Mercurial > hg > nginx-quic
view src/event/modules/ngx_win32_select_module.c @ 8759:56dec0d4e5b1 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) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> static ngx_int_t ngx_select_init(ngx_cycle_t *cycle, ngx_msec_t timer); static void ngx_select_done(ngx_cycle_t *cycle); static ngx_int_t ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_select_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags); static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle); static char *ngx_select_init_conf(ngx_cycle_t *cycle, void *conf); static fd_set master_read_fd_set; static fd_set master_write_fd_set; static fd_set work_read_fd_set; static fd_set work_write_fd_set; static fd_set work_except_fd_set; static ngx_uint_t max_read; static ngx_uint_t max_write; static ngx_uint_t nevents; static ngx_event_t **event_index; static ngx_str_t select_name = ngx_string("select"); static ngx_event_module_t ngx_select_module_ctx = { &select_name, NULL, /* create configuration */ ngx_select_init_conf, /* init configuration */ { ngx_select_add_event, /* add an event */ ngx_select_del_event, /* delete an event */ ngx_select_add_event, /* enable an event */ ngx_select_del_event, /* disable an event */ NULL, /* add an connection */ NULL, /* delete an connection */ NULL, /* trigger a notify */ ngx_select_process_events, /* process the events */ ngx_select_init, /* init the events */ ngx_select_done /* done the events */ } }; ngx_module_t ngx_select_module = { NGX_MODULE_V1, &ngx_select_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_select_init(ngx_cycle_t *cycle, ngx_msec_t timer) { ngx_event_t **index; if (event_index == NULL) { FD_ZERO(&master_read_fd_set); FD_ZERO(&master_write_fd_set); nevents = 0; } if (ngx_process >= NGX_PROCESS_WORKER || cycle->old_cycle == NULL || cycle->old_cycle->connection_n < cycle->connection_n) { index = ngx_alloc(sizeof(ngx_event_t *) * 2 * cycle->connection_n, cycle->log); if (index == NULL) { return NGX_ERROR; } if (event_index) { ngx_memcpy(index, event_index, sizeof(ngx_event_t *) * nevents); ngx_free(event_index); } event_index = index; } ngx_io = ngx_os_io; ngx_event_actions = ngx_select_module_ctx.actions; ngx_event_flags = NGX_USE_LEVEL_EVENT; max_read = 0; max_write = 0; return NGX_OK; } static void ngx_select_done(ngx_cycle_t *cycle) { ngx_free(event_index); event_index = NULL; } static ngx_int_t ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_connection_t *c; c = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "select add event fd:%d ev:%i", c->fd, event); if (ev->index != NGX_INVALID_INDEX) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "select event fd:%d ev:%i is already set", c->fd, event); return NGX_OK; } if ((event == NGX_READ_EVENT && ev->write) || (event == NGX_WRITE_EVENT && !ev->write)) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "invalid select %s event fd:%d ev:%i", ev->write ? "write" : "read", c->fd, event); return NGX_ERROR; } if ((event == NGX_READ_EVENT && max_read >= FD_SETSIZE) || (event == NGX_WRITE_EVENT && max_write >= FD_SETSIZE)) { ngx_log_error(NGX_LOG_ERR, ev->log, 0, "maximum number of descriptors " "supported by select() is %d", FD_SETSIZE); return NGX_ERROR; } if (event == NGX_READ_EVENT) { FD_SET(c->fd, &master_read_fd_set); max_read++; } else if (event == NGX_WRITE_EVENT) { FD_SET(c->fd, &master_write_fd_set); max_write++; } ev->active = 1; event_index[nevents] = ev; ev->index = nevents; nevents++; return NGX_OK; } static ngx_int_t ngx_select_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) { return NGX_OK; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "select del event fd:%d ev:%i", c->fd, event); if (event == NGX_READ_EVENT) { FD_CLR(c->fd, &master_read_fd_set); max_read--; } else if (event == NGX_WRITE_EVENT) { FD_CLR(c->fd, &master_write_fd_set); max_write--; } if (ev->index < --nevents) { e = event_index[nevents]; event_index[ev->index] = e; e->index = ev->index; } ev->index = NGX_INVALID_INDEX; return NGX_OK; } static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags) { int ready, nready; ngx_err_t err; ngx_uint_t i, found; ngx_event_t *ev; ngx_queue_t *queue; struct timeval tv, *tp; ngx_connection_t *c; #if (NGX_DEBUG) if (cycle->log->log_level & NGX_LOG_DEBUG_ALL) { for (i = 0; i < nevents; i++) { ev = event_index[i]; c = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select event: fd:%d wr:%d", c->fd, ev->write); } } #endif if (timer == NGX_TIMER_INFINITE) { tp = NULL; } else { tv.tv_sec = (long) (timer / 1000); tv.tv_usec = (long) ((timer % 1000) * 1000); tp = &tv; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select timer: %M", timer); work_read_fd_set = master_read_fd_set; work_write_fd_set = master_write_fd_set; work_except_fd_set = master_write_fd_set; if (max_read || max_write) { ready = select(0, &work_read_fd_set, &work_write_fd_set, &work_except_fd_set, tp); } else { /* * Winsock select() requires that at least one descriptor set must be * be non-null, and any non-null descriptor set must contain at least * one handle to a socket. Otherwise select() returns WSAEINVAL. */ ngx_msleep(timer); ready = 0; } err = (ready == -1) ? ngx_socket_errno : 0; if (flags & NGX_UPDATE_TIME) { ngx_time_update(); } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select ready %d", ready); if (err) { ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "select() failed"); if (err == WSAENOTSOCK) { ngx_select_repair_fd_sets(cycle); } return NGX_ERROR; } if (ready == 0) { if (timer != NGX_TIMER_INFINITE) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "select() returned no events without timeout"); return NGX_ERROR; } nready = 0; for (i = 0; i < nevents; i++) { ev = event_index[i]; c = ev->data; found = 0; if (ev->write) { if (FD_ISSET(c->fd, &work_write_fd_set)) { found++; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select write %d", c->fd); } if (FD_ISSET(c->fd, &work_except_fd_set)) { found++; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select except %d", c->fd); } } else { if (FD_ISSET(c->fd, &work_read_fd_set)) { found++; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select read %d", c->fd); } } if (found) { ev->ready = 1; ev->available = -1; queue = ev->accept ? &ngx_posted_accept_events : &ngx_posted_events; ngx_post_event(ev, queue); nready += found; } } if (ready != nready) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "select ready != events: %d:%d", ready, nready); ngx_select_repair_fd_sets(cycle); } return NGX_OK; } static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle) { int n; u_int i; socklen_t len; ngx_err_t err; ngx_socket_t s; for (i = 0; i < master_read_fd_set.fd_count; i++) { s = master_read_fd_set.fd_array[i]; len = sizeof(int); if (getsockopt(s, SOL_SOCKET, SO_TYPE, (char *) &n, &len) == -1) { err = ngx_socket_errno; ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "invalid descriptor #%d in read fd_set", s); FD_CLR(s, &master_read_fd_set); } } for (i = 0; i < master_write_fd_set.fd_count; i++) { s = master_write_fd_set.fd_array[i]; len = sizeof(int); if (getsockopt(s, SOL_SOCKET, SO_TYPE, (char *) &n, &len) == -1) { err = ngx_socket_errno; ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "invalid descriptor #%d in write fd_set", s); FD_CLR(s, &master_write_fd_set); } } } static char * ngx_select_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_select_module.ctx_index) { return NGX_CONF_OK; } return NGX_CONF_OK; }