Linux-Block Archive on lore.kernel.org
 help / color / Atom feed
From: Nabeel M Mohamed <nmeeramohide@micron.com>
To: <linux-kernel@vger.kernel.org>, <linux-block@vger.kernel.org>,
	<linux-nvme@lists.infradead.org>, <linux-mm@kvack.org>,
	<linux-nvdimm@lists.01.org>
Cc: <smoyer@micron.com>, <gbecker@micron.com>, <plabat@micron.com>,
	<jgroves@micron.com>, Nabeel M Mohamed <nmeeramohide@micron.com>
Subject: [PATCH v2 08/22] mpool: add pool metadata routines to manage object lifecycle and IO
Date: Mon, 12 Oct 2020 11:27:22 -0500
Message-ID: <20201012162736.65241-9-nmeeramohide@micron.com> (raw)
In-Reply-To: <20201012162736.65241-1-nmeeramohide@micron.com>

Metadata manager interface to allocate, commit, abort, erase, read,
write, and destroy objects.

Metadata containers (MDC-1 through MDC-255) store the metadata for
accessing client allocated objects (mblocks and mlogs). An object
identifier for an mblock or mlog encodes the MDC storing its
metadata for faster lookup.

The layout descriptor (struct pmd_layout) is the in-memory
representation of an object. It is a refcounted structure storing
the object ID, state, device ID, zone start address and the number
of consecutive zones, and a rw sempahore protecting the layout
fields.

An object is in uncommitted state on allocation with its storage
reserved from the free space map. An uncommitted object lives only
in memory, i.e., no metadata records are logged. An object's
metadata is persisted in the metadata container only at commit
time. The uncommitted and committed objects are tracked using
separate rbtrees stored in each metadata container. Support for
object persistence is added in a future patch.

The metadata manager interfaces with the PD layer to discard the
zones at object abort/delete, flush the device cache at object
commit and issue read/write requests to the block layer.

Co-developed-by: Greg Becker <gbecker@micron.com>
Signed-off-by: Greg Becker <gbecker@micron.com>
Co-developed-by: Pierre Labat <plabat@micron.com>
Signed-off-by: Pierre Labat <plabat@micron.com>
Co-developed-by: John Groves <jgroves@micron.com>
Signed-off-by: John Groves <jgroves@micron.com>
Signed-off-by: Nabeel M Mohamed <nmeeramohide@micron.com>
---
 drivers/mpool/init.c    |    8 +
 drivers/mpool/omf.c     |    2 -
 drivers/mpool/pmd_obj.c | 1577 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 1585 insertions(+), 2 deletions(-)
 create mode 100644 drivers/mpool/pmd_obj.c

diff --git a/drivers/mpool/init.c b/drivers/mpool/init.c
index 261ce67e94dd..eb1217f63746 100644
--- a/drivers/mpool/init.c
+++ b/drivers/mpool/init.c
@@ -10,6 +10,7 @@
 #include "omf_if.h"
 #include "pd.h"
 #include "smap.h"
+#include "pmd_obj.h"
 #include "sb.h"
 
 /*
@@ -25,6 +26,7 @@ MODULE_PARM_DESC(chunk_size_kb, "Chunk size (in KiB) for device I/O");
 
 static void mpool_exit_impl(void)
 {
+	pmd_exit();
 	smap_exit();
 	sb_exit();
 	omf_exit();
@@ -60,6 +62,12 @@ static __init int mpool_init(void)
 		goto errout;
 	}
 
+	rc = pmd_init();
+	if (rc) {
+		errmsg = "pmd init failed";
+		goto errout;
+	}
+
 errout:
 	if (rc) {
 		mp_pr_err("%s", rc, errmsg);
diff --git a/drivers/mpool/omf.c b/drivers/mpool/omf.c
index 8e612d35b19a..9f83fb20c4a8 100644
--- a/drivers/mpool/omf.c
+++ b/drivers/mpool/omf.c
@@ -580,10 +580,8 @@ static int omf_pmd_layout_unpack_letoh(struct mpool_descriptor *mp, struct omf_m
 		return rc;
 	}
 
