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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 9E9EEC28CC0 for ; Thu, 30 May 2019 09:31:50 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7BA75255AF for ; Thu, 30 May 2019 09:31:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BA75255AF 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 ([127.0.0.1]:49949 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWHPZ-00029p-Mr for qemu-devel@archiver.kernel.org; Thu, 30 May 2019 05:31:49 -0400 Received: from eggs.gnu.org ([209.51.188.92]:44477) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWHNR-0000i3-20 for qemu-devel@nongnu.org; Thu, 30 May 2019 05:29:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hWHNQ-0001Kd-5m for qemu-devel@nongnu.org; Thu, 30 May 2019 05:29:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45584) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hWHNQ-0001Jh-0E for qemu-devel@nongnu.org; Thu, 30 May 2019 05:29:36 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 5EFA7C13070F for ; Thu, 30 May 2019 09:29:35 +0000 (UTC) Received: from xz-x1.redhat.com (ovpn-12-221.pek2.redhat.com [10.72.12.221]) by smtp.corp.redhat.com (Postfix) with ESMTP id E4EC51001DF6; Thu, 30 May 2019 09:29:31 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 30 May 2019 17:29:09 +0800 Message-Id: <20190530092919.26059-3-peterx@redhat.com> In-Reply-To: <20190530092919.26059-1-peterx@redhat.com> References: <20190530092919.26059-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 30 May 2019 09:29:35 +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 v3 02/12] 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+qemu-devel=archiver.kernel.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 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) { -- 2.17.1