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LU-11089 obd: rename lu_keys_guard to lu_context_remembered_guard
[fs/lustre-release.git] / lustre / obdclass / lu_object.c
index 618c5bc..fbe034a 100644 (file)
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
@@ -27,7 +23,7 @@
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2011, 2013, Intel Corporation.
+ * Copyright (c) 2011, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
 
 #define DEBUG_SUBSYSTEM S_CLASS
 
-#include <libcfs/libcfs.h>
-
-#ifdef __KERNEL__
-# include <linux/module.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#ifdef HAVE_PROCESSOR_H
+#include <linux/processor.h>
+#else
+#include <libcfs/linux/processor.h>
 #endif
 
-/* hash_long() */
-#include <libcfs/libcfs_hash.h>
+#include <libcfs/libcfs.h>
+#include <libcfs/libcfs_hash.h> /* hash_long() */
+#include <libcfs/linux/linux-mem.h>
 #include <obd_class.h>
 #include <obd_support.h>
 #include <lustre_disk.h>
 #include <lustre_fid.h>
 #include <lu_object.h>
 #include <lu_ref.h>
-#include <libcfs/list.h>
 
-extern spinlock_t obd_types_lock;
+struct lu_site_bkt_data {
+       /**
+        * LRU list, updated on each access to object. Protected by
+        * bucket lock of lu_site::ls_obj_hash.
+        *
+        * "Cold" end of LRU is lu_site::ls_lru.next. Accessed object are
+        * moved to the lu_site::ls_lru.prev (this is due to the non-existence
+        * of list_for_each_entry_safe_reverse()).
+        */
+       struct list_head                lsb_lru;
+       /**
+        * Wait-queue signaled when an object in this site is ultimately
+        * destroyed (lu_object_free()). It is used by lu_object_find() to
+        * wait before re-trying when object in the process of destruction is
+        * found in the hash table.
+        *
+        * \see htable_lookup().
+        */
+       wait_queue_head_t               lsb_marche_funebre;
+};
 
 enum {
        LU_CACHE_PERCENT_MAX     = 50,
        LU_CACHE_PERCENT_DEFAULT = 20
 };
 
-#define        LU_CACHE_NR_MAX_ADJUST          128
+#define        LU_CACHE_NR_MAX_ADJUST          512
 #define        LU_CACHE_NR_UNLIMITED           -1
 #define        LU_CACHE_NR_DEFAULT             LU_CACHE_NR_UNLIMITED
 #define        LU_CACHE_NR_LDISKFS_LIMIT       LU_CACHE_NR_UNLIMITED
@@ -76,6 +93,7 @@ enum {
 
 #define LU_SITE_BITS_MIN    12
 #define LU_SITE_BITS_MAX    24
+#define LU_SITE_BITS_MAX_CL 19
 /**
  * total 256 buckets, we don't want too many buckets because:
  * - consume too much memory
@@ -85,14 +103,27 @@ enum {
 
 
 static unsigned int lu_cache_percent = LU_CACHE_PERCENT_DEFAULT;
-CFS_MODULE_PARM(lu_cache_percent, "i", int, 0644,
-               "Percentage of memory to be used as lu_object cache");
+module_param(lu_cache_percent, int, 0644);
+MODULE_PARM_DESC(lu_cache_percent, "Percentage of memory to be used as lu_object cache");
 
 static long lu_cache_nr = LU_CACHE_NR_DEFAULT;
-CFS_MODULE_PARM(lu_cache_nr, "l", long, 0644,
-               "Maximum number of objects in lu_object cache");
+module_param(lu_cache_nr, long, 0644);
+MODULE_PARM_DESC(lu_cache_nr, "Maximum number of objects in lu_object cache");
 
 static void lu_object_free(const struct lu_env *env, struct lu_object *o);
+static __u32 ls_stats_read(struct lprocfs_stats *stats, int idx);
+
+wait_queue_head_t *
+lu_site_wq_from_fid(struct lu_site *site, struct lu_fid *fid)
+{
+       struct cfs_hash_bd bd;
+       struct lu_site_bkt_data *bkt;
+
+       cfs_hash_bd_get(site->ls_obj_hash, fid, &bd);
+       bkt = cfs_hash_bd_extra_get(site->ls_obj_hash, &bd);
+       return &bkt->lsb_marche_funebre;
+}
+EXPORT_SYMBOL(lu_site_wq_from_fid);
 
