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Add a rangelock implementation, intended to be used to range-locking

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the i/o regions of the vnode data space. The implementation is quite
simple-minded, it uses the list of the lock requests, ordered by
arrival time. Each request may be for read or for write. The
implementation is fair FIFO.

MFC after:     2 month
This commit is contained in:
kib 2012-05-30 16:06:38 +00:00
parent b4b050eda2
commit 6f4e16f833
7 changed files with 342 additions and 0 deletions
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1
sys/conf/files
View File

@ -2562,6 +2562,7 @@ kern/kern_priv.c standard
kern/kern_proc.c standard
kern/kern_prot.c standard
kern/kern_racct.c standard
kern/kern_rangelock.c standard
kern/kern_rctl.c standard
kern/kern_resource.c standard
kern/kern_rmlock.c standard

246
sys/kern/kern_rangelock.c Normal file
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@ -0,0 +1,246 @@
/*-
* Copyright (c) 2009 Konstantin Belousov <kib@FreeBSD.org>
* All rights reserved.
*
* 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 unmodified, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/rangelock.h>
#include <sys/systm.h>
#include <vm/uma.h>
struct rl_q_entry {
TAILQ_ENTRY(rl_q_entry) rl_q_link;
off_t rl_q_start, rl_q_end;
int rl_q_flags;
};
static uma_zone_t rl_entry_zone;
static void
rangelock_sys_init(void)
{
rl_entry_zone = uma_zcreate("rl_entry", sizeof(struct rl_q_entry),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
}
SYSINIT(vfs, SI_SUB_LOCK, SI_ORDER_ANY, rangelock_sys_init, NULL);
static struct rl_q_entry *
rlqentry_alloc(void)
{
return (uma_zalloc(rl_entry_zone, M_WAITOK));
}
void
rlqentry_free(struct rl_q_entry *rleq)
{
uma_zfree(rl_entry_zone, rleq);
}
void
rangelock_init(struct rangelock *lock)
{
TAILQ_INIT(&lock->rl_waiters);
lock->rl_currdep = NULL;
}
void
rangelock_destroy(struct rangelock *lock)
{
KASSERT(TAILQ_EMPTY(&lock->rl_waiters), ("Dangling waiters"));
}
/*
* Verifies the supplied rl_q_entries for compatibility. Returns true
* if the rangelock queue entries are not compatible, false if they are.
*
* Two entries are compatible if their ranges do not overlap, or both
* entries are for read.
*/
static int
rangelock_incompatible(const struct rl_q_entry *e1,
const struct rl_q_entry *e2)
{
if ((e1->rl_q_flags & RL_LOCK_TYPE_MASK) == RL_LOCK_READ &&
(e2->rl_q_flags & RL_LOCK_TYPE_MASK) == RL_LOCK_READ)
return (0);
if (e1->rl_q_start < e2->rl_q_end && e1->rl_q_end > e2->rl_q_start)
return (1);
return (0);
}
/*
* Recalculate the lock->rl_currdep after an unlock.
*/
static void
rangelock_calc_block(struct rangelock *lock)
{
struct rl_q_entry *entry, *entry1, *whead;
if (lock->rl_currdep == TAILQ_FIRST(&lock->rl_waiters) &&
lock->rl_currdep != NULL)
lock->rl_currdep = TAILQ_NEXT(lock->rl_currdep, rl_q_link);
for (entry = lock->rl_currdep; entry != NULL;
entry = TAILQ_NEXT(entry, rl_q_link)) {
TAILQ_FOREACH(entry1, &lock->rl_waiters, rl_q_link) {
if (rangelock_incompatible(entry, entry1))
goto out;
if (entry1 == entry)
break;
}
}
out:
lock->rl_currdep = entry;
TAILQ_FOREACH(whead, &lock->rl_waiters, rl_q_link) {
if (whead == lock->rl_currdep)
break;
if (!(whead->rl_q_flags & RL_LOCK_GRANTED)) {
whead->rl_q_flags |= RL_LOCK_GRANTED;
wakeup(whead);
}
}
}
static void
rangelock_unlock_locked(struct rangelock *lock, struct rl_q_entry *entry,
struct mtx *ilk)
{
MPASS(lock != NULL && entry != NULL && ilk != NULL);
mtx_assert(ilk, MA_OWNED);
KASSERT(entry != lock->rl_currdep, ("stuck currdep"));
TAILQ_REMOVE(&lock->rl_waiters, entry, rl_q_link);
rangelock_calc_block(lock);
mtx_unlock(ilk);
if (curthread->td_rlqe == NULL)
curthread->td_rlqe = entry;
else
rlqentry_free(entry);
}
void
rangelock_unlock(struct rangelock *lock, void *cookie, struct mtx *ilk)
{
MPASS(lock != NULL && cookie != NULL && ilk != NULL);
mtx_lock(ilk);
rangelock_unlock_locked(lock, cookie, ilk);
}
/*
* Unlock the sub-range of granted lock.
*/
void *
rangelock_unlock_range(struct rangelock *lock, void *cookie, off_t start,
off_t end, struct mtx *ilk)
{
struct rl_q_entry *entry;
MPASS(lock != NULL && cookie != NULL && ilk != NULL);
entry = cookie;
KASSERT(entry->rl_q_flags & RL_LOCK_GRANTED,
("Unlocking non-granted lock"));
KASSERT(entry->rl_q_start == start, ("wrong start"));
KASSERT(entry->rl_q_end >= end, ("wrong end"));
mtx_lock(ilk);
if (entry->rl_q_end == end) {
rangelock_unlock_locked(lock, cookie, ilk);
return (NULL);
}
entry->rl_q_end = end;
rangelock_calc_block(lock);
mtx_unlock(ilk);
return (cookie);
}
/*
* Add the lock request to the queue of the pending requests for
* rangelock. Sleep until the request can be granted.
*/
static void *
rangelock_enqueue(struct rangelock *lock, off_t start, off_t end, int mode,
struct mtx *ilk)
{
struct rl_q_entry *entry;
struct thread *td;
MPASS(lock != NULL && ilk != NULL);
td = curthread;
if (td->td_rlqe != NULL) {
entry = td->td_rlqe;
td->td_rlqe = NULL;
} else
entry = rlqentry_alloc();
MPASS(entry != NULL);
entry->rl_q_flags = mode;
entry->rl_q_start = start;
entry->rl_q_end = end;
mtx_lock(ilk);
/*
* XXXKIB TODO. Check that a thread does not try to enqueue a
* lock that is incompatible with another request from the same
* thread.
*/
TAILQ_INSERT_TAIL(&lock->rl_waiters, entry, rl_q_link);
if (lock->rl_currdep == NULL)
lock->rl_currdep = entry;
rangelock_calc_block(lock);
while (!(entry->rl_q_flags & RL_LOCK_GRANTED))
msleep(entry, ilk, 0, "range", 0);
mtx_unlock(ilk);
return (entry);
}
void *
rangelock_rlock(struct rangelock *lock, off_t start, off_t end, struct mtx *ilk)
{
return (rangelock_enqueue(lock, start, end, RL_LOCK_READ, ilk));
}
void *
rangelock_wlock(struct rangelock *lock, off_t start, off_t end, struct mtx *ilk)
{
return (rangelock_enqueue(lock, start, end, RL_LOCK_WRITE, ilk));
}

