From patchwork Mon Jun 3 06:50:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 1109079 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) 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=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 45HQhp26gQz9s7h for ; Mon, 3 Jun 2019 16:52:05 +1000 (AEST) Received: from localhost ([127.0.0.1]:58679 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hXgp9-0007Jt-1r for incoming@patchwork.ozlabs.org; Mon, 03 Jun 2019 02:52:03 -0400 Received: from eggs.gnu.org ([209.51.188.92]:49444) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hXgoE-0007I4-T9 for qemu-devel@nongnu.org; Mon, 03 Jun 2019 02:51:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hXgoD-0001uc-SS for qemu-devel@nongnu.org; Mon, 03 Jun 2019 02:51:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55608) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hXgoD-0001ti-NE for qemu-devel@nongnu.org; Mon, 03 Jun 2019 02:51:05 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 027CB3082AFF for ; Mon, 3 Jun 2019 06:51:05 +0000 (UTC) Received: from xz-x1.nay.redhat.com (dhcp-15-205.nay.redhat.com [10.66.15.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id ED099648B5; Mon, 3 Jun 2019 06:51:02 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Mon, 3 Jun 2019 14:50:46 +0800 Message-Id: <20190603065056.25211-2-peterx@redhat.com> In-Reply-To: <20190603065056.25211-1-peterx@redhat.com> References: <20190603065056.25211-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Mon, 03 Jun 2019 06:51:05 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v4 01/11] migration: No need to take rcu during sync_dirty_bitmap X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Paolo Bonzini , "Dr . David Alan Gilbert" , peterx@redhat.com, Juan Quintela Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" cpu_physical_memory_sync_dirty_bitmap() has one RAMBlock* as parameter, which means that it must be with RCU read lock held already. Taking it again inside seems redundant. Removing it. Instead comment on the functions about the RCU read lock. Reviewed-by: Paolo Bonzini Reviewed-by: Juan Quintela Signed-off-by: Peter Xu --- include/exec/ram_addr.h | 5 +---- migration/ram.c | 1 + 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index 139ad79390..6fc49e5db5 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -408,6 +408,7 @@ static inline void cpu_physical_memory_clear_dirty_range(ram_addr_t start, } +/* Called with RCU critical section */ static inline uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, ram_addr_t start, @@ -431,8 +432,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, DIRTY_MEMORY_BLOCK_SIZE); unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS); - rcu_read_lock(); - src = atomic_rcu_read( &ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION])->blocks; @@ -452,8 +451,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, idx++; } } - - rcu_read_unlock(); } else { ram_addr_t offset = rb->offset; diff --git a/migration/ram.c b/migration/ram.c index 4c60869226..dc916042fb 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1678,6 +1678,7 @@ static inline bool migration_bitmap_clear_dirty(RAMState *rs, return ret; } +/* Called with RCU critical section */ static void migration_bitmap_sync_range(RAMState *rs, RAMBlock *rb, ram_addr_t length) {