{"id":816857,"url":"http://patchwork.ozlabs.org/api/patches/816857/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170921131707.17364-2-el13635@mail.ntua.gr/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170921131707.17364-2-el13635@mail.ntua.gr>","list_archive_url":null,"date":"2017-09-21T13:17:05","name":"[v2,1/3] block: add bdrv_co_drain_end callback","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"621a273538d4d3be3d676b9fb776811eb5796e55","submitter":{"id":71571,"url":"http://patchwork.ozlabs.org/api/people/71571/?format=json","name":"Manos Pitsidianakis","email":"el13635@mail.ntua.gr"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170921131707.17364-2-el13635@mail.ntua.gr/mbox/","series":[{"id":4383,"url":"http://patchwork.ozlabs.org/api/series/4383/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=4383","date":"2017-09-21T13:17:04","name":"add bdrv_co_drain_begin/end BlockDriver callbacks","version":2,"mbox":"http://patchwork.ozlabs.org/series/4383/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/816857/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/816857/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":"ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xycdT5nL7z9s7h\n\tfor ;\n\tThu, 21 Sep 2017 23:19:09 +1000 (AEST)","from localhost ([::1]:53664 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dv1Nj-0005Hl-RI\n\tfor incoming@patchwork.ozlabs.org; Thu, 21 Sep 2017 09:19:07 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:56354)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dv1Mo-00057a-H2\n\tfor qemu-devel@nongnu.org; Thu, 21 Sep 2017 09:18:14 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dv1Mn-00049Q-6a\n\tfor qemu-devel@nongnu.org; Thu, 21 Sep 2017 09:18:10 -0400","from smtp1.ntua.gr ([2001:648:2000:de::183]:39074)\n\tby eggs.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from )\n\tid 1dv1Ma-00040G-AG; Thu, 21 Sep 2017 09:17:56 -0400","from mail.ntua.gr (carp0.noc.ntua.gr [147.102.222.60])\n\t(authenticated bits=0)\n\tby smtp1.ntua.gr (8.15.2/8.15.2) with ESMTPSA id v8LDHoWi083306\n\t(version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256\n\tverify=NOT); Thu, 21 Sep 2017 16:17:50 +0300 (EEST)\n\t(envelope-from el13635@mail.ntua.gr)"],"X-Authentication-Warning":"smtp1.ntua.gr: Host carp0.noc.ntua.gr\n\t[147.102.222.60] claimed to be mail.ntua.gr","From":"Manos Pitsidianakis ","To":"qemu-devel ","Date":"Thu, 21 Sep 2017 16:17:05 +0300","Message-Id":"<20170921131707.17364-2-el13635@mail.ntua.gr>","X-Mailer":"git-send-email 2.11.0","In-Reply-To":"<20170921131707.17364-1-el13635@mail.ntua.gr>","References":"<20170921131707.17364-1-el13635@mail.ntua.gr>","X-detected-operating-system":"by eggs.gnu.org: Genre and OS details not\n\trecognized.","X-Received-From":"2001:648:2000:de::183","Subject":"[Qemu-devel] [PATCH v2 1/3] block: add bdrv_co_drain_end callback","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Kevin Wolf , Fam Zheng ,\n\tStefan Hajnoczi ,\n\tqemu-block , Max Reitz ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"},"content":"BlockDriverState has a bdrv_do_drain() callback but no equivalent for the end\nof the drain. The throttle driver (block/throttle.c) needs a way to mark the\nend of the drain in order to toggle io_limits_disabled correctly, thus\nbdrv_co_drain_end is needed.\n\nSigned-off-by: Manos Pitsidianakis \n---\n include/block/block_int.h | 6 ++++++\n block/io.c | 48 +++++++++++++++++++++++++++++++++--------------\n 2 files changed, 40 insertions(+), 14 deletions(-)","diff":"diff --git a/include/block/block_int.h b/include/block/block_int.h\nindex ba4c383393..21950cfda3 100644\n--- a/include/block/block_int.h\n+++ b/include/block/block_int.h\n@@ -356,8 +356,14 @@ struct BlockDriver {\n /**\n * Drain and stop any internal sources of requests in the driver, and\n * remain so until next I/O callback (e.g. bdrv_co_writev) is called.\n+ *\n+ * The callbacks are called at the beginning and ending of the drain\n+ * respectively. They should be implemented if the driver needs to e.g.\n+ * manage scheduled I/O requests, or toggle an internal state. After an\n+ * bdrv_co_drain_end() invocation new requests will continue normally.