-#ifdef COMP_PMD_ENABLED
 	ecl = pmd_layout_alloc(&cdr->u.obj.omd_uuid, cdr->u.obj.omd_objid, cdr->u.obj.omd_gen,
 			       cdr->u.obj.omd_mblen, cdr->u.obj.omd_old.ol_zcnt);
-#endif
 	if (!ecl) {
 		rc = -ENOMEM;
 		mp_pr_err("mpool %s, unpacking layout failed, could not allocate layout structure",
diff --git a/drivers/mpool/pmd_obj.c b/drivers/mpool/pmd_obj.c
new file mode 100644
index 000000000000..8966fc0abd0e
--- /dev/null
+++ b/drivers/mpool/pmd_obj.c
@@ -0,0 +1,1577 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015-2020 Micron Technology, Inc.  All rights reserved.
+ */
+
+/*
+ * DOC: Module info.
+ *
+ * Pool metadata (pmd) module.
+ *
+ * Defines functions for probing, reading, and writing drives in an mpool.
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/atomic.h>
+#include <linux/delay.h>
+
+#include "mpool_printk.h"
+#include "uuid.h"
+#include "assert.h"
+
+#include "pd.h"
+#include "omf_if.h"
+#include "sb.h"
+#include "mclass.h"
+#include "smap.h"
+#include "mpcore.h"
+#include "pmd.h"
+
+static struct kmem_cache *pmd_obj_erase_work_cache __read_mostly;
+static struct kmem_cache *pmd_layout_priv_cache __read_mostly;
+static struct kmem_cache *pmd_layout_cache __read_mostly;
+
+static int pmd_mdc0_meta_update(struct mpool_descriptor *mp, struct pmd_layout *layout);
+static struct pmd_layout *pmd_layout_find(struct rb_root *root, u64 key);
+static struct pmd_layout *pmd_layout_insert(struct rb_root *root, struct pmd_layout *item);
+
+/* Committed object tree operations... */
+void pmd_co_rlock(struct pmd_mdc_info *cinfo, u8 slot)
+{
+	down_read_nested(&cinfo->mmi_co_lock, slot > 0 ? PMD_MDC_NORMAL : PMD_MDC_ZERO);
+}
+
+void pmd_co_runlock(struct pmd_mdc_info *cinfo)
+{
+	up_read(&cinfo->mmi_co_lock);
+}
+
+static void pmd_co_wlock(struct pmd_mdc_info *cinfo, u8 slot)
+{
+	down_write_nested(&cinfo->mmi_co_lock, slot > 0 ? PMD_MDC_NORMAL : PMD_MDC_ZERO);
+}
+
+static void pmd_co_wunlock(struct pmd_mdc_info *cinfo)
+{
+	up_write(&cinfo->mmi_co_lock);
+}
+
+struct pmd_layout *pmd_co_find(struct pmd_mdc_info *cinfo, u64 objid)
+{
+	return pmd_layout_find(&cinfo->mmi_co_root, objid);
+}
+
+struct pmd_layout *pmd_co_insert(struct pmd_mdc_info *cinfo, struct pmd_layout *layout)
+{
+	return pmd_layout_insert(&cinfo->mmi_co_root, layout);
+}
+
+struct pmd_layout *pmd_co_remove(struct pmd_mdc_info *cinfo, struct pmd_layout *layout)
+{
+	struct pmd_layout *found;
+
+	found = pmd_co_find(cinfo, layout->eld_objid);
+	if (found)
+		rb_erase(&found->eld_nodemdc, &cinfo->mmi_co_root);
+
+	return found;
+}
+
+/* Uncommitted object tree operations... */
+static void pmd_uc_lock(struct pmd_mdc_info *cinfo, u8 slot)
+{
+	mutex_lock_nested(&cinfo->mmi_uc_lock, slot > 0 ? PMD_MDC_NORMAL : PMD_MDC_ZERO);
+}
+
+static void pmd_uc_unlock(struct pmd_mdc_info *cinfo)
+{
+	mutex_unlock(&cinfo->mmi_uc_lock);
+}
+
+static struct pmd_layout *pmd_uc_find(struct pmd_mdc_info *cinfo, u64 objid)
+{
+	return pmd_layout_find(&cinfo->mmi_uc_root, objid);
+}
+
+static struct pmd_layout *pmd_uc_insert(struct pmd_mdc_info *cinfo, struct pmd_layout *layout)
+{
+	return pmd_layout_insert(&cinfo->mmi_uc_root, layout);
+}
+
+static struct pmd_layout *pmd_uc_remove(struct pmd_mdc_info *cinfo, struct pmd_layout *layout)
+{
+	struct pmd_layout *found;
+
+	found = pmd_uc_find(cinfo, layout->eld_objid);
+	if (found)
+		rb_erase(&found->eld_nodemdc, &cinfo->mmi_uc_root);
+
+	return found;
+}
+
+/*
+ * General object operations for both internal and external callers...
+ *
+ * See pmd.h for the various nesting levels for a locking class.
+ */
+void pmd_obj_rdlock(struct pmd_layout *layout)
+{
+	enum pmd_lock_class lc __maybe_unused = PMD_MDC_NORMAL;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	if (objid_slot(layout->eld_objid))
+		lc = PMD_OBJ_CLIENT;
+	else if (objid_mdc0log(layout->eld_objid))
+		lc = PMD_MDC_ZERO;
+#endif
+
+	down_read_nested(&layout->eld_rwlock, lc);
+}
+
+void pmd_obj_rdunlock(struct pmd_layout *layout)
+{
+	up_read(&layout->eld_rwlock);
+}
+
+void pmd_obj_wrlock(struct pmd_layout *layout)
+{
+	enum pmd_lock_class lc __maybe_unused = PMD_MDC_NORMAL;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	if (objid_slot(layout->eld_objid))
+		lc = PMD_OBJ_CLIENT;
+	else if (objid_mdc0log(layout->eld_objid))
+		lc = PMD_MDC_ZERO;
+#endif
+
+	down_write_nested(&layout->eld_rwlock, lc);
+}
+
+void pmd_obj_wrunlock(struct pmd_layout *layout)
+{
+	up_write(&layout->eld_rwlock);
+}
+
+/*
+ * Alloc and init object layout; non-arg fields and all strip descriptor
+ * fields are set to 0/UNDEF/NONE; no auxiliary object info is allocated.
+ *
+ * Returns NULL if allocation fails.
+ */
+struct pmd_layout *pmd_layout_alloc(struct mpool_uuid *uuid, u64 objid,
+				    u64 gen, u64 mblen, u32 zcnt)
+{
+	struct kmem_cache *cache = pmd_layout_cache;
+	struct pmd_layout *layout;
+
+	if (pmd_objid_type(objid) == OMF_OBJ_MLOG)
+		cache = pmd_layout_priv_cache;
+
+	layout = kmem_cache_zalloc(cache, GFP_KERNEL);
+	if (!layout)
+		return NULL;
+
+	layout->eld_objid     = objid;
+	layout->eld_gen       = gen;
+	layout->eld_mblen     = mblen;
+	layout->eld_ld.ol_zcnt = zcnt;
+	kref_init(&layout->eld_ref);
+	init_rwsem(&layout->eld_rwlock);
+
+	if (pmd_objid_type(objid) == OMF_OBJ_MLOG)
+		mpool_uuid_copy(&layout->eld_uuid, uuid);
+
+	return layout;
+}
+
+/*
+ * Deallocate all memory associated with object layout.
+ */
+void pmd_layout_release(struct kref *refp)
+{
+	struct kmem_cache *cache = pmd_layout_cache;
+	struct pmd_layout *layout;
+
+	layout = container_of(refp, typeof(*layout), eld_ref);
+
+	ASSERT(layout->eld_objid > 0);
+	ASSERT(kref_read(&layout->eld_ref) == 0);
+
+	if (pmd_objid_type(layout->eld_objid) == OMF_OBJ_MLOG)
+		cache = pmd_layout_priv_cache;
+
+	layout->eld_objid = 0;
+
+	kmem_cache_free(cache, layout);
+}
+
+static struct pmd_layout *pmd_layout_find(struct rb_root *root, u64 key)
+{
+	struct rb_node *node = root->rb_node;
+	struct pmd_layout *this;
+
+	while (node) {
+		this = rb_entry(node, typeof(*this), eld_nodemdc);
+
+		if (key < this->eld_objid)
+			node = node->rb_left;
+		else if (key > this->eld_objid)
+			node = node->rb_right;
+		else
+			return this;
+	}
+
+	return NULL;
+}
+
+static struct pmd_layout *pmd_layout_insert(struct rb_root *root, struct pmd_layout *item)
+{
+	struct rb_node **pos = &root->rb_node, *parent = NULL;
+	struct pmd_layout *this;
+
+	/*
+	 * Figure out where to insert given layout, or return the colliding
+	 * layout if there's already a layout in the tree with the given ID.
+	 */
+	while (*pos) {
+		this = rb_entry(*pos, typeof(*this), eld_nodemdc);
+		parent = *pos;
+
+		if (item->eld_objid < this->eld_objid)
+			pos = &(*pos)->rb_left;
+		else if (item->eld_objid > this->eld_objid)
+			pos = &(*pos)->rb_right;
+		else
+			return this;
+	}
+
+	/* Add new node and rebalance tree. */
+	rb_link_node(&item->eld_nodemdc, parent, pos);
+	rb_insert_color(&item->eld_nodemdc, root);
+
+	return NULL;
+}
+
+static void pmd_layout_unprovision(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	int rc;
+	u16 pdh;
+
+	pdh = layout->eld_ld.ol_pdh;
