From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Vladimir Davydov Subject: [PATCH 02/11] vinyl: refactor quota use/unuse methods Date: Thu, 20 Sep 2018 12:34:07 +0300 Message-Id: <213cb4e19dc12ad5b95c0022e2e027a6a88bb98b.1537435404.git.vdavydov.dev@gmail.com> In-Reply-To: References: In-Reply-To: References: To: kostja@tarantool.org Cc: tarantool-patches@freelists.org List-ID: Some minor refactoring targeted at beautifying the code: - Rename vy_quota_is_exceeded to vy_quota_may_use and pass the requested amount of quota to it explicitly instead of incrementing quota before calling this function and decremented after. Move the definition closer to vy_quota_use, where this function is used. - Implement quota consumption in vy_quota_use via vy_quota_force_use so that there's the only function that increments quota. - Factor out vy_quota_unuse out of vy_qouta_adjust. This function is opposite to vy_quota_force_use. --- src/box/vy_quota.c | 55 +++++++++++++++++++++++++----------------------------- 1 file changed, 25 insertions(+), 30 deletions(-) diff --git a/src/box/vy_quota.c b/src/box/vy_quota.c index d3588b6e..8ead5c4b 100644 --- a/src/box/vy_quota.c +++ b/src/box/vy_quota.c @@ -68,16 +68,6 @@ static const size_t VY_DEFAULT_DUMP_BANDWIDTH = 10 * 1024 * 1024; */ enum { VY_DUMP_BANDWIDTH_PCT = 10 }; -/** - * Returns true if the quota limit is exceeded and so consumers - * have to wait. - */ -static inline bool -vy_quota_is_exceeded(struct vy_quota *q) -{ - return q->used > q->limit; -} - static void vy_quota_timer_cb(ev_loop *loop, ev_timer *timer, int events) { @@ -209,25 +199,29 @@ vy_quota_force_use(struct vy_quota *q, size_t size) q->quota_exceeded_cb(q); } +/** + * Returns true if the requested amount of quota may be consumed, + * or false if consumers have to wait. + */ +static bool +vy_quota_may_use(struct vy_quota *q, size_t size) +{ + return q->used + size <= q->limit; +} + int vy_quota_use(struct vy_quota *q, size_t size, double timeout) { - q->used += size; - q->use_curr += size; - if (vy_quota_is_exceeded(q)) { + if (!vy_quota_may_use(q, size)) { /* Wait for quota. */ double start_time = ev_monotonic_now(loop()); double deadline = start_time + timeout; do { q->quota_exceeded_cb(q); - q->used -= size; - q->use_curr -= size; if (fiber_cond_wait_deadline(&q->cond, deadline) != 0) return -1; /* timed out */ - q->used += size; - q->use_curr += size; - } while (vy_quota_is_exceeded(q)); + } while (!vy_quota_may_use(q, size)); double wait_time = ev_monotonic_now(loop()) - start_time; if (wait_time > q->too_long_threshold) { @@ -240,24 +234,25 @@ vy_quota_use(struct vy_quota *q, size_t size, double timeout) */ fiber_cond_signal(&q->cond); } - if (q->used >= q->watermark) - q->quota_exceeded_cb(q); + vy_quota_force_use(q, size); return 0; } +static void +vy_quota_unuse(struct vy_quota *q, size_t size) +{ + assert(q->used >= size); + q->used -= size; + /* use_curr could have been reset on timeout. */ + q->use_curr -= MIN(q->use_curr, size); + fiber_cond_signal(&q->cond); +} + void vy_quota_adjust(struct vy_quota *q, size_t reserved, size_t used) { - if (reserved > used) { - size_t excess = reserved - used; - assert(q->used >= excess); - q->used -= excess; - if (q->use_curr >= excess) - q->use_curr -= excess; - else /* was reset by timeout */ - q->use_curr = 0; - fiber_cond_signal(&q->cond); - } + if (reserved > used) + vy_quota_unuse(q, reserved - used); if (reserved < used) vy_quota_force_use(q, used - reserved); } -- 2.11.0