Mercurial > hg > nginx
view src/os/unix/ngx_file_aio_read.c @ 5980:ccad84a174e0
Refactored sendfile() AIO preload.
This reduces layering violation and simplifies the logic of AIO preread, since
it's now triggered by the send chain function itself without falling back to
the copy filter. The context of AIO operation is now stored per file buffer,
which makes it possible to properly handle cases when multiple buffers come
from different locations, each with its own configuration.
author | Valentin Bartenev <vbart@nginx.com> |
---|---|
date | Wed, 11 Feb 2015 17:52:15 +0300 |
parents | 30eff7580d0c |
children | f01ab2dbcfdc |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> /* * FreeBSD file AIO features and quirks: * * if an asked data are already in VM cache, then aio_error() returns 0, * and the data are already copied in buffer; * * aio_read() preread in VM cache as minimum 16K (probably BKVASIZE); * the first AIO preload may be up to 128K; * * aio_read/aio_error() may return EINPROGRESS for just written data; * * kqueue EVFILT_AIO filter is level triggered only: an event repeats * until aio_return() will be called; * * aio_cancel() cannot cancel file AIO: it returns AIO_NOTCANCELED always. */ extern int ngx_kqueue; static ssize_t ngx_file_aio_result(ngx_file_t *file, ngx_event_aio_t *aio, ngx_event_t *ev); static void ngx_file_aio_event_handler(ngx_event_t *ev); ngx_int_t ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool) { ngx_event_aio_t *aio; aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t)); if (aio == NULL) { return NGX_ERROR; } aio->file = file; aio->fd = file->fd; aio->event.data = aio; aio->event.ready = 1; aio->event.log = file->log; file->aio = aio; return NGX_OK; } ssize_t ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset, ngx_pool_t *pool) { int n; ngx_event_t *ev; ngx_event_aio_t *aio; if (!ngx_file_aio) { return ngx_read_file(file, buf, size, offset); } if (file->aio == NULL && ngx_file_aio_init(file, pool) != NGX_OK) { return NGX_ERROR; } aio = file->aio; ev = &aio->event; if (!ev->ready) { ngx_log_error(NGX_LOG_ALERT, file->log, 0, "second aio post for \"%V\"", &file->name); return NGX_AGAIN; } ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0, "aio complete:%d @%O:%z %V", ev->complete, offset, size, &file->name); if (ev->complete) { ev->complete = 0; ngx_set_errno(aio->err); if (aio->err == 0) { return aio->nbytes; } ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno, "aio read \"%s\" failed", file->name.data); return NGX_ERROR; } ngx_memzero(&aio->aiocb, sizeof(struct aiocb)); aio->aiocb.aio_fildes = file->fd; aio->aiocb.aio_offset = offset; aio->aiocb.aio_buf = buf; aio->aiocb.aio_nbytes = size; #if (NGX_HAVE_KQUEUE) aio->aiocb.aio_sigevent.sigev_notify_kqueue = ngx_kqueue; aio->aiocb.aio_sigevent.sigev_notify = SIGEV_KEVENT; aio->aiocb.aio_sigevent.sigev_value.sigval_ptr = ev; #endif ev->handler = ngx_file_aio_event_handler; n = aio_read(&aio->aiocb); if (n == -1) { n = ngx_errno; if (n == NGX_EAGAIN) { return ngx_read_file(file, buf, size, offset); } ngx_log_error(NGX_LOG_CRIT, file->log, n, "aio_read(\"%V\") failed", &file->name); if (n == NGX_ENOSYS) { ngx_file_aio = 0; return ngx_read_file(file, buf, size, offset); } return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0, "aio_read: fd:%d %d", file->fd, n); ev->active = 1; ev->ready = 0; ev->complete = 0; return ngx_file_aio_result(aio->file, aio, ev); } static ssize_t ngx_file_aio_result(ngx_file_t *file, ngx_event_aio_t *aio, ngx_event_t *ev) { int n; ngx_err_t err; n = aio_error(&aio->aiocb); ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0, "aio_error: fd:%d %d", file->fd, n); if (n == -1) { err = ngx_errno; aio->err = err; ngx_log_error(NGX_LOG_ALERT, file->log, err, "aio_error(\"%V\") failed", &file->name); return NGX_ERROR; } if (n == NGX_EINPROGRESS) { if (ev->ready) { ev->ready = 0; ngx_log_error(NGX_LOG_ALERT, file->log, n, "aio_read(\"%V\") still in progress", &file->name); } return NGX_AGAIN; } n = aio_return(&aio->aiocb); if (n == -1) { err = ngx_errno; aio->err = err; ev->ready = 1; ngx_log_error(NGX_LOG_CRIT, file->log, err, "aio_return(\"%V\") failed", &file->name); return NGX_ERROR; } aio->err = 0; aio->nbytes = n; ev->ready = 1; ev->active = 0; ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0, "aio_return: fd:%d %d", file->fd, n); return n; } static void ngx_file_aio_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; aio = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_CORE, ev->log, 0, "aio event handler fd:%d %V", aio->fd, &aio->file->name); if (ngx_file_aio_result(aio->file, aio, ev) != NGX_AGAIN) { aio->handler(ev); } }