Add TRIM support for L2ARC.

This adds TRIM support to cache vdevs. When ARC buffers are removed
from the L2ARC in arc_hdr_destroy(), arc_release() or l2arc_evict(),
the size previously occupied by the buffer gets scheduled for TRIMming.
As always, actual TRIMs are only issued to the L2ARC after
txg_trim_limit.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	https://github.com/dechamps/zfs/commit/31aae373994fd112256607edba7de2359da3e9dc
MFC after:	2 weeks

4 files changed, 14 insertions, 8 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
index 6bf2337..3ac20d0 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
@@ -130,6 +130,7 @@
 #endif
 #include <sys/callb.h>
 #include <sys/kstat.h>
+#include <sys/trim_map.h>
 #include <zfs_fletcher.h>
 #include <sys/sdt.h>
 
@@ -1691,6 +1692,8 @@ arc_hdr_destroy(arc_buf_hdr_t *hdr)
 		}
 
 		if (l2hdr != NULL) {
+			trim_map_free(l2hdr->b_dev->l2ad_vdev, l2hdr->b_daddr,
+			    hdr->b_size);
 			list_remove(l2hdr->b_dev->l2ad_buflist, hdr);
 			ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size);
 			kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t));
@@ -3528,6 +3531,8 @@ arc_release(arc_buf_t *buf, void *tag)
 	buf->b_private = NULL;
 
 	if (l2hdr) {
+		trim_map_free(l2hdr->b_dev->l2ad_vdev, l2hdr->b_daddr,
+		    hdr->b_size);
 		list_remove(l2hdr->b_dev->l2ad_buflist, hdr);
 		kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t));
 		ARCSTAT_INCR(arcstat_l2_size, -buf_size);
@@ -4442,6 +4447,8 @@ l2arc_write_done(zio_t *zio)
 			list_remove(buflist, ab);
 			abl2 = ab->b_l2hdr;
 			ab->b_l2hdr = NULL;
+			trim_map_free(abl2->b_dev->l2ad_vdev, abl2->b_daddr,
+			    ab->b_size);
 			kmem_free(abl2, sizeof (l2arc_buf_hdr_t));
 			ARCSTAT_INCR(arcstat_l2_size, -ab->b_size);
 		}
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h
index ba82a05..4f06256 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/trim_map.h
@@ -36,7 +36,7 @@ extern "C" {
 
 extern void trim_map_create(vdev_t *vd);
 extern void trim_map_destroy(vdev_t *vd);
-extern void trim_map_free(zio_t *zio);
+extern void trim_map_free(vdev_t *vd, uint64_t offset, uint64_t size);
 extern boolean_t trim_map_write_start(zio_t *zio);
 extern void trim_map_write_done(zio_t *zio);
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
index 4bf0734..bd24d4a 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
@@ -36,8 +36,8 @@
  * than it would otherwise be as well as ensuring that entire
  * blocks are invalidated by writes.
  */
-#define	TRIM_ZIO_END(zio)	((zio)->io_offset +		\
- 	P2ROUNDUP((zio)->io_size, 1ULL << (zio)->io_vd->vdev_top->vdev_ashift))
+#define	TRIM_ZIO_END(vd, offset, size)	(offset +		\
+ 	P2ROUNDUP(size, 1ULL << vd->vdev_top->vdev_ashift))
 
 typedef struct trim_map {
 	list_t		tm_head;		/* List of segments sorted by txg. */
@@ -272,16 +272,15 @@ trim_map_free_locked(trim_map_t *tm, uint64_t start, uint64_t end, uint64_t txg)
 }
 
 void
-trim_map_free(zio_t *zio)
+trim_map_free(vdev_t *vd, uint64_t offset, uint64_t size)
 {
-	vdev_t *vd = zio->io_vd;
 	trim_map_t *tm = vd->vdev_trimmap;
 
 	if (zfs_notrim || vd->vdev_notrim || tm == NULL)
 		return;
 
 	mutex_enter(&tm->tm_lock);
-	trim_map_free_locked(tm, zio->io_offset, TRIM_ZIO_END(zio),
+	trim_map_free_locked(tm, offset, TRIM_ZIO_END(vd, offset, size),
 	    vd->vdev_spa->spa_syncing_txg);
 	mutex_exit(&tm->tm_lock);
 }
@@ -299,7 +298,7 @@ trim_map_write_start(zio_t *zio)
 		return (B_TRUE);
 
 	start = zio->io_offset;
-	end = TRIM_ZIO_END(zio);
+	end = TRIM_ZIO_END(zio->io_vd, start, zio->io_size);
 	tsearch.ts_start = start;
 	tsearch.ts_end = end;
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
index 60071fc..1852338d 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zio.c
@@ -2475,7 +2475,7 @@ zio_vdev_io_start(zio_t *zio)
 	}
 
 	if (vd->vdev_ops->vdev_op_leaf && zio->io_type == ZIO_TYPE_FREE) {
-		trim_map_free(zio);
+		trim_map_free(vd, zio->io_offset, zio->io_size);
 		return (ZIO_PIPELINE_CONTINUE);
 	}