+
+	/* smap_free() should never fail */
+
+	rc = smap_free(mp, pdh, layout->eld_ld.ol_zaddr, layout->eld_ld.ol_zcnt);
+	if (rc)
+		mp_pr_err("releasing %s drive %s space for layout failed, objid 0x%lx",
+			  rc, mp->pds_name, mp->pds_pdv[pdh].pdi_name, (ulong)layout->eld_objid);
+
+	/* Drop birth reference... */
+	pmd_obj_put(layout);
+}
+
+static void pmd_layout_calculate(struct mpool_descriptor *mp, struct pmd_obj_capacity *ocap,
+				 struct media_class *mc, u64 *zcnt)
+{
+	u32 zonepg;
+
+	if (!ocap->moc_captgt) {
+		/* Obj capacity not specified; use one zone. */
+		*zcnt = 1;
+		return;
+	}
+
+	zonepg = mp->pds_pdv[mc->mc_pdmc].pdi_parm.dpr_zonepg;
+	*zcnt = 1 + ((ocap->moc_captgt - 1) / (zonepg << PAGE_SHIFT));
+}
+
+/**
+ * pmd_layout_provision() - provision storage for the given layout
+ * @mp:
+ * @ocap:
+ * @otype:
+ * @layoutp:
+ * @mc:		media class
+ * @zcnt:
+ */
+static int pmd_layout_provision(struct mpool_descriptor *mp, struct pmd_obj_capacity *ocap,
+				struct pmd_layout *layout, struct media_class *mc, u64 zcnt)
+{
+	enum smap_space_type spctype;
+	struct mc_smap_parms mcsp;
+	u64 zoneaddr, align;
+	u8 pdh;
+	int rc;
+
+	spctype = SMAP_SPC_USABLE_ONLY;
+	if (ocap->moc_spare)
+		spctype = SMAP_SPC_SPARE_2_USABLE;
+
+	/* To reduce/eliminate fragmenation, make sure the alignment is a power of 2. */
+	rc = mc_smap_parms_get(&mp->pds_mc[mc->mc_parms.mcp_classp], &mp->pds_params, &mcsp);
+	if (rc)
+		return rc;
+
+	align = min_t(u64, zcnt, mcsp.mcsp_align);
+	align = roundup_pow_of_two(align);
+
+	pdh = mc->mc_pdmc;
+	rc = smap_alloc(mp, pdh, zcnt, spctype, &zoneaddr, align);
+	if (rc)
+		return rc;
+
+	layout->eld_ld.ol_pdh = pdh;
+	layout->eld_ld.ol_zaddr = zoneaddr;
+
+	return 0;
+}
+
+int pmd_layout_rw(struct mpool_descriptor *mp, struct pmd_layout *layout,
+		  const struct kvec *iov, int iovcnt, u64 boff, int flags, u8 rw)
+{
+	struct mpool_dev_info *pd;
+	u64 zaddr;
+	int rc;
+
+	if (!mp || !layout || !iov)
+		return -EINVAL;
+
+	if (rw != MPOOL_OP_READ && rw != MPOOL_OP_WRITE)
+		return -EINVAL;
+
+	pd = &mp->pds_pdv[layout->eld_ld.ol_pdh];
+	if (mpool_pd_status_get(pd) != PD_STAT_ONLINE)
+		return -EIO;
+
+	if (iovcnt == 0)
+		return 0;
+
+	zaddr = layout->eld_ld.ol_zaddr;
+	if (rw == MPOOL_OP_READ)
+		rc = pd_zone_preadv(&pd->pdi_parm, iov, iovcnt, zaddr, boff);
+	else
+		rc = pd_zone_pwritev(&pd->pdi_parm, iov, iovcnt, zaddr, boff, flags);
+
+	if (rc)
+		mpool_pd_status_set(pd, PD_STAT_OFFLINE);
+
+	return rc;
+}
+
+int pmd_layout_erase(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	struct mpool_dev_info *pd;
+	int rc;
+
+	if (!mp || !layout)
+		return -EINVAL;
+
+	pd = &mp->pds_pdv[layout->eld_ld.ol_pdh];
+	if (mpool_pd_status_get(pd) != PD_STAT_ONLINE)
+		return -EIO;
+
+	rc = pd_zone_erase(&pd->pdi_parm, layout->eld_ld.ol_zaddr, layout->eld_ld.ol_zcnt,
+			   pmd_objid_type(layout->eld_objid) == OMF_OBJ_MLOG);
+	if (rc)
+		mpool_pd_status_set(pd, PD_STAT_OFFLINE);
+
+	return rc;
+}
+
+u64 pmd_layout_cap_get(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	enum obj_type_omf otype = pmd_objid_type(layout->eld_objid);
+	u32 zonepg;
+
+	switch (otype) {
+	case OMF_OBJ_MBLOCK:
+	case OMF_OBJ_MLOG:
+		zonepg = mp->pds_pdv[layout->eld_ld.ol_pdh].pdi_parm.dpr_zonepg;
+		return ((u64)zonepg * layout->eld_ld.ol_zcnt) << PAGE_SHIFT;
+
+	case OMF_OBJ_UNDEF:
+		break;
+	}
+
+	mp_pr_warn("mpool %s objid 0x%lx, undefined object type %d",
+		   mp->pds_name, (ulong)layout->eld_objid, otype);
+
+	return 0;
+}
+
+struct mpool_dev_info *pmd_layout_pd_get(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	return &mp->pds_pdv[layout->eld_ld.ol_pdh];
+}
+
+int pmd_smap_insert(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	int rc;
+	u16 pdh;
+
+	pdh = layout->eld_ld.ol_pdh;
+
+	/* Insert should never fail */
+
+	rc = smap_insert(mp, pdh, layout->eld_ld.ol_zaddr, layout->eld_ld.ol_zcnt);
+	if (rc)
+		mp_pr_err("mpool %s, allocating drive %s space for layout failed, objid 0x%lx",
+			  rc, mp->pds_name, mp->pds_pdv[pdh].pdi_name, (ulong)layout->eld_objid);
+
+	return rc;
+}
+
+struct pmd_layout *pmd_obj_find_get(struct mpool_descriptor *mp, u64 objid, int which)
+{
+	struct pmd_mdc_info *cinfo;
+	struct pmd_layout *found;
+	u8 cslot;
+
+	if (!objtype_user(objid_type(objid)))
+		return NULL;
+
+	cslot = objid_slot(objid);
+	cinfo = &mp->pds_mda.mdi_slotv[cslot];
+	found = NULL;
+
+	/*
+	 * which < 0  - search uncommitted tree only
+	 * which > 0  - search tree only
+	 * which == 0 - search both trees
+	 */
+	if (which <= 0) {
+		pmd_uc_lock(cinfo, cslot);
+		found = pmd_uc_find(cinfo, objid);
+		if (found)
+			kref_get(&found->eld_ref);
+		pmd_uc_unlock(cinfo);
+	}
+
+	if (!found && which >= 0) {
+		pmd_co_rlock(cinfo, cslot);
+		found = pmd_co_find(cinfo, objid);
+		if (found)
+			kref_get(&found->eld_ref);
+		pmd_co_runlock(cinfo);
+	}
+
+	return found;
+}
+
+int pmd_obj_alloc(struct mpool_descriptor *mp, enum obj_type_omf otype,
+		  struct pmd_obj_capacity *ocap, enum mp_media_classp mclassp,
+		  struct pmd_layout **layoutp)
+{
+	return pmd_obj_alloc_cmn(mp, 0, otype, ocap, mclassp, 0, true, layoutp);
+}
+
+int pmd_obj_realloc(struct mpool_descriptor *mp, u64 objid, struct pmd_obj_capacity *ocap,
+		    enum mp_media_classp mclassp, struct pmd_layout **layoutp)
+{
+	if (!pmd_objid_isuser(objid)) {
+		*layoutp = NULL;
+		return -EINVAL;
+	}
+
+	return pmd_obj_alloc_cmn(mp, objid, objid_type(objid), ocap, mclassp, 1, true, layoutp);
+}
+
+int pmd_obj_commit(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	struct pmd_mdc_info *cinfo;
+	struct pmd_layout *found;
+	int rc;
+	u8 cslot;
+
+	if (!objtype_user(objid_type(layout->eld_objid)))
+		return -EINVAL;
+
+	pmd_obj_wrlock(layout);
+	if (layout->eld_state & PMD_LYT_COMMITTED) {
+		pmd_obj_wrunlock(layout);
+		return 0;
+	}
+
+	/*
+	 * must log create before marking object committed to guarantee it will
+	 * exist after a crash; must hold cinfo.compactclock while log create,
+	 * update layout.state, and add to list of committed objects to prevent
+	 * a race with mdc compaction
+	 */
+	cslot = objid_slot(layout->eld_objid);
+	cinfo = &mp->pds_mda.mdi_slotv[cslot];
+
+	pmd_mdc_lock(&cinfo->mmi_compactlock, cslot);
+
+#ifdef OBJ_PERSISTENCE_ENABLED
+	rc = pmd_log_create(mp, layout);
+#endif
+	if (!rc) {
+		pmd_uc_lock(cinfo, cslot);
+		found = pmd_uc_remove(cinfo, layout);
+		pmd_uc_unlock(cinfo);
+
+		pmd_co_wlock(cinfo, cslot);
+		found = pmd_co_insert(cinfo, layout);
+		if (!found)
+			layout->eld_state |= PMD_LYT_COMMITTED;
+		pmd_co_wunlock(cinfo);
+
+		if (found) {
+			rc = -EEXIST;
+
+			/*
+			 * if objid exists in committed object list this is a
+			 * SERIOUS bug; need to log a warning message; should
+			 * never happen. Note in this case we are stuck because
+			 * we just logged a second create for an existing
+			 * object.  If mdc compaction runs before a restart this
+			 * extraneous create record will be eliminated,
+			 * otherwise pmd_objs_load() will see the conflict and
+			 * fail the next mpool activation.  We could make
+			 * pmd_objs_load() tolerate this but for now it is
