Mercurial > hg > nginx
view src/os/unix/ngx_darwin_sendfile_chain.c @ 7985:ec2e6893caaa
Simplified sendfile(SF_NODISKIO) usage.
Starting with FreeBSD 11, there is no need to use AIO operations to preload
data into cache for sendfile(SF_NODISKIO) to work. Instead, sendfile()
handles non-blocking loading data from disk by itself. It still can, however,
return EBUSY if a page is already being loaded (for example, by a different
process). If this happens, we now post an event for the next event loop
iteration, so sendfile() is retried "after a short period", as manpage
recommends.
The limit of the number of EBUSY tolerated without any progress is preserved,
but now it does not result in an alert, since on an idle system event loop
iteration might be very short and EBUSY can happen many times in a row.
Instead, SF_NODISKIO is simply disabled for one call once the limit is
reached.
With this change, sendfile(SF_NODISKIO) is now used automatically as long as
sendfile() is enabled, and no longer requires "aio on;".
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 27 Dec 2021 19:48:33 +0300 |
parents | 7cc2d3a96ea3 |
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> /* * It seems that Darwin 9.4 (Mac OS X 1.5) sendfile() has the same * old bug as early FreeBSD sendfile() syscall: * http://bugs.freebsd.org/33771 * * Besides sendfile() has another bug: if one calls sendfile() * with both a header and a trailer, then sendfile() ignores a file part * at all and sends only the header and the trailer together. * For this reason we send a trailer only if there is no a header. * * Although sendfile() allows to pass a header or a trailer, * it may send the header or the trailer and a part of the file * in different packets. And FreeBSD workaround (TCP_NOPUSH option) * does not help. */ ngx_chain_t * ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { int rc; off_t send, prev_send, sent; off_t file_size; ssize_t n; ngx_uint_t eintr; ngx_err_t err; ngx_buf_t *file; ngx_event_t *wev; ngx_chain_t *cl; ngx_iovec_t header, trailer; struct sf_hdtr hdtr; struct iovec headers[NGX_IOVS_PREALLOCATE]; struct iovec trailers[NGX_IOVS_PREALLOCATE]; wev = c->write; if (!wev->ready) { return in; } #if (NGX_HAVE_KQUEUE) if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) { (void) ngx_connection_error(c, wev->kq_errno, "kevent() reported about an closed connection"); wev->error = 1; return NGX_CHAIN_ERROR; } #endif /* the maximum limit size is the maximum size_t value - the page size */ if (limit == 0 || limit > (off_t) (NGX_MAX_SIZE_T_VALUE - ngx_pagesize)) { limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize; } send = 0; header.iovs = headers; header.nalloc = NGX_IOVS_PREALLOCATE; trailer.iovs = trailers; trailer.nalloc = NGX_IOVS_PREALLOCATE; for ( ;; ) { eintr = 0; prev_send = send; /* create the header iovec and coalesce the neighbouring bufs */ cl = ngx_output_chain_to_iovec(&header, in, limit - send, c->log); if (cl == NGX_CHAIN_ERROR) { return NGX_CHAIN_ERROR; } send += header.size; if (cl && cl->buf->in_file && send < limit) { file = cl->buf; /* coalesce the neighbouring file bufs */ file_size = ngx_chain_coalesce_file(&cl, limit - send); send += file_size; if (header.count == 0 && send < limit) { /* * create the trailer iovec and coalesce the neighbouring bufs */ cl = ngx_output_chain_to_iovec(&trailer, cl, limit - send, c->log); if (cl == NGX_CHAIN_ERROR) { return NGX_CHAIN_ERROR; } send += trailer.size; } else { trailer.count = 0; } /* * sendfile() returns EINVAL if sf_hdtr's count is 0, * but corresponding pointer is not NULL */ hdtr.headers = header.count ? header.iovs : NULL; hdtr.hdr_cnt = header.count; hdtr.trailers = trailer.count ? trailer.iovs : NULL; hdtr.trl_cnt = trailer.count; sent = header.size + file_size; ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0, "sendfile: @%O %O h:%uz", file->file_pos, sent, header.size); rc = sendfile(file->file->fd, c->fd, file->file_pos, &sent, &hdtr, 0); if (rc == -1) { err = ngx_errno; switch (err) { case NGX_EAGAIN: break; case NGX_EINTR: eintr = 1; break; default: wev->error = 1; (void) ngx_connection_error(c, err, "sendfile() failed"); return NGX_CHAIN_ERROR; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, err, "sendfile() sent only %O bytes", sent); } if (rc == 0 && sent == 0) { /* * if rc and sent equal to zero, then someone * has truncated the file, so the offset became beyond * the end of the file */ ngx_log_error(NGX_LOG_ALERT, c->log, 0, "sendfile() reported that \"%s\" was truncated", file->file->name.data); return NGX_CHAIN_ERROR; } ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0, "sendfile: %d, @%O %O:%O", rc, file->file_pos, sent, file_size + header.size); } else { n = ngx_writev(c, &header); if (n == NGX_ERROR) { return NGX_CHAIN_ERROR; } sent = (n == NGX_AGAIN) ? 0 : n; } c->sent += sent; in = ngx_chain_update_sent(in, sent); if (eintr) { send = prev_send + sent; continue; } if (send - prev_send != sent) { wev->ready = 0; return in; } if (send >= limit || in == NULL) { return in; } } }