From nobody Mon Feb 9 12:42:45 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; 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=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1623656178691374.7743991135411; Mon, 14 Jun 2021 00:36:18 -0700 (PDT) Received: from localhost ([::1]:38542 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lsh8r-0000LQ-JR for importer@patchew.org; Mon, 14 Jun 2021 03:36:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35132) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lsh6n-0005Ss-E3 for qemu-devel@nongnu.org; Mon, 14 Jun 2021 03:34:09 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:41177) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lsh6k-0004yG-Rs for qemu-devel@nongnu.org; Mon, 14 Jun 2021 03:34:09 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-22-_m7E2ZwgNDGdXIdJ-bR79g-1; Mon, 14 Jun 2021 03:34:04 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9DDB9C73A3; Mon, 14 Jun 2021 07:34:03 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-49.ams2.redhat.com [10.36.113.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3FEEC5D6A8; Mon, 14 Jun 2021 07:34:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623656046; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EvdNo2jN1RTKp8NL2EIbvTOSqp1wlOQAcn+JbkB17J4=; b=cmPiR+1kLv1fEn5sw1xgrx6tWV0+OItcyFnynFdVAvb2gSzIg9vl1e4MuXHtM7XxyxlYdw JfrQWuyCl/PkFWcoOqkpediRoipwLkjaQ+qfJA6+vQLzi91wbIxOkJkKxuKuufb6Fuus9b bAis8pbHE1QMYpn2to2HcAlYPKFbuKc= X-MC-Unique: _m7E2ZwgNDGdXIdJ-bR79g-1 From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [PATCH v4 2/6] block-copy: streamline choice of copy_range vs. read/write Date: Mon, 14 Jun 2021 09:33:46 +0200 Message-Id: <20210614073350.17048-3-eesposit@redhat.com> In-Reply-To: <20210614073350.17048-1-eesposit@redhat.com> References: <20210614073350.17048-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable 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=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.199, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Emanuele Giuseppe Esposito , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi , Paolo Bonzini , John Snow Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" From: Paolo Bonzini Put the logic to determine the copy size in a separate function, so that there is a simple state machine for the possible methods of copying data from one BlockDriverState to the other. Use .method instead of .copy_range as in-out argument, and include also .zeroes as an additional copy method. While at it, store the common computation of block_copy_max_transfer into a new field of BlockCopyState, and make sure that we always obey max_transfer; that's more efficient even for the COPY_RANGE_READ_WRITE case. Signed-off-by: Emanuele Giuseppe Esposito Signed-off-by: Paolo Bonzini Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/block-copy.c | 174 +++++++++++++++++++++++---------------------- 1 file changed, 89 insertions(+), 85 deletions(-) diff --git a/block/block-copy.c b/block/block-copy.c index f0dbb4912b..3f26be8ddc 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -28,6 +28,14 @@ #define BLOCK_COPY_MAX_WORKERS 64 #define BLOCK_COPY_SLICE_TIME 100000000ULL /* ns */ =20 +typedef enum { + COPY_READ_WRITE_CLUSTER, + COPY_READ_WRITE, + COPY_WRITE_ZEROES, + COPY_RANGE_SMALL, + COPY_RANGE_FULL +} BlockCopyMethod; + static coroutine_fn int block_copy_task_entry(AioTask *task); =20 typedef struct BlockCopyCallState { @@ -64,8 +72,7 @@ typedef struct BlockCopyTask { BlockCopyCallState *call_state; int64_t offset; int64_t bytes; - bool zeroes; - bool copy_range; + BlockCopyMethod method; QLIST_ENTRY(BlockCopyTask) list; CoQueue wait_queue; /* coroutines blocked on this task */ } BlockCopyTask; @@ -86,8 +93,8 @@ typedef struct BlockCopyState { BdrvDirtyBitmap *copy_bitmap; int64_t in_flight_bytes; int64_t cluster_size; - bool use_copy_range; - int64_t copy_size; + BlockCopyMethod method; + int64_t max_transfer; uint64_t len; QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy ca= lls */ QLIST_HEAD(, BlockCopyCallState) calls; @@ -149,6 +156,24 @@ static bool coroutine_fn block_copy_wait_one(BlockCopy= State *s, int64_t offset, return true; } =20 +static int64_t block_copy_chunk_size(BlockCopyState *s) +{ + switch (s->method) { + case COPY_READ_WRITE_CLUSTER: + return s->cluster_size; + case COPY_READ_WRITE: + case COPY_RANGE_SMALL: + return MIN(MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER), + s->max_transfer); + case COPY_RANGE_FULL: + return MIN(MAX(s->cluster_size, BLOCK_COPY_MAX_COPY_RANGE), + s->max_transfer); + default: + /* Cannot have COPY_WRITE_ZEROES here. */ + abort(); + } +} + /* * Search for the first dirty area in offset/bytes range and create task at * the beginning of it. @@ -158,8 +183,9 @@ static BlockCopyTask *block_copy_task_create(BlockCopyS= tate *s, int64_t offset, int64_t bytes) { BlockCopyTask *task; - int64_t max_chunk =3D MIN_NON_ZERO(s->copy_size, call_state->max_chunk= ); + int64_t max_chunk =3D block_copy_chunk_size(s); =20 + max_chunk =3D MIN_NON_ZERO(max_chunk, call_state->max_chunk); if (!bdrv_dirty_bitmap_next_dirty_area(s->copy_bitmap, offset, offset + bytes, max_chunk, &offset, &bytes)) @@ -183,7 +209,7 @@ static BlockCopyTask *block_copy_task_create(BlockCopyS= tate *s, .call_state =3D call_state, .offset =3D offset, .bytes =3D bytes, - .copy_range =3D s->use_copy_range, + .method =3D s->method, }; qemu_co_queue_init(&task->wait_queue); QLIST_INSERT_HEAD(&s->tasks, task, list); @@ -267,28 +293,28 @@ BlockCopyState *block_copy_state_new(BdrvChild *sourc= e, BdrvChild *target, .len =3D bdrv_dirty_bitmap_size(copy_bitmap), .write_flags =3D write_flags, .mem =3D shres_create(BLOCK_COPY_MAX_MEM), + .max_transfer =3D QEMU_ALIGN_DOWN( + block_copy_max_transfer(source, target= ), + cluster_size), }; =20 - if (block_copy_max_transfer(source, target) < cluster_size) { + if (s->max_transfer < cluster_size) { /* * copy_range does not respect max_transfer. We don't want to both= er * with requests smaller than block-copy cluster size, so fallback= to * buffered copying (read and write respect max_transfer on their * behalf). */ - s->use_copy_range =3D false; - s->copy_size =3D cluster_size; + s->method =3D COPY_READ_WRITE_CLUSTER; } else if (write_flags & BDRV_REQ_WRITE_COMPRESSED) { /* Compression supports only cluster-size writes and no copy-range= . */ - s->use_copy_range =3D false; - s->copy_size =3D cluster_size; + s->method =3D COPY_READ_WRITE_CLUSTER; } else { /* * We enable copy-range, but keep small copy_size, until first * successful copy_range (look at block_copy_do_copy). */ - s->use_copy_range =3D use_copy_range; - s->copy_size =3D MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER); + s->method =3D use_copy_range ? COPY_RANGE_SMALL : COPY_READ_WRITE; } =20 ratelimit_init(&s->rate_limit); @@ -343,17 +369,14 @@ static coroutine_fn int block_copy_task_run(AioTaskPo= ol *pool, * * No sync here: nor bitmap neighter intersecting requests handling, only = copy. * - * @copy_range is an in-out argument: if *copy_range is false, copy_range = is not - * done. If *copy_range is true, copy_range is attempted. If the copy_range - * attempt fails, the function falls back to the usual read+write and - * *copy_range is set to false. *copy_range and zeroes must not be true - * simultaneously. - * + * @method is an in-out argument, so that copy_range can be either extende= d to + * a full-size buffer or disabled if the copy_range attempt fails. The ou= tput + * value of @method should be used for subsequent tasks. * Returns 0 on success. */ static int coroutine_fn block_copy_do_copy(BlockCopyState *s, int64_t offset, int64_t bytes, - bool zeroes, bool *copy_range, + BlockCopyMethod *method, bool *error_is_read) { int ret; @@ -367,9 +390,9 @@ static int coroutine_fn block_copy_do_copy(BlockCopySta= te *s, assert(offset + bytes <=3D s->len || offset + bytes =3D=3D QEMU_ALIGN_UP(s->len, s->cluster_size)); assert(nbytes < INT_MAX); - assert(!