diff --git a/src/common/btree.c b/src/common/btree.c
index 0657bf384dc..579b921d768 100644
--- a/src/common/btree.c
+++ b/src/common/btree.c
@@ -3888,7 +3888,6 @@ btr_tree_destroy(struct btr_context *tcx, void *args, bool *destroyed)
 		tcx->tc_tins.ti_root_off, tcx->tc_order);
 
 	root = tcx->tc_tins.ti_root;
-	tcx->tc_tins.ti_destroy = 1;
 	if (root && !UMOFF_IS_NULL(root->tr_node)) {
 		/* destroy the root and all descendants */
 		rc = btr_node_destroy(tcx, root->tr_node, args, &empty);
diff --git a/src/include/daos/btree.h b/src/include/daos/btree.h
index 51f7999e47a..24c7b95cbe4 100644
--- a/src/include/daos/btree.h
+++ b/src/include/daos/btree.h
@@ -429,8 +429,6 @@ struct btr_instance {
 	struct btr_root			*ti_root;
 	/** Customized operations for the tree */
 	btr_ops_t			*ti_ops;
-	/** The context is used for tree destroy */
-	unsigned int			 ti_destroy : 1;
 };
 
 /**
diff --git a/src/vos/vos_container.c b/src/vos/vos_container.c
index 6e6cbeeeb2a..0972b6d7e1b 100644
--- a/src/vos/vos_container.c
+++ b/src/vos/vos_container.c
@@ -63,7 +63,7 @@ cont_df_rec_free(struct btr_instance *tins, struct btr_record *rec, void *args)
 	cont_df = umem_off2ptr(&tins->ti_umm, rec->rec_off);
 	vos_ts_evict(&cont_df->cd_ts_idx, VOS_TS_TYPE_CONT, vos_pool->vp_sysdb);
 
-	return gc_add_item(vos_pool, DAOS_HDL_INVAL, GC_CONT, rec->rec_off, 0);
+	return gc_add_item(vos_pool, DAOS_HDL_INVAL, GC_CONT, rec->rec_off, NULL);
 }
 
 static int
diff --git a/src/vos/vos_gc.c b/src/vos/vos_gc.c
index b90cd5d1199..1be9be47d83 100644
--- a/src/vos/vos_gc.c
+++ b/src/vos/vos_gc.c
@@ -74,12 +74,26 @@ struct vos_gc {
  */
 static int
 gc_drain_btr(struct vos_gc *gc, struct vos_pool *pool, daos_handle_t coh,
-	     struct btr_root *root, int *credits, bool *empty)
+	     struct vos_gc_item *item, struct btr_root *root, int *credits, bool *empty)
 {
-	daos_handle_t	toh;
-	int		rc;
+	struct vos_object	 dummy_obj = { 0 };
+	struct vos_container	 dummy_cont = { 0 };
+	daos_handle_t		 toh;
+	void			*priv;
+	int			 rc, i;
+
+	if (gc->gc_type == GC_CONT) {
+		priv = pool;
+	} else {
+		dummy_cont.vc_pool = pool;
+		dummy_obj.obj_cont = &dummy_cont;
+		dummy_obj.obj_bkt_allot = 1;
+		for (i = 0; i < VOS_GC_BKTS_MAX; i++)
+			dummy_obj.obj_bkt_ids[i] = item->it_bkt_ids[i];
+		priv = &dummy_obj;
+	}
 
-	rc = dbtree_open_inplace_ex(root, &pool->vp_uma, coh, pool, &toh);
+	rc = dbtree_open_inplace_ex(root, &pool->vp_uma, coh, priv, &toh);
 	if (rc == -DER_NONEXIST) { /* empty tree */
 		*empty = true;
 		return 0;
@@ -126,7 +140,7 @@ gc_drain_evt(struct vos_gc *gc, struct vos_pool *pool, daos_handle_t coh,
 
 	D_DEBUG(DB_TRACE, "drain %s evtree, creds=%d\n", gc->gc_name, *credits);
 	rc = evt_drain(toh, credits, empty);
-	D_ASSERT(evt_close(toh) == 0);
+	evt_close(toh);
 	if (rc)
 		goto failed;
 
