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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:reply-to :from:date:message-id:subject:to:cc; bh=xcZNayE5oU5dBtbAGsQUJ3Zj2ltDf7+hnDrNa5iSNTQ=; b=Bau7QWsU9P2PtfhUE6iUc8sYSYLKAJOtBAvT7CHSomL9wROb9wQMBMGJu84tVmwkYL DeTGvPpCzio0CsobiUehSyNuxasJ+vGOkrEwgxRC0hs2HvtLN6E1jiCT592wvhv+eLOo ZuKSZiI1HXgbPaGoE6nQR4BJOQgDWABw6acTaatUATqNoHP+BdI7gJpmNPtFc5rpKhkO 2i0VR6OIYevFae9I3h2zO1rtXZmsE82dbkY2DNo/9GUqrqOKUjqISKiV+PmVGK/pBWvk 6PcedDNlhRUVgERMz4cTlTjevbzgOCWHM1ZZCulVbi+UeeWfm8dxEsQNEymd8FWjCZB4 tj5Q== X-Gm-Message-State: APjAAAWTAkWtIDaSS1MU5SgokQuJ4NlvZ4i9lsKiXQvmxyalh9fhq071 ZgMiNXCUT5thbqb3aQ18/w5gh4LWgQ0gTvMVbQhL5g== X-Google-Smtp-Source: APXvYqyhmGEjeVgwzisYZ6T0q/v9sXXvBCXB5JsYKm395a0Qgn2eZY+8a56XnpzK3BShY91qHmp3DxzsmQnF0cJX2FQ= X-Received: by 2002:a50:a56d:: with SMTP id z42mr73807008edb.241.1563990533638; Wed, 24 Jul 2019 10:48:53 -0700 (PDT) MIME-Version: 1.0 References: <20190723071342.383909-1-sgarzare@redhat.com> In-Reply-To: <20190723071342.383909-1-sgarzare@redhat.com> From: Jason Dillaman Date: Wed, 24 Jul 2019 13:48:42 -0400 Message-ID: To: Stefano Garzarella Content-Type: text/plain; charset="UTF-8" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.208.68 Subject: Re: [Qemu-devel] [PATCH v3] block/rbd: add preallocation support 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: , Reply-To: dillaman@redhat.com Cc: Kevin Wolf , qemu-block , Markus Armbruster , qemu-devel , Max Reitz , Jason Dillaman Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jul 23, 2019 at 3:13 AM Stefano Garzarella wrote: > > This patch adds the support of preallocation (off/full) for the RBD > block driver. > If rbd_writesame() is available and supports zeroed buffers, we use > it to quickly fill the image when full preallocation is required. > > Signed-off-by: Stefano Garzarella > --- > v3: > - rebased on master > - filled with zeroed buffer [Max] > - used rbd_writesame() only when we can disable the discard of zeroed > buffers > - added 'since: 4.2' in qapi/block-core.json [Max] > - used buffer as large as the "stripe unit" > --- > block/rbd.c | 202 ++++++++++++++++++++++++++++++++++++++++--- > qapi/block-core.json | 5 +- > 2 files changed, 192 insertions(+), 15 deletions(-) > > diff --git a/block/rbd.c b/block/rbd.c > index 59757b3120..d923a5a26c 100644 > --- a/block/rbd.c > +++ b/block/rbd.c > @@ -64,6 +64,7 @@ > #define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER) > > #define RBD_MAX_SNAPS 100 > +#define RBD_DEFAULT_CONCURRENT_OPS 10 > > /* The LIBRBD_SUPPORTS_IOVEC is defined in librbd.h */ > #ifdef LIBRBD_SUPPORTS_IOVEC > @@ -104,6 +105,7 @@ typedef struct BDRVRBDState { > char *image_name; > char *snap; > uint64_t image_size; > + bool ws_zero_supported; /* rbd_writesame() supports zeroed buffers */ > } BDRVRBDState; > > static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx, > @@ -333,6 +335,155 @@ static void qemu_rbd_memset(RADOSCB *rcb, int64_t offs) > } > } > > +static int qemu_rbd_get_max_concurrent_ops(rados_t cluster) > +{ > + char buf[16]; > + int ret, max_concurrent_ops; > + > + ret = rados_conf_get(cluster, "rbd_concurrent_management_ops", buf, > + sizeof(buf)); > + if (ret < 0) { > + return RBD_DEFAULT_CONCURRENT_OPS; > + } > + > + ret = qemu_strtoi(buf, NULL, 10, &max_concurrent_ops); > + if (ret < 0) { > + return RBD_DEFAULT_CONCURRENT_OPS; > + } > + > + return max_concurrent_ops; > +} > + > +static int qemu_rbd_do_truncate(rados_t cluster, rbd_image_t image, > + int64_t offset, PreallocMode prealloc, > + bool ws_zero_supported, Error **errp) > +{ > + uint64_t current_length; > + char *buf = NULL; > + int ret; > + > + ret = rbd_get_size(image, ¤t_length); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Failed to get file length"); > + goto out; > + } > + > + if (current_length > offset && prealloc != PREALLOC_MODE_OFF) { > + error_setg(errp, "Cannot use preallocation for shrinking files"); > + ret = -ENOTSUP; > + goto out; > + } > + > + switch (prealloc) { > + case PREALLOC_MODE_FULL: { > + uint64_t buf_size, current_offset = current_length; > + ssize_t bytes; > + > + ret = rbd_get_stripe_unit(image, &buf_size); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Failed to get stripe unit"); > + goto out; > + } > + > + ret = rbd_resize(image, offset); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Failed to resize file"); > + goto out; > + } > + > + buf = g_malloc0(buf_size); > + > +#ifdef LIBRBD_SUPPORTS_WRITESAME > + if (ws_zero_supported) { > + uint64_t writesame_max_size; > + int max_concurrent_ops; > + > + max_concurrent_ops = qemu_rbd_get_max_concurrent_ops(cluster); > + /* > + * We limit the rbd_writesame() size to avoid to spawn more then > + * 'rbd_concurrent_management_ops' concurrent operations. > + */ > + writesame_max_size = MIN(buf_size * max_concurrent_ops, INT_MAX); In the most efficient world, the 'buf_size' would be some small, fixed power of 2 value (like 512 bytes) since there isn't much need to send extra zeroes. You would then want to writesame the full stripe period (if possible), where a stripe period is the data block object size (defaults to 4MiB and is availble via 'rbd_stat') * the stripe count. In this case, the stripe count becomes the number of in-flight IOs. Therefore, you could substitute its value w/ the max_concurrent_ops to ensure you are issuing exactly max_concurrent_ops IOs per rbd_writesame call. > + > + while (offset - current_offset > buf_size) { > + bytes = MIN(offset - current_offset, writesame_max_size); > + /* > + * rbd_writesame() supports only request where the size of the > + * operation is multiple of buffer size. > + */ > + bytes -= bytes % buf_size; > + > + bytes = rbd_writesame(image, current_offset, bytes, buf, > + buf_size, 0); If the RBD in-memory cache is enabled during this operation, the writesame will effectively just be turned into a write. Therefore, when pre-allocating, you will want to disable the cache. > + if (bytes < 0) { > + ret = bytes; > + error_setg_errno(errp, -ret, > + "Failed to write for preallocation"); > + goto out; > + } > + > + current_offset += bytes; > + } > + } > +#endif /* LIBRBD_SUPPORTS_WRITESAME */ > + > + while (current_offset < offset) { > + bytes = rbd_write(image, current_offset, > + MIN(offset - current_offset, buf_size), buf); > + if (bytes < 0) { > + ret = bytes; > + error_setg_errno(errp, -ret, > + "Failed to write for preallocation"); > + goto out; > + } > + > + current_offset += bytes; > + } > + > + ret = rbd_flush(image); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Failed to flush the file"); > + goto out; > + } > + > + break; > + } > + case PREALLOC_MODE_OFF: > + ret = rbd_resize(image, offset); I'm not familiar enough w/ the QEMU block code, but why would the PREALLOC_MODE_FULL case not need to resize the image? > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Failed to resize file"); > + goto out; > + } > + break; > + default: > + error_setg(errp, "Unsupported preallocation mode: %s", > + PreallocMode_str(prealloc)); > + ret = -ENOTSUP; > + goto out; > + } > + > + ret = 0; > + > +out: > + g_free(buf); > + return ret; > +} > + > +static bool qemu_rbd_writesame_zero_supported(rados_t *cluster) > +{ > + int ret = 1; > + > +#ifdef LIBRBD_SUPPORTS_WRITESAME > + /* > + * When "rbd_discard_on_zeroed_write_same" is not available, rbd_writesame() > + * can discard requests with zeroed buffer. > + */ > + ret = rados_conf_set(*cluster, "rbd_discard_on_zeroed_write_same", "false"); > +#endif > + > + return ret == 0; > +} > + > static QemuOptsList runtime_opts = { > .name = "rbd", > .