 /**
  * Decrease reference counter on object. If last reference is freed, return
@@ -101,30 +132,26 @@ static void lu_object_free(const struct lu_env *env, struct lu_object *o);
  */
 void lu_object_put(const struct lu_env *env, struct lu_object *o)
 {
-        struct lu_site_bkt_data *bkt;
-        struct lu_object_header *top;
-        struct lu_site          *site;
-        struct lu_object        *orig;
-        cfs_hash_bd_t            bd;
-       const struct lu_fid     *fid;
-
-        top  = o->lo_header;
-        site = o->lo_dev->ld_site;
-        orig = o;
+       struct lu_site_bkt_data *bkt;
+       struct lu_object_header *top = o->lo_header;
+       struct lu_site *site = o->lo_dev->ld_site;
+       struct lu_object *orig = o;
+       struct cfs_hash_bd bd;
+       const struct lu_fid *fid = lu_object_fid(o);
+       bool is_dying;
 
        /*
         * till we have full fids-on-OST implemented anonymous objects
         * are possible in OSP. such an object isn't listed in the site
         * so we should not remove it from the site.
         */
-       fid = lu_object_fid(o);
        if (fid_is_zero(fid)) {
                LASSERT(top->loh_hash.next == NULL
                        && top->loh_hash.pprev == NULL);
-               LASSERT(cfs_list_empty(&top->loh_lru));
+               LASSERT(list_empty(&top->loh_lru));
                if (!atomic_dec_and_test(&top->loh_ref))
                        return;
-               cfs_list_for_each_entry_reverse(o, &top->loh_layers, lo_linkage) {
+               list_for_each_entry_reverse(o, &top->loh_layers, lo_linkage) {
                        if (o->lo_ops->loo_object_release != NULL)
                                o->lo_ops->loo_object_release(env, o);
                }
@@ -132,12 +159,17 @@ void lu_object_put(const struct lu_env *env, struct lu_object *o)
                return;
        }
 
-        cfs_hash_bd_get(site->ls_obj_hash, &top->loh_fid, &bd);
-        bkt = cfs_hash_bd_extra_get(site->ls_obj_hash, &bd);
+       cfs_hash_bd_get(site->ls_obj_hash, &top->loh_fid, &bd);
+       bkt = cfs_hash_bd_extra_get(site->ls_obj_hash, &bd);
 
+       is_dying = lu_object_is_dying(top);
        if (!cfs_hash_bd_dec_and_lock(site->ls_obj_hash, &bd, &top->loh_ref)) {
-               if (lu_object_is_dying(top)) {
-
+               /* at this point the object reference is dropped and lock is
+                * not taken, so lu_object should not be touched because it
+                * can be freed by concurrent thread. Use local variable for
+                * check.
+                */
+               if (is_dying) {
                        /*
                         * somebody may be waiting for this, currently only
                         * used for cl_object, see cl_object_put_last().
@@ -147,43 +179,49 @@ void lu_object_put(const struct lu_env *env, struct lu_object *o)
                return;
        }
 
-        LASSERT(bkt->lsb_busy > 0);
-        bkt->lsb_busy--;
-        /*
-         * When last reference is released, iterate over object
-         * layers, and notify them that object is no longer busy.
-         */
-        cfs_list_for_each_entry_reverse(o, &top->loh_layers, lo_linkage) {
-                if (o->lo_ops->loo_object_release != NULL)
-                        o->lo_ops->loo_object_release(env, o);
-        }
+       /*
+        * When last reference is released, iterate over object
+        * layers, and notify them that object is no longer busy.
+        */
+       list_for_each_entry_reverse(o, &top->loh_layers, lo_linkage) {
+               if (o->lo_ops->loo_object_release != NULL)
+                       o->lo_ops->loo_object_release(env, o);
+       }
 