+			 * better to get an activation failure so that
+			 * it's obvious this bug occurred. Best we can do is put
+			 * the layout back in the uncommitted object list so the
+			 * caller can abort after getting the commit failure.
+			 */
+			mp_pr_crit("mpool %s, obj 0x%lx collided during commit",
+				   rc, mp->pds_name, (ulong)layout->eld_objid);
+
+			/* Put the object back in the uncommitted objects tree */
+			pmd_uc_lock(cinfo, cslot);
+			pmd_uc_insert(cinfo, layout);
+			pmd_uc_unlock(cinfo);
+		} else {
+			atomic_inc(&cinfo->mmi_pco_cnt.pcc_cr);
+			atomic_inc(&cinfo->mmi_pco_cnt.pcc_cobj);
+		}
+	}
+
+	pmd_mdc_unlock(&cinfo->mmi_compactlock);
+	pmd_obj_wrunlock(layout);
+
+	if (!rc)
+		pmd_update_obj_stats(mp, layout, cinfo, PMD_OBJ_COMMIT);
+
+	return rc;
+}
+
+static void pmd_obj_erase_cb(struct work_struct *work)
+{
+	struct pmd_obj_erase_work *oef;
+	struct mpool_descriptor *mp;
+	struct pmd_layout *layout;
+
+	oef = container_of(work, struct pmd_obj_erase_work, oef_wqstruct);
+	mp = oef->oef_mp;
+	layout = oef->oef_layout;
+
+	pmd_layout_erase(mp, layout);
+
+	if (oef->oef_cache)
+		kmem_cache_free(oef->oef_cache, oef);
+
+	pmd_layout_unprovision(mp, layout);
+}
+
+static void pmd_obj_erase_start(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	struct pmd_obj_erase_work oefbuf, *oef;
+	bool async = true;
+
+	oef = kmem_cache_zalloc(pmd_obj_erase_work_cache, GFP_KERNEL);
+	if (!oef) {
+		oef = &oefbuf;
+		async = false;
+	}
+
+	/* If async oef will be freed in pmd_obj_erase_and_free() */
+	oef->oef_mp = mp;
+	oef->oef_layout = layout;
+	oef->oef_cache = async ? pmd_obj_erase_work_cache : NULL;
+	INIT_WORK(&oef->oef_wqstruct, pmd_obj_erase_cb);
+
+	queue_work(mp->pds_erase_wq, &oef->oef_wqstruct);
+
+	if (!async)
+		flush_work(&oef->oef_wqstruct);
+}
+
+int pmd_obj_abort(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	struct pmd_mdc_info *cinfo;
+	struct pmd_layout *found;
+	long refcnt;
+	u8 cslot;
+
+	if (!objtype_user(objid_type(layout->eld_objid)))
+		return -EINVAL;
+
+	cslot = objid_slot(layout->eld_objid);
+	cinfo = &mp->pds_mda.mdi_slotv[cslot];
+	found = NULL;
+
+	pmd_obj_wrlock(layout);
+
+	pmd_uc_lock(cinfo, cslot);
+	refcnt = kref_read(&layout->eld_ref);
+	if (refcnt == 2) {
+		found = pmd_uc_remove(cinfo, layout);
+		if (found)
+			found->eld_state |= PMD_LYT_REMOVED;
+	}
+	pmd_uc_unlock(cinfo);
+
+	pmd_obj_wrunlock(layout);
+
+	if (!found)
+		return (refcnt > 2) ? -EBUSY : -EINVAL;
+
+	pmd_update_obj_stats(mp, layout, cinfo, PMD_OBJ_ABORT);
+	pmd_obj_erase_start(mp, layout);
+
+	/* Drop caller's reference... */
+	pmd_obj_put(layout);
+
+	return 0;
+}
+
+int pmd_obj_delete(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	struct pmd_mdc_info *cinfo;
+	struct pmd_layout *found;
+	long refcnt;
+	u64 objid;
+	u8 cslot;
+	int rc;
+
+	if (!objtype_user(objid_type(layout->eld_objid)))
+		return -EINVAL;
+
+	objid = layout->eld_objid;
+	cslot = objid_slot(objid);
+	cinfo = &mp->pds_mda.mdi_slotv[cslot];
+	found = NULL;
+
+	/*
+	 * Must log delete record before removing object for crash recovery.
+	 * Must hold cinfo.compactlock while logging delete record and
+	 * removing object from the list of committed objects to prevent
+	 * race with MDC compaction
+	 */
+	pmd_obj_wrlock(layout);
+	pmd_mdc_lock(&cinfo->mmi_compactlock, cslot);
+
+	refcnt = kref_read(&layout->eld_ref);
+	if (refcnt != 2) {
+		pmd_mdc_unlock(&cinfo->mmi_compactlock);
+		pmd_obj_wrunlock(layout);
+
+		return (refcnt > 2) ? -EBUSY : -EINVAL;
+	}
+
+#ifdef OBJ_PERSISTENCE_ENABLED
+	rc = pmd_log_delete(mp, objid);
+#endif
+	if (!rc) {
+		pmd_co_wlock(cinfo, cslot);
+		found = pmd_co_remove(cinfo, layout);
+		if (found)
+			found->eld_state |= PMD_LYT_REMOVED;
+		pmd_co_wunlock(cinfo);
+	}
+
+	pmd_mdc_unlock(&cinfo->mmi_compactlock);
+	pmd_obj_wrunlock(layout);
+
+	if (!found) {
+		mp_pr_rl("mpool %s, objid 0x%lx, pmd_log_del failed",
+			 rc, mp->pds_name, (ulong)objid);
+		return rc;
+	}
+
+	atomic_inc(&cinfo->mmi_pco_cnt.pcc_del);
+	atomic_dec(&cinfo->mmi_pco_cnt.pcc_cobj);
+	pmd_update_obj_stats(mp, layout, cinfo, PMD_OBJ_DELETE);
+	pmd_obj_erase_start(mp, layout);
+
+	/* Drop caller's reference... */
+	pmd_obj_put(layout);
+
+	return 0;
+}
+
+int pmd_obj_erase(struct mpool_descriptor *mp, struct pmd_layout *layout, u64 gen)
+{
+	u64 objid = layout->eld_objid;
+	int rc;
+
+	if ((pmd_objid_type(objid) != OMF_OBJ_MLOG) ||
+	     (!(layout->eld_state & PMD_LYT_COMMITTED)) ||
+	     (layout->eld_state & PMD_LYT_REMOVED) || (gen <= layout->eld_gen)) {
+		mp_pr_warn("mpool %s, object erase failed to start, objid 0x%lx state 0x%x gen %lu",
+			   mp->pds_name, (ulong)objid, layout->eld_state, (ulong)gen);
+
+		return -EINVAL;
+	}
+
+	/*
+	 * Must log the higher gen number for the old active mlog before
+	 * updating object state (layout->eld_gen of the old active mlog).
+	 * It is to guarantee that a activate after crash will know which is the
+	 * new active mlog.
+	 */
+
+	if (objid_mdc0log(objid)) {
+		/* Compact lock is held by the caller */
+
+		/*
+		 * Change MDC0 metadata image in RAM
+		 */
+		if (objid == MDC0_OBJID_LOG1)
+			mp->pds_sbmdc0.osb_mdc01gen = gen;
+		else
+			mp->pds_sbmdc0.osb_mdc02gen = gen;
+
+		/*
+		 * Write the updated MDC0 metadata in the super blocks of the
+		 * drives holding MDC0 metadata.
+		 * Note: for 1.0, there is only one drive.
+		 */
+		rc = pmd_mdc0_meta_update(mp, layout);
+		if (!rc)
+			/*
+			 * Update in-memory eld_gen, only if on-media
+			 * gen gets successfully updated
+			 */
+			layout->eld_gen = gen;
+	} else {
+		struct pmd_mdc_info *cinfo;
+		u8                   cslot;
+
+		/*
+		 * Take the MDC0 (or mlog MDCi for user MDC) compact lock to
+		 * avoid a race with MDC0 (or mlog MDCi) compaction).
+		 */
+		cslot = objid_slot(layout->eld_objid);
+		cinfo = &mp->pds_mda.mdi_slotv[cslot];
+
+		pmd_mdc_lock(&cinfo->mmi_compactlock, cslot);
+
+#ifdef OBJ_PERSISTENCE_ENABLED
+		rc = pmd_log_erase(mp, layout->eld_objid, gen);
+#endif
+		if (!rc) {
+			layout->eld_gen = gen;
+			if (cslot)
+				atomic_inc(&cinfo->mmi_pco_cnt.pcc_er);
+
+		}
+		pmd_mdc_unlock(&cinfo->mmi_compactlock);
+	}
+
+	return rc;
+}
+
+/**
+ * pmd_alloc_idgen() - generate an id for an allocated object.
+ * @mp:
+ * @otype:
+ * @objid: outpout
+ *
+ * Does a round robin on the MDC1/255 avoiding the ones that are candidate
+ * for pre compaction.
+ *
+ * The round robin has a bias toward the MDCs with the smaller number of
+ * objects. This is to recover from rare and very big allocation bursts.
+ * During an allocation, the MDC[s] candidate for pre compaction are avoided.
+ * If the allocation is a big burst, the result is that these MDC[s] have much
+ * less objects in them as compared to the other ones.
+ * After the burst if a relatively constant allocation rate takes place, the
+ * deficit in objects of the MDCs avoided during the burst, is never recovered.
+ * The bias in the round robin allows to recover. After a while all MDCs ends
+ * up again with about the same number of objects.
+ */
