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[Qemu-devel] [PATCH 04/12] block: throttle-groups: Use BlockBackend poin
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 04/12] block: throttle-groups: Use BlockBackend pointers internally |
Date: |
Tue, 22 Mar 2016 16:33:04 +0100 |
As a first step towards moving I/O throttling to the BlockBackend level,
this patch changes all pointers in struct ThrottleGroup from referencing
a BlockDriverState to referencing a BlockBackend.
This change is valid because we made sure that throttling can only be
enabled on BDSes which have a BB attached.
Signed-off-by: Kevin Wolf <address@hidden>
---
block/io.c | 4 +-
block/throttle-groups.c | 132 ++++++++++++++++++++--------------------
include/block/block_int.h | 1 -
include/block/throttle-groups.h | 4 +-
include/sysemu/block-backend.h | 4 ++
tests/test-throttle.c | 13 ++--
6 files changed, 82 insertions(+), 76 deletions(-)
diff --git a/block/io.c b/block/io.c
index e4438da..fbfbbb2 100644
--- a/block/io.c
+++ b/block/io.c
@@ -93,14 +93,14 @@ void bdrv_io_limits_disable(BlockDriverState *bs)
{
bs->io_limits_enabled = false;
bdrv_start_throttled_reqs(bs);
- throttle_group_unregister_bs(bs);
+ throttle_group_unregister_blk(bs->blk);
}
/* 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);
- throttle_group_register_bs(bs, group);
+ throttle_group_register_blk(bs->blk, group);
bs->io_limits_enabled = true;
}
diff --git a/block/throttle-groups.c b/block/throttle-groups.c
index 4920e09..4ba0fa3 100644
--- a/block/throttle-groups.c
+++ b/block/throttle-groups.c
@@ -23,6 +23,7 @@
*/
#include "qemu/osdep.h"
+#include "sysemu/block-backend.h"
#include "block/throttle-groups.h"
#include "qemu/queue.h"
#include "qemu/thread.h"
@@ -57,8 +58,8 @@ typedef struct ThrottleGroup {
QemuMutex lock; /* This lock protects the following four fields */
ThrottleState ts;
- QLIST_HEAD(, BlockDriverState) head;
- BlockDriverState *tokens[2];
+ QLIST_HEAD(, BlockBackendPublic) head;
+ BlockBackend *tokens[2];
bool any_timer_armed[2];
/* These two are protected by the global throttle_groups_lock */
@@ -145,77 +146,77 @@ const char *throttle_group_get_name(BlockDriverState *bs)
return tg->name;
}
-/* Return the next BlockDriverState in the round-robin sequence,
- * simulating a circular list.
+/* Return the next BlockBackend in the round-robin sequence, simulating a
+ * circular list.
*
* This assumes that tg->lock is held.
*
- * @bs: the current BlockDriverState
- * @ret: the next BlockDriverState in the sequence
+ * @blk: the current BlockBackend
+ * @ret: the next BlockBackend in the sequence
*/
-static BlockDriverState *throttle_group_next_bs(BlockDriverState *bs)
+static BlockBackend *throttle_group_next_blk(BlockBackend *blk)
{
+ BlockDriverState *bs = blk_bs(blk);
ThrottleState *ts = bs->throttle_state;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
- BlockDriverState *next = QLIST_NEXT(bs, round_robin);
+ BlockBackendPublic *next = QLIST_NEXT(blk_get_public(blk), round_robin);
if (!next) {
- return QLIST_FIRST(&tg->head);
+ next = QLIST_FIRST(&tg->head);
}
- return next;
+ return blk_by_public(next);
}
-/* Return the next BlockDriverState in the round-robin sequence with
- * pending I/O requests.
+/* Return the next BlockBackend in the round-robin sequence with pending I/O
+ * requests.
*
* This assumes that tg->lock is held.
*
- * @bs: the current BlockDriverState
+ * @blk: the current BlockBackend
* @is_write: the type of operation (read/write)
- * @ret: the next BlockDriverState with pending requests, or bs
- * if there is none.
+ * @ret: the next BlockBackend with pending requests, or blk if there is
+ * none.
