Unify arc_prune_async() code

There is no sense to have separate implementations for FreeBSD and
Linux.  Make Linux code shared as more functional and just register
FreeBSD-specific prune callback with arc_add_prune_callback() API.

Aside of code cleanup this should fix excessive pruning on FreeBSD:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=274698

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Johnston <markj@FreeBSD.org>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #15456
This commit is contained in:
Alexander Motin
2023-10-30 19:56:04 -04:00
committed by Tony Hutter
parent bd7a02c251
commit 3ec4ea68d4
8 changed files with 87 additions and 117 deletions
+52
View File
@@ -886,6 +886,8 @@ static void l2arc_do_free_on_write(void);
static void l2arc_hdr_arcstats_update(arc_buf_hdr_t *hdr, boolean_t incr,
boolean_t state_only);
static void arc_prune_async(uint64_t adjust);
#define l2arc_hdr_arcstats_increment(hdr) \
l2arc_hdr_arcstats_update((hdr), B_TRUE, B_FALSE)
#define l2arc_hdr_arcstats_decrement(hdr) \
@@ -6050,6 +6052,56 @@ arc_remove_prune_callback(arc_prune_t *p)
kmem_free(p, sizeof (*p));
}
/*
* Helper function for arc_prune_async() it is responsible for safely
* handling the execution of a registered arc_prune_func_t.
*/
static void
arc_prune_task(void *ptr)
{
arc_prune_t *ap = (arc_prune_t *)ptr;
arc_prune_func_t *func = ap->p_pfunc;
if (func != NULL)
func(ap->p_adjust, ap->p_private);
zfs_refcount_remove(&ap->p_refcnt, func);
}
/*
* Notify registered consumers they must drop holds on a portion of the ARC
* buffers they reference. This provides a mechanism to ensure the ARC can
* honor the metadata limit and reclaim otherwise pinned ARC buffers.
*
* This operation is performed asynchronously so it may be safely called
* in the context of the arc_reclaim_thread(). A reference is taken here
* for each registered arc_prune_t and the arc_prune_task() is responsible
* for releasing it once the registered arc_prune_func_t has completed.
*/
static void
arc_prune_async(uint64_t adjust)
{
arc_prune_t *ap;
mutex_enter(&arc_prune_mtx);
for (ap = list_head(&arc_prune_list); ap != NULL;
ap = list_next(&arc_prune_list, ap)) {
if (zfs_refcount_count(&ap->p_refcnt) >= 2)
continue;
zfs_refcount_add(&ap->p_refcnt, ap->p_pfunc);
ap->p_adjust = adjust;
if (taskq_dispatch(arc_prune_taskq, arc_prune_task,
ap, TQ_SLEEP) == TASKQID_INVALID) {
zfs_refcount_remove(&ap->p_refcnt, ap->p_pfunc);
continue;
}
ARCSTAT_BUMP(arcstat_prune);
}
mutex_exit(&arc_prune_mtx);
}
/*
* Notify the arc that a block was freed, and thus will never be used again.
*/