Mercurial > hg > nginx
view src/event/modules/ngx_win32_poll_module.c @ 8946:56dec0d4e5b1 quic
QUIC: avoid excessive buffer allocations in stream output.
Previously, when a few bytes were send to a QUIC stream by the application, a
4K buffer was allocated for these bytes. Then a STREAM frame was created and
that entire buffer was used as data for that frame. The frame with the buffer
were in use up until the frame was acked by client. Meanwhile, when more
bytes were send to the stream, more buffers were allocated and assigned as
data to newer STREAM frames. In this scenario most buffer memory is unused.
Now the unused part of the stream output buffer is available for further
stream output while earlier parts of the buffer are waiting to be acked.
This is achieved by splitting the output buffer.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Fri, 24 Dec 2021 18:13:51 +0300 |
parents | efd71d49bde0 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Maxim Dounin * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> static ngx_int_t ngx_poll_init(ngx_cycle_t *cycle, ngx_msec_t timer); static void ngx_poll_done(ngx_cycle_t *cycle); static ngx_int_t ngx_poll_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_poll_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_poll_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags); static char *ngx_poll_init_conf(ngx_cycle_t *cycle, void *conf); static struct pollfd *event_list; static ngx_connection_t **event_index; static ngx_uint_t nevents; static ngx_str_t poll_name = ngx_string("poll"); static ngx_event_module_t ngx_poll_module_ctx = { &poll_name, NULL, /* create configuration */ ngx_poll_init_conf, /* init configuration */ { ngx_poll_add_event, /* add an event */ ngx_poll_del_event, /* delete an event */ ngx_poll_add_event, /* enable an event */ ngx_poll_del_event, /* disable an event */ NULL, /* add an connection */ NULL, /* delete an connection */ NULL, /* trigger a notify */ ngx_poll_process_events, /* process the events */ ngx_poll_init, /* init the events */ ngx_poll_done /* done the events */ } }; ngx_module_t ngx_poll_module = { NGX_MODULE_V1, &ngx_poll_module_ctx, /* module context */ NULL, /* module directives */ NGX_EVENT_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_int_t ngx_poll_init(ngx_cycle_t *cycle, ngx_msec_t timer) { struct pollfd *list; ngx_connection_t **index; if (event_list == NULL) { nevents = 0; } if (ngx_process >= NGX_PROCESS_WORKER || cycle->old_cycle == NULL || cycle->old_cycle->connection_n < cycle->connection_n) { list = ngx_alloc(sizeof(struct pollfd) * cycle->connection_n, cycle->log); if (list == NULL) { return NGX_ERROR; } if (event_list) { ngx_memcpy(list, event_list, sizeof(struct pollfd) * nevents); ngx_free(event_list); } event_list = list; index = ngx_alloc(sizeof(ngx_connection_t *) * cycle->connection_n, cycle->log); if (index == NULL) { return NGX_ERROR; } if (event_index) { ngx_memcpy(index, event_index, sizeof(ngx_connection_t *) * nevents); ngx_free(event_index); } event_index = index; } ngx_io = ngx_os_io; ngx_event_actions = ngx_poll_module_ctx.actions; ngx_event_flags = NGX_USE_LEVEL_EVENT; return NGX_OK; } static void ngx_poll_done(ngx_cycle_t *cycle) { ngx_free(event_list); ngx_free(event_index); event_list = NULL; event_index = NULL; } static ngx_int_t ngx_poll_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_event_t *e; ngx_connection_t *c; c = ev->data; ev->active = 1; if (ev->index != NGX_INVALID_INDEX) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "poll event fd:%d ev:%i is already set", c->fd, event); return NGX_OK; } if (event == NGX_READ_EVENT) { e = c->write; #if (NGX_READ_EVENT != POLLIN) event = POLLIN; #endif } else { e = c->read; #if (NGX_WRITE_EVENT != POLLOUT) event = POLLOUT; #endif } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll add event: fd:%d ev:%i", c->fd, event); if (e == NULL || e->index == NGX_INVALID_INDEX) { event_list[nevents].fd = c->fd; event_list[nevents].events = (short) event; event_list[nevents].revents = 0; event_index[nevents] = c; ev->index = nevents; nevents++; } else { ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll add index: %i", e->index); event_list[e->index].events |= (short) event; ev->index = e->index; } return NGX_OK; } static ngx_int_t ngx_poll_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_event_t *e; ngx_connection_t *c; c = ev->data; ev->active = 0; if (ev->index == NGX_INVALID_INDEX) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "poll event fd:%d ev:%i is already