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authorManos Pitsidianakis <el13635@mail.ntua.gr>2017-08-25 16:20:27 +0300
committerKevin Wolf <kwolf@redhat.com>2017-09-06 10:12:02 +0200
commitd8e7d87ec49c1458f516d50d109b3f201da736a1 (patch)
tree79513899899eac436824afc1108b64953acc0cc7 /block/throttle.c
parent432d889e55e2614bd0e8bb559af18a61ac217565 (diff)
downloadqemu-arm-d8e7d87ec49c1458f516d50d109b3f201da736a1.tar.gz
block: add throttle block filter driver
block/throttle.c uses existing I/O throttle infrastructure inside a block filter driver. I/O operations are intercepted in the filter's read/write coroutines, and referred to block/throttle-groups.c The driver can be used with the syntax -drive driver=throttle,file.filename=foo.qcow2,throttle-group=bar which registers the throttle filter node with the ThrottleGroup 'bar'. The given group must be created beforehand with object-add or -object. Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/throttle.c')
-rw-r--r--block/throttle.c237
1 files changed, 237 insertions, 0 deletions
diff --git a/block/throttle.c b/block/throttle.c
new file mode 100644
index 0000000000..5bca76300f
--- /dev/null
+++ b/block/throttle.c
@@ -0,0 +1,237 @@
+/*
+ * QEMU block throttling filter driver infrastructure
+ *
+ * Copyright (c) 2017 Manos Pitsidianakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 or
+ * (at your option) version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "block/throttle-groups.h"
+#include "qemu/throttle-options.h"
+#include "qapi/error.h"
+
+static QemuOptsList throttle_opts = {
+ .name = "throttle",
+ .head = QTAILQ_HEAD_INITIALIZER(throttle_opts.head),
+ .desc = {
+ {
+ .name = QEMU_OPT_THROTTLE_GROUP_NAME,
+ .type = QEMU_OPT_STRING,
+ .help = "Name of the throttle group",
+ },
+ { /* end of list */ }
+ },
+};
+
+static int throttle_configure_tgm(BlockDriverState *bs,
+ ThrottleGroupMember *tgm,
+ QDict *options, Error **errp)
+{
+ int ret;
+ const char *group_name;
+ Error *local_err = NULL;
+ QemuOpts *opts = qemu_opts_create(&throttle_opts, NULL, 0, &error_abort);
+
+ qemu_opts_absorb_qdict(opts, options, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ ret = -EINVAL;
+ goto fin;
+ }
+
+ group_name = qemu_opt_get(opts, QEMU_OPT_THROTTLE_GROUP_NAME);
+ if (!group_name) {
+ error_setg(errp, "Please specify a throttle group");
+ ret = -EINVAL;
+ goto fin;
+ } else if (!throttle_group_exists(group_name)) {
+ error_setg(errp, "Throttle group '%s' does not exist", group_name);
+ ret = -EINVAL;
+ goto fin;
+ }
+
+ /* Register membership to group with name group_name */
+ throttle_group_register_tgm(tgm, group_name, bdrv_get_aio_context(bs));
+ ret = 0;
+fin:
+ qemu_opts_del(opts);
+ return ret;
+}
+
+static int throttle_open(BlockDriverState *bs, QDict *options,
+ int flags, Error **errp)
+{
+ ThrottleGroupMember *tgm = bs->opaque;
+
+ bs->file = bdrv_open_child(NULL, options, "file", bs,
+ &child_file, false, errp);
+ if (!bs->file) {
+ return -EINVAL;
+ }
+ bs->supported_write_flags = bs->file->bs->supported_write_flags;
+ bs->supported_zero_flags = bs->file->bs->supported_zero_flags;
+
+ return throttle_configure_tgm(bs, tgm, options, errp);
+}
+
+static void throttle_close(BlockDriverState *bs)
+{
+ ThrottleGroupMember *tgm = bs->opaque;
+ throttle_group_unregister_tgm(tgm);
+}
+
+
+static int64_t throttle_getlength(BlockDriverState *bs)
+{
+ return bdrv_getlength(bs->file->bs);
+}
+
+static int coroutine_fn throttle_co_preadv(BlockDriverState *bs,
+ uint64_t offset, uint64_t bytes,
+ QEMUIOVector *qiov, int flags)
+{
+
+ ThrottleGroupMember *tgm = bs->opaque;
