/* * 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/module.h" #include "qemu/option.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 */ } }, }; /* * If this function succeeds then the throttle group name is stored in * @group and must be freed by the caller. * If there's an error then @group remains unmodified. */ static int throttle_parse_options(QDict *options, char **group, Error **errp) { int ret; const char *group_name; QemuOpts *opts = qemu_opts_create(&throttle_opts, NULL, 0, &error_abort); if (!qemu_opts_absorb_qdict(opts, options, errp)) { 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; } *group = g_strdup(group_name); 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; char *group; int ret; bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, false, errp); if (!bs->file) { return -EINVAL; } bs->supported_write_flags = bs->file->bs->supported_write_flags | BDRV_REQ_WRITE_UNCHANGED; bs->supported_zero_flags = bs->file->bs->supported_zero_flags | BDRV_REQ_WRITE_UNCHANGED; ret = throttle_parse_options(options, &group, errp); if (ret == 0) { /* Register membership to group with name group_name */ throttle_group_register_tgm(tgm, group, bdrv_get_aio_context(bs)); g_free(group); } return ret; } 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, offset, bytes); } static int coroutine_fn throttle_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov) { return throttle_co_pwritev(bs, offset, bytes, qiov, BDRV_REQ_WRITE_COMPRESSED); } 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) { int ret; char *group = NULL; assert(reopen_state != NULL); assert(reopen_state->bs != NULL); ret = throttle_parse_options(reopen_state->options, &group, errp); reopen_state->opaque = group; return ret; } static void throttle_reopen_commit(BDRVReopenState *reopen_state) { BlockDriverState *bs = reopen_state->bs; ThrottleGroupMember *tgm = bs->opaque; char *group = reopen_state->opaque; assert(group); if (strcmp(group, throttle_group_get_name(tgm))) { throttle_group_unregister_tgm(tgm); throttle_group_register_tgm(tgm, group, bdrv_get_aio_context(bs)); } g_free(reopen_state->opaque); reopen_state->opaque = NULL; } static void throttle_reopen_abort(BDRVReopenState *reopen_state) { g_free(reopen_state->opaque); reopen_state->opaque = NULL; } static void coroutine_fn throttle_co_drain_begin(BlockDriverState *bs) { ThrottleGroupMember *tgm = bs->opaque; if (qatomic_fetch_inc(&tgm->io_limits_disabled) == 0) { throttle_group_restart_tgm(tgm); } } static void coroutine_fn throttle_co_drain_end(BlockDriverState *bs) { ThrottleGroupMember *tgm = bs->opaque; assert(tgm->io_limits_disabled); qatomic_dec(&tgm->io_limits_disabled); } static const char *const throttle_strong_runtime_opts[] = { QEMU_OPT_THROTTLE_GROUP_NAME, NULL }; static BlockDriver bdrv_throttle = { .format_name = "throttle", .instance_size = sizeof(ThrottleGroupMember), .bdrv_open = throttle_open, .bdrv_close = throttle_close, .bdrv_co_flush = throttle_co_flush, .bdrv_child_perm = bdrv_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_co_pwritev_compressed = throttle_co_pwritev_compressed, .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_drain_begin = throttle_co_drain_begin, .bdrv_co_drain_end = throttle_co_drain_end, .is_filter = true, .strong_runtime_opts = throttle_strong_runtime_opts, }; static void bdrv_throttle_init(void) { bdrv_register(&bdrv_throttle); } block_init(bdrv_throttle_init);