From 12f436718963f8343e38ad6d0e8f7251c95984cd Mon Sep 17 00:00:00 2001 From: Valentin Bartenev Date: Fri, 13 May 2016 17:19:23 +0300 Subject: 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. --- src/os/unix/ngx_recv.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'src/os/unix/ngx_recv.c') diff --git a/src/os/unix/ngx_recv.c b/src/os/unix/ngx_recv.c index 5013ae34c..c85fd453c 100644 --- a/src/os/unix/ngx_recv.c +++ b/src/os/unix/ngx_recv.c @@ -48,6 +48,21 @@ ngx_unix_recv(ngx_connection_t *c, u_char *buf, size_t size) } } +#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 { @@ -99,6 +114,24 @@ ngx_unix_recv(ngx_connection_t *c, u_char *buf, size_t size) return n; } +#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 -- cgit v1.2.3