From 25b8e4db7f3baca47244ccd945eb62b32a6e2019 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Thu, 2 Aug 2018 17:50:26 +0300 Subject: throttle-groups: Don't allow timers without throttled requests Commit 6fccbb475bc6effc313ee9481726a1748b6dae57 fixed a bug caused by QEMU attempting to remove a throttle group member with no pending requests but an active timer set. This was the result of a previous bdrv_drained_begin() call processing the throttled requests but leaving the timer untouched. Although the commit does solve the problem, the situation shouldn't happen in the first place. If we try to drain a throttle group member which has a timer set, we should cancel the timer instead of ignoring it. Signed-off-by: Alberto Garcia Signed-off-by: Kevin Wolf --- block/throttle-groups.c | 32 ++++++++++++++++++++++---------- 1 file changed, 22 insertions(+), 10 deletions(-) (limited to 'block/throttle-groups.c') diff --git a/block/throttle-groups.c b/block/throttle-groups.c index d46c56b..5d8213a 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -36,6 +36,7 @@ static void throttle_group_obj_init(Object *obj); static void throttle_group_obj_complete(UserCreatable *obj, Error **errp); +static void timer_cb(ThrottleGroupMember *tgm, bool is_write); /* The ThrottleGroup structure (with its ThrottleState) is shared * among different ThrottleGroupMembers and it's independent from @@ -424,15 +425,31 @@ static void throttle_group_restart_queue(ThrottleGroupMember *tgm, bool is_write rd->tgm = tgm; rd->is_write = is_write; + /* This function is called when a timer is fired or when + * throttle_group_restart_tgm() is called. Either way, there can + * be no timer pending on this tgm at this point */ + assert(!timer_pending(tgm->throttle_timers.timers[is_write])); + co = qemu_coroutine_create(throttle_group_restart_queue_entry, rd); aio_co_enter(tgm->aio_context, co); } void throttle_group_restart_tgm(ThrottleGroupMember *tgm) { + int i; + if (tgm->throttle_state) { - throttle_group_restart_queue(tgm, 0); - throttle_group_restart_queue(tgm, 1); + for (i = 0; i < 2; i++) { + QEMUTimer *t = tgm->throttle_timers.timers[i]; + if (timer_pending(t)) { + /* If there's a pending timer on this tgm, fire it now */ + timer_del(t); + timer_cb(tgm, i); + } else { + /* Else run the next request from the queue manually */ + throttle_group_restart_queue(tgm, i); + } + } } } @@ -567,16 +584,11 @@ void throttle_group_unregister_tgm(ThrottleGroupMember *tgm) return; } - assert(tgm->pending_reqs[0] == 0 && tgm->pending_reqs[1] == 0); - assert(qemu_co_queue_empty(&tgm->throttled_reqs[0])); - assert(qemu_co_queue_empty(&tgm->throttled_reqs[1])); - qemu_mutex_lock(&tg->lock); for (i = 0; i < 2; i++) { - if (timer_pending(tgm->throttle_timers.timers[i])) { - tg->any_timer_armed[i] = false; - schedule_next_request(tgm, i); - } + assert(tgm->pending_reqs[i] == 0); + assert(qemu_co_queue_empty(&tgm->throttled_reqs[i])); + assert(!timer_pending(tgm->throttle_timers.timers[i])); if (tg->tokens[i] == tgm) { token = throttle_group_next_tgm(tgm); /* Take care of the case where this is the last tgm in the group */ -- cgit v1.1