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lockf: free state only when recycling the vnode

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This avoids malloc/free cycles when locking/unlocking the vnode when
nobody is contending.

Tested by:	pho
This commit is contained in:
Mateusz Guzik 2018-04-23 07:51:19 +00:00
parent 5992da2c7b
commit 0d3323f557
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=332878
1 changed files with 56 additions and 77 deletions
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133
sys/kern/kern_lockf.c
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@ -412,7 +412,7 @@ int
lf_advlockasync(struct vop_advlockasync_args *ap, struct lockf **statep,
u_quad_t size)
{
struct lockf *state, *freestate = NULL;
struct lockf *state;
struct flock *fl = ap->a_fl;
struct lockf_entry *lock;
struct vnode *vp = ap->a_vp;
@ -721,38 +721,17 @@ lf_advlockasync(struct vop_advlockasync_args *ap, struct lockf **statep,
#endif
sx_xunlock(&state->ls_lock);
/*
* If we have removed the last active lock on the vnode and
* this is the last thread that was in-progress, we can free
* the state structure. We update the caller's pointer inside
* the vnode interlock but call free outside.
*
* XXX alternatively, keep the state structure around until
* the filesystem recycles - requires a callback from the
* filesystem.
*/
VI_LOCK(vp);
state->ls_threads--;
wakeup(state);
if (LIST_EMPTY(&state->ls_active) && state->ls_threads == 0) {
KASSERT(LIST_EMPTY(&state->ls_pending),
("freeing state with pending locks"));
freestate = state;
*statep = NULL;
("freeable state with pending locks"));
}
VI_UNLOCK(vp);
if (freestate != NULL) {
sx_xlock(&lf_lock_states_lock);
LIST_REMOVE(freestate, ls_link);
sx_xunlock(&lf_lock_states_lock);
sx_destroy(&freestate->ls_lock);
free(freestate, M_LOCKF);
freestate = NULL;
}
if (error == EDOOFUS) {
KASSERT(ap->a_op == F_SETLK, ("EDOOFUS"));
goto retry_setlock;
@ -793,62 +772,62 @@ lf_purgelocks(struct vnode *vp, struct lockf **statep)
KASSERT(vp->v_iflag & VI_DOOMED,
("lf_purgelocks: vp %p has not vgone yet", vp));
state = *statep;
if (state) {
*statep = NULL;
state->ls_threads++;
VI_UNLOCK(vp);
sx_xlock(&state->ls_lock);
sx_xlock(&lf_owner_graph_lock);
LIST_FOREACH_SAFE(lock, &state->ls_pending, lf_link, nlock) {
LIST_REMOVE(lock, lf_link);
lf_remove_outgoing(lock);
lf_remove_incoming(lock);
/*
* If its an async lock, we can just free it
* here, otherwise we let the sleeping thread
* free it.
*/
if (lock->lf_async_task) {
lf_free_lock(lock);
} else {
lock->lf_flags |= F_INTR;
wakeup(lock);
}
}
sx_xunlock(&lf_owner_graph_lock);
sx_xunlock(&state->ls_lock);
/*
* Wait for all other threads, sleeping and otherwise
* to leave.
*/
VI_LOCK(vp);
while (state->ls_threads > 1)
msleep(state, VI_MTX(vp), 0, "purgelocks", 0);
VI_UNLOCK(vp);
/*
* We can just free all the active locks since they
* will have no dependencies (we removed them all
* above). We don't need to bother locking since we
* are the last thread using this state structure.
*/
KASSERT(LIST_EMPTY(&state->ls_pending),
("lock pending for %p", state));
LIST_FOREACH_SAFE(lock, &state->ls_active, lf_link, nlock) {
LIST_REMOVE(lock, lf_link);
lf_free_lock(lock);
}
sx_xlock(&lf_lock_states_lock);
LIST_REMOVE(state, ls_link);
sx_xunlock(&lf_lock_states_lock);
sx_destroy(&state->ls_lock);
free(state, M_LOCKF);
} else {
if (state == NULL) {
VI_UNLOCK(vp);
return;
}
*statep = NULL;
state->ls_threads++;
VI_UNLOCK(vp);
sx_xlock(&state->ls_lock);
sx_xlock(&lf_owner_graph_lock);
LIST_FOREACH_SAFE(lock, &state->ls_pending, lf_link, nlock) {
LIST_REMOVE(lock, lf_link);
lf_remove_outgoing(lock);
lf_remove_incoming(lock);
/*
* If its an async lock, we can just free it
* here, otherwise we let the sleeping thread
* free it.
*/
if (lock->lf_async_task) {
lf_free_lock(lock);
} else {
lock->lf_flags |= F_INTR;
wakeup(lock);
}
}
sx_xunlock(&lf_owner_graph_lock);
sx_xunlock(&state->ls_lock);
/*
* Wait for all other threads, sleeping and otherwise
* to leave.
*/
VI_LOCK(vp);
while (state->ls_threads > 1)
msleep(state, VI_MTX(vp), 0, "purgelocks", 0);
VI_UNLOCK(vp);
/*
* We can just free all the active locks since they
* will have no dependencies (we removed them all
* above). We don't need to bother locking since we
* are the last thread using this state structure.
*/
KASSERT(LIST_EMPTY(&state->ls_pending),
("lock pending for %p", state));
LIST_FOREACH_SAFE(lock, &state->ls_active, lf_link, nlock) {
LIST_REMOVE(lock, lf_link);
lf_free_lock(lock);
}
sx_xlock(&lf_lock_states_lock);
LIST_REMOVE(state, ls_link);
sx_xunlock(&lf_lock_states_lock);
sx_destroy(&state->ls_lock);
free(state, M_LOCKF);
}
/*