+static int pmd_alloc_idgen(struct mpool_descriptor *mp, enum obj_type_omf otype, u64 *objid)
+{
+	struct pmd_mdc_info *cinfo = NULL;
+	int rc = 0;
+	u8 cslot;
+	u32 tidx;
+
+	if (mp->pds_mda.mdi_slotvcnt < 2) {
+		/* No mdc available to assign object to; cannot use mdc0 */
+		rc = -ENOSPC;
+		mp_pr_err("mpool %s, no MDCi with i>0", rc, mp->pds_name);
+		*objid = 0;
+		return rc;
+	}
+
+	/* Get next mdc for allocation */
+	tidx = atomic_inc_return(&mp->pds_mda.mdi_sel.mds_tbl_idx) % MDC_TBL_SZ;
+	ASSERT(tidx <= MDC_TBL_SZ);
+
+	cslot = mp->pds_mda.mdi_sel.mds_tbl[tidx];
+	cinfo = &mp->pds_mda.mdi_slotv[cslot];
+
+	pmd_mdc_lock(&cinfo->mmi_uqlock, cslot);
+	*objid = objid_make(cinfo->mmi_luniq + 1, otype, cslot);
+	if (objid_ckpt(*objid)) {
+
+		/*
+		 * Must checkpoint objid before assigning it to an object
+		 * to guarantee it will not reissue objid after a crash.
+		 * Must hold cinfo.compactlock while log checkpoint to mdc
+		 * to prevent a race with mdc compaction.
+		 */
+		pmd_mdc_lock(&cinfo->mmi_compactlock, cslot);
+#ifdef OBJ_PERSISTENCE_ENABLED
+		rc = pmd_log_idckpt(mp, *objid);
+#endif
+		if (!rc)
+			cinfo->mmi_lckpt = *objid;
+		pmd_mdc_unlock(&cinfo->mmi_compactlock);
+	}
+
+	if (!rc)
+		cinfo->mmi_luniq = cinfo->mmi_luniq + 1;
+	pmd_mdc_unlock(&cinfo->mmi_uqlock);
+
+	if (rc) {
+		mp_pr_rl("mpool %s, checkpoint append for objid 0x%lx failed",
+			 rc, mp->pds_name, (ulong)*objid);
+		*objid = 0;
+		return rc;
+	}
+
+	return 0;
+}
+
+static int pmd_realloc_idvalidate(struct mpool_descriptor *mp, u64 objid)
+{
+	struct pmd_mdc_info *cinfo = NULL;
+	u8 cslot = objid_slot(objid);
+	u64 uniq = objid_uniq(objid);
+	int rc = 0;
+
+	/* We never realloc objects in mdc0 */
+	if (!cslot) {
+		rc = -EINVAL;
+		mp_pr_err("mpool %s, can't re-allocate an object 0x%lx associated to MDC0",
+			  rc, mp->pds_name, (ulong)objid);
+		return rc;
+	}
+
+	spin_lock(&mp->pds_mda.mdi_slotvlock);
+	if (cslot >= mp->pds_mda.mdi_slotvcnt)
+		rc = -EINVAL;
+	spin_unlock(&mp->pds_mda.mdi_slotvlock);
+
+	if (rc) {
+		mp_pr_err("mpool %s, realloc failed, slot number %u is too big %u 0x%lx",
+			  rc, mp->pds_name, cslot, mp->pds_mda.mdi_slotvcnt, (ulong)objid);
+	} else {
+		cinfo = &mp->pds_mda.mdi_slotv[cslot];
+
+		pmd_mdc_lock(&cinfo->mmi_uqlock, cslot);
+		if (uniq > cinfo->mmi_luniq)
+			rc = -EINVAL;
+		pmd_mdc_unlock(&cinfo->mmi_uqlock);
+
+		if (rc) {
+			mp_pr_err("mpool %s, realloc failed, unique id %lu too big %lu 0x%lx",
+				  rc, mp->pds_name, (ulong)uniq,
+				  (ulong)cinfo->mmi_luniq, (ulong)objid);
+		}
+	}
+
+	return rc;
+}
+
+/**
+ * pmd_alloc_argcheck() -
+ * @mp:      Mpool descriptor
+ * @objid:   Object ID
+ * @otype:   Object type
+ * @mclassp: Media class
+ */
+static int pmd_alloc_argcheck(struct mpool_descriptor *mp, u64 objid,
+			      enum obj_type_omf otype, enum mp_media_classp mclassp)
+{
+	int rc = -EINVAL;
+
+	if (!mp)
+		return rc;
+
+	if (!objtype_user(otype) || !mclass_isvalid(mclassp)) {
+		mp_pr_err("mpool %s, unknown object type or media class %d %d",
+			  rc, mp->pds_name, otype, mclassp);
+		return rc;
+	}
+
+	if (objid && objid_type(objid) != otype) {
+		mp_pr_err("mpool %s, unknown object type mismatch %d %d",
+			  rc, mp->pds_name, objid_type(objid), otype);
+		return rc;
+	}
+
+	return 0;
+}
+
+int pmd_obj_alloc_cmn(struct mpool_descriptor *mp, u64 objid, enum obj_type_omf otype,
+		      struct pmd_obj_capacity *ocap, enum mp_media_classp mclass,
+		      int realloc, bool needref, struct pmd_layout **layoutp)
+{
+	struct pmd_mdc_info *cinfo;
+	struct media_class *mc;
+	struct pmd_layout *layout;
+	struct mpool_uuid uuid;
+	int retries, flush, rc;
+	u64 zcnt = 0;
+	u8  cslot;
+
+	*layoutp = NULL;
+
+	rc = pmd_alloc_argcheck(mp, objid, otype, mclass);
+	if (rc)
+		return rc;
+
+	if (!objid) {
+		/*
+		 * alloc: generate objid, checkpoint as needed to
+		 * support realloc of uncommitted objects after crash and to
+		 * guarantee objids never reuse
+		 */
+		rc = pmd_alloc_idgen(mp, otype, &objid);
+	} else if (realloc) {
+		/* realloc: validate objid */
+		rc = pmd_realloc_idvalidate(mp, objid);
+	}
+	if (rc)
+		return rc;
+
+	if (otype == OMF_OBJ_MLOG)
+		mpool_generate_uuid(&uuid);
+
+	/*
+	 * Retry from 128 to 256ms with a flush every 1/8th of the retries.
+	 * This is a workaround for the async mblock trim problem.
+	 */
+	retries = 1024;
+	flush   = retries >> 3;
+
+retry:
+	down_read(&mp->pds_pdvlock);
+
+	mc = &mp->pds_mc[mclass];
+	if (mc->mc_pdmc < 0) {
+		up_read(&mp->pds_pdvlock);
+		return -ENOENT;
+	}
+
+	/* Calculate the height (zcnt) of layout. */
+	pmd_layout_calculate(mp, ocap, mc, &zcnt);
+
+	layout = pmd_layout_alloc(&uuid, objid, 0, 0, zcnt);
+	if (!layout) {
+		up_read(&mp->pds_pdvlock);
+		return -ENOMEM;
+	}
+
+	/* Try to allocate zones from drives in media class */
+	rc = pmd_layout_provision(mp, ocap, layout, mc, zcnt);
+	up_read(&mp->pds_pdvlock);
+
+	if (rc) {
+		pmd_obj_put(layout);
+
+		/* TODO: Retry only if mperasewq is busy... */
+		if (retries-- > 0) {
+			usleep_range(128, 256);
+
+			if (flush && (retries % flush == 0))
+				flush_workqueue(mp->pds_erase_wq);
+
+			goto retry;
+		}
+
+		mp_pr_rl("mpool %s, layout alloc failed: objid 0x%lx %lu %u",
+			 rc, mp->pds_name, (ulong)objid, (ulong)zcnt, otype);
+
+		return rc;
+	}
+
+	cslot = objid_slot(objid);
+	cinfo = &mp->pds_mda.mdi_slotv[cslot];
+
+	pmd_update_obj_stats(mp, layout, cinfo, PMD_OBJ_ALLOC);
+
+	if (needref)
+		kref_get(&layout->eld_ref);
+
+	/*
+	 * If realloc, we MUST confirm (while holding the uncommitted obj
+	 * tree lock) that objid is not in the committed obj tree in order
+	 * to protect against an invalid *_realloc() call.
+	 */
+	pmd_uc_lock(cinfo, cslot);
+	if (realloc) {
+		pmd_co_rlock(cinfo, cslot);
+		if (pmd_co_find(cinfo, objid))
+			rc = -EEXIST;
+		pmd_co_runlock(cinfo);
+	}
+
+	/*
+	 * For both alloc and realloc, confirm that objid is not in the
+	 * uncommitted obj tree and insert it.  Note that a reallocated
+	 * objid can collide, but a generated objid should never collide.
+	 */
+	if (!rc && pmd_uc_insert(cinfo, layout))
+		rc = -EEXIST;
+	pmd_uc_unlock(cinfo);
+
+	if (rc) {
+		mp_pr_err("mpool %s, %sallocated obj 0x%lx should not be in the %scommitted tree",
+			  rc, mp->pds_name, realloc ? "re-" : "",
+			  (ulong)objid, realloc ? "" : "un");
+
+		if (needref)
+			pmd_obj_put(layout);
+
+		/*
+		 * Since object insertion failed, we need to undo the
+		 * per-mdc stats update we did earlier in this routine
+		 */
+		pmd_update_obj_stats(mp, layout, cinfo, PMD_OBJ_ABORT);
+		pmd_layout_unprovision(mp, layout);
+		layout = NULL;
+	}
+
+	*layoutp = layout;
+
+	return rc;
+}
+
+void pmd_mpool_usage(struct mpool_descriptor *mp, struct mpool_usage *usage)
+{
+	int sidx;
+	u16 slotvcnt;
+
+	/*
+	 * Get a local copy of MDC count (slotvcnt), and then drop the lock
+	 * It's okay another MDC is added concurrently, since pds_ds_info
+	 * is always stale by design
+	 */
+	spin_lock(&mp->pds_mda.mdi_slotvlock);
+	slotvcnt = mp->pds_mda.mdi_slotvcnt;
+	spin_unlock(&mp->pds_mda.mdi_slotvlock);
+
+	for (sidx = 1; sidx < slotvcnt; sidx++) {
+		struct pmd_mdc_stats *pms;
