+++ /dev/null
-<?xml version="1.0" encoding="iso-8859-1"?>
-<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
-<refentry id="vfs_aio_linux.8">
-
-<refmeta>
- <refentrytitle>vfs_aio_linux</refentrytitle>
- <manvolnum>8</manvolnum>
- <refmiscinfo class="source">Samba</refmiscinfo>
- <refmiscinfo class="manual">System Administration tools</refmiscinfo>
- <refmiscinfo class="version">4.7</refmiscinfo>
-</refmeta>
-
-
-<refnamediv>
- <refname>vfs_aio_linux</refname>
- <refpurpose>implement async I/O in Samba vfs using Linux kernel aio calls</refpurpose>
-</refnamediv>
-
-<refsynopsisdiv>
- <cmdsynopsis>
- <command>vfs objects = aio_linux</command>
- </cmdsynopsis>
-</refsynopsisdiv>
-
-<refsect1>
- <title>DESCRIPTION</title>
-
- <para>This VFS module is part of the
- <citerefentry><refentrytitle>samba</refentrytitle>
- <manvolnum>7</manvolnum></citerefentry> suite.</para>
-
- <para>The <command>aio_linux</command> VFS module enables asynchronous
- I/O for Samba on Linux kernels that have the kernel AIO calls available
- without using the Posix AIO interface. Posix AIO can suffer from severe
- limitations. For example, on some Linux versions the
- real-time signals that it uses are broken under heavy load.
- Other systems only allow AIO when special kernel modules are
- loaded or only allow a certain system-wide amount of async
- requests being scheduled. Systems based on glibc (most Linux
- systems) only allow a single outstanding request per file
- descriptor which essentially makes Posix AIO useless on systems
- using the glibc implementation.</para>
-
- <para>To work around all these limitations, the aio_linux module
- was written. It uses the Linux kernel AIO interface instead of the
- internal Posix AIO interface to allow read and write calls
- to be processed asynchronously. A queue size of 128 events
- is used by default. To change this limit set the "aio num events"
- parameter below.
- </para>
-
- <para>
- Note that the smb.conf parameters <command>aio read size</command>
- and <command>aio write size</command> must also be set appropriately
- for this module to be active.
- </para>
-
- <para>This module MUST be listed last in any module stack as
- the Samba VFS pread/pwrite interface is not thread-safe. This
- module makes direct pread and pwrite system calls and does
- NOT call the Samba VFS pread and pwrite interfaces.</para>
-
-</refsect1>
-
-
-<refsect1>
- <title>EXAMPLES</title>
-
- <para>Straight forward use:</para>
-
-<programlisting>
- <smbconfsection name="[cooldata]"/>
- <smbconfoption name="path">/data/ice</smbconfoption>
- <smbconfoption name="aio read size">1024</smbconfoption>
- <smbconfoption name="aio write size">1024</smbconfoption>
- <smbconfoption name="vfs objects">aio_linux</smbconfoption>
-</programlisting>
-
-</refsect1>
-
-<refsect1>
- <title>OPTIONS</title>
-
- <variablelist>
-
- <varlistentry>
- <term>aio_linux:aio num events = INTEGER</term>
- <listitem>
- <para>Set the maximum size of the event queue
- that is used to limit outstanding IO requests.
- </para>
- <para>By default this is set to 128.</para>
- </listitem>
- </varlistentry>
-
- </variablelist>
-</refsect1>
-<refsect1>
- <title>VERSION</title>
-
- <para>This man page is correct for version 4.0 of the Samba suite.
- </para>
-</refsect1>
-
-<refsect1>
- <title>AUTHOR</title>
-
- <para>The original Samba software and related utilities
- were created by Andrew Tridgell. Samba is now developed
- by the Samba Team as an Open Source project similar
- to the way the Linux kernel is developed.</para>
-
-</refsect1>
-
-</refentry>
+++ /dev/null
-/*
- * Simulate Posix AIO using Linux kernel AIO.
- *
- * Copyright (C) Jeremy Allison 2012
- * Copyright (C) Volker Lendecke 2012
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-#include "includes.h"
-#include "system/filesys.h"
-#include "smbd/smbd.h"
-#include "smbd/globals.h"
-#include "lib/util/tevent_unix.h"
-#include "lib/util/sys_rw.h"
-#include <sys/eventfd.h>
-#include <libaio.h>
-#include "smbprofile.h"
-
-static int event_fd = -1;
-static io_context_t io_ctx;
-static struct tevent_fd *aio_read_event;
-static bool used;
-static unsigned num_busy;
-
-static void aio_linux_done(struct tevent_context *event_ctx,
- struct tevent_fd *event,
- uint16_t flags, void *private_data);
-
-/************************************************************************
- Housekeeping. Cleanup if no activity for 30 seconds.
