp.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/util/qsp.c b/util/qsp.c index 62265417fd..7d5147f1b2 100644 --- a/util/qsp.c +++ b/util/qsp.c @@ -598,7 +598,6 @@ static void qsp_ht_delete(void *p, uint32_t h, void *htp) static void qsp_mktree(GTree *tree, bool callsite_coalesce) { - QSPSnapshot *snap; struct qht ht, coalesce_ht; struct qht *htp; @@ -610,20 +609,19 @@ static void qsp_mktree(GTree *tree, bool callsite_coalesce) * We must remain in an RCU read-side critical section until we're done * with the snapshot. */ - rcu_read_lock(); - snap = atomic_rcu_read(&qsp_snapshot); + WITH_RCU_READ_LOCK_GUARD() { + QSPSnapshot *snap = atomic_rcu_read(&qsp_snapshot); - /* Aggregate all results from the global hash table into a local one */ - qht_init(&ht, qsp_entry_no_thread_cmp, QSP_INITIAL_SIZE, - QHT_MODE_AUTO_RESIZE | QHT_MODE_RAW_MUTEXES); - qht_iter(&qsp_ht, qsp_aggregate, &ht); + /* Aggregate all results from the global hash table into a local one */ + qht_init(&ht, qsp_entry_no_thread_cmp, QSP_INITIAL_SIZE, + QHT_MODE_AUTO_RESIZE | QHT_MODE_RAW_MUTEXES); + qht_iter(&qsp_ht, qsp_aggregate, &ht); - /* compute the difference wrt the snapshot, if any */ - if (snap) { - qsp_diff(&snap->ht, &ht); + /* compute the difference wrt the snapshot, if any */ + if (snap) { + qsp_diff(&snap->ht, &ht); + } } - /* done with the snapshot; RCU can reclaim it */ - rcu_read_unlock(); htp = &ht; if (callsite_coalesce) {