316 lines
8.8 KiB
C
316 lines
8.8 KiB
C
/* $NetBSD: sync_subr.c,v 1.28 2007/02/09 21:55:36 ad Exp $ */
|
|
|
|
/*
|
|
* Copyright 1997 Marshall Kirk McKusick. All Rights Reserved.
|
|
*
|
|
* This code is derived from work done by Greg Ganger at the
|
|
* University of Michigan.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. None of the names of McKusick, Ganger, or the University of Michigan
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY MARSHALL KIRK MCKUSICK ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL MARSHALL KIRK MCKUSICK BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__KERNEL_RCSID(0, "$NetBSD: sync_subr.c,v 1.28 2007/02/09 21:55:36 ad Exp $");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/mount.h>
|
|
#include <sys/time.h>
|
|
#include <sys/vnode.h>
|
|
#include <sys/buf.h>
|
|
#include <sys/errno.h>
|
|
#include <sys/malloc.h>
|
|
|
|
#include <miscfs/genfs/genfs.h>
|
|
#include <miscfs/syncfs/syncfs.h>
|
|
|
|
/*
|
|
* Defines and variables for the syncer process.
|
|
*/
|
|
int syncer_maxdelay = SYNCER_MAXDELAY; /* maximum delay time */
|
|
time_t syncdelay = 30; /* max time to delay syncing data */
|
|
time_t filedelay = 30; /* time to delay syncing files */
|
|
time_t dirdelay = 15; /* time to delay syncing directories */
|
|
time_t metadelay = 10; /* time to delay syncing metadata */
|
|
|
|
kmutex_t syncer_mutex; /* used to freeze syncer */
|
|
|
|
static int rushjob; /* number of slots to run ASAP */
|
|
static int stat_rush_requests; /* number of times I/O speeded up */
|
|
|
|
static int syncer_delayno = 0;
|
|
static long syncer_last;
|
|
static struct synclist *syncer_workitem_pending;
|
|
struct lwp *updateproc = NULL;
|
|
|
|
void
|
|
vn_initialize_syncerd()
|
|
{
|
|
int i;
|
|
|
|
syncer_last = SYNCER_MAXDELAY + 2;
|
|
|
|
syncer_workitem_pending = malloc(syncer_last * sizeof (struct synclist),
|
|
M_VNODE, M_WAITOK);
|
|
|
|
for (i = 0; i < syncer_last; i++)
|
|
TAILQ_INIT(&syncer_workitem_pending[i]);
|
|
|
|
mutex_init(&syncer_mutex, MUTEX_DEFAULT, IPL_NONE);
|
|
}
|
|
|
|
/*
|
|
* The workitem queue.
|
|
*
|
|
* It is useful to delay writes of file data and filesystem metadata
|
|
* for tens of seconds so that quickly created and deleted files need
|
|
* not waste disk bandwidth being created and removed. To realize this,
|
|
* we append vnodes to a "workitem" queue. When running with a soft
|
|
* updates implementation, most pending metadata dependencies should
|
|
* not wait for more than a few seconds. Thus, mounted on block devices
|
|
* are delayed only about a half the time that file data is delayed.
|
|
* Similarly, directory updates are more critical, so are only delayed
|
|
* about a third the time that file data is delayed. Thus, there are
|
|
* SYNCER_MAXDELAY queues that are processed round-robin at a rate of
|
|
* one each second (driven off the filesystem syner process). The
|
|
* syncer_delayno variable indicates the next queue that is to be processed.
|
|
* Items that need to be processed soon are placed in this queue:
|
|
*
|
|
* syncer_workitem_pending[syncer_delayno]
|
|
*
|
|
* A delay of fifteen seconds is done by placing the request fifteen
|
|
* entries later in the queue:
|
|
*
|
|
* syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* Add an item to the syncer work queue.
|
|
*/
|
|
void
|
|
vn_syncer_add_to_worklist(vp, delayx)
|
|
struct vnode *vp;
|
|
int delayx;
|
|
{
|
|
struct synclist *slp;
|
|
int s;
|
|
|
|
s = splbio();
|
|
|
|
if (vp->v_flag & VONWORKLST) {
|
|
slp = &syncer_workitem_pending[vp->v_synclist_slot];
|
|
TAILQ_REMOVE(slp, vp, v_synclist);
|
|
}
|
|
|
|
if (delayx > syncer_maxdelay - 2)
|
|
delayx = syncer_maxdelay - 2;
|
|
vp->v_synclist_slot = (syncer_delayno + delayx) % syncer_last;
|
|
|
|
slp = &syncer_workitem_pending[vp->v_synclist_slot];
|
|
TAILQ_INSERT_TAIL(slp, vp, v_synclist);
|
|
vp->v_flag |= VONWORKLST;
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* Remove an item from the syncer work queue.
|
|
*/
|
|
void
|
|
vn_syncer_remove_from_worklist(vp)
|
|
struct vnode *vp;
|
|
{
|
|
struct synclist *slp;
|
|
int s;
|
|
|
|
s = splbio();
|
|
|
|
if (vp->v_flag & VONWORKLST) {
|
|
vp->v_flag &= ~VONWORKLST;
|
|
slp = &syncer_workitem_pending[vp->v_synclist_slot];
|
|
TAILQ_REMOVE(slp, vp, v_synclist);
|
|
}
|
|
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* System filesystem synchronizer daemon.