-***********************************************************************/
-
-static void aio_linux_housekeeping(struct tevent_context *event_ctx,
- struct tevent_timer *te,
- struct timeval now,
- void *private_data)
-{
- /* Remove this timed event handler. */
- TALLOC_FREE(te);
-
- if ((num_busy != 0) || used) {
- used = false;
-
- /* Still busy. Look again in 30 seconds. */
- (void)tevent_add_timer(event_ctx,
- NULL,
- timeval_current_ofs(30, 0),
- aio_linux_housekeeping,
- NULL);
- return;
- }
-
- /* No activity for 30 seconds. Close out kernel resources. */
- io_queue_release(io_ctx);
- memset(&io_ctx, '\0', sizeof(io_ctx));
-
- if (event_fd != -1) {
- close(event_fd);
- event_fd = -1;
- }
-
- TALLOC_FREE(aio_read_event);
-}
-
-/************************************************************************
- Ensure event fd and aio context are initialized.
-***********************************************************************/
-
-static bool init_aio_linux(struct vfs_handle_struct *handle)
-{
- struct tevent_timer *te = NULL;
-
- if (event_fd != -1) {
- /* Already initialized. */
- return true;
- }
-
- /* Schedule a shutdown event for 30 seconds from now. */
- te = tevent_add_timer(handle->conn->sconn->ev_ctx,
- NULL,
- timeval_current_ofs(30, 0),
- aio_linux_housekeeping,
- NULL);
-
- if (te == NULL) {
- goto fail;
- }
-
- event_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
- if (event_fd == -1) {
- goto fail;
- }
-
- aio_read_event = tevent_add_fd(server_event_context(),
- NULL,
- event_fd,
- TEVENT_FD_READ,
- aio_linux_done,
- NULL);
- if (aio_read_event == NULL) {
- goto fail;
- }
-
- if (io_queue_init(lp_aio_max_threads(), &io_ctx)) {
- goto fail;
- }
-
- DEBUG(10,("init_aio_linux: initialized with up to %d events\n",
- (int)lp_aio_max_threads()));
-
- return true;
-
- fail:
-
- DEBUG(10,("init_aio_linux: initialization failed\n"));
-
- TALLOC_FREE(te);
- TALLOC_FREE(aio_read_event);
- if (event_fd != -1) {
- close(event_fd);
- event_fd = -1;
- }
- memset(&io_ctx, '\0', sizeof(io_ctx));
- return false;
-}
-
-struct aio_linux_state {
- struct iocb event_iocb;
- ssize_t ret;
- struct vfs_aio_state vfs_aio_state;
- struct timespec start;
-};
-
-static struct tevent_req *aio_linux_pread_send(
- struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
- struct tevent_context *ev, struct files_struct *fsp,
- void *data, size_t n, off_t offset)
-{
- struct tevent_req *req;
- struct aio_linux_state *state;
- struct iocb *piocb;
- int ret;
-
- req = tevent_req_create(mem_ctx, &state, struct aio_linux_state);
- if (req == NULL) {
- return NULL;
- }
- if (!init_aio_linux(handle)) {
- tevent_req_error(req, EIO);
- return tevent_req_post(req, ev);
- }
-
- io_prep_pread(&state->event_iocb, fsp->fh->fd, data, n, offset);
- io_set_eventfd(&state->event_iocb, event_fd);
- state->event_iocb.data = req;
-
- piocb = &state->event_iocb;
-
- PROFILE_TIMESTAMP(&state->start);
- ret = io_submit(io_ctx, 1, &piocb);
- if (ret < 0) {
- tevent_req_error(req, -ret);
- return tevent_req_post(req, ev);
- }
- num_busy += 1;
- used = true;
- return req;
-}
-
-static struct tevent_req *aio_linux_pwrite_send(
- struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
- struct tevent_context *ev, struct files_struct *fsp,
- const void *data, size_t n, off_t offset)
-{
- struct tevent_req *req;
- struct aio_linux_state *state;
- struct iocb *piocb;
- int ret;
-
- req = tevent_req_create(mem_ctx, &state, struct aio_linux_state);
- if (req == NULL) {
- return NULL;
- }
- if (!init_aio_linux(handle)) {
- tevent_req_error(req, EIO);
- return tevent_req_post(req, ev);
