[Qemu-devel] [PATCH v1 5/8] throttle: Add a way to know if throttle_schedule_timer had armed a timer

["Benoît Canet" <benoit.canet@nodalink.com>]

This will be needed by the group throttling patches for the algorithm to be
accurate.

Signed-off-by: Benoit Canet <benoit.canet@nodalink.com>
---
 block.c                 |  7 +++++--
 include/qemu/throttle.h |  3 ++-
 util/throttle.c         | 12 +++++++-----
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/block.c b/block.c
index 079b0dc..527ea48 100644
--- a/block.c
+++ b/block.c
@@ -202,10 +202,13 @@ static void bdrv_io_limits_intercept(BlockDriverState *bs,
                                      unsigned int bytes,
                                      bool is_write)
 {
+    bool armed;
+
     /* does this io must wait */
     bool must_wait = throttle_schedule_timer(&bs->throttle_state,
                                              &bs->throttle_timers,
-                                             is_write);
+                                             is_write,
+                                             &armed);
 
     /* if must wait or any request of this type throttled queue the IO */
     if (must_wait ||
@@ -219,7 +222,7 @@ static void bdrv_io_limits_intercept(BlockDriverState *bs,
 
     /* if the next request must wait -> do nothing */
     if (throttle_schedule_timer(&bs->throttle_state, &bs->throttle_timers,
-                                is_write)) {
+                                is_write, &armed)) {
         return;
     }
 
diff --git a/include/qemu/throttle.h b/include/qemu/throttle.h
index 3aece3a..3a16c48 100644
--- a/include/qemu/throttle.h
+++ b/include/qemu/throttle.h
@@ -124,7 +124,8 @@ void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg);
 /* usage */
 bool throttle_schedule_timer(ThrottleState *ts,
                              ThrottleTimers *tt,
-                             bool is_write);
+                             bool is_write,
+                             bool *armed);
 
 void throttle_timer_fired(ThrottleState *ts, bool is_write);
 
diff --git a/util/throttle.c b/util/throttle.c
index 0e305e3..a273acb 100644
--- a/util/throttle.c
+++ b/util/throttle.c
@@ -375,11 +375,13 @@ void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg)
  */
 bool throttle_schedule_timer(ThrottleState *ts,
                              ThrottleTimers *tt,
-                             bool is_write)
+                             bool is_write,
+                             bool *armed)
 {
     int64_t now = qemu_clock_get_ns(tt->clock_type);
     int64_t next_timestamp;
     bool must_wait;
+    *armed = false;
 
     must_wait = throttle_compute_timer(ts,
                                        is_write,
@@ -392,12 +394,12 @@ bool throttle_schedule_timer(ThrottleState *ts,
     }
 
     /* request throttled and any timer pending -> do nothing */
-    if (ts->any_timer_armed[is_write]) {
-        return true;
+    if (!ts->any_timer_armed[is_write]) {
+        *armed = true;
+        ts->any_timer_armed[is_write] = true;
+        timer_mod(tt->timers[is_write], next_timestamp);
     }
 
-    ts->any_timer_armed[is_write] = true;
-    timer_mod(tt->timers[is_write], next_timestamp);
     return true;
 }
 
-- 
2.1.1