(*copy_range && zeroes)); =20 - if (zeroes) { + switch (*method) { + case COPY_WRITE_ZEROES: ret =3D bdrv_co_pwrite_zeroes(s->target, offset, nbytes, s->write_= flags & ~BDRV_REQ_WRITE_COMPRESSED); if (ret < 0) { @@ -377,76 +400,59 @@ static int coroutine_fn block_copy_do_copy(BlockCopyS= tate *s, *error_is_read =3D false; } return ret; - } =20 - if (*copy_range) { + case COPY_RANGE_SMALL: + case COPY_RANGE_FULL: ret =3D bdrv_co_copy_range(s->source, offset, s->target, offset, n= bytes, 0, s->write_flags); - if (ret < 0) { - trace_block_copy_copy_range_fail(s, offset, ret); - *copy_range =3D false; - /* Fallback to read+write with allocated buffer */ - } else { + if (ret >=3D 0) { + /* Successful copy-range, increase copy_size. */ + *method =3D COPY_RANGE_FULL; return 0; } - } =20 - /* - * In case of failed copy_range request above, we may proceed with buf= fered - * request larger than BLOCK_COPY_MAX_BUFFER. Still, further requests = will - * be properly limited, so don't care too much. Moreover the most like= ly - * case (copy_range is unsupported for the configuration, so the very = first - * copy_range request fails) is handled by setting large copy_size only - * after first successful copy_range. - */ + trace_block_copy_copy_range_fail(s, offset, ret); + *method =3D COPY_READ_WRITE; + /* Fall through to read+write with allocated buffer */ =20 - bounce_buffer =3D qemu_blockalign(s->source->bs, nbytes); + case COPY_READ_WRITE_CLUSTER: + case COPY_READ_WRITE: + /* + * In case of failed copy_range request above, we may proceed with + * buffered request larger than BLOCK_COPY_MAX_BUFFER. + * Still, further requests will be properly limited, so don't care= too + * much. Moreover the most likely case (copy_range is unsupported = for + * the configuration, so the very first copy_range request fails) + * is handled by setting large copy_size only after first successf= ul + * copy_range. + */ =20 - ret =3D bdrv_co_pread(s->source, offset, nbytes, bounce_buffer, 0); - if (ret < 0) { - trace_block_copy_read_fail(s, offset, ret); - *error_is_read =3D true; - goto out; - } + bounce_buffer =3D qemu_blockalign(s->source->bs, nbytes); =20 - ret =3D bdrv_co_pwrite(s->target, offset, nbytes, bounce_buffer, - s->write_flags); - if (ret < 0) { - trace_block_copy_write_fail(s, offset, ret); - *error_is_read =3D false; - goto out; - } + ret =3D bdrv_co_pread(s->source, offset, nbytes, bounce_buffer, 0); + if (ret < 0) { + trace_block_copy_read_fail(s, offset, ret); + *error_is_read =3D true; + goto out; + } =20 -out: - qemu_vfree(bounce_buffer); + ret =3D bdrv_co_pwrite(s->target, offset, nbytes, bounce_buffer, + s->write_flags); + if (ret < 0) { + trace_block_copy_write_fail(s, offset, ret); + *error_is_read =3D false; + goto out; + } =20 - return ret; -} + out: + qemu_vfree(bounce_buffer); + break; =20 -static void block_copy_handle_copy_range_result(BlockCopyState *s, - bool is_success) -{ - if (!s->use_copy_range) { - /* already disabled */ - return; + default: + abort(); } =20 - if (is_success) { - /* - * Successful copy-range. Now increase copy_size. copy_range - * does not respect max_transfer (it's a TODO), so we factor - * that in here. - */ - s->copy_size =3D - MIN(MAX(s->cluster_size, BLOCK_COPY_MAX_COPY_RANGE), - QEMU_ALIGN_DOWN(block_copy_max_transfer(s->source, - s->target), - s->cluster_size)); - } else { - /* Copy-range failed, disable it. */ - s->use_copy_range =3D false; - s->copy_size =3D MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER); - } + return ret; } =20 static coroutine_fn int block_copy_task_entry(AioTask *task) @@ -454,13 +460,12 @@ static coroutine_fn int block_copy_task_entry(AioTask= *task) BlockCopyTask *t =3D container_of(task, BlockCopyTask, task); BlockCopyState *s =3D t->s; bool error_is_read =3D false; - bool copy_range =3D t->copy_range; + BlockCopyMethod method =3D t->method; int ret; =20 - ret =3D block_copy_do_copy(s, t->offset, t->bytes, t->zeroes, - ©_range, &error_is_read); - if (t->copy_range) { - block_copy_handle_copy_range_result(s, copy_range); + ret =3D block_copy_do_copy(s, t->offset, t->bytes, &method, &error_is_= read); + if (s->method =3D=3D t->method) { + s->method =3D method; } if (ret < 0) { if (!t->call_state->ret) { @@ -643,8 +648,7 @@ block_copy_dirty_clusters(BlockCopyCallState *call_stat= e) continue; } if (ret & BDRV_BLOCK_ZERO) { - task->zeroes =3D true; - task->copy_range =3D false; + task->method =3D COPY_WRITE_ZEROES; } =20 if (!call_state->ignore_ratelimit) { --=20 2.31.1