From patchwork Wed Feb 24 20:35:37 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 8414251 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id E6941C0553 for ; Wed, 24 Feb 2016 20:41:32 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1AF7E20295 for ; Wed, 24 Feb 2016 20:41:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 13D7D20279 for ; Wed, 24 Feb 2016 20:41:31 +0000 (UTC) Received: from localhost ([::1]:38281 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aYgFW-0004nW-Bw for patchwork-qemu-devel@patchwork.kernel.org; Wed, 24 Feb 2016 15:41:30 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40748) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aYg9z-0002ij-Ku for qemu-devel@nongnu.org; Wed, 24 Feb 2016 15:35:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aYg9y-00052e-8S for qemu-devel@nongnu.org; Wed, 24 Feb 2016 15:35:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52474) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aYg9t-00051Y-Ky; Wed, 24 Feb 2016 15:35:41 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 497DA486BD; Wed, 24 Feb 2016 20:35:41 +0000 (UTC) Received: from redhat.com (vpn1-6-57.ams2.redhat.com [10.36.6.57]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id u1OKZbCQ001102; Wed, 24 Feb 2016 15:35:38 -0500 Date: Wed, 24 Feb 2016 22:35:37 +0200 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <1456343639-3471-11-git-send-email-mst@redhat.com> References: <1456343639-3471-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1456343639-3471-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Peter Maydell , Fam Zheng , qemu-block@nongnu.org, Juan Quintela , Stefan Hajnoczi , Amit Shah , Paolo Bonzini Subject: [Qemu-devel] [PULL 10/23] block-migration: acquire AioContext as necessary X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Paolo Bonzini This is needed because dataplane will run during block migration as well. The block device migration code is quite liberal in taking the iothread mutex. For simplicity, keep it the same way, even though one could actually choose between the BQL (for regular BlockDriverStates) and the AioContext (for dataplane BlockDriverStates). When the block layer is made fully thread safe, aio_context_acquire shall go away altogether. Signed-off-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Acked-by: Stefan Hajnoczi Reviewed-by: Fam Zheng --- migration/block.c | 65 ++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 52 insertions(+), 13 deletions(-) diff --git a/migration/block.c b/migration/block.c index 3a8330a..72883d7 100644 --- a/migration/block.c +++ b/migration/block.c @@ -54,17 +54,25 @@ typedef struct BlkMigDevState { int shared_base; int64_t total_sectors; QSIMPLEQ_ENTRY(BlkMigDevState) entry; + Error *blocker; /* Only used by migration thread. Does not need a lock. */ int bulk_completed; int64_t cur_sector; int64_t cur_dirty; - /* Protected by block migration lock. */ + /* Data in the aio_bitmap is protected by block migration lock. + * Allocation and free happen during setup and cleanup respectively. + */ unsigned long *aio_bitmap; + + /* Protected by block migration lock. */ int64_t completed_sectors; + + /* During migration this is protected by iothread lock / AioContext. + * Allocation and free happen during setup and cleanup respectively. + */ BdrvDirtyBitmap *dirty_bitmap; - Error *blocker; } BlkMigDevState; typedef struct BlkMigBlock { @@ -100,7 +108,7 @@ typedef struct BlkMigState { int prev_progress; int bulk_completed; - /* Lock must be taken _inside_ the iothread lock. */ + /* Lock must be taken _inside_ the iothread lock and any AioContexts. */ QemuMutex lock; } BlkMigState; @@ -264,11 +272,13 @@ static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds) if (bmds->shared_base) { qemu_mutex_lock_iothread(); + aio_context_acquire(bdrv_get_aio_context(bs)); while (cur_sector < total_sectors && !bdrv_is_allocated(bs, cur_sector, MAX_IS_ALLOCATED_SEARCH, &nr_sectors)) { cur_sector += nr_sectors; } + aio_context_release(bdrv_get_aio_context(bs)); qemu_mutex_unlock_iothread(); } @@ -302,11 +312,21 @@ static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds) block_mig_state.submitted++; blk_mig_unlock(); + /* We do not know if bs is under the main thread (and thus does + * not acquire the AioContext when doing AIO) or rather under + * dataplane. Thus acquire both the iothread mutex and the + * AioContext. + * + * This is ugly and will disappear when we make bdrv_* thread-safe, + * without the need to acquire the AioContext. + */ qemu_mutex_lock_iothread(); + aio_context_acquire(bdrv_get_aio_context(bmds->bs)); blk->aiocb = bdrv_aio_readv(bs, cur_sector, &blk->qiov, nr_sectors, blk_mig_read_cb, blk); bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector, nr_sectors); + aio_context_release(bdrv_get_aio_context(bmds->bs)); qemu_mutex_unlock_iothread(); bmds->cur_sector = cur_sector + nr_sectors; @@ -321,8 +341,10 @@ static int set_dirty_tracking(void) int ret; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { + aio_context_acquire(bdrv_get_aio_context(bmds->bs)); bmds->dirty_bitmap = bdrv_create_dirty_bitmap(bmds->bs, BLOCK_SIZE, NULL, NULL); + aio_context_release(bdrv_get_aio_context(bmds->bs)); if (!bmds->dirty_bitmap) { ret = -errno; goto fail; @@ -333,18 +355,24 @@ static int set_dirty_tracking(void) fail: QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { if (bmds->dirty_bitmap) { + aio_context_acquire(bdrv_get_aio_context(bmds->bs)); bdrv_release_dirty_bitmap(bmds->bs, bmds->dirty_bitmap); + aio_context_release(bdrv_get_aio_context(bmds->bs)); } } return ret; } +/* Called with iothread lock taken. */ + static void unset_dirty_tracking(void) { BlkMigDevState *bmds; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { + aio_context_acquire(bdrv_get_aio_context(bmds->bs)); bdrv_release_dirty_bitmap(bmds->bs, bmds->dirty_bitmap); + aio_context_release(bdrv_get_aio_context(bmds->bs)); } } @@ -444,7 +472,7 @@ static void blk_mig_reset_dirty_cursor(void) } } -/* Called with iothread lock taken. */ +/* Called with iothread lock and AioContext taken. */ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds, int is_async) @@ -527,7 +555,9 @@ static int blk_mig_save_dirty_block(QEMUFile *f, int is_async) int ret = 1; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { + aio_context_acquire(bdrv_get_aio_context(bmds->bs)); ret = mig_save_device_dirty(f, bmds, is_async); + aio_context_release(bdrv_get_aio_context(bmds->bs)); if (ret <= 0) { break; } @@ -585,7 +615,9 @@ static int64_t get_remaining_dirty(void) int64_t dirty = 0; QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { + aio_context_acquire(bdrv_get_aio_context(bmds->bs)); dirty += bdrv_get_dirty_count(bmds->dirty_bitmap); + aio_context_release(bdrv_get_aio_context(bmds->bs)); } return dirty << BDRV_SECTOR_BITS; @@ -597,21 +629,28 @@ static void block_migration_cleanup(void *opaque) { BlkMigDevState *bmds; BlkMigBlock *blk; + AioContext *ctx; bdrv_drain_all(); unset_dirty_tracking(); - blk_mig_lock(); while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) { QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry); bdrv_op_unblock_all(bmds->bs, bmds->blocker); error_free(bmds->blocker); + + /* Save ctx, because bmds->bs can disappear during bdrv_unref. */ + ctx = bdrv_get_aio_context(bmds->bs); + aio_context_acquire(ctx); bdrv_unref(bmds->bs); + aio_context_release(ctx); + g_free(bmds->aio_bitmap); g_free(bmds); } + blk_mig_lock(); while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) { QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry); g_free(blk->buf); @@ -633,13 +672,12 @@ static int block_save_setup(QEMUFile *f, void *opaque) /* start track dirty blocks */ ret = set_dirty_tracking(); + qemu_mutex_unlock_iothread(); + if (ret) { - qemu_mutex_unlock_iothread(); return ret; } - qemu_mutex_unlock_iothread(); - ret = flush_blks(f); blk_mig_reset_dirty_cursor(); qemu_put_be64(f, BLK_MIG_FLAG_EOS); @@ -761,17 +799,18 @@ static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size, uint64_t pending; qemu_mutex_lock_iothread(); + pending = get_remaining_dirty(); + qemu_mutex_unlock_iothread(); + blk_mig_lock(); - pending = get_remaining_dirty() + - block_mig_state.submitted * BLOCK_SIZE + - block_mig_state.read_done * BLOCK_SIZE; + pending += block_mig_state.submitted * BLOCK_SIZE + + block_mig_state.read_done * BLOCK_SIZE; + blk_mig_unlock(); /* Report at least one block pending during bulk phase */ if (pending <= max_size && !block_mig_state.bulk_completed) { pending = max_size + BLOCK_SIZE; } - blk_mig_unlock(); - qemu_mutex_unlock_iothread(); DPRINTF("Enter save live pending %" PRIu64 "\n", pending); /* We don't do postcopy */