From nobody Thu Apr 3 11:34:00 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1742981336; cv=none; d=zohomail.com; s=zohoarc; b=GuUsBIRW+heVPNJBJl7PpqDpA7HAJ17OuKwQXSyOMtQyWwDHtLWtucJjC8Qh/Uce2xM/MA67s7GTfdiXjLYdHE3lprEKbx3w8tH3diavkUKd1yvZengesqJnR0stwps9AAICk3cKk4G4gaMX4hpEbgUxy82QO40kCINTN93lAmk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1742981336; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Reply-To:Reply-To:References:Sender:Subject:Subject:To:To:Message-Id; bh=GSuWQ5xsQ7qQXmK3cRDVJmDRLlC+ZAaqhVdCxNrLegc=; b=nkuHl2Yw744H62OOGHGg7Vy4JkxFNDnCRg+Gj8M7E5rKV5PJP4xdjtcCw83TcGmi6wRer6maQZMsRzaITwZJYWKeX4lJJ/a3IcyiKKWXGDO4S/UHgYgABSBpzyZSGfcVpWC/A7ousFL/IlAke9bRYH3BjBM8auerOy9ehFElAVk= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1742981336709446.4933830235452; Wed, 26 Mar 2025 02:28:56 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1txN3m-0005lG-Jh; Wed, 26 Mar 2025 05:28:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1txN3c-0005X3-3v; Wed, 26 Mar 2025 05:28:20 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1txN3Y-0002tD-3e; Wed, 26 Mar 2025 05:28:18 -0400 Received: from mail.maildlp.com (unknown [172.19.163.44]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4ZN1YZ4yzjz1f1hH; Wed, 26 Mar 2025 17:23:30 +0800 (CST) Received: from kwepemk500007.china.huawei.com (unknown [7.202.194.92]) by mail.maildlp.com (Postfix) with ESMTPS id 9A495140144; Wed, 26 Mar 2025 17:28:10 +0800 (CST) Received: from huawei.com (10.246.99.19) by kwepemk500007.china.huawei.com (7.202.194.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 26 Mar 2025 17:28:08 +0800 To: CC: , , , , , , , , , , , , , , , , , Subject: [PATCH v3 1/2] io/block: Refactoring the bdrv_drained_begin() function and implement a timeout mechanism. Date: Wed, 26 Mar 2025 17:26:33 +0800 Message-ID: <20250326092634.1691355-2-zoudongjie@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20250326092634.1691355-1-zoudongjie@huawei.com> References: <20250326092634.1691355-1-zoudongjie@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.246.99.19] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemk500007.china.huawei.com (7.202.194.92) Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=45.249.212.35; envelope-from=zoudongjie@huawei.com; helo=szxga07-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: zoudongjie From: zoudongjie via Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1742981340327019100 Content-Type: text/plain; charset="utf-8" From: Zhu Yangyang The bdrv_drained_begin() function is a blocking function. In scenarios wher= e network storage is used and network links fail, it may block for a long time. Therefore, we add a timeout parameter to control the duration of the block. Since bdrv_drained_begin() has been widely adopted, both bdrv_drained_begin= () and bdrv_drained_begin_timeout() will be retained. Signed-off-by: Zhu Yangyang --- block/io.c | 58 +++++++++++++++++++++++++++++++++------- include/block/aio-wait.h | 47 +++++++++++++++++++++++--------- include/block/block-io.h | 22 ++++++++++++++- util/aio-wait.c | 5 ++++ 4 files changed, 108 insertions(+), 24 deletions(-) diff --git a/block/io.c b/block/io.c index 1ba8d1aeea..912b76c4a4 100644 --- a/block/io.c +++ b/block/io.c @@ -255,6 +255,8 @@ typedef struct { bool begin; bool poll; BdrvChild *parent; + uint64_t timeout_ns; + int ret; } BdrvCoDrainData; =20 /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() = */ @@ -283,6 +285,10 @@ static bool bdrv_drain_poll_top_level(BlockDriverState= *bs, return bdrv_drain_poll(bs, ignore_parent, false); } =20 +static int bdrv_do_drained_begin_timeout(BlockDriverState *bs, + BdrvChild *parent, + bool poll, + uint64_t timeout_ns); static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, bool