*/
-static BlockDriverState *next_throttle_token(BlockDriverState *bs,
- bool is_write)
+static BlockBackend *next_throttle_token(BlockBackend *blk, bool is_write)
{
- ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts);
- BlockDriverState *token, *start;
+ ThrottleGroup *tg = container_of(blk_bs(blk)->throttle_state,
+ ThrottleGroup, ts);
+ BlockBackend *token, *start;
start = token = tg->tokens[is_write];
/* get next bs round in round robin style */
- token = throttle_group_next_bs(token);
- while (token != start && !token->pending_reqs[is_write]) {
- token = throttle_group_next_bs(token);
+ token = throttle_group_next_blk(token);
+ while (token != start && !blk_bs(token)->pending_reqs[is_write]) {
+ token = throttle_group_next_blk(token);
}
/* If no IO are queued for scheduling on the next round robin token
* then decide the token is the current bs because chances are
* the current bs get the current request queued.
*/
- if (token == start && !token->pending_reqs[is_write]) {
- token = bs;
+ if (token == start && !blk_bs(token)->pending_reqs[is_write]) {
+ token = blk;
}
return token;
}
-/* Check if the next I/O request for a BlockDriverState needs to be
- * throttled or not. If there's no timer set in this group, set one
- * and update the token accordingly.
+/* Check if the next I/O request for a BlockBackend needs to be throttled or
+ * not. If there's no timer set in this group, set one and update the token
+ * accordingly.
*
* This assumes that tg->lock is held.
*
- * @bs: the current BlockDriverState
+ * @blk: the current BlockBackend
* @is_write: the type of operation (read/write)
* @ret: whether the I/O request needs to be throttled or not
*/
-static bool throttle_group_schedule_timer(BlockDriverState *bs,
- bool is_write)
+static bool throttle_group_schedule_timer(BlockBackend *blk, bool is_write)
{
- ThrottleState *ts = bs->throttle_state;
- ThrottleTimers *tt = &bs->throttle_timers;
+ ThrottleState *ts = blk_bs(blk)->throttle_state;
+ ThrottleTimers *tt = &blk_bs(blk)->throttle_timers;
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
bool must_wait;
@@ -226,9 +227,9 @@ static bool throttle_group_schedule_timer(BlockDriverState
*bs,
must_wait = throttle_schedule_timer(ts, tt, is_write);
- /* If a timer just got armed, set bs as the current token */
+ /* If a timer just got armed, set blk as the current token */
if (must_wait) {
- tg->tokens[is_write] = bs;
+ tg->tokens[is_write] = blk;
tg->any_timer_armed[is_write] = true;
}
@@ -239,18 +240,19 @@ static bool
throttle_group_schedule_timer(BlockDriverState *bs,
*
* This assumes that tg->lock is held.
*
- * @bs: the current BlockDriverState
+ * @blk: the current BlockBackend
* @is_write: the type of operation (read/write)
*/
-static void schedule_next_request(BlockDriverState *bs, bool is_write)
+static void schedule_next_request(BlockBackend *blk, bool is_write)
{
+ BlockDriverState *bs = blk_bs(blk);
ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts);
bool must_wait;
- BlockDriverState *token;
+ BlockBackend *token;
/* Check if there's any pending request to schedule next */
- token = next_throttle_token(bs, is_write);
- if (!token->pending_reqs[is_write]) {
+ token = next_throttle_token(blk, is_write);
+ if (!blk_bs(token)->pending_reqs[is_write]) {
return;
}
@@ -262,9 +264,9 @@ static void schedule_next_request(BlockDriverState *bs,
bool is_write)
/* Give preference to requests from the current bs */
if (qemu_in_coroutine() &&
qemu_co_queue_next(&bs->throttled_reqs[is_write])) {
- token = bs;
+ token = blk;
} else {
- ThrottleTimers *tt = &token->throttle_timers;
+ ThrottleTimers *tt = &blk_bs(token)->throttle_timers;
int64_t now = qemu_clock_get_ns(tt->clock_type);
timer_mod(tt->timers[is_write], now + 1);
tg->any_timer_armed[is_write] = true;
@@ -286,13 +288,13 @@ void coroutine_fn
throttle_group_co_io_limits_intercept(BlockDriverState *bs,
bool is_write)
{
bool must_wait;
- BlockDriverState *token;
+ BlockBackend *token;
ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts);
qemu_mutex_lock(&tg->lock);
/* First we check if this I/O has to be throttled. */
- token = next_throttle_token(bs, is_write);
+ token = next_throttle_token(bs->blk, is_write);
must_wait = throttle_group_schedule_timer(token, is_write);
/* Wait if there's a timer set or queued requests of this type */
@@ -308,7 +310,7 @@ void coroutine_fn
throttle_group_co_io_limits_intercept(BlockDriverState *bs,
throttle_account(bs->throttle_state, is_write, bytes);
/* Schedule the next request */
- schedule_next_request(bs, is_write);
+ schedule_next_request(bs->blk, is_write);
qemu_mutex_unlock(&tg->lock);
}
@@ -377,7 +379,7 @@ static void timer_cb(BlockDriverState *bs, bool is_write)
* scheduling the next one */
if (empty_queue) {
qemu_mutex_lock(&tg->lock);
- schedule_next_request(bs, is_write);
+ schedule_next_request(bs->blk, is_write);
qemu_mutex_unlock(&tg->lock);
}
}
@@ -392,17 +394,17 @@ static void write_timer_cb(void *opaque)
timer_cb(opaque, true);
}
-/* Register a BlockDriverState in the throttling group, also
- * initializing its timers and updating its throttle_state pointer to
- * point to it. If a throttling group with that name does not exist
- * yet, it will be created.