@@ -160,7 +174,7 @@ gc_drain_key(struct vos_gc *gc, struct vos_pool *pool, daos_handle_t coh,
 	}
 
 	if (key->kr_bmap & KREC_BF_BTR) {
-		rc = gc_drain_btr(gc, pool, coh, &key->kr_btr, credits, empty);
+		rc = gc_drain_btr(gc, pool, coh, item, &key->kr_btr, credits, empty);
 
 	} else if (key->kr_bmap & KREC_BF_EVT) {
 		D_ASSERT(gc->gc_type == GC_AKEY);
@@ -195,7 +209,7 @@ gc_free_dkey(struct vos_gc *gc, struct vos_pool *pool, daos_handle_t coh, struct
 
 	D_ASSERT(krec->kr_bmap & KREC_BF_DKEY);
 	if (krec->kr_bmap & KREC_BF_NO_AKEY)
-		gc_add_item(pool, coh, GC_AKEY, item->it_addr, item->it_args);
+		gc_add_item(pool, coh, GC_AKEY, item->it_addr, &item->it_bkt_ids[0]);
 	else
 		umem_free(&pool->vp_umm, item->it_addr);
 	return 0;
@@ -211,7 +225,7 @@ gc_drain_obj(struct vos_gc *gc, struct vos_pool *pool, daos_handle_t coh,
 {
 	struct vos_obj_df *obj = umem_off2ptr(&pool->vp_umm, item->it_addr);
 
-	return gc_drain_btr(gc, pool, coh, &obj->vo_tree, credits, empty);
+	return gc_drain_btr(gc, pool, coh, item, &obj->vo_tree, credits, empty);
 }
 
 static int
@@ -298,8 +312,7 @@ gc_drain_cont(struct vos_gc *gc, struct vos_pool *pool, daos_handle_t coh,
 	}
 
 	D_ASSERT(daos_handle_is_inval(coh));
-	return gc_drain_btr(gc, pool, coh, &cont->cd_obj_root,
-			    credits, empty);
+	return gc_drain_btr(gc, pool, coh, item, &cont->cd_obj_root, credits, empty);
 }
 
 static int
@@ -627,12 +640,12 @@ gc_free_item(struct vos_gc *gc, struct vos_pool *pool,
  */
 int
 gc_add_item(struct vos_pool *pool, daos_handle_t coh,
-	    enum vos_gc_type type, umem_off_t item_off, uint64_t args)
+	    enum vos_gc_type type, umem_off_t item_off, uint32_t *bkt_ids)
 {
 	struct vos_container	*cont = vos_hdl2cont(coh);
 	struct vos_gc_bin_df	*bin = gc_type2bin(pool, cont, type);
 	struct vos_gc_item	 item;
-	int			 rc;
+	int			 rc, i;
 
 	D_DEBUG(DB_TRACE, "Add %s addr="DF_X64"\n",
 		gc_type2name(type), item_off);
@@ -641,7 +654,9 @@ gc_add_item(struct vos_pool *pool, daos_handle_t coh,
 		return 0; /* OK to ignore because the pool is being deleted */
 
 	item.it_addr = item_off;
-	item.it_args = args;
+	for (i = 0; i < VOS_GC_BKTS_MAX; i++)
+		item.it_bkt_ids[i] = bkt_ids ? bkt_ids[i] : UMEM_DEFAULT_MBKT_ID;
+
 	rc = gc_bin_add_item(&pool->vp_umm, bin, &item);
 	if (rc) {
 		D_ERROR("Failed to add item, pool=" DF_UUID ", rc=" DF_RC "\n",
@@ -712,28 +727,41 @@ gc_reclaim_pool(struct vos_pool *pool, int *credits, bool *empty_ret)
 	struct vos_container	*cont = gc_get_container(pool);
 	struct vos_gc		*gc    = &gc_table[0]; /* start from akey */
 	int			 creds = *credits;
+	uint32_t		 bkt = UMEM_DEFAULT_MBKT_ID, pinned_bkt = UMEM_DEFAULT_MBKT_ID;
+	struct umem_pin_handle	*pin_hdl = NULL;
+	struct umem_cache_range	 rg;
 	int			 rc;
 
 	if (pool->vp_dying) {
 		*empty_ret = true;
 		D_GOTO(done, rc = 0);
 	}
+	*empty_ret = false;
 