+ throttle_group_co_io_limits_intercept(tgm, bytes, false);
+
+ return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
+}
+
+static int coroutine_fn throttle_co_pwritev(BlockDriverState *bs,
+ uint64_t offset, uint64_t bytes,
+ QEMUIOVector *qiov, int flags)
+{
+ ThrottleGroupMember *tgm = bs->opaque;
+ throttle_group_co_io_limits_intercept(tgm, bytes, true);
+
+ return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
+}
+
+static int coroutine_fn throttle_co_pwrite_zeroes(BlockDriverState *bs,
+ int64_t offset, int bytes,
+ BdrvRequestFlags flags)
+{
+ ThrottleGroupMember *tgm = bs->opaque;
+ throttle_group_co_io_limits_intercept(tgm, bytes, true);
+
+ return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
+}
+
+static int coroutine_fn throttle_co_pdiscard(BlockDriverState *bs,
+ int64_t offset, int bytes)
+{
+ ThrottleGroupMember *tgm = bs->opaque;
+ throttle_group_co_io_limits_intercept(tgm, bytes, true);
+
+ return bdrv_co_pdiscard(bs->file->bs, offset, bytes);
+}
+
+static int throttle_co_flush(BlockDriverState *bs)
+{
+ return bdrv_co_flush(bs->file->bs);
+}
+
+static void throttle_detach_aio_context(BlockDriverState *bs)
+{
+ ThrottleGroupMember *tgm = bs->opaque;
+ throttle_group_detach_aio_context(tgm);
+}
+
+static void throttle_attach_aio_context(BlockDriverState *bs,
+ AioContext *new_context)
+{
+ ThrottleGroupMember *tgm = bs->opaque;
+ throttle_group_attach_aio_context(tgm, new_context);
+}
+
+static int throttle_reopen_prepare(BDRVReopenState *reopen_state,
+ BlockReopenQueue *queue, Error **errp)
+{
+ ThrottleGroupMember *tgm;
+
+ assert(reopen_state != NULL);
+ assert(reopen_state->bs != NULL);
+
+ reopen_state->opaque = g_new0(ThrottleGroupMember, 1);
+ tgm = reopen_state->opaque;
+
+ return throttle_configure_tgm(reopen_state->bs, tgm, reopen_state->options,
+ errp);
+}
+
+static void throttle_reopen_commit(BDRVReopenState *reopen_state)
+{
+ ThrottleGroupMember *old_tgm = reopen_state->bs->opaque;
+ ThrottleGroupMember *new_tgm = reopen_state->opaque;
+
+ throttle_group_unregister_tgm(old_tgm);
+ g_free(old_tgm);
+ reopen_state->bs->opaque = new_tgm;
+ reopen_state->opaque = NULL;
+}
+
+static void throttle_reopen_abort(BDRVReopenState *reopen_state)
+{
+ ThrottleGroupMember *tgm = reopen_state->opaque;
+
+ throttle_group_unregister_tgm(tgm);
+ g_free(tgm);
+ reopen_state->opaque = NULL;
+}
+
+static bool throttle_recurse_is_first_non_filter(BlockDriverState *bs,
+ BlockDriverState *candidate)
+{
+ return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate);
+}
+
+static BlockDriver bdrv_throttle = {
+ .format_name = "throttle",
+ .protocol_name = "throttle",
+ .instance_size = sizeof(ThrottleGroupMember),
+
+ .bdrv_file_open = throttle_open,
+ .bdrv_close = throttle_close,
+ .bdrv_co_flush = throttle_co_flush,
+
+ .bdrv_child_perm = bdrv_filter_default_perms,
+
+ .bdrv_getlength = throttle_getlength,
+
+ .bdrv_co_preadv = throttle_co_preadv,
+ .bdrv_co_pwritev = throttle_co_pwritev,
+
+ .bdrv_co_pwrite_zeroes = throttle_co_pwrite_zeroes,
+ .bdrv_co_pdiscard = throttle_co_pdiscard,
+
+ .bdrv_recurse_is_first_non_filter = throttle_recurse_is_first_non_filter,
+
+ .bdrv_attach_aio_context = throttle_attach_aio_context,
+ .bdrv_detach_aio_context = throttle_detach_aio_context,
+
+ .bdrv_reopen_prepare = throttle_reopen_prepare,
+ .bdrv_reopen_commit = throttle_reopen_commit,
+ .bdrv_reopen_abort = throttle_reopen_abort,
+ .bdrv_co_get_block_status = bdrv_co_get_block_status_from_file,
+
+ .is_filter = true,
+};
+
+static void bdrv_throttle_init(void)
+{
+ bdrv_register(&bdrv_throttle);
+}
+
+block_init(bdrv_throttle_init);