blob: 4d499a3aefc89ab4b81459ce77dd701bdcbcc1c4 [file] [log] [blame]
/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
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_AGAIN: the all busy locks are held but we will wait the specified time
* NGX_BUSY: ctx->timer == 0: there are many the busy locks
* ctx->timer != 0: there are many the waiting locks
* NGX_ERROR: an error occured 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_mutex_lock(bl->mutex) == NGX_ERROR) {
return NGX_ERROR;
}
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->handler = ngx_event_busy_lock_handler;
if (bl->events) {
bl->last->next = ctx;
} else {
bl->events = ctx;
}
bl->last = ctx;
rc = NGX_AGAIN;
} else {
rc = NGX_BUSY;
}
ngx_mutex_unlock(bl->mutex);
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_mutex_lock(bl->mutex) == NGX_ERROR) {
return NGX_ERROR;
}
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->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;
}
}
ngx_mutex_unlock(bl->mutex);
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_mutex_lock(bl->mutex) == NGX_ERROR) {
return NGX_ERROR;
}
if (bl->events) {
wakeup = bl->events;
bl->events = bl->events->next;
} else {
wakeup = NULL;
bl->busy--;
}
/*
* MP: all ctx's and their queue must be in shared memory,
* each ctx has pid to wake up
*/
if (wakeup == NULL) {
ngx_mutex_unlock(bl->mutex);
return NGX_OK;
}
if (ctx->md5) {
for (wakeup = bl->events; wakeup; wakeup = wakeup->next) {
if (wakeup->md5 == NULL || wakeup->slot != ctx->slot) {
continue;
}
wakeup->handler = ngx_event_busy_lock_posted_handler;
wakeup->cache_updated = 1;
ev = wakeup->event;
if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) {
return NGX_ERROR;
}
ngx_post_event(ev);
ngx_mutex_unlock(ngx_posted_events_mutex);
}
ngx_mutex_unlock(bl->mutex);
} else {
bl->waiting--;
ngx_mutex_unlock(bl->mutex);
wakeup->handler = ngx_event_busy_lock_posted_handler;
wakeup->locked = 1;
ev = wakeup->event;
if (ev->timer_set) {
ngx_del_timer(ev);
}
if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) {
return NGX_ERROR;
}
ngx_post_event(ev);
ngx_mutex_unlock(ngx_posted_events_mutex);
}
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_mutex_lock(bl->mutex) == NGX_ERROR) {
return NGX_ERROR;
}
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;
}
}
ngx_mutex_unlock(bl->mutex);
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) {
ctx->waiting = 1;
ctx->slot = i;
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)
{
if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) {
return;
}
ngx_post_event(ev);
ngx_mutex_unlock(ngx_posted_events_mutex);
ev->handler = ngx_event_busy_lock_posted_handler;
}
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);
}