 	/* take an extra ref to avoid concurrent container destroy/free */
 	if (cont != NULL)
 		vos_cont_addref(cont);
 
+pin_obj:
+	if (bkt != UMEM_DEFAULT_MBKT_ID) {
+		rg.cr_off = umem_get_mb_base_offset(vos_pool2umm(pool), bkt);
+		rg.cr_size = vos_pool2store(pool)->cache->ca_page_sz;
+
+		rc = umem_cache_pin(vos_pool2store(pool), &rg, 1, false, &pin_hdl);
+		if (rc) {
+			DL_ERROR(rc, "Failed to pin bucket %u.", bkt);
+			goto tx_error;
+		}
+		pinned_bkt = bkt;
+	}
+
 	rc = umem_tx_begin(&pool->vp_umm, NULL);
 	if (rc) {
 		D_ERROR("Failed to start transacton for " DF_UUID ": " DF_RC "\n",
 			DP_UUID(pool->vp_id), DP_RC(rc));
-		if (cont != NULL)
-			vos_cont_decref(cont);
-		*empty_ret = false;
-		goto done;
+		goto tx_error;
 	}
 
-	*empty_ret = false;
 	while (creds > 0) {
 		struct vos_gc_item *item;
 		bool		    empty = false;
@@ -769,6 +797,25 @@ gc_reclaim_pool(struct vos_pool *pool, int *credits, bool *empty_ret)
 		if (DAOS_FAIL_CHECK(DAOS_VOS_GC_CONT))
 			D_ASSERT(cont != NULL);
 
+		bkt = item->it_bkt_ids[0];
+		if (bkt != UMEM_DEFAULT_MBKT_ID && bkt != pinned_bkt) {
+			D_ASSERT(gc->gc_type != GC_CONT);
+			D_ASSERT(vos_pool_is_p2(pool));
+
+			rc = umem_tx_end(&pool->vp_umm, rc);
+			if (rc != 0) {
+				DL_ERROR(rc, "Transaction commit failed.");
+				goto tx_error;
+			}
+
+			if (pin_hdl != NULL) {
+				umem_cache_unpin(vos_pool2store(pool), pin_hdl);
+				pin_hdl = NULL;
+			}
+
+			goto pin_obj;
+		}
+
 		rc = gc_drain_item(gc, pool, vos_cont2hdl(cont), item, &creds,
 				   &empty);
 		if (rc < 0) {
@@ -815,6 +862,11 @@ gc_reclaim_pool(struct vos_pool *pool, int *credits, bool *empty_ret)
 	rc = umem_tx_end(&pool->vp_umm, rc);
 	if (rc == 0)
 		*credits = creds;
+tx_error:
+	if (pin_hdl != NULL) {
+		umem_cache_unpin(vos_pool2store(pool), pin_hdl);
+		pin_hdl = NULL;
+	}
 
 	if (cont != NULL && d_list_empty(&cont->vc_gc_link)) {
 		/** The container may not be empty so add it back to end of
diff --git a/src/vos/vos_internal.h b/src/vos/vos_internal.h
index 72275c1d41c..e382e0d2f0a 100644
--- a/src/vos/vos_internal.h
+++ b/src/vos/vos_internal.h
@@ -1371,7 +1371,7 @@ void
 gc_check_cont(struct vos_container *cont);
 int
 gc_add_item(struct vos_pool *pool, daos_handle_t coh,
-	    enum vos_gc_type type, umem_off_t item_off, uint64_t args);
+	    enum vos_gc_type type, umem_off_t item_off, uint32_t *bkt_ids);
 int
 vos_gc_pool_tight(daos_handle_t poh, int *credits);
 void
diff --git a/src/vos/vos_layout.h b/src/vos/vos_layout.h
index 0400a351175..1bfc84b69c9 100644
--- a/src/vos/vos_layout.h
+++ b/src/vos/vos_layout.h
@@ -43,6 +43,16 @@ struct vos_gc_bin_df {
 	uint16_t		bin_pad16;
 };
 