poll); static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent); @@ -296,7 +302,9 @@ static void bdrv_co_drain_bh_cb(void *opaque) if (bs) { bdrv_dec_in_flight(bs); if (data->begin) { - bdrv_do_drained_begin(bs, data->parent, data->poll); + data->ret =3D bdrv_do_drained_begin_timeout(bs, data->parent, + data->poll, + data->timeout_ns); } else { assert(!data->poll); bdrv_do_drained_end(bs, data->parent); @@ -310,10 +318,11 @@ static void bdrv_co_drain_bh_cb(void *opaque) aio_co_wake(co); } =20 -static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, - bool begin, - BdrvChild *parent, - bool poll) +static int coroutine_fn bdrv_co_yield_to_drain_timeout(BlockDriverState *b= s, + bool begin, + BdrvChild *parent, + bool poll, + uint64_t timeout_ns) { BdrvCoDrainData data; Coroutine *self =3D qemu_coroutine_self(); @@ -329,6 +338,8 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDr= iverState *bs, .begin =3D begin, .parent =3D parent, .poll =3D poll, + .timeout_ns =3D timeout_ns, + .ret =3D 0 }; =20 if (bs) { @@ -342,16 +353,27 @@ static void coroutine_fn bdrv_co_yield_to_drain(Block= DriverState *bs, /* If we are resumed from some other event (such as an aio completion = or a * timer callback), it is a bug in the caller that should be fixed. */ assert(data.done); + return data.ret; } =20 -static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, - bool poll) +static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, + bool begin, + BdrvChild *parent, + bool poll) +{ + bdrv_co_yield_to_drain_timeout(bs, begin, parent, poll, 0); +} + +static int bdrv_do_drained_begin_timeout(BlockDriverState *bs, + BdrvChild *parent, + bool poll, + uint64_t timeout_ns) { IO_OR_GS_CODE(); =20 if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs, true, parent, poll); - return; + return bdrv_co_yield_to_drain_timeout(bs, true, parent, poll, + timeout_ns); } =20 GLOBAL_STATE_CODE(); @@ -375,8 +397,17 @@ static void bdrv_do_drained_begin(BlockDriverState *bs= , BdrvChild *parent, * nodes. */ if (poll) { - BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, parent)); + return BDRV_POLL_WHILE_TIMEOUT(bs, + bdrv_drain_poll_top_level(bs, paren= t), + timeout_ns); } + return 0; +} + +static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, + bool poll) +{ + bdrv_do_drained_begin_timeout(bs, parent, poll, 0); } =20 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent) @@ -391,6 +422,13 @@ bdrv_drained_begin(BlockDriverState *bs) bdrv_do_drained_begin(bs, NULL, true); } =20 +int coroutine_mixed_fn +bdrv_drained_begin_timeout(BlockDriverState *bs, uint64_t timeout_ns) +{ + IO_OR_GS_CODE(); + return bdrv_do_drained_begin_timeout(bs, NULL, true, timeout_ns); +} + /** * This function does not poll, nor must any of its recursively called * functions. diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h index cf5e8bde1c..7610880b61 100644 --- a/include/block/aio-wait.h +++ b/include/block/aio-wait.h @@ -59,10 +59,12 @@ typedef struct { extern AioWait global_aio_wait; =20 /** - * AIO_WAIT_WHILE_INTERNAL: + * AIO_WAIT_WHILE_TIMEOUT: * @ctx: the aio context, or NULL if multiple aio contexts (for which the * caller does not hold a lock) are involved in the polling conditio= n. * @cond: wait while this conditional expression is true + * @timeout_ns: maximum duration to wait, in nanoseconds, except the value + * is unsigned, 0 means infinite. * * Wait while a condition is true. Use this to implement synchronous * operations that require event loop activity. @@ -74,37 +76,54 @@ extern AioWait global_aio_wait; * thread (with @ctx acquired exactly once). This function cannot be used= to * wait on conditions between two IOThreads since that could lead to deadl= ock, * go via the main loop