From patchwork Wed Sep 11 19:06:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 1161248 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 TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 46TBLN0hmBz9s7T for ; Thu, 12 Sep 2019 05:10:20 +1000 (AEST) Received: from localhost ([::1]:55658 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i880Q-0007bq-2F for incoming@patchwork.ozlabs.org; Wed, 11 Sep 2019 15:10:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54091) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i87wk-0003yy-Pq for qemu-devel@nongnu.org; Wed, 11 Sep 2019 15:06:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i87wj-0006bH-Kz for qemu-devel@nongnu.org; Wed, 11 Sep 2019 15:06:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35462) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i87wj-0006an-C9 for qemu-devel@nongnu.org; Wed, 11 Sep 2019 15:06:29 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B3A015AFE3 for ; Wed, 11 Sep 2019 19:06:28 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-117-243.ams2.redhat.com [10.36.117.243]) by smtp.corp.redhat.com (Postfix) with ESMTP id 874F860167; Wed, 11 Sep 2019 19:06:27 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, pbonzini@redhat.com, ehabkost@redhat.com, berrange@redhat.com, quintela@redhat.com Date: Wed, 11 Sep 2019 20:06:19 +0100 Message-Id: <20190911190622.7629-3-dgilbert@redhat.com> In-Reply-To: <20190911190622.7629-1-dgilbert@redhat.com> References: <20190911190622.7629-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Wed, 11 Sep 2019 19:06:28 +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 v2 2/5] migration: Use automatic rcu_read unlock in ram.c 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" Use the automatic read unlocker in migration/ram.c; only for the cases where the unlock is at the end of the function. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Daniel P. Berrangé --- migration/ram.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index b2bd618a89..1bb82acfe0 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -181,14 +181,14 @@ int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque) RAMBlock *block; int ret = 0; - rcu_read_lock(); + RCU_READ_LOCK_AUTO; + RAMBLOCK_FOREACH_NOT_IGNORED(block) { ret = func(block, opaque); if (ret) { break; } } - rcu_read_unlock(); return ret; } @@ -2398,13 +2398,12 @@ static void migration_page_queue_free(RAMState *rs) /* This queue generally should be empty - but in the case of a failed * migration might have some droppings in. */ - rcu_read_lock(); + RCU_READ_LOCK_AUTO; QSIMPLEQ_FOREACH_SAFE(mspr, &rs->src_page_requests, next_req, next_mspr) { memory_region_unref(mspr->rb->mr); QSIMPLEQ_REMOVE_HEAD(&rs->src_page_requests, next_req); g_free(mspr); } - rcu_read_unlock(); } /** @@ -2425,7 +2424,8 @@ int ram_save_queue_pages(const char *rbname, ram_addr_t start, ram_addr_t len) RAMState *rs = ram_state; ram_counters.postcopy_requests++; - rcu_read_lock(); + RCU_READ_LOCK_AUTO; + if (!rbname) { /* Reuse last RAMBlock */ ramblock = rs->last_req_rb; @@ -2467,12 +2467,10 @@ int ram_save_queue_pages(const char *rbname, ram_addr_t start, ram_addr_t len) QSIMPLEQ_INSERT_TAIL(&rs->src_page_requests, new_entry, next_req); migration_make_urgent_request(); qemu_mutex_unlock(&rs->src_page_req_mutex); - rcu_read_unlock(); return 0; err: - rcu_read_unlock(); return -1; } @@ -2712,7 +2710,8 @@ static uint64_t ram_bytes_total_common(bool count_ignored) RAMBlock *block; uint64_t total = 0; - rcu_read_lock(); + RCU_READ_LOCK_AUTO; + if (count_ignored) { RAMBLOCK_FOREACH_MIGRATABLE(block) { total += block->used_length; @@ -2722,7 +2721,6 @@ static uint64_t ram_bytes_total_common(bool count_ignored) total += block->used_length; } } - rcu_read_unlock(); return total; } @@ -3086,7 +3084,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms) RAMBlock *block; int ret; - rcu_read_lock(); + RCU_READ_LOCK_AUTO; /* This should be our last sync, the src is now paused */ migration_bitmap_sync(rs); @@ -3107,13 +3105,11 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms) * point. */ error_report("migration ram resized during precopy phase"); - rcu_read_unlock(); return -EINVAL; } /* Deal with TPS != HPS and huge pages */ ret = postcopy_chunk_hostpages(ms, block); if (ret) { - rcu_read_unlock(); return ret; } @@ -3128,7 +3124,6 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms) trace_ram_postcopy_send_discard_bitmap(); ret = postcopy_each_ram_send_discard(ms); - rcu_read_unlock(); return ret; } @@ -3149,7 +3144,7 @@ int ram_discard_range(const char *rbname, uint64_t start, size_t length) trace_ram_discard_range(rbname, start, length); - rcu_read_lock(); + RCU_READ_LOCK_AUTO; RAMBlock *rb = qemu_ram_block_by_name(rbname); if (!rb) { @@ -3169,8 +3164,6 @@ int ram_discard_range(const char *rbname, uint64_t start, size_t length) ret = ram_block_discard_range(rb, start, length); err: - rcu_read_unlock(); - return ret; }