# HG changeset patch # User Valentin Bartenev # Date 1463149163 -10800 # Node ID f7849bfb6d21146b2ef5692a5ce349c697d88731 # Parent db699978a33fe19d786e95e00143eb2b6a1662c0 Improved EPOLLRDHUP handling. When it's known that the kernel supports EPOLLRDHUP, there is no need in additional recv() call to get EOF or error when the flag is absent in the event generated by the kernel. A special runtime test is done at startup to detect if EPOLLRDHUP is actually supported by the kernel because epoll_ctl() silently ignores unknown flags. With this knowledge it's now possible to drop the "ready" flag for partial read. Previously, the "ready" flag was kept until the recv() returned EOF or error. In particular, this change allows the lingering close heuristics (which relies on the "ready" flag state) to actually work on Linux, and not wait for more data in most cases. The "available" flag is now used in the read event with the semantics similar to the corresponding counter in kqueue. diff --git a/src/event/modules/ngx_epoll_module.c b/src/event/modules/ngx_epoll_module.c --- a/src/event/modules/ngx_epoll_module.c +++ b/src/event/modules/ngx_epoll_module.c @@ -123,6 +123,7 @@ static ngx_int_t ngx_epoll_process_event static void ngx_epoll_eventfd_handler(ngx_event_t *ev); #endif +static ngx_int_t ngx_epoll_module_init(ngx_cycle_t *cycle); static void *ngx_epoll_create_conf(ngx_cycle_t *cycle); static char *ngx_epoll_init_conf(ngx_cycle_t *cycle, void *conf); @@ -146,6 +147,10 @@ static ngx_connection_t ngx_eventfd_ #endif +#if (NGX_HAVE_EPOLLRDHUP) +ngx_uint_t ngx_use_epoll_rdhup; +#endif + static ngx_str_t epoll_name = ngx_string("epoll"); static ngx_command_t ngx_epoll_commands[] = { @@ -197,7 +202,7 @@ ngx_module_t ngx_epoll_module = { ngx_epoll_commands, /* module directives */ NGX_EVENT_MODULE, /* module type */ NULL, /* init master */ - NULL, /* init module */ + ngx_epoll_module_init, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ @@ -808,6 +813,8 @@ ngx_epoll_process_events(ngx_cycle_t *cy if (revents & EPOLLRDHUP) { rev->pending_eof = 1; } + + rev->available = 1; #endif rev->ready = 1; @@ -943,6 +950,69 @@ ngx_epoll_eventfd_handler(ngx_event_t *e #endif +static ngx_int_t +ngx_epoll_module_init(ngx_cycle_t *cycle) +{ +#if (NGX_HAVE_EPOLLRDHUP) + int epfd, s[2], events; + struct epoll_event ee; + + epfd = epoll_create(1); + + if (epfd == -1) { + ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, + "epoll_create() failed"); + return NGX_ERROR; + } + + if (socketpair(AF_UNIX, SOCK_STREAM, 0, s) == -1) { + ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, + "socketpair() failed"); + return NGX_ERROR; + } + + ee.events = EPOLLET|EPOLLIN|EPOLLRDHUP; + + if (epoll_ctl(epfd, EPOLL_CTL_ADD, s[0], &ee) == -1) { + ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, + "epoll_ctl() failed"); + return NGX_ERROR; + } + + if (close(s[1]) == -1) { + ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, + "close() failed"); + return NGX_ERROR; + } + + events = epoll_wait(epfd, &ee, 1, 5000); + + if (events == -1) { + ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, + "epoll_wait() failed"); + return NGX_ERROR; + } + + (void) close(s[0]); + (void) close(epfd); + + if (events) { + ngx_use_epoll_rdhup = ee.events & EPOLLRDHUP; + + } else { + ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, + "epoll_wait() timedout"); + } + + ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, + "testing the EPOLLRDHUP flag: %s", + ngx_use_epoll_rdhup ? "success" : "fail"); +#endif + + return NGX_OK; +} + + static void * ngx_epoll_create_conf(ngx_cycle_t *cycle) { diff --git a/src/event/ngx_event.h b/src/event/ngx_event.h --- a/src/event/ngx_event.h +++ b/src/event/ngx_event.h @@ -96,6 +96,10 @@ struct ngx_event_s { * write: available space in buffer when event is ready * or lowat when event is set with NGX_LOWAT_EVENT flag * + * epoll with EPOLLRDHUP: + * accept: 1 if accept many, 0 otherwise + * read: 1 if there can be data to read, 0 otherwise + * * iocp: TODO * * otherwise: @@ -196,6 +200,9 @@ typedef struct { extern ngx_event_actions_t ngx_event_actions; +#if (NGX_HAVE_EPOLLRDHUP) +extern ngx_uint_t ngx_use_epoll_rdhup; +#endif /* diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c --- a/src/http/ngx_http_request.c +++ b/src/http/ngx_http_request.c @@ -2752,9 +2752,13 @@ ngx_http_test_reading(ngx_http_request_t #if (NGX_HAVE_EPOLLRDHUP) - if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) && rev->pending_eof) { + if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) && ngx_use_epoll_rdhup) { socklen_t len; + if (!rev->pending_eof) { + return; + } + rev->eof = 1; c->error = 1; diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c --- a/src/http/ngx_http_upstream.c +++ b/src/http/ngx_http_upstream.c @@ -1222,9 +1222,13 @@ ngx_http_upstream_check_broken_connectio #if (NGX_HAVE_EPOLLRDHUP) - if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) && ev->pending_eof) { + if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) && ngx_use_epoll_rdhup) { socklen_t len; + if (!ev->pending_eof) { + return; + } + ev->eof = 1; c->error = 1; diff --git a/src/os/unix/ngx_readv_chain.c b/src/os/unix/ngx_readv_chain.c --- a/src/os/unix/ngx_readv_chain.c +++ b/src/os/unix/ngx_readv_chain.c @@ -53,6 +53,20 @@ ngx_readv_chain(ngx_connection_t *c, ngx #endif +#if (NGX_HAVE_EPOLLRDHUP) + + if (ngx_event_flags & NGX_USE_EPOLL_EVENT) { + ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, + "readv: eof:%d, avail:%d", + rev->pending_eof, rev->available); + + if (!rev->available && !rev->pending_eof) { + return NGX_AGAIN; + } + } + +#endif + prev = NULL; iov = NULL; size = 0; @@ -151,6 +165,24 @@ ngx_readv_chain(ngx_connection_t *c, ngx #endif +#if (NGX_HAVE_EPOLLRDHUP) + + if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) + && ngx_use_epoll_rdhup) + { + if (n < size) { + if (!rev->pending_eof) { + rev->ready = 0; + } + + rev->available = 0; + } + + return n; + } + +#endif + if (n < size && !(ngx_event_flags & NGX_USE_GREEDY_EVENT)) { rev->ready = 0; } diff --git a/src/os/unix/ngx_recv.c b/src/os/unix/ngx_recv.c --- a/src/os/unix/ngx_recv.c +++ b/src/os/unix/ngx_recv.c @@ -50,6 +50,21 @@ ngx_unix_recv(ngx_connection_t *c, u_cha #endif +#if (NGX_HAVE_EPOLLRDHUP) + + if (ngx_event_flags & NGX_USE_EPOLL_EVENT) { + ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, + "recv: eof:%d, avail:%d", + rev->pending_eof, rev->available); + + if (!rev->available && !rev->pending_eof) { + rev->ready = 0; + return NGX_AGAIN; + } + } + +#endif + do { n = recv(c->fd, buf, size, 0); @@ -101,6 +116,24 @@ ngx_unix_recv(ngx_connection_t *c, u_cha #endif +#if (NGX_HAVE_EPOLLRDHUP) + + if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) + && ngx_use_epoll_rdhup) + { + if ((size_t) n < size) { + if (!rev->pending_eof) { + rev->ready = 0; + } + + rev->available = 0; + } + + return n; + } + +#endif + if ((size_t) n < size && !(ngx_event_flags & NGX_USE_GREEDY_EVENT)) {