MFC r305323: MFV r302991: 6950 ARC should cache compressed data

illumos/illumos-gate@dcbf3bd6a1f1360fc1afcee9e22c6dcff7844bf2
https://github.com/illumos/illumos-gate/commit/dcbf3bd6a1f1360fc1afcee9e22c6dcff
7844bf2

https://www.illumos.org/issues/6950
  When reading compressed data from disk, the ARC should keep the compressed
  block cached and only decompress it when consumers access the block. The
  uncompressed data should be short-lived allowing the ARC to cache a much large
r
  amount of data. The DMU would also maintain a smaller cache of uncompressed
  blocks to minimize the impact of decompressing frequently accessed blocks.

Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Don Brady <don.brady@intel.com>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
Author: George Wilson <george.wilson@delphix.com>

1 files changed, 5 insertions, 10 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
index fe0c0db..b6ae968 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
@@ -316,8 +316,6 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 
 		if (DMU_OS_IS_L2CACHEABLE(os))
 			aflags |= ARC_FLAG_L2CACHE;
-		if (DMU_OS_IS_L2COMPRESSIBLE(os))
-			aflags |= ARC_FLAG_L2COMPRESS;
 
 		dprintf_bp(os->os_rootbp, "reading %s", "");
 		err = arc_read(NULL, spa, os->os_rootbp,
@@ -334,14 +332,13 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 		/* Increase the blocksize if we are permitted. */
 		if (spa_version(spa) >= SPA_VERSION_USERSPACE &&
 		    arc_buf_size(os->os_phys_buf) < sizeof (objset_phys_t)) {
-			arc_buf_t *buf = arc_buf_alloc(spa,
+			arc_buf_t *buf = arc_alloc_buf(spa,
 			    sizeof (objset_phys_t), &os->os_phys_buf,
 			    ARC_BUFC_METADATA);
 			bzero(buf->b_data, sizeof (objset_phys_t));
 			bcopy(os->os_phys_buf->b_data, buf->b_data,
 			    arc_buf_size(os->os_phys_buf));
-			(void) arc_buf_remove_ref(os->os_phys_buf,
-			    &os->os_phys_buf);
+			arc_buf_destroy(os->os_phys_buf, &os->os_phys_buf);
 			os->os_phys_buf = buf;
 		}
 
@@ -350,7 +347,7 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 	} else {
 		int size = spa_version(spa) >= SPA_VERSION_USERSPACE ?
 		    sizeof (objset_phys_t) : OBJSET_OLD_PHYS_SIZE;
-		os->os_phys_buf = arc_buf_alloc(spa, size,
+		os->os_phys_buf = arc_alloc_buf(spa, size,
 		    &os->os_phys_buf, ARC_BUFC_METADATA);
 		os->os_phys = os->os_phys_buf->b_data;
 		bzero(os->os_phys, size);
@@ -428,8 +425,7 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 		if (needlock)
 			dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
 		if (err != 0) {
-			VERIFY(arc_buf_remove_ref(os->os_phys_buf,
-			    &os->os_phys_buf));
+			arc_buf_destroy(os->os_phys_buf, &os->os_phys_buf);
 			kmem_free(os, sizeof (objset_t));
 			return (err);
 		}
@@ -731,7 +727,7 @@ dmu_objset_evict_done(objset_t *os)
 	}
 	zil_free(os->os_zil);
 
-	VERIFY(arc_buf_remove_ref(os->os_phys_buf, &os->os_phys_buf));
+	arc_buf_destroy(os->os_phys_buf, &os->os_phys_buf);
 
 	/*
 	 * This is a barrier to prevent the objset from going away in
@@ -1128,7 +1124,6 @@ dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
 
 	zio = arc_write(pio, os->os_spa, tx->tx_txg,
 	    os->os_rootbp, os->os_phys_buf, DMU_OS_IS_L2CACHEABLE(os),
-	    DMU_OS_IS_L2COMPRESSIBLE(os),
 	    &zp, dmu_objset_write_ready, NULL, NULL, dmu_objset_write_done,
 	    os, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);