+/* Register a BlockBackend in the throttling group, also initializing its
+ * timers and updating its throttle_state pointer to point to it. If a
+ * throttling group with that name does not exist yet, it will be created.
*
- * @bs: the BlockDriverState to insert
+ * @blk: the BlockBackend to insert
* @groupname: the name of the group
*/
-void throttle_group_register_bs(BlockDriverState *bs, const char *groupname)
+void throttle_group_register_blk(BlockBackend *blk, const char *groupname)
{
int i;
+ BlockDriverState *bs = blk_bs(blk);
ThrottleState *ts = throttle_group_incref(groupname);
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
int clock_type = QEMU_CLOCK_REALTIME;
@@ -415,14 +417,14 @@ void throttle_group_register_bs(BlockDriverState *bs,
const char *groupname)
bs->throttle_state = ts;
qemu_mutex_lock(&tg->lock);
- /* If the ThrottleGroup is new set this BlockDriverState as the token */
+ /* If the ThrottleGroup is new set this BlockBackend as the token */
for (i = 0; i < 2; i++) {
if (!tg->tokens[i]) {
- tg->tokens[i] = bs;
+ tg->tokens[i] = blk;
}
}
- QLIST_INSERT_HEAD(&tg->head, bs, round_robin);
+ QLIST_INSERT_HEAD(&tg->head, blk_get_public(blk), round_robin);
throttle_timers_init(&bs->throttle_timers,
bdrv_get_aio_context(bs),
@@ -434,19 +436,19 @@ void throttle_group_register_bs(BlockDriverState *bs,
const char *groupname)
qemu_mutex_unlock(&tg->lock);
}
-/* Unregister a BlockDriverState from its group, removing it from the
- * list, destroying the timers and setting the throttle_state pointer
- * to NULL.
+/* Unregister a BlockBackend from its group, removing it from the list,
+ * destroying the timers and setting the throttle_state pointer to NULL.
*
- * The BlockDriverState must not have pending throttled requests, so
- * the caller has to drain them first.
+ * The BlockBackend must not have pending throttled requests, so the caller has
+ * to drain them first.
*
* The group will be destroyed if it's empty after this operation.
*
- * @bs: the BlockDriverState to remove
+ * @blk: the BlockBackend to remove
*/
-void throttle_group_unregister_bs(BlockDriverState *bs)
+void throttle_group_unregister_blk(BlockBackend *blk)
{
+ BlockDriverState *bs = blk_bs(blk);
ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts);
int i;
@@ -456,10 +458,10 @@ void throttle_group_unregister_bs(BlockDriverState *bs)
qemu_mutex_lock(&tg->lock);
for (i = 0; i < 2; i++) {
- if (tg->tokens[i] == bs) {
- BlockDriverState *token = throttle_group_next_bs(bs);
+ if (tg->tokens[i] == blk) {
+ BlockBackend *token = throttle_group_next_blk(blk);
/* Take care of the case where this is the last bs in the group */
- if (token == bs) {
+ if (token == blk) {
token = NULL;
}
tg->tokens[i] = token;
@@ -467,7 +469,7 @@ void throttle_group_unregister_bs(BlockDriverState *bs)
}
/* remove the current bs from the list */
- QLIST_REMOVE(bs, round_robin);
+ QLIST_REMOVE(blk_get_public(blk), round_robin);
throttle_timers_destroy(&bs->throttle_timers);
qemu_mutex_unlock(&tg->lock);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 9c56bd9..ade6276 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -426,7 +426,6 @@ struct BlockDriverState {
ThrottleState *throttle_state;
ThrottleTimers throttle_timers;
unsigned pending_reqs[2];
- QLIST_ENTRY(BlockDriverState) round_robin;
/* Offset after the highest byte written to */
uint64_t wr_highest_offset;
diff --git a/include/block/throttle-groups.h b/include/block/throttle-groups.h
index aba28f3..46b843e 100644
--- a/include/block/throttle-groups.h
+++ b/include/block/throttle-groups.h
@@ -36,8 +36,8 @@ void throttle_group_unref(ThrottleState *ts);
void throttle_group_config(BlockDriverState *bs, ThrottleConfig *cfg);
void throttle_group_get_config(BlockDriverState *bs, ThrottleConfig *cfg);
-void throttle_group_register_bs(BlockDriverState *bs, const char *groupname);
-void throttle_group_unregister_bs(BlockDriverState *bs);
+void throttle_group_register_blk(BlockBackend *blk, const char *groupname);
+void throttle_group_unregister_blk(BlockBackend *blk);
void coroutine_fn throttle_group_co_io_limits_intercept(BlockDriverState *bs,
unsigned int bytes,
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index bb4ff6f..af2abf3 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -63,6 +63,10 @@ typedef struct BlockDevOps {
* fields that must be public. This is in particular for QLIST_ENTRY() and
* friends so that BlockBackends can be kept in lists outside block-backend.c
*/
typedef struct BlockBackendPublic {
+ /* I/O throttling */
+ /* The following fields are protected by the ThrottleGroup lock.