deleted", c->fd, event); return NGX_OK; } if (event == NGX_READ_EVENT) { e = c->write; #if (NGX_READ_EVENT != POLLIN) event = POLLIN; #endif } else { e = c->read; #if (NGX_WRITE_EVENT != POLLOUT) event = POLLOUT; #endif } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll del event: fd:%d ev:%i", c->fd, event); if (e == NULL || e->index == NGX_INVALID_INDEX) { nevents--; if (ev->index < nevents) { ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "index: copy event %ui to %i", nevents, ev->index); event_list[ev->index] = event_list[nevents]; event_index[ev->index] = event_index[nevents]; c = event_index[ev->index]; if (c->fd == (ngx_socket_t) -1) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "unexpected last event"); } else { if (c->read->index == nevents) { c->read->index = ev->index; } if (c->write->index == nevents) { c->write->index = ev->index; } } } } else { ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ev->log, 0, "poll del index: %i", e->index); event_list[e->index].events &= (short) ~event; } ev->index = NGX_INVALID_INDEX; return NGX_OK; } static ngx_int_t ngx_poll_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags) { int ready, revents; ngx_err_t err; ngx_uint_t i, found; ngx_event_t *ev; ngx_queue_t *queue; ngx_connection_t *c; /* NGX_TIMER_INFINITE == INFTIM */ #if (NGX_DEBUG0) if (cycle->log->log_level & NGX_LOG_DEBUG_ALL) { for (i = 0; i < nevents; i++) { ngx_log_debug3(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll: %ui: fd:%d ev:%04Xd", i, event_list[i].fd, event_list[i].events); } } #endif ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll timer: %M", timer); ready = WSAPoll(event_list, (u_int) nevents, (int) timer); err = (ready == -1) ? ngx_errno : 0; if (flags & NGX_UPDATE_TIME || ngx_event_timer_alarm) { ngx_time_update(); } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll ready %d of %ui", ready, nevents); if (err) { ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "WSAPoll() failed"); return NGX_ERROR; } if (ready == 0) { if (timer != NGX_TIMER_INFINITE) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "WSAPoll() returned no events without timeout"); return NGX_ERROR; } for (i = 0; i < nevents && ready; i++) { revents = event_list[i].revents; #if 1 ngx_log_debug4(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll: %ui: fd:%d ev:%04Xd rev:%04Xd", i, event_list[i].fd, event_list[i].events, revents); #else if (revents) { ngx_log_debug4(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "poll: %ui: fd:%d ev:%04Xd rev:%04Xd", i, event_list[i].fd, event_list[i].events, revents); } #endif if (revents & POLLNVAL) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "poll() error fd:%d ev:%04Xd rev:%04Xd", event_list[i].fd, event_list[i].events, revents); } if (revents & ~(POLLIN|POLLOUT|POLLERR|POLLHUP|POLLNVAL)) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "strange poll() events fd:%d ev:%04Xd rev:%04Xd", event_list[i].fd, event_list[i].events, revents); } if (event_list[i].fd == (ngx_socket_t) -1) { /* * the disabled event, a workaround for our possible bug, * see the comment below */ continue; } c = event_index[i]; if (c->fd == (ngx_socket_t) -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "unexpected event"); /* * it is certainly our fault and it should be investigated, * in the meantime we disable this event to avoid a CPU spinning */ if (i == nevents - 1) { nevents--; } else { event_list[i].fd = (ngx_socket_t) -1; } continue; } if (revents & (POLLERR|POLLHUP|POLLNVAL)) { /* * if the error events were returned, add POLLIN and POLLOUT * to handle the events at least in one active handler */ revents |= POLLIN|POLLOUT; } found = 0; if ((revents & POLLIN) && c->read->active) { found = 1; ev = c->read; ev->ready = 1; ev->available = -1; queue = ev->accept ? &ngx_posted_accept_events : &ngx_posted_events; ngx_post_event(ev, queue); } if ((revents & POLLOUT) && c->write->active) { found = 1; ev = c->write; ev->ready = 1; ngx_post_event(ev, &ngx_posted_events); } if (found) { ready--; continue; } } if (ready != 0) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "poll ready != events"); } return NGX_OK; } static char * ngx_poll_init_conf(ngx_cycle_t *cycle, void *conf) { ngx_event_conf_t *ecf; ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module); if (ecf->use != ngx_poll_module.ctx_index) { return NGX_CONF_OK; } #if (NGX_LOAD_WSAPOLL) if (!ngx_have_wsapoll) { ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "poll is not available on this platform"); return NGX_CONF_ERROR; } #endif return NGX_CONF_OK; }