From: Paolo Bonzini <pbonz...@redhat.com>
Extract the handling of throttling from bdrv_flush_io_queue. These
new functions will soon become BdrvChildRole callbacks, as they can
be generalized to "beginning of drain" and "end of drain".
Reviewed-by: Alberto Garcia <be...@igalia.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Acked-by: Stefan Hajnoczi <stefa...@redhat.com>
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
block.c | 1 -
block/block-backend.c | 6 ++----
block/io.c | 33 +++++++++++++++++++++------------
block/throttle-groups.c | 4 ++++
include/block/block_int.h | 9 ++++++---
5 files changed, 33 insertions(+), 20 deletions(-)
diff --git a/block.c b/block.c
index d4939b4..6cbad0e 100644
--- a/block.c
+++ b/block.c
@@ -2261,7 +2261,6 @@ static void swap_feature_fields(BlockDriverState *bs_top,
assert(!bs_new->throttle_state);
if (bs_top->throttle_state) {
- assert(bs_top->io_limits_enabled);
bdrv_io_limits_enable(bs_new, throttle_group_get_name(bs_top));
bdrv_io_limits_disable(bs_top);
}
diff --git a/block/block-backend.c b/block/block-backend.c
index 16c9d5e..9538e79 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -794,7 +794,6 @@ int blk_read_unthrottled(BlockBackend *blk, int64_t
sector_num, uint8_t *buf,
int nb_sectors)
{
BlockDriverState *bs = blk_bs(blk);
- bool enabled;
int ret;
ret = blk_check_request(blk, sector_num, nb_sectors);
@@ -802,10 +801,9 @@ int blk_read_unthrottled(BlockBackend *blk, int64_t
sector_num, uint8_t *buf,
return ret;
}
- enabled = bs->io_limits_enabled;
- bs->io_limits_enabled = false;
+ bdrv_no_throttling_begin(bs);
ret = blk_read(blk, sector_num, buf, nb_sectors);
- bs->io_limits_enabled = enabled;
+ bdrv_no_throttling_end(bs);
return ret;
}
diff --git a/block/io.c b/block/io.c
index c484856..b798040 100644
--- a/block/io.c
+++ b/block/io.c
@@ -65,28 +65,32 @@ void bdrv_set_io_limits(BlockDriverState *bs,
throttle_group_config(bs, cfg);
}
-static void bdrv_start_throttled_reqs(BlockDriverState *bs)
+void bdrv_no_throttling_begin(BlockDriverState *bs)
{
- bool enabled = bs->io_limits_enabled;
+ if (bs->io_limits_disabled++ == 0) {
+ throttle_group_restart_bs(bs);
+ }
+}
- bs->io_limits_enabled = false;
- throttle_group_restart_bs(bs);
- bs->io_limits_enabled = enabled;
+void bdrv_no_throttling_end(BlockDriverState *bs)
+{
+ assert(bs->io_limits_disabled);
+ --bs->io_limits_disabled;
}
void bdrv_io_limits_disable(BlockDriverState *bs)
{
- bs->io_limits_enabled = false;
- bdrv_start_throttled_reqs(bs);
+ assert(bs->throttle_state);
+ bdrv_no_throttling_begin(bs);
throttle_group_unregister_bs(bs);
+ bdrv_no_throttling_end(bs);
}
/* should be called before bdrv_set_io_limits if a limit is set */
void bdrv_io_limits_enable(BlockDriverState *bs, const char *group)
{
- assert(!bs->io_limits_enabled);
+ assert(!bs->throttle_state);
throttle_group_register_bs(bs, group);
- bs->io_limits_enabled = true;
}
void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group)
@@ -302,18 +306,22 @@ static void coroutine_fn
bdrv_co_yield_to_drain(BlockDriverState *bs)
*/
void coroutine_fn bdrv_co_drain(BlockDriverState *bs)
{
+ bdrv_no_throttling_begin(bs);
bdrv_drain_recurse(bs);
bdrv_co_yield_to_drain(bs);
+ bdrv_no_throttling_end(bs);
}
void bdrv_drain(BlockDriverState *bs)
{
+ bdrv_no_throttling_begin(bs);
bdrv_drain_recurse(bs);
if (qemu_in_coroutine()) {
bdrv_co_yield_to_drain(bs);
} else {
bdrv_drain_poll(bs);
}
+ bdrv_no_throttling_end(bs);
}
/*
@@ -336,6 +344,7 @@ void bdrv_drain_all(void)
if (bs->job) {
block_job_pause(bs->job);
}
+ bdrv_no_throttling_begin(bs);
bdrv_drain_recurse(bs);
aio_context_release(aio_context);
@@ -377,6 +386,7 @@ void bdrv_drain_all(void)
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
+ bdrv_no_throttling_end(bs);
if (bs->job) {
block_job_resume(bs->job);
}
@@ -980,7 +990,7 @@ int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
}
/* throttling disk I/O */
- if (bs->io_limits_enabled) {
+ if (bs->throttle_state) {
throttle_group_co_io_limits_intercept(bs, bytes, false);
}
@@ -1330,7 +1340,7 @@ int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
}
/* throttling disk I/O */
- if (bs->io_limits_enabled) {
+ if (bs->throttle_state) {
throttle_group_co_io_limits_intercept(bs, bytes, true);
}
@@ -2772,7 +2782,6 @@ void bdrv_flush_io_queue(BlockDriverState *bs)
} else if (bs->file) {
bdrv_flush_io_queue(bs->file->bs);
}
- bdrv_start_throttled_reqs(bs);
}
void bdrv_drained_begin(BlockDriverState *bs)
diff --git a/block/throttle-groups.c b/block/throttle-groups.c
index b796f6b..9ac063a 100644
--- a/block/throttle-groups.c
+++ b/block/throttle-groups.c
@@ -219,6 +219,10 @@ static bool throttle_group_schedule_timer(BlockDriverState
*bs,
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
bool must_wait;
+ if (bs->io_limits_disabled) {
+ return false;
+ }
+
/* Check if any of the timers in this group is already armed */
if (tg->any_timer_armed[is_write]) {
return true;
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 10d8759..ed9314b 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -424,10 +424,10 @@ struct BlockDriverState {
/* I/O throttling.
* throttle_state tells us if this BDS has I/O limits configured.
- * io_limits_enabled tells us if they are currently being
- * enforced, but it can be temporarily set to false */
+ * io_limits_disabled tells us if they are currently being enforced */
CoQueue throttled_reqs[2];
- bool io_limits_enabled;
+ unsigned int io_limits_disabled;
+
/* The following fields are protected by the ThrottleGroup lock.
* See the ThrottleGroup documentation for details. */
ThrottleState *throttle_state;
@@ -713,6 +713,9 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState
*child_bs,
const BdrvChildRole *child_role);
void bdrv_root_unref_child(BdrvChild *child);
+void bdrv_no_throttling_begin(BlockDriverState *bs);
+void bdrv_no_throttling_end(BlockDriverState *bs);
+
void blk_dev_change_media_cb(BlockBackend *blk, bool load);
bool blk_dev_has_removable_media(BlockBackend *blk);
bool blk_dev_has_tray(BlockBackend *blk);
--
1.8.3.1