- }
-
- io_prep_pwrite(&state->event_iocb, fsp->fh->fd, discard_const(data),
- n, offset);
- io_set_eventfd(&state->event_iocb, event_fd);
- state->event_iocb.data = req;
-
- piocb = &state->event_iocb;
-
- PROFILE_TIMESTAMP(&state->start);
- ret = io_submit(io_ctx, 1, &piocb);
- if (ret < 0) {
- tevent_req_error(req, -ret);
- return tevent_req_post(req, ev);
- }
- num_busy += 1;
- used = true;
- return req;
-}
-
-static struct tevent_req *aio_linux_fsync_send(
- struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
- struct tevent_context *ev, struct files_struct *fsp)
-{
- struct tevent_req *req;
- struct aio_linux_state *state;
- struct iocb *piocb;
- int ret;
-
- req = tevent_req_create(mem_ctx, &state, struct aio_linux_state);
- if (req == NULL) {
- return NULL;
- }
- if (!init_aio_linux(handle)) {
- tevent_req_error(req, EIO);
- return tevent_req_post(req, ev);
- }
-
- io_prep_fsync(&state->event_iocb, fsp->fh->fd);
- io_set_eventfd(&state->event_iocb, event_fd);
- state->event_iocb.data = req;
-
- piocb = &state->event_iocb;
-
- PROFILE_TIMESTAMP(&state->start);
- ret = io_submit(io_ctx, 1, &piocb);
- if (ret < 0) {
- tevent_req_error(req, -ret);
- return tevent_req_post(req, ev);
- }
- num_busy += 1;
- used = true;
- return req;
-}
-
-static void aio_linux_done(struct tevent_context *event_ctx,
- struct tevent_fd *event,
- uint16_t flags, void *private_data)
-{
- uint64_t num_events = 0;
- struct timespec end;
-
- DEBUG(10, ("aio_linux_done called with flags=%d\n",
- (int)flags));
-
- PROFILE_TIMESTAMP(&end);
-
- /* Read the number of events available. */
- if (sys_read(event_fd, &num_events, sizeof(num_events)) !=
- sizeof(num_events)) {
- smb_panic("aio_linux_handle_completion: invalid read");
- }
-
- while (num_events > 0) {
- struct timespec ts = { 0, };
- struct io_event finished;
- struct tevent_req *req;
- struct aio_linux_state *state;
- int ret;
-
- ret = io_getevents(io_ctx, 1, 1, &finished, &ts);
- if (ret < 0) {
- DEBUG(1, ("aio_linux_done: io_getevents returned %s\n",
- strerror(-ret)));
- return;
- }
- if (ret == 0) {
- DEBUG(10, ("aio_linux_done: io_getvents returned "
- "0\n"));
- continue;
- }
-
- num_busy -= 1;
-
- req = talloc_get_type_abort(finished.data,
- struct tevent_req);
- state = tevent_req_data(req, struct aio_linux_state);
-
- if (finished.res < 0) {
- state->ret = -1;
- state->vfs_aio_state.error = -finished.res;
- } else {
- state->ret = finished.res;
- }
- state->vfs_aio_state.duration = nsec_time_diff(&end, &state->start);
- tevent_req_done(req);
- num_events -= 1;
- }
-}
-
-static ssize_t aio_linux_recv(struct tevent_req *req,
- struct vfs_aio_state *vfs_aio_state)
-{
- struct aio_linux_state *state = tevent_req_data(
- req, struct aio_linux_state);
-
- if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
- return -1;
- }
- *vfs_aio_state = state->vfs_aio_state;
- return state->ret;
-}
-
-static int aio_linux_int_recv(struct tevent_req *req,
- struct vfs_aio_state *vfs_aio_state)
-{
- /*
- * Use implicit conversion ssize_t->int
- */
- return aio_linux_recv(req, vfs_aio_state);
-}
-
-static struct vfs_fn_pointers vfs_aio_linux_fns = {
- .pread_send_fn = aio_linux_pread_send,
- .pread_recv_fn = aio_linux_recv,
- .pwrite_send_fn = aio_linux_pwrite_send,
- .pwrite_recv_fn = aio_linux_recv,
- .fsync_send_fn = aio_linux_fsync_send,
- .fsync_recv_fn = aio_linux_int_recv,
-};
-
-static_decl_vfs;
-NTSTATUS vfs_aio_linux_init(TALLOC_CTX *ctx)
-{
- return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
- "aio_linux", &vfs_aio_linux_fns);
-}
git.samba.org / garming / samba-autobuild / .git / commitdiff