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head), > @@ -378,6 +529,7 @@ static int qemu_rbd_do_create(BlockdevCreateOptions *options, > BlockdevCreateOptionsRbd *opts = &options->u.rbd; > rados_t cluster; > rados_ioctx_t io_ctx; > + rbd_image_t image; > int obj_order = 0; > int ret; > > @@ -406,13 +558,23 @@ static int qemu_rbd_do_create(BlockdevCreateOptions *options, > return ret; > } > > - ret = rbd_create(io_ctx, opts->location->image, opts->size, &obj_order); > + ret = rbd_create(io_ctx, opts->location->image, 0, &obj_order); > if (ret < 0) { > error_setg_errno(errp, -ret, "error rbd create"); > goto out; > } > > - ret = 0; > + ret = rbd_open(io_ctx, opts->location->image, &image, NULL); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "error rbd open"); > + goto out; > + } > + > + ret = qemu_rbd_do_truncate(cluster, image, opts->size, opts->preallocation, > + qemu_rbd_writesame_zero_supported(&cluster), > + errp); > + > + rbd_close(image); > out: > rados_ioctx_destroy(io_ctx); > rados_shutdown(cluster); > @@ -433,6 +595,7 @@ static int coroutine_fn qemu_rbd_co_create_opts(const char *filename, > BlockdevOptionsRbd *loc; > Error *local_err = NULL; > const char *keypairs, *password_secret; > + char *prealloc; > QDict *options = NULL; > int ret = 0; > > @@ -451,6 +614,16 @@ static int coroutine_fn qemu_rbd_co_create_opts(const char *filename, > BLOCK_OPT_CLUSTER_SIZE, 0); > rbd_opts->has_cluster_size = (rbd_opts->cluster_size != 0); > > + prealloc = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); > + rbd_opts->preallocation = qapi_enum_parse(&PreallocMode_lookup, prealloc, > + PREALLOC_MODE_OFF, &local_err); > + g_free(prealloc); > + if (local_err) { > + ret = -EINVAL; > + error_propagate(errp, local_err); > + goto exit; > + } > + > options = qdict_new(); > qemu_rbd_parse_filename(filename, options, &local_err); > if (local_err) { > @@ -770,6 +943,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags, > > s->snap = g_strdup(opts->snapshot); > s->image_name = g_strdup(opts->image); > + s->ws_zero_supported = qemu_rbd_writesame_zero_supported(&s->cluster); > > /* rbd_open is always r/w */ > r = rbd_open(s->io_ctx, s->image_name, &s->image, s->snap); > @@ -1089,21 +1263,16 @@ static int coroutine_fn qemu_rbd_co_truncate(BlockDriverState *bs, > PreallocMode prealloc, > Error **errp) > { > - int r; > - > - if (prealloc != PREALLOC_MODE_OFF) { > - error_setg(errp, "Unsupported preallocation mode '%s'", > - PreallocMode_str(prealloc)); > - return -ENOTSUP; > - } > + BDRVRBDState *s = bs->opaque; > + int ret; > > - r = qemu_rbd_resize(bs, offset); > - if (r < 0) { > - error_setg_errno(errp, -r, "Failed to resize file"); > - return r; > + ret = qemu_rbd_do_truncate(s->cluster, s->image, offset, prealloc, > + s->ws_zero_supported, errp); > + if (ret == 0) { > + s->image_size = offset; > } > > - return 0; > + return ret; > } > > static int qemu_rbd_snap_create(BlockDriverState *bs, > @@ -1256,6 +1425,11 @@ static QemuOptsList qemu_rbd_create_opts = { > .type = QEMU_OPT_SIZE, > .help = "RBD object size" > }, > + { > + .name = BLOCK_OPT_PREALLOC, > + .type = QEMU_OPT_STRING, > + .help = "Preallocation mode (allowed values: off, full)" > + }, > { > .name = "password-secret", > .type = QEMU_OPT_STRING, > diff --git a/qapi/block-core.json b/qapi/block-core.json > index 0d43d4f37c..ff55171f8d 100644 > --- a/qapi/block-core.json > +++ b/qapi/block-core.json > @@ -4346,13 +4346,16 @@ > # point to a snapshot. > # @size Size of the virtual disk in bytes > # @cluster-size RBD object size > +# @preallocation Preallocation mode for the new image (since: 4.2) > +# (default: off; allowed values: off, full) > # > # Since: 2.12 > ## > { 'struct': 'BlockdevCreateOptionsRbd', > 'data': { 'location': 'BlockdevOptionsRbd', > 'size': 'size', > - '*cluster-size' : 'size' } } > + '*cluster-size' : 'size', > + '*preallocation': 'PreallocMode' } } > > ## > # @BlockdevVmdkSubformat: > -- > 2.20.1 > -- Jason