+		struct pmd_mdc_info *cinfo;
+
+		cinfo = &mp->pds_mda.mdi_slotv[sidx];
+		pms   = &cinfo->mmi_stats;
+
+		mutex_lock(&cinfo->mmi_stats_lock);
+		usage->mpu_mblock_alen += pms->pms_mblock_alen;
+		usage->mpu_mblock_wlen += pms->pms_mblock_wlen;
+		usage->mpu_mlog_alen   += pms->pms_mlog_alen;
+		usage->mpu_mblock_cnt  += pms->pms_mblock_cnt;
+		usage->mpu_mlog_cnt    += pms->pms_mlog_cnt;
+		mutex_unlock(&cinfo->mmi_stats_lock);
+	}
+
+	if (slotvcnt < 2)
+		return;
+
+	usage->mpu_alen = (usage->mpu_mblock_alen + usage->mpu_mlog_alen);
+	usage->mpu_wlen = (usage->mpu_mblock_wlen + usage->mpu_mlog_alen);
+}
+
+/**
+ * pmd_mdc0_meta_update_update() - update on media the MDC0 metadata.
+ * @mp:
+ * @layout: Used to know on which drives to write the MDC0 metadata.
+ *
+ * For now write the whole super block, but only the MDC0 metadata needs
+ * to be updated, the rest of the superblock doesn't change.
+ *
+ * In 1.0 the MDC0 metadata is replicated on the 4 superblocks of the drive.
+ * In case of failure, the SBs of a same drive may end up having different
+ * values for the MDC0 metadata.
+ * To address this situation voting could be used along with the SB gen number
+ * psb_gen. But for 1.0 a simpler approach is taken: SB gen number is not used
+ * and SB0 is the authoritative replica. The other 3 replicas of MDC0 metadata
+ * are not used when the mpool activates.
+ */
+static int pmd_mdc0_meta_update(struct mpool_descriptor *mp, struct pmd_layout *layout)
+{
+	struct omf_sb_descriptor *sb;
+	struct mpool_dev_info *pd;
+	struct mc_parms mc_parms;
+	int rc;
+
+	pd = &(mp->pds_pdv[layout->eld_ld.ol_pdh]);
+	if (mpool_pd_status_get(pd) != PD_STAT_ONLINE) {
+		rc = -EIO;
+		mp_pr_err("%s: pd %s unavailable or offline, status %d",
+			  rc, mp->pds_name, pd->pdi_name, mpool_pd_status_get(pd));
+		return rc;
+	}
+
+	sb = kzalloc(sizeof(*sb), GFP_KERNEL);
+	if (!sb)
+		return -ENOMEM;
+
+	/*
+	 * set superblock values common to all new drives in pool
+	 * (new or extant)
+	 */
+	sb->osb_magic = OMF_SB_MAGIC;
+	strlcpy((char *) sb->osb_name, mp->pds_name, sizeof(sb->osb_name));
+	sb->osb_vers = OMF_SB_DESC_VER_LAST;
+	mpool_uuid_copy(&sb->osb_poolid, &mp->pds_poolid);
+	sb->osb_gen = 1;
+
+	/* Set superblock values specific to this drive */
+	mpool_uuid_copy(&sb->osb_parm.odp_devid, &pd->pdi_devid);
+	sb->osb_parm.odp_devsz = pd->pdi_parm.dpr_devsz;
+	sb->osb_parm.odp_zonetot = pd->pdi_parm.dpr_zonetot;
+	mc_pd_prop2mc_parms(&pd->pdi_parm.dpr_prop, &mc_parms);
+	mc_parms2omf_devparm(&mc_parms, &sb->osb_parm);
+
+	sbutil_mdc0_copy(sb, &mp->pds_sbmdc0);
+
+	mp_pr_debug("MDC0 compaction gen1 %lu gen2 %lu",
+		    0, (ulong)sb->osb_mdc01gen, (ulong)sb->osb_mdc02gen);
+
+	/*
+	 * sb_write_update() succeeds if at least SB0 is written. It is
+	 * not a problem to have SB1 not written because the authoritative
+	 * MDC0 metadata replica is the one in SB0.
+	 */
+	rc = sb_write_update(&pd->pdi_parm, sb);
+	if (rc)
+		mp_pr_err("compacting %s MDC0, writing superblock on drive %s failed",
+			  rc, mp->pds_name, pd->pdi_name);
+
+	kfree(sb);
+	return rc;
+}
+
+/**
+ * pmd_update_obj_stats() - update per-MDC space usage
+ * @mp:
+ * @layout:
+ * @cinfo:
+ * @op: object opcode
+ */
+void pmd_update_obj_stats(struct mpool_descriptor *mp, struct pmd_layout *layout,
+			  struct pmd_mdc_info *cinfo, enum pmd_obj_op op)
+{
+	struct pmd_mdc_stats *pms;
+	enum obj_type_omf otype;
+	u64 cap;
+
+	otype = pmd_objid_type(layout->eld_objid);
+
+	mutex_lock(&cinfo->mmi_stats_lock);
+	pms = &cinfo->mmi_stats;
+
+	/* Update space usage and mblock/mlog count */
+	switch (op) {
+	case PMD_OBJ_LOAD:
+		if (otype == OMF_OBJ_MBLOCK)
+			pms->pms_mblock_wlen += layout->eld_mblen;
+		fallthrough;
+
+	case PMD_OBJ_ALLOC:
+		cap = pmd_layout_cap_get(mp, layout);
+		if (otype == OMF_OBJ_MLOG) {
+			pms->pms_mlog_cnt++;
+			pms->pms_mlog_alen += cap;
+		} else if (otype == OMF_OBJ_MBLOCK) {
+			pms->pms_mblock_cnt++;
+			pms->pms_mblock_alen += cap;
+		}
+		break;
+
+	case PMD_OBJ_COMMIT:
+		if (otype == OMF_OBJ_MBLOCK)
+			pms->pms_mblock_wlen += layout->eld_mblen;
+		break;
+
+	case PMD_OBJ_DELETE:
+		if (otype == OMF_OBJ_MBLOCK)
+			pms->pms_mblock_wlen -= layout->eld_mblen;
+		fallthrough;
+
+	case PMD_OBJ_ABORT:
+		cap = pmd_layout_cap_get(mp, layout);
+		if (otype == OMF_OBJ_MLOG) {
+			pms->pms_mlog_cnt--;
+			pms->pms_mlog_alen -= cap;
+		} else if (otype == OMF_OBJ_MBLOCK) {
+			pms->pms_mblock_cnt--;
+			pms->pms_mblock_alen -= cap;
+		}
+		break;
+
+	default:
+		ASSERT(0);
+		break;
+	}
+
+	mutex_unlock(&cinfo->mmi_stats_lock);
+}
+
+/**
+ * pmd_compare_free_space() - compare free space between MDCs
+ * @f:  First  MDC
+ * @s:  Second MDC
+ *
+ * Arrange MDCs in descending order of free space
+ */
+static int pmd_compare_free_space(const void *first, const void *second)
+{
+	const struct pmd_mdc_info *f = *(const struct pmd_mdc_info **)first;
+	const struct pmd_mdc_info *s = *(const struct pmd_mdc_info **)second;
+
+	/* return < 0 - first member should be ahead for second */
+	if (f->mmi_credit.ci_free > s->mmi_credit.ci_free)
+		return -1;
+
+	/* return > 0 - first member should be after second */
+	if (f->mmi_credit.ci_free < s->mmi_credit.ci_free)
+		return 1;
+
+	return 0;
+
+}
+
+/**
+ * pmd_update_ms_tbl() - udpates mds_tlb with MDC slot numbers
+ * @mp:  mpool descriptor
+ * @slotnum:  array of slot numbers
+ *
+ * This function creates an array of mdc slot and credit sets by interleaving
+ * MDC slots. Interleave maximize the interval at which the slots appear in
+ * the mds_tbl.
+ *
+ * The first set in the array is reference set with only 1 member and has max
+ * assigned credits. Subsequent sets are formed to match the reference set and
+ * may contain one or more member such that total credit of the set will match
+ * the reference set. The last set may have fewer credit than the reference set
+ *
+ * Locking: no lock need to be held when calling this function.
+ *
+ */
+static void pmd_update_mds_tbl(struct mpool_descriptor *mp, u8 num_mdc, u8 *slotnum)
+{
+	struct mdc_credit_set *cset, *cs;
+	struct pmd_mdc_info *cinfo;
+	u16 refcredit, neededcredit, tidx, totalcredit = 0;
+	u8 csidx, csmidx, num_cset, i;
+
+	cset = kcalloc(num_mdc, sizeof(*cset), GFP_KERNEL);
+	if (!cset)
+		return;
+
+	cinfo = &mp->pds_mda.mdi_slotv[slotnum[0]];
+	refcredit = cinfo->mmi_credit.ci_credit;
+
+	csidx = 0; /* creditset index */
+	i     = 0; /* slotnum index   */
+	while (i < num_mdc) {
+		cs = &cset[csidx++];
+		neededcredit = refcredit;
+
+		csmidx = 0;
+		/* Setup members of the credit set */
+		while (csmidx < MPOOL_MDC_SET_SZ  && i < num_mdc) {
+			/* slot 0 should never be there */
+			ASSERT(slotnum[i] != 0);
+
+			cinfo = &mp->pds_mda.mdi_slotv[slotnum[i]];
+			cs->cs_num_csm = csmidx + 1;
+			cs->csm[csmidx].m_slot = slotnum[i];
+
+			if (neededcredit <= cinfo->mmi_credit.ci_credit) {
+				/*
+				 * More than required credit is available,
+				 * leftover will be assigned to the next set.
+				 */
+				cs->csm[csmidx].m_credit    += neededcredit;
+				cinfo->mmi_credit.ci_credit -= neededcredit;