3
sys/kern/kern_thread.c
View File

@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/rangelock.h>
#include <sys/resourcevar.h>
#include <sys/sdt.h>
#include <sys/smp.h>
@ -205,6 +206,7 @@ thread_init(void *mem, int size, int flags)
td->td_sleepqueue = sleepq_alloc();
td->td_turnstile = turnstile_alloc();
td->td_rlqe = NULL;
EVENTHANDLER_INVOKE(thread_init, td);
td->td_sched = (struct td_sched *)&td[1];
umtx_thread_init(td);
@ -222,6 +224,7 @@ thread_fini(void *mem, int size)
td = (struct thread *)mem;
EVENTHANDLER_INVOKE(thread_fini, td);
rlqentry_free(td->td_rlqe);
turnstile_free(td->td_turnstile);
sleepq_free(td->td_sleepqueue);
umtx_thread_fini(td);

2
sys/kern/vfs_subr.c
View File

@ -1027,6 +1027,7 @@ alloc:
if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
vp->v_vflag |= VV_NOKNOTE;
}
rangelock_init(&vp->v_rl);
*vpp = vp;
return (0);
@ -2468,6 +2469,7 @@ vdropl(struct vnode *vp)
/* XXX Elsewhere we detect an already freed vnode via NULL v_op. */
vp->v_op = NULL;
#endif
rangelock_destroy(&vp->v_rl);
lockdestroy(vp->v_vnlock);
mtx_destroy(&vp->v_interlock);
mtx_destroy(BO_MTX(bo));