instead. + * + * Returns: 0 if succeeded; -ETIMEDOUT when a timeout occurs. */ -#define AIO_WAIT_WHILE_INTERNAL(ctx, cond) ({ \ - bool waited_ =3D false; \ +#define AIO_WAIT_WHILE_TIMEOUT(ctx, cond, timeout_ns) ({ \ + int ret_ =3D 0; \ + uint64_t timeout_ =3D (timeout_ns); \ AioWait *wait_ =3D &global_aio_wait; \ AioContext *ctx_ =3D (ctx); \ + AioContext *current_ctx_ =3D NULL; \ + QEMUTimer timer_; \ /* Increment wait_->num_waiters before evaluating cond. */ \ qatomic_inc(&wait_->num_waiters); \ /* Paired with smp_mb in aio_wait_kick(). */ \ smp_mb__after_rmw(); \ if (ctx_ && in_aio_context_home_thread(ctx_)) { \ - while ((cond)) { \ - aio_poll(ctx_, true); \ - waited_ =3D true; \ - } \ + current_ctx_ =3D ctx_; \ } else { \ assert(qemu_get_current_aio_context() =3D=3D \ qemu_get_aio_context()); \ - while ((cond)) { \ - aio_poll(qemu_get_aio_context(), true); \ - waited_ =3D true; \ + current_ctx_ =3D qemu_get_aio_context(); \ + } \ + if (timeout_ > 0) { \ + timer_init_full(&timer_, ¤t_ctx_->tlg, \ + QEMU_CLOCK_REALTIME, \ + SCALE_NS, 0, aio_wait_timer_cb, NULL); \ + timer_mod_ns(&timer_, \ + qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + \ + timeout_); \ + } \ + while ((cond)) { \ + aio_poll(current_ctx_, true); \ + if (timeout_ > 0 && !timer_pending(&timer_)) { \ + ret_ =3D -ETIMEDOUT; \ + break; \ } \ } \ + if (timeout_ > 0) { \ + timer_del(&timer_); \ + } \ qatomic_dec(&wait_->num_waiters); \ - waited_; }) + ret_; }) =20 #define AIO_WAIT_WHILE(ctx, cond) \ - AIO_WAIT_WHILE_INTERNAL(ctx, cond) + AIO_WAIT_WHILE_TIMEOUT(ctx, cond, 0) =20 /* TODO replace this with AIO_WAIT_WHILE() in a future patch */ #define AIO_WAIT_WHILE_UNLOCKED(ctx, cond) \ - AIO_WAIT_WHILE_INTERNAL(ctx, cond) + AIO_WAIT_WHILE_TIMEOUT(ctx, cond, 0) =20 /** * aio_wait_kick: @@ -149,4 +168,6 @@ static inline bool in_aio_context_home_thread(AioContex= t *ctx) } } =20 +void aio_wait_timer_cb(void *opaque); + #endif /* QEMU_AIO_WAIT_H */ diff --git a/include/block/block-io.h b/include/block/block-io.h index b49e0537dd..844e9cf350 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -354,6 +354,11 @@ bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, AIO_WAIT_WHILE(bdrv_get_aio_context(bs_), \ cond); }) =20 +#define BDRV_POLL_WHILE_TIMEOUT(bs, cond, timeout_ns) ({ \ + BlockDriverState *bs_ =3D (bs); \ + AIO_WAIT_WHILE_TIMEOUT(bdrv_get_aio_context(bs_), \ + cond, timeout_ns); }) + void bdrv_drain(BlockDriverState *bs); =20 int co_wrapper_mixed_bdrv_rdlock @@ -432,7 +437,22 @@ bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignor= e_parent, void bdrv_drained_begin(BlockDriverState *bs); =20 /** - * bdrv_do_drained_begin_quiesce: + * bdrv_drained_begin_timeout: + * + * Added timeout parameter for bdrv_drained_begin() to make a time limited. + * + * @timeout_ns: maximum duration to wait; 0 means infinite, equal to call + * bdrv_drained_begin(). + * + * Returns: 0 if succeeded; -ETIMEDOUT when a timeout occurs. + * + * Note: when the timeout fails, we've already begin aquiesced section, so= we + * still need to call bdrv_drained_end() to end the quiescent section. + */ +int bdrv_drained_begin_timeout(BlockDriverState *bs, uint64_t timeout_ns); + +/** + * bdrv_do_drained_badegin_quiesce: * * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already * running requests to complete. diff --git a/util/aio-wait.c b/util/aio-wait.c index b5336cf5fd..64c3714fb8 100644 --- a/util/aio-wait.c +++ b/util/aio-wait.c @@ -84,3 +84,8 @@ void aio_wait_bh_oneshot(AioContext *ctx, QEMUBHFunc *cb,= void *opaque) aio_bh_schedule_oneshot(ctx, aio_wait_bh, &data); AIO_WAIT_WHILE_UNLOCKED(NULL, !data.done); } + +void aio_wait_timer_cb(void *opaque) +{ + /* The point is to make AIO_WAIT_WHILE_TIMEOUT()'s aio_poll() return */ +} --=20 2.33.0