+				totalcredit += neededcredit; /* Debug */
+				neededcredit = 0;
+
+				/* Some credit available stay at this mdc */
+				if (cinfo->mmi_credit.ci_credit == 0)
+					i++;
+				break;
+			}
+
+			/*
+			 * Available credit is < needed, assign all
+			 * the available credit and move to the next
+			 * mdc slot.
+			 */
+			cs->csm[csmidx].m_credit += cinfo->mmi_credit.ci_credit;
+			neededcredit -= cinfo->mmi_credit.ci_credit;
+			totalcredit  += cinfo->mmi_credit.ci_credit;
+			cinfo->mmi_credit.ci_credit = 0;
+
+			/* Move to the next mdcslot and set member */
+			i++;
+			csmidx++;
+		}
+	}
+
+	ASSERT(totalcredit == MDC_TBL_SZ);
+	num_cset = csidx;
+
+	tidx  = 0;
+	csidx = 0;
+	while (tidx < MDC_TBL_SZ) {
+		cs = &cset[csidx];
+		if (cs->cs_idx < cs->cs_num_csm) {
+			csmidx = cs->cs_idx;
+			if (cs->csm[csmidx].m_credit) {
+				cs->csm[csmidx].m_credit--;
+				mp->pds_mda.mdi_sel.mds_tbl[tidx] = cs->csm[csmidx].m_slot;
+				totalcredit--;
+
+				if (cs->csm[csmidx].m_credit == 0)
+					cs->cs_idx += 1;
+
+				tidx++;
+			}
+		}
+		/* Loop over the sets */
+		csidx = (csidx + 1) % num_cset;
+	}
+
+	ASSERT(totalcredit == 0);
+
+	kfree(cset);
+}
+
+/**
+ * pmd_update_credit() - udpates MDC credit if new MDCs should be created
+ * @mp:  mpool descriptor
+ *
+ * Credits are assigned as a ratio between MDC such that MDC with least free
+ * space will fill up at the same time as other MDC.
+ *
+ * Locking: no lock need to be held when calling this function.
+ */
+void pmd_update_credit(struct mpool_descriptor *mp)
+{
+	struct pre_compact_ctrs *pco_cnt;
+	struct pmd_mdc_info *cinfo;
+	u64 cap, used, free, nmtoc;
+	u16 credit, cslot;
+	u8 sidx, nidx, num_mdc;
+	u8 *slotnum;
+	void **sarray = mp->pds_mda.mdi_sel.mds_smdc;
+	u32 nbnoalloc = (u32)mp->pds_params.mp_pconbnoalloc;
+
+	if (mp->pds_mda.mdi_slotvcnt < 2) {
+		mp_pr_warn("Not enough MDCn %u", mp->pds_mda.mdi_slotvcnt - 1);
+		return;
+	}
+
+	slotnum = kcalloc(MDC_SLOTS, sizeof(*slotnum), GFP_KERNEL);
+	if (!slotnum)
+		return;
+
+	nmtoc = atomic_read(&mp->pds_pco.pco_nmtoc);
+	nmtoc = nmtoc % (mp->pds_mda.mdi_slotvcnt - 1) + 1;
+
+	/*
+	 * slotvcnt includes MDC 0 and MDCn that are in precompaction
+	 * list and should be excluded. If there are less than (nbnoalloc
+	 * +2) MDCs exclusion is not possible. 2 is added to account for
+	 * MDC0 and the MDC pointed to by pco_nmtoc.
+	 *
+	 * MDC that is in pre-compacting state and two MDCs that follows
+	 * are excluded from allocation. This is done to prevent stall/
+	 * delays for a sync that follows an allocation as both
+	 * take a compaction lock.
+	 */
+	if (mp->pds_mda.mdi_slotvcnt < (nbnoalloc + 2)) {
+		num_mdc = mp->pds_mda.mdi_slotvcnt - 1;
+		cslot  = 1;
+		mp_pr_debug("MDCn cnt %u, cannot skip %u num_mdc %u",
+			    0, mp->pds_mda.mdi_slotvcnt - 1, (u32)nmtoc, num_mdc);
+	} else {
+		num_mdc = mp->pds_mda.mdi_slotvcnt - (nbnoalloc + 2);
+		cslot = (nmtoc + nbnoalloc) % (mp->pds_mda.mdi_slotvcnt - 1);
+	}
+
+
+	/* Walkthrough all MDCs and exclude MDCs that are almost full */
+	for (nidx = 0, sidx = 0; nidx < num_mdc; nidx++) {
+		cslot = cslot % (mp->pds_mda.mdi_slotvcnt - 1) + 1;
+
+		if (cslot == 0)
+			cslot = 1;
+
+		cinfo = &mp->pds_mda.mdi_slotv[cslot];
+		pco_cnt = &(cinfo->mmi_pco_cnt);
+
+		cap  = atomic64_read(&pco_cnt->pcc_cap);
+		used = atomic64_read(&pco_cnt->pcc_len);
+
+		if ((cap - used) < (cap / 400)) {
+			/* Consider < .25% free space as full */
+			mp_pr_warn("MDC slot %u almost full", cslot);
+			continue;
+		}
+		sarray[sidx++] = cinfo;
+		cinfo->mmi_credit.ci_free = cap - used;
+	}
+
+	/* Sort the array with decreasing order of space */
+	sort((void *)sarray, sidx, sizeof(sarray[0]), pmd_compare_free_space, NULL);
+	num_mdc = sidx;
+
+	/* Calculate total free space across the chosen MDC set */
+	for (sidx = 0, free = 0; sidx < num_mdc; sidx++) {
+		cinfo = sarray[sidx];
+		free += cinfo->mmi_credit.ci_free;
+		slotnum[sidx] = cinfo->mmi_credit.ci_slot;
+	}
+
+	/*
+	 * Assign credit to MDCs in the MDC set. Credit is relative and
+	 * will not exceed the total slots in mds_tbl
+	 */
+	for (sidx = 0, credit = 0; sidx < num_mdc; sidx++) {
+		cinfo = &mp->pds_mda.mdi_slotv[slotnum[sidx]];
+		cinfo->mmi_credit.ci_credit = (MDC_TBL_SZ * cinfo->mmi_credit.ci_free) / free;
+		credit += cinfo->mmi_credit.ci_credit;
+	}
+
+	ASSERT(credit <= MDC_TBL_SZ);
+
+	/*
+	 * If the credit is not equal to the table size, assign
+	 * credits so table can be filled all the way.
+	 */
+	if (credit < MDC_TBL_SZ) {
+		credit = MDC_TBL_SZ - credit;
+
+		sidx = 0;
+		while (credit > 0) {
+			sidx = (sidx % num_mdc);
+			cinfo = &mp->pds_mda.mdi_slotv[slotnum[sidx]];
+			cinfo->mmi_credit.ci_credit += 1;
+			sidx++;
+			credit--;
+		}
+	}
+
+	pmd_update_mds_tbl(mp, num_mdc, slotnum);
+
+	kfree(slotnum);
+}
+
+/*
+ * pmd_mlogid2cslot() - Given an mlog object ID which makes one of the mpool
+ *	core MDCs (MDCi with i >0), it returns i.
+ *	Given an client created object ID (mblock or mlog), it returns -1.
+ * @mlogid:
+ */
+static int pmd_mlogid2cslot(u64 mlogid)
+{
+	u64 uniq;
+
+	if (pmd_objid_type(mlogid) != OMF_OBJ_MLOG)
+		return -1;
+	if (objid_slot(mlogid))
+		return -1;
+	uniq = objid_uniq(mlogid);
+	if (uniq > (2 * MDC_SLOTS) - 1)
+		return -1;
+
+	return(uniq/2);
+}
+
+void pmd_precompact_alsz(struct mpool_descriptor *mp, u64 objid, u64 len, u64 cap)
+{
+	struct pre_compact_ctrs *pco_cnt;
+	struct pmd_mdc_info *cinfo;
+	int ret;
+	u8 cslot;
+
+	ret = pmd_mlogid2cslot(objid);
+	if (ret <= 0)
+		return;
+
+	cslot = ret;
+	cinfo = &mp->pds_mda.mdi_slotv[cslot];
+	pco_cnt = &(cinfo->mmi_pco_cnt);
+	atomic64_set(&pco_cnt->pcc_len, len);
+	atomic64_set(&pco_cnt->pcc_cap, cap);
+}
+
+int pmd_init(void)
+{
+	int rc = 0;
+
+	/* Initialize the slab caches. */
+	pmd_layout_cache = kmem_cache_create("mpool_pmd_layout", sizeof(struct pmd_layout),
+					     0, SLAB_HWCACHE_ALIGN | SLAB_POISON, NULL);
+	if (!pmd_layout_cache) {
+		rc = -ENOMEM;
+		mp_pr_err("kmem_cache_create(pmd_layout, %zu) failed",
+			  rc, sizeof(struct pmd_layout));
+		goto errout;
+	}
+
+	pmd_layout_priv_cache = kmem_cache_create("mpool_pmd_layout_priv",
+				sizeof(struct pmd_layout) + sizeof(union pmd_layout_priv),
+				0, SLAB_HWCACHE_ALIGN | SLAB_POISON, NULL);
+	if (!pmd_layout_priv_cache) {
+		rc = -ENOMEM;
+		mp_pr_err("kmem_cache_create(pmd priv, %zu) failed",
+			  rc, sizeof(union pmd_layout_priv));
+		goto errout;
+	}
+
+	pmd_obj_erase_work_cache = kmem_cache_create("mpool_pmd_obj_erase_work",
+						     sizeof(struct pmd_obj_erase_work),
+						     0, SLAB_HWCACHE_ALIGN | SLAB_POISON, NULL);
+	if (!pmd_obj_erase_work_cache) {
+		rc = -ENOMEM;
+		mp_pr_err("kmem_cache_create(pmd_obj_erase, %zu) failed",
+			  rc, sizeof(struct pmd_obj_erase_work));
+		goto errout;
+	}
+
+errout:
+	if (rc)
+		pmd_exit();
+
+	return rc;
+}
+
+void pmd_exit(void)
+{
+	kmem_cache_destroy(pmd_obj_erase_work_cache);
+	kmem_cache_destroy(pmd_layout_priv_cache);
+	kmem_cache_destroy(pmd_layout_cache);
+
+	pmd_obj_erase_work_cache = NULL;
+	pmd_layout_priv_cache = NULL;
+	pmd_layout_cache = NULL;
+}
-- 
2.17.2