+/*
+ * This is smaller than the VOS_OBJ_BKTS_MAX for object durable format, because
+ * I don't want to increase each GC item size (the amount of GC item is massive)
+ * for an imagined requirement.
+ *
+ * If we really need to support more than 2 evict-able buckets per object in the
+ * futhure, we can enlarge the GC item then.
+ */
+#define VOS_GC_BKTS_MAX		2
+
 struct vos_gc_bag_df {
 	/** index of the first item in FIFO */
 	uint16_t		bag_item_first;
@@ -57,19 +67,12 @@ struct vos_gc_bag_df {
 	struct vos_gc_item {
 		/* address of the item to be freed */
 		umem_off_t		it_addr;
-		/** Reserved, argument for GC_VEA/BIO (e.g. size of extent) */
-		uint64_t		it_args;
+		/* object buckets for GC_AKEY/DKEY/OBJ of the md-on-ssd p2 pool */
+		uint32_t		it_bkt_ids[VOS_GC_BKTS_MAX];
 	}			bag_items[0];
 };
 
 enum vos_gc_type {
-	/* XXX: we could define GC_VEA, which can free NVMe/SCM space.
-	 * So svt_rec_free() and evt_desc_bio_free() only need to call
-	 * gc_add_item() to register BIO address for GC.
-	 *
-	 * However, GC_VEA could have extra overhead of reassigning SCM
-	 * pointers, but it also has low latency for undo changes.
-	 */
 	GC_AKEY,
 	GC_DKEY,
 	GC_OBJ,
@@ -378,6 +381,7 @@ struct vos_obj_df {
 };
 
 #define	VOS_OBJ_BKTS_MAX	4
+D_CASSERT(VOS_GC_BKTS_MAX <= VOS_OBJ_BKTS_MAX);
 
 /*
  * VOS object durable format for md-on-ssd phase2. The size is fit to the 128 bytes
diff --git a/src/vos/vos_obj_cache.c b/src/vos/vos_obj_cache.c
index 502aafa6306..71717884300 100644
--- a/src/vos/vos_obj_cache.c
+++ b/src/vos/vos_obj_cache.c
@@ -470,6 +470,25 @@ vos_obj_incarnate(struct vos_object *obj, daos_epoch_range_t *epr, daos_epoch_t
 		return -DER_TX_RESTART;
 	}
 
+	if (obj->obj_bkt_ids[0] != UMEM_DEFAULT_MBKT_ID) {
+		struct vos_obj_p2_df *p2 = (struct vos_obj_p2_df *)obj->obj_df;
+
+		D_ASSERT(vos_pool_is_p2(vos_obj2pool(obj)));
+		D_ASSERT(obj->obj_bkt_allot);
+
+		if (p2->p2_bkt_ids[0] == UMEM_DEFAULT_MBKT_ID) {
+			p2->p2_bkt_ids[0] = obj->obj_bkt_ids[0];
+			rc = umem_tx_add_ptr(vos_cont2umm(cont), &p2->p2_bkt_ids[0],
+					     sizeof(p2->p2_bkt_ids[0]));
+			if (rc) {
+				DL_ERROR(rc, "Add bucket ID failed.");
+				return rc;
+			}
+		} else {
+			D_ASSERT(p2->p2_bkt_ids[0] == obj->obj_bkt_ids[0]);
+		}
+	}
+
 	/* It's done for DAOS_INTENT_PUNCH case */
 	if (intent == DAOS_INTENT_PUNCH)
 		return 0;
diff --git a/src/vos/vos_obj_index.c b/src/vos/vos_obj_index.c
index e6111cd0746..e385d9d8460 100644
--- a/src/vos/vos_obj_index.c
+++ b/src/vos/vos_obj_index.c
@@ -145,6 +145,7 @@ oi_rec_free(struct btr_instance *tins, struct btr_record *rec, void *args)
 	daos_handle_t		 coh = { 0 };
 	int			 rc;
 	struct vos_pool		*pool;
+	uint32_t		*bkt_ids = NULL;
 
 	obj = umem_off2ptr(umm, rec->rec_off);
 
