From d85b08c6e27d796dbb653b8ae9584080361c1498 Mon Sep 17 00:00:00 2001 From: zhenwei pi Date: Fri, 28 Jul 2023 10:20:00 +0800 Subject: [PATCH] throttle: support read-only and write-only Only one direction is necessary in several scenarios: - a read-only disk - operations on a device are considered as *write* only. For example, encrypt/decrypt/sign/verify operations on a cryptodev use a single *write* timer(read timer callback is defined, but never invoked). Allow a single direction in throttle, this reduces memory, and uplayer does not need a dummy callback any more. Reviewed-by: Alberto Garcia Reviewed-by: Hanna Czenczek Signed-off-by: zhenwei pi Message-Id: <20230728022006.1098509-4-pizhenwei@bytedance.com> Signed-off-by: Hanna Czenczek --- util/throttle.c | 42 ++++++++++++++++++++++++++++-------------- 1 file changed, 28 insertions(+), 14 deletions(-) diff --git a/util/throttle.c b/util/throttle.c index 5642e61763..0439028d21 100644 --- a/util/throttle.c +++ b/util/throttle.c @@ -199,12 +199,15 @@ static bool throttle_compute_timer(ThrottleState *ts, void throttle_timers_attach_aio_context(ThrottleTimers *tt, AioContext *new_context) { - tt->timers[THROTTLE_READ] = - aio_timer_new(new_context, tt->clock_type, SCALE_NS, - tt->timer_cb[THROTTLE_READ], tt->timer_opaque); - tt->timers[THROTTLE_WRITE] = - aio_timer_new(new_context, tt->clock_type, SCALE_NS, - tt->timer_cb[THROTTLE_WRITE], tt->timer_opaque); + ThrottleDirection dir; + + for (dir = THROTTLE_READ; dir < THROTTLE_MAX; dir++) { + if (tt->timer_cb[dir]) { + tt->timers[dir] = + aio_timer_new(new_context, tt->clock_type, SCALE_NS, + tt->timer_cb[dir], tt->timer_opaque); + } + } } /* @@ -235,6 +238,7 @@ void throttle_timers_init(ThrottleTimers *tt, QEMUTimerCB *write_timer_cb, void *timer_opaque) { + assert(read_timer_cb || write_timer_cb); memset(tt, 0, sizeof(ThrottleTimers)); tt->clock_type = clock_type; @@ -247,7 +251,9 @@ void throttle_timers_init(ThrottleTimers *tt, /* destroy a timer */ static void throttle_timer_destroy(QEMUTimer **timer) { - assert(*timer != NULL); + if (*timer == NULL) { + return; + } timer_free(*timer); *timer = NULL; @@ -256,10 +262,10 @@ static void throttle_timer_destroy(QEMUTimer **timer) /* Remove timers from event loop */ void throttle_timers_detach_aio_context(ThrottleTimers *tt) { - int i; + ThrottleDirection dir; - for (i = 0; i < THROTTLE_MAX; i++) { - throttle_timer_destroy(&tt->timers[i]); + for (dir = THROTTLE_READ; dir < THROTTLE_MAX; dir++) { + throttle_timer_destroy(&tt->timers[dir]); } } @@ -272,8 +278,12 @@ void throttle_timers_destroy(ThrottleTimers *tt) /* is any throttling timer configured */ bool throttle_timers_are_initialized(ThrottleTimers *tt) { - if (tt->timers[0]) { - return true; + ThrottleDirection dir; + + for (dir = THROTTLE_READ; dir < THROTTLE_MAX; dir++) { + if (tt->timers[dir]) { + return true; + } } return false; @@ -424,8 +434,12 @@ bool throttle_schedule_timer(ThrottleState *ts, { int64_t now = qemu_clock_get_ns(tt->clock_type); int64_t next_timestamp; + QEMUTimer *timer; bool must_wait; + timer = is_write ? tt->timers[THROTTLE_WRITE] : tt->timers[THROTTLE_READ]; + assert(timer); + must_wait = throttle_compute_timer(ts, is_write, now, @@ -437,12 +451,12 @@ bool throttle_schedule_timer(ThrottleState *ts, } /* request throttled and timer pending -> do nothing */ - if (timer_pending(tt->timers[is_write])) { + if (timer_pending(timer)) { return true; } /* request throttled and timer not pending -> arm timer */ - timer_mod(tt->timers[is_write], next_timestamp); + timer_mod(timer, next_timestamp); return true; }