  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12 16:27 [PATCH v2 00/22] add Object Storage Media Pool (mpool) Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 01/22] mpool: add utility routines and ioctl definitions Nabeel M Mohamed
2020-10-12 16:45   ` Randy Dunlap
2020-10-12 16:48     ` Randy Dunlap
2020-10-12 16:27 ` [PATCH v2 02/22] mpool: add in-memory struct definitions Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 03/22] mpool: add on-media " Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 04/22] mpool: add pool drive component which handles mpool IO using the block layer API Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 05/22] mpool: add space map component which manages free space on mpool devices Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 06/22] mpool: add on-media pack, unpack and upgrade routines Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 07/22] mpool: add superblock management routines Nabeel M Mohamed
2020-10-12 16:27 ` Nabeel M Mohamed [this message]
2020-10-12 16:27 ` [PATCH v2 09/22] mpool: add mblock lifecycle management and IO routines Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 10/22] mpool: add mlog IO utility routines Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 11/22] mpool: add mlog lifecycle management and IO routines Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 12/22] mpool: add metadata container or mlog-pair framework Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 13/22] mpool: add utility routines for mpool lifecycle management Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 14/22] mpool: add pool metadata routines to create persistent mpools Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 15/22] mpool: add mpool lifecycle management routines Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 16/22] mpool: add mpool control plane utility routines Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 17/22] mpool: add mpool lifecycle management ioctls Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 18/22] mpool: add object " Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 19/22] mpool: add support to mmap arbitrary collection of mblocks Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 20/22] mpool: add support to proactively evict cached mblock data from the page-cache Nabeel M Mohamed
2020-10-12 16:27 ` [PATCH v2 21/22] mpool: add documentation Nabeel M Mohamed
2020-10-12 16:53   ` Randy Dunlap
2020-10-12 16:27 ` [PATCH v2 22/22] mpool: add Kconfig and Makefile Nabeel M Mohamed
2020-10-15  8:02 ` [PATCH v2 00/22] add Object Storage Media Pool (mpool) Christoph Hellwig
2020-10-16 21:58   ` [EXT] " Nabeel Meeramohideen Mohamed (nmeeramohide)
2020-10-16 22:11     ` Dan Williams
2020-10-19 22:30       ` Nabeel Meeramohideen Mohamed (nmeeramohide)
2020-10-20 21:35         ` Dan Williams
2020-10-21 17:10           ` Nabeel Meeramohideen Mohamed (nmeeramohide)
2020-10-21 17:48             ` Dan Williams
2020-10-21 14:24       ` Mike Snitzer
2020-10-21 16:24         ` Dan Williams

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201012162736.65241-9-nmeeramohide@micron.com \
    --to=nmeeramohide@micron.com \
    --cc=gbecker@micron.com \
    --cc=jgroves@micron.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=plabat@micron.com \
    --cc=smoyer@micron.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-block/0 linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ https://lore.kernel.org/linux-block \
		linux-block@vger.kernel.org
	public-inbox-index linux-block

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-block


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git