1
sys/sys/proc.h
View File

@ -213,6 +213,7 @@ struct thread {
struct seltd *td_sel; /* Select queue/channel. */
struct sleepqueue *td_sleepqueue; /* (k) Associated sleep queue. */
struct turnstile *td_turnstile; /* (k) Associated turnstile. */
struct rl_q_entry *td_rlqe; /* (k) Associated range lock entry. */
struct umtx_q *td_umtxq; /* (c?) Link for when we're blocked. */
lwpid_t td_tid; /* (b) Thread ID. */
sigqueue_t td_sigqueue; /* (c) Sigs arrived, not delivered. */

78
sys/sys/rangelock.h Normal file
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@ -0,0 +1,78 @@
/*-
* Copyright (c) 2009 Konstantin Belousov <kib@FreeBSD.org>
* All rights reserved.
*
* 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 unmodified, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _SYS_RANGELOCK_H
#define _SYS_RANGELOCK_H
#include <sys/queue.h>
#define RL_LOCK_READ 0x0001
#define RL_LOCK_WRITE 0x0002
#define RL_LOCK_TYPE_MASK 0x0003
#define RL_LOCK_GRANTED 0x0004
struct rl_q_entry;
/*
* The structure representing the range lock. Caller may request
* read or write access to the range of bytes. Access is granted if
* all existing lock owners are compatible with the request. Two lock
* owners are compatible if their ranges do not overlap, or both
* owners are for read.
*
* Access to the structure itself is synchronized with the externally
* supplied mutex.
*
* rl_waiters is the queue of lock requests in the order of arrival.
* rl_currdep is the first lock request that cannot be granted now due
* to the preceding requests conflicting with it.
*/
struct rangelock {
TAILQ_HEAD(, rl_q_entry) rl_waiters;
struct rl_q_entry *rl_currdep;
};
#ifdef _KERNEL
struct mtx;
void rangelock_init(struct rangelock *lock);
void rangelock_destroy(struct rangelock *lock);
void rangelock_unlock(struct rangelock *lock, void *cookie,
struct mtx *ilk);
void *rangelock_unlock_range(struct rangelock *lock, void *cookie,
off_t start, off_t end, struct mtx *ilk);
void *rangelock_rlock(struct rangelock *lock, off_t start, off_t end,
struct mtx *ilk);
void *rangelock_wlock(struct rangelock *lock, off_t start, off_t end,
struct mtx *ilk);
void rlqentry_free(struct rl_q_entry *rlqe);
#endif /* _KERNEL */
#endif /* _SYS_RANGELOCK_H */

11
sys/sys/vnode.h
View File

@ -38,6 +38,7 @@
#include <sys/lock.h>
#include <sys/lockmgr.h>
#include <sys/mutex.h>
#include <sys/rangelock.h>
#include <sys/selinfo.h>
#include <sys/uio.h>
#include <sys/acl.h>
@ -165,6 +166,7 @@ struct vnode {
struct vpollinfo *v_pollinfo; /* i Poll events, p for *v_pi */
struct label *v_label; /* MAC label for vnode */
struct lockf *v_lockf; /* Byte-level advisory lock list */
struct rangelock v_rl; /* Byte-range lock */
};
#endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
@ -679,6 +681,15 @@ int vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
int vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags,
struct vnode **rvp);
#define vn_rangelock_unlock(vp, cookie) \
rangelock_unlock(&(vp)->v_rl, (cookie), VI_MTX(vp))
#define vn_rangelock_unlock_range(vp, cookie, start, end) \
rangelock_unlock_range(&(vp)->v_rl, (cookie), (start), (end), \
VI_MTX(vp))
#define vn_rangelock_rlock(vp, start, end) \
rangelock_rlock(&(vp)->v_rl, (start), (end), VI_MTX(vp))
#define vn_rangelock_wlock(vp, start, end) \
rangelock_wlock(&(vp)->v_rl, (start), (end), VI_MTX(vp))
int vfs_cache_lookup(struct vop_lookup_args *ap);
void vfs_timestamp(struct timespec *);