@@ -173,7 +174,14 @@ oi_rec_free(struct btr_instance *tins, struct btr_record *rec, void *args)
 
 	if (del_arg != NULL)
 		coh = vos_cont2hdl((struct vos_container *)del_arg->cont);
-	return gc_add_item(tins->ti_priv, coh, GC_OBJ, rec->rec_off, 0);
+
+	if (vos_pool_is_p2(pool)) {
+		struct vos_obj_p2_df *p2 = (struct vos_obj_p2_df *)obj;
+
+		bkt_ids = &p2->p2_bkt_ids[0];
+	}
+
+	return gc_add_item(tins->ti_priv, coh, GC_OBJ, rec->rec_off, bkt_ids);
 }
 
 static int
diff --git a/src/vos/vos_tree.c b/src/vos/vos_tree.c
index b2245e626d9..3659cd026d7 100644
--- a/src/vos/vos_tree.c
+++ b/src/vos/vos_tree.c
@@ -156,7 +156,6 @@ ktr_hkey_gen(struct btr_instance *tins, d_iov_t *key_iov, void *hkey)
 	struct umem_pool        *umm_pool = tins->ti_umm.umm_pool;
 	struct vos_pool         *pool;
 
-	D_ASSERT(tins->ti_destroy == 0);
 	pool = vos_obj2pool(tins->ti_priv);
 	D_ASSERT(key_iov->iov_len < pool->vp_pool_df->pd_scm_sz);
 	hkey_common_gen(key_iov, hkey);
@@ -257,7 +256,6 @@ ktr_rec_alloc(struct btr_instance *tins, d_iov_t *key_iov,
 
 	rbund = iov2rec_bundle(val_iov);
 
-	D_ASSERT(tins->ti_destroy == 0);
 	rec->rec_off = vos_obj_alloc(&tins->ti_umm, tins->ti_priv, vos_krec_size(rbund), true);
 	if (UMOFF_IS_NULL(rec->rec_off))
 		return -DER_NOSPACE;
@@ -289,6 +287,8 @@ ktr_rec_free(struct btr_instance *tins, struct btr_record *rec, void *args)
 	int			 gc;
 	int			 rc;
 	struct vos_pool		*pool;
+	struct vos_object	*obj;
+	uint32_t		*bkt_ids = NULL;
 
 	if (UMOFF_IS_NULL(rec->rec_off))
 		return 0;
@@ -302,17 +302,21 @@ ktr_rec_free(struct btr_instance *tins, struct btr_record *rec, void *args)
 		return rc;
 
 	D_ASSERT(tins->ti_priv);
-	if (tins->ti_destroy)
-		pool = (struct vos_pool *)tins->ti_priv;
-	else
-		pool = vos_obj2pool(tins->ti_priv);
+	obj = tins->ti_priv;
+	pool = vos_obj2pool(obj);
 
 	vos_ilog_ts_evict(&krec->kr_ilog, (krec->kr_bmap & KREC_BF_DKEY) ?
 			  VOS_TS_TYPE_DKEY : VOS_TS_TYPE_AKEY, pool->vp_sysdb);
 
 	gc = (krec->kr_bmap & KREC_BF_DKEY) ? GC_DKEY : GC_AKEY;
 	coh = vos_cont2hdl(args);
-	return gc_add_item(pool, coh, gc, rec->rec_off, 0);
+
+	if (vos_pool_is_p2(pool)) {
+		D_ASSERT(obj->obj_bkt_allot == 1);
+		bkt_ids = &obj->obj_bkt_ids[0];
+	}
+
+	return gc_add_item(pool, coh, gc, rec->rec_off, bkt_ids);
 }
 
 static int
@@ -358,7 +362,6 @@ ktr_rec_update(struct btr_instance *tins, struct btr_record *rec,
 static umem_off_t
 ktr_node_alloc(struct btr_instance *tins, int size)
 {
-	D_ASSERT(tins->ti_destroy == 0);
 	return vos_obj_alloc(&tins->ti_umm, tins->ti_priv, size, true);
 }
 
@@ -631,10 +634,7 @@ svt_rec_free_internal(struct btr_instance *tins, struct btr_record *rec,
 			struct vos_pool *pool;
 
 			D_ASSERT(tins->ti_priv != NULL);
-			if (tins->ti_destroy)
-				pool = (struct vos_pool *)tins->ti_priv;
-			else
-				pool = vos_obj2pool(tins->ti_priv);
+			pool = vos_obj2pool(tins->ti_priv);
 			rc = vos_bio_addr_free(pool, addr, irec->ir_size);
 			if (rc)
 				return rc;