Mercurial > hg > nginx-quic
view src/os/unix/ngx_file_aio_read.c @ 7971:0a04e5e4c40b
Large block sizes on Linux are now ignored (ticket #1168).
NFS on Linux is known to report wsize as a block size (in both f_bsize
and f_frsize, both in statfs() and statvfs()). On the other hand,
typical file system block sizes on Linux (ext2/ext3/ext4, XFS) are limited
to pagesize. (With FAT, block sizes can be at least up to 512k in
extreme cases, but this doesn't really matter, see below.)
To avoid too aggressive cache clearing on NFS volumes on Linux, block
sizes larger than pagesize are now ignored.
Note that it is safe to ignore large block sizes. Since 3899:e7cd13b7f759
(1.0.1) cache size is calculated based on fstat() st_blocks, and rounding
to file system block size is preserved mostly for Windows.
Note well that on other OSes valid block sizes seen are at least up
to 65536. In particular, UFS on FreeBSD is known to work well with block
and fragment sizes set to 65536.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 22 Jun 2020 18:02:58 +0300 |
parents | 7f035fd1ec7b |
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> /* * 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:%uz %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.sival_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); } }