|
|
*/
|
|
void
|
|
sched_sync(void *v)
|
|
{
|
|
struct synclist *slp;
|
|
struct vnode *vp;
|
|
struct mount *mp;
|
|
long starttime;
|
|
int s;
|
|
|
|
updateproc = curlwp;
|
|
|
|
for (;;) {
|
|
starttime = time_second;
|
|
|
|
/*
|
|
* Push files whose dirty time has expired. Be careful
|
|
* of interrupt race on slp queue.
|
|
*/
|
|
s = splbio();
|
|
slp = &syncer_workitem_pending[syncer_delayno];
|
|
syncer_delayno += 1;
|
|
if (syncer_delayno >= syncer_last)
|
|
syncer_delayno = 0;
|
|
splx(s);
|
|
|
|
mutex_enter(&syncer_mutex);
|
|
|
|
while ((vp = TAILQ_FIRST(slp)) != NULL) {
|
|
if (vn_start_write(vp, &mp, V_NOWAIT) == 0) {
|
|
if (vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT)
|
|
== 0) {
|
|
(void) VOP_FSYNC(vp, curlwp->l_cred,
|
|
FSYNC_LAZY, 0, 0, curlwp);
|
|
VOP_UNLOCK(vp, 0);
|
|
}
|
|
vn_finished_write(mp, 0);
|
|
}
|
|
s = splbio();
|
|
if (TAILQ_FIRST(slp) == vp) {
|
|
|
|
/*
|
|
* Put us back on the worklist. The worklist
|
|
* routine will remove us from our current
|
|
* position and then add us back in at a later
|
|
* position.
|
|
*/
|
|
|
|
vn_syncer_add_to_worklist(vp, syncdelay);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* Do soft update processing.
|
|
*/
|
|
if (bioops.io_sync)
|
|
(*bioops.io_sync)(NULL);
|
|
|
|
mutex_exit(&syncer_mutex);
|
|
|
|
/*
|
|
* The variable rushjob allows the kernel to speed up the
|
|
* processing of the filesystem syncer process. A rushjob
|
|
* value of N tells the filesystem syncer to process the next
|
|
* N seconds worth of work on its queue ASAP. Currently rushjob
|
|
* is used by the soft update code to speed up the filesystem
|
|
* syncer process when the incore state is getting so far
|
|
* ahead of the disk that the kernel memory pool is being
|
|
* threatened with exhaustion.
|
|
*/
|
|
if (rushjob > 0) {
|
|
rushjob--;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If it has taken us less than a second to process the
|
|
* current work, then wait. Otherwise start right over
|
|
* again. We can still lose time if any single round
|
|
* takes more than two seconds, but it does not really
|
|
* matter as we are just trying to generally pace the
|
|
* filesystem activity.
|
|
*/
|
|
if (time_second == starttime)
|
|
tsleep(&rushjob, PPAUSE, "syncer", hz);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Request the syncer daemon to speed up its work.
|
|
* We never push it to speed up more than half of its
|
|
* normal turn time, otherwise it could take over the CPU.
|
|
*/
|
|
int
|
|
speedup_syncer()
|
|
{
|
|
if (rushjob >= syncdelay / 2) {
|
|
return (0);
|
|
}
|
|
|
|
rushjob++;
|
|
wakeup(&rushjob);
|
|
stat_rush_requests += 1;
|
|
return (1);
|
|
}
|
|
|
|
SYSCTL_SETUP(sysctl_vfs_syncfs_setup, "sysctl vfs.sync subtree setup")
|
|
{
|
|
const struct sysctlnode *rnode, *cnode;
|
|
|
|
sysctl_createv(clog, 0, NULL, &rnode,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_NODE, "vfs", NULL,
|
|
NULL, 0, NULL, 0,
|
|
CTL_VFS, CTL_EOL);
|
|
|
|
sysctl_createv(clog, 0, &rnode, &rnode,
|
|
CTLFLAG_PERMANENT,
|
|
CTLTYPE_NODE, "sync",
|
|
SYSCTL_DESCR("syncer options"),
|
|
NULL, 0, NULL, 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
|
|
sysctl_createv(clog, 0, &rnode, &cnode,
|
|
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
|
|
CTLTYPE_INT, "delay",
|
|
SYSCTL_DESCR("max time to delay syncing data"),
|
|
NULL, 0, &syncdelay, 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
|
|
sysctl_createv(clog, 0, &rnode, &cnode,
|
|
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
|
|
CTLTYPE_INT, "filedelay",
|
|
SYSCTL_DESCR("time to delay syncing files"),
|
|
NULL, 0, &filedelay, 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
|
|
sysctl_createv(clog, 0, &rnode, &cnode,
|
|
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
|
|
CTLTYPE_INT, "dirdelay",
|
|
SYSCTL_DESCR("time to delay syncing directories"),
|
|
NULL, 0, &dirdelay, 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
|
|
sysctl_createv(clog, 0, &rnode, &cnode,
|
|
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
|
|
CTLTYPE_INT, "metadelay",
|
|
SYSCTL_DESCR("time to delay syncing metadata"),
|
|
NULL, 0, &metadelay, 0,
|
|
CTL_CREATE, CTL_EOL);
|
|
}
|