Mercurial > hg > nginx
view src/event/ngx_event_busy_lock.c @ 276:a2d1ccc96111
nginx-0.0.2-2004-03-03-00:14:37 import
author | Igor Sysoev <igor@sysoev.ru> |
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date | Tue, 02 Mar 2004 21:14:37 +0000 |
parents | |
children | e91499541410 |
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#include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> /* * TODO: eliminate mutex and use atomic_xchg(): * ev->next = ev; ngx_atomic_xchg(ngx_posted_events, ev->next); * in ngx_event_busy_unlock() and ngx_event_busy_lock_handler() */ static int ngx_event_busy_lock_look_cachable(ngx_event_busy_lock_t *bl, ngx_event_busy_lock_ctx_t *ctx); static void ngx_event_busy_lock_handler(ngx_event_t *ev); static void ngx_event_busy_lock_posted_handler(ngx_event_t *ev); /* * NGX_OK: the busy lock is held * NGX_BUSY: there are many the busy locks or many the waiting locks * NGX_AGAIN: the all busy locks are held but we will wait the specified time * NGX_ERROR: there was error while the mutex locking */ ngx_int_t ngx_event_busy_lock(ngx_event_busy_lock_t *bl, ngx_event_busy_lock_ctx_t *ctx) { ngx_int_t rc; #if (NGX_THREADS) if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) { return NGX_ERROR; } #endif ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ctx->event->log, 0, "event busy lock: b:%d mb:%d", bl->busy, bl->max_busy); if (bl->busy < bl->max_busy) { bl->busy++; rc = NGX_OK; } else if (ctx->timer && bl->waiting < bl->max_waiting) { bl->waiting++; ngx_add_timer(ctx->event, ctx->timer); ctx->event->event_handler = ngx_event_busy_lock_handler; if (bl->events == NULL) { bl->events = ctx; } else { bl->last->next = ctx; } bl->last = ctx; rc = NGX_AGAIN; } else { rc = NGX_BUSY; } #if (NGX_THREADS) ngx_mutex_unlock(bl->mutex); #endif return rc; } ngx_int_t ngx_event_busy_lock_cachable(ngx_event_busy_lock_t *bl, ngx_event_busy_lock_ctx_t *ctx) { ngx_int_t rc; #if (NGX_THREADS) if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) { return NGX_ERROR; } #endif rc = ngx_event_busy_lock_look_cachable(bl, ctx); ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ctx->event->log, 0, "event busy lock: %d w:%d mw:%d", rc, bl->waiting, bl->max_waiting); /* * NGX_OK: no the same request, there is free slot and we locked it * NGX_BUSY: no the same request and there is no free slot * NGX_AGAIN: the same request is processing */ if (rc == NGX_AGAIN) { if (ctx->timer && bl->waiting < bl->max_waiting) { bl->waiting++; ngx_add_timer(ctx->event, ctx->timer); ctx->event->event_handler = ngx_event_busy_lock_handler; if (bl->events == NULL) { bl->events = ctx; } else { bl->last->next = ctx; } bl->last = ctx; } else { rc = NGX_BUSY; } } #if (NGX_THREADS) ngx_mutex_unlock(bl->mutex); #endif return rc; } ngx_int_t ngx_event_busy_unlock(ngx_event_busy_lock_t *bl, ngx_event_busy_lock_ctx_t *ctx) { ngx_event_t *ev; ngx_event_busy_lock_ctx_t *wakeup; #if (NGX_THREADS) if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) { return NGX_ERROR; } #endif if (bl->events) { wakeup = bl->events; bl->events = bl->events->next; } else { wakeup = NULL; bl->busy--; } /* * MP: * nocachable (bl->md5 == NULL): ngx_shared_mutex_unlock(mutex, !wakeup) * cachable (bl->md5): ??? */ if (wakeup == NULL) { #if (NGX_THREADS) ngx_mutex_unlock(bl->mutex); #endif return NGX_OK; } if (ctx->md5) { for (wakeup = bl->events; wakeup; wakeup = wakeup->next) { if (wakeup->md5 == NULL) { continue; } if (ngx_memcmp(ctx->md5, wakeup->md5, 16) != 0) { continue; } wakeup->handler = ngx_event_busy_lock_posted_handler; wakeup->cache_updated = 1; ev = wakeup->event; #if (NGX_THREADS) if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) { return NGX_ERROR; } #endif ev->next = (ngx_event_t *) ngx_posted_events; ngx_posted_events = ev; #if (NGX_THREADS) ngx_mutex_unlock(ngx_posted_events_mutex); #endif } #if (NGX_THREADS) ngx_mutex_unlock(bl->mutex); #endif } else { bl->waiting--; #if (NGX_THREADS) ngx_mutex_unlock(bl->mutex); #endif wakeup->handler = ngx_event_busy_lock_posted_handler; wakeup->locked = 1; ev = wakeup->event; if (ev->timer_set) { ngx_del_timer(ev); } #if (NGX_THREADS) if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) { return NGX_ERROR; } #endif ev->next = (ngx_event_t *) ngx_posted_events; ngx_posted_events = ev; #if (NGX_THREADS) ngx_mutex_unlock(ngx_posted_events_mutex); #endif } return NGX_OK; } ngx_int_t ngx_event_busy_lock_cancel(ngx_event_busy_lock_t *bl, ngx_event_busy_lock_ctx_t *ctx) { ngx_event_busy_lock_ctx_t *c, *p; #if (NGX_THREADS) if (ngx_mutex_lock(bl->mutex) == NGX_ERROR) { return NGX_ERROR; } #endif bl->waiting--; if (ctx == bl->events) { bl->events = ctx->next; } else { p = bl->events; for (c = bl->events->next; c; c = c->next) { if (c == ctx) { p->next = ctx->next; break; } p = c; } } #if (NGX_THREADS) ngx_mutex_unlock(bl->mutex); #endif return NGX_OK; } static int ngx_event_busy_lock_look_cachable(ngx_event_busy_lock_t *bl, ngx_event_busy_lock_ctx_t *ctx) { ngx_int_t free; ngx_uint_t i, bit, cachable, mask; bit = 0; cachable = 0; free = -1; #if (NGX_SUPPRESS_WARN) mask = 0; #endif for (i = 0; i < bl->max_busy; i++) { if ((bit & 7) == 0) { mask = bl->md5_mask[i / 8]; } if (mask & 1) { if (ngx_memcmp(&bl->md5[i * 16], ctx->md5, 16) == 0) { return NGX_AGAIN; } cachable++; } else if (free == -1) { free = i; } if (cachable == bl->cachable) { if (free == -1 && cachable < bl->max_busy) { free = i + 1; } break; } mask >>= 1; bit++; } if (free == -1) { return NGX_BUSY; } #if 0 if (bl->busy == bl->max_busy) { return NGX_BUSY; } #endif ngx_memcpy(&bl->md5[free * 16], ctx->md5, 16); bl->md5_mask[free / 8] |= 1 << (free & 7); ctx->slot = free; bl->cachable++; bl->busy++; return NGX_OK; } static void ngx_event_busy_lock_handler(ngx_event_t *ev) { ev->event_handler = ngx_event_busy_lock_posted_handler; #if (NGX_THREADS) if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) { return; } #endif ev->next = (ngx_event_t *) ngx_posted_events; ngx_posted_events = ev; #if (NGX_THREADS) ngx_mutex_unlock(ngx_posted_events_mutex); #endif } static void ngx_event_busy_lock_posted_handler(ngx_event_t *ev) { ngx_event_busy_lock_ctx_t *ctx; ctx = ev->data; ctx->handler(ev); }