\n */\n void coroutine_fn (*bdrv_co_drain)(BlockDriverState *bs);\n+ void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs);\n \n void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child,\n Error **errp);\ndiff --git a/block/io.c b/block/io.c\nindex 4378ae4c7d..b0a10ad3ef 100644\n--- a/block/io.c\n+++ b/block/io.c\n@@ -153,6 +153,7 @@ typedef struct {\n Coroutine *co;\n BlockDriverState *bs;\n bool done;\n+ bool begin;\n } BdrvCoDrainData;\n \n static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)\n@@ -160,18 +161,23 @@ static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)\n BdrvCoDrainData *data = opaque;\n BlockDriverState *bs = data->bs;\n \n- bs->drv->bdrv_co_drain(bs);\n+ if (data->begin) {\n+ bs->drv->bdrv_co_drain(bs);\n+ } else {\n+ bs->drv->bdrv_co_drain_end(bs);\n+ }\n \n /* Set data->done before reading bs->wakeup. */\n atomic_mb_set(&data->done, true);\n bdrv_wakeup(bs);\n }\n \n-static void bdrv_drain_invoke(BlockDriverState *bs)\n+static void bdrv_drain_invoke(BlockDriverState *bs, bool begin)\n {\n- BdrvCoDrainData data = { .bs = bs, .done = false };\n+ BdrvCoDrainData data = { .bs = bs, .done = false, .begin = begin};\n \n- if (!bs->drv || !bs->drv->bdrv_co_drain) {\n+ if (!bs->drv || (begin && !bs->drv->bdrv_co_drain) ||\n+ (!begin && !bs->drv->bdrv_co_drain_end)) {\n return;\n }\n \n@@ -180,15 +186,16 @@ static void bdrv_drain_invoke(BlockDriverState *bs)\n BDRV_POLL_WHILE(bs, !data.done);\n }\n \n-static bool bdrv_drain_recurse(BlockDriverState *bs)\n+static bool bdrv_drain_recurse(BlockDriverState *bs, bool begin)\n {\n BdrvChild *child, *tmp;\n bool waited;\n \n- waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0);\n-\n /* Ensure any pending metadata writes are submitted to bs->file. */\n- bdrv_drain_invoke(bs);\n+ bdrv_drain_invoke(bs, begin);\n+\n+ /* Wait for drained requests to finish */\n+ waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0);\n \n QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) {\n BlockDriverState *bs = child->bs;\n@@ -205,7 +212,7 @@ static bool bdrv_drain_recurse(BlockDriverState *bs)\n */\n bdrv_ref(bs);\n }\n- waited |= bdrv_drain_recurse(bs);\n+ waited |= bdrv_drain_recurse(bs, begin);\n if (in_main_loop) {\n bdrv_unref(bs);\n }\n@@ -221,12 +228,18 @@ static void bdrv_co_drain_bh_cb(void *opaque)\n BlockDriverState *bs = data->bs;\n \n bdrv_dec_in_flight(bs);\n- bdrv_drained_begin(bs);\n+ if (data->begin) {\n+ bdrv_drained_begin(bs);\n+ } else {\n+ bdrv_drained_end(bs);\n+ }\n+\n data->done = true;\n aio_co_wake(co);\n }\n \n-static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)\n+static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,\n+ bool begin)\n {\n BdrvCoDrainData data;\n \n@@ -239,6 +252,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)\n .co = qemu_coroutine_self(),\n .bs = bs,\n .done = false,\n+ .begin = begin,\n };\n bdrv_inc_in_flight(bs);\n aio_bh_schedule_oneshot(bdrv_get_aio_context(bs),\n@@ -253,7 +267,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)\n void bdrv_drained_begin(BlockDriverState *bs)\n {\n if (qemu_in_coroutine()) {\n- bdrv_co_yield_to_drain(bs);\n+ bdrv_co_yield_to_drain(bs, true);\n return;\n }\n \n@@ -262,17 +276,22 @@ void bdrv_drained_begin(BlockDriverState *bs)\n bdrv_parent_drained_begin(bs);\n }\n \n- bdrv_drain_recurse(bs);\n+ bdrv_drain_recurse(bs, true);\n }\n \n void bdrv_drained_end(BlockDriverState *bs)\n {\n+ if (qemu_in_coroutine()) {\n+ bdrv_co_yield_to_drain(bs, false);\n+ return;\n+ }\n assert(bs->quiesce_counter > 0);\n if (atomic_fetch_dec(&bs->quiesce_counter) > 1) {\n return;\n }\n \n bdrv_parent_drained_end(bs);\n+ bdrv_drain_recurse(bs, false);\n aio_enable_external(bdrv_get_aio_context(bs));\n }\n \n@@ -350,7 +369,7 @@ void bdrv_drain_all_begin(void)\n aio_context_acquire(aio_context);\n for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {\n if (aio_context == bdrv_get_aio_context(bs)) {\n- waited |= bdrv_drain_recurse(bs);\n+ waited |= bdrv_drain_recurse(bs, true);\n }\n }\n aio_context_release(aio_context);\n@@ -371,6 +390,7 @@ void bdrv_drain_all_end(void)\n aio_context_acquire(aio_context);\n aio_enable_external(aio_context);\n bdrv_parent_drained_end(bs);\n+ bdrv_drain_recurse(bs, false);\n aio_context_release(aio_context);\n }\n \n","prefixes":["v2","1/3"]}