+ * See the ThrottleGroup documentation for details. */
+ QLIST_ENTRY(BlockBackendPublic) round_robin;
} BlockBackendPublic;
BlockBackend *blk_new(Error **errp);
diff --git a/tests/test-throttle.c b/tests/test-throttle.c
index d0b3c86..f03f71a 100644
--- a/tests/test-throttle.c
+++ b/tests/test-throttle.c
@@ -19,6 +19,7 @@
#include "qemu/throttle.h"
#include "qemu/error-report.h"
#include "block/throttle-groups.h"
+#include "sysemu/block-backend.h"
static AioContext *ctx;
static LeakyBucket bkt;
@@ -588,9 +589,9 @@ static void test_groups(void)
g_assert(bdrv2->throttle_state == NULL);
g_assert(bdrv3->throttle_state == NULL);
- throttle_group_register_bs(bdrv1, "bar");
- throttle_group_register_bs(bdrv2, "foo");
- throttle_group_register_bs(bdrv3, "bar");
+ throttle_group_register_blk(blk1, "bar");
+ throttle_group_register_blk(blk2, "foo");
+ throttle_group_register_blk(blk3, "bar");
g_assert(bdrv1->throttle_state != NULL);
g_assert(bdrv2->throttle_state != NULL);
@@ -622,9 +623,9 @@ static void test_groups(void)
throttle_group_get_config(bdrv3, &cfg2);
g_assert(!memcmp(&cfg1, &cfg2, sizeof(cfg1)));
- throttle_group_unregister_bs(bdrv1);
- throttle_group_unregister_bs(bdrv2);
- throttle_group_unregister_bs(bdrv3);
+ throttle_group_unregister_blk(blk1);
+ throttle_group_unregister_blk(blk2);
+ throttle_group_unregister_blk(blk3);
g_assert(bdrv1->throttle_state == NULL);
g_assert(bdrv2->throttle_state == NULL);
--
1.8.3.1
- [Qemu-devel] [PATCH 02/12] block: Make sure throttled BDSes always have a BB, (continued)
[Qemu-devel] [PATCH 04/12] block: throttle-groups: Use BlockBackend pointers internally,
Kevin Wolf <=
[Qemu-devel] [PATCH 08/12] block: Move I/O throttling configuration functions to BlockBackend, Kevin Wolf, 2016/03/22
[Qemu-devel] [PATCH 11/12] block: Decouple throttling from BlockDriverState, Kevin Wolf, 2016/03/22
[Qemu-devel] [PATCH 05/12] block: Convert throttle_group_get_name() to BlockBackend, Kevin Wolf, 2016/03/22
[Qemu-devel] [PATCH 07/12] block: Move actual I/O throttling to BlockBackend, Kevin Wolf, 2016/03/22
[Qemu-devel] [PATCH 10/12] block: Drain throttling queue with BdrvChild callback, Kevin Wolf, 2016/03/22
[Qemu-devel] [PATCH 06/12] block: Move throttling fields from BDS to BB, Kevin Wolf, 2016/03/22
[Qemu-devel] [PATCH 12/12] block: Don't check throttled reqs in bdrv_requests_pending(), Kevin Wolf, 2016/03/22