-        if (!lu_object_is_dying(top)) {
-                LASSERT(cfs_list_empty(&top->loh_lru));
-                cfs_list_add_tail(&top->loh_lru, &bkt->lsb_lru);
-                cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1);
-                return;
-        }
+       /* don't use local 'is_dying' here because if was taken without lock
+        * but here we need the latest actual value of it so check lu_object
+        * directly here.
+        */
+       if (!lu_object_is_dying(top) &&
+           (lu_object_exists(orig) || lu_object_is_cl(orig))) {
+               LASSERT(list_empty(&top->loh_lru));
+               list_add_tail(&top->loh_lru, &bkt->lsb_lru);
+               percpu_counter_inc(&site->ls_lru_len_counter);
+               CDEBUG(D_INODE, "Add %p/%p to site lru. hash: %p, bkt: %p\n",
+                      orig, top, site->ls_obj_hash, bkt);
+               cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1);
+               return;
+       }
 
-        /*
-         * If object is dying (will not be cached), removed it
-         * from hash table and LRU.
-         *
-         * This is done with hash table and LRU lists locked. As the only
-         * way to acquire first reference to previously unreferenced
-         * object is through hash-table lookup (lu_object_find()),
-         * or LRU scanning (lu_site_purge()), that are done under hash-table
-         * and LRU lock, no race with concurrent object lookup is possible
-         * and we can safely destroy object below.
-         */
+       /*
+        * If object is dying (will not be cached) then remove it
+        * from hash table and LRU.
+        *
+        * This is done with hash table and LRU lists locked. As the only
+        * way to acquire first reference to previously unreferenced
+        * object is through hash-table lookup (lu_object_find()),
+        * or LRU scanning (lu_site_purge()), that are done under hash-table
+        * and LRU lock, no race with concurrent object lookup is possible
+        * and we can safely destroy object below.
+        */
        if (!test_and_set_bit(LU_OBJECT_UNHASHED, &top->loh_flags))
                cfs_hash_bd_del_locked(site->ls_obj_hash, &bd, &top->loh_hash);
-        cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1);
-        /*
-         * Object was already removed from hash and lru above, can
-         * kill it.
-         */
-        lu_object_free(env, orig);
+       cfs_hash_bd_unlock(site->ls_obj_hash, &bd, 1);
+       /*
+        * Object was already removed from hash and lru above, can
+        * kill it.
+        */
+       lu_object_free(env, orig);
 }
 EXPORT_SYMBOL(lu_object_put);
 
@@ -209,11 +247,18 @@ void lu_object_unhash(const struct lu_env *env, struct lu_object *o)
        top = o->lo_header;
        set_bit(LU_OBJECT_HEARD_BANSHEE, &top->loh_flags);
        if (!test_and_set_bit(LU_OBJECT_UNHASHED, &top->loh_flags)) {
-               cfs_hash_t *obj_hash = o->lo_dev->ld_site->ls_obj_hash;
-               cfs_hash_bd_t bd;
+               struct lu_site *site = o->lo_dev->ld_site;
+               struct cfs_hash *obj_hash = site->ls_obj_hash;
+               struct cfs_hash_bd bd;
 
                cfs_hash_bd_get_and_lock(obj_hash, &top->loh_fid, &bd, 1);
-               cfs_list_del_init(&top->loh_lru);
+               if (!list_empty(&top->loh_lru)) {
+                       struct lu_site_bkt_data *bkt;
+
+                       list_del_init(&top->loh_lru);
+                       bkt = cfs_hash_bd_extra_get(obj_hash, &bd);
+                       percpu_counter_dec(&site->ls_lru_len_counter);
+               }
                cfs_hash_bd_del_locked(obj_hash, &bd, &top->loh_hash);
                cfs_hash_bd_unlock(obj_hash, &bd, 1);
        }
@@ -233,7 +278,7 @@ static struct lu_object *lu_object_alloc(const struct lu_env *env,
 {
        struct lu_object *scan;
        struct lu_object *top;
-       cfs_list_t *layers;
+       struct list_head *layers;
        unsigned int init_mask = 0;
        unsigned int init_flag;
        int clean;
@@ -263,7 +308,7 @@ static struct lu_object *lu_object_alloc(const struct lu_env *env,
                 */
                clean = 1;
                init_flag = 1;
-               cfs_list_for_each_entry(scan, layers, lo_linkage) {
+               list_for_each_entry(scan, layers, lo_linkage) {
                        if (init_mask & init_flag)
                                goto next;
                        clean = 0;
@@ -279,7 +324,7 @@ next:
                }
        } while (!clean);
 
-        cfs_list_for_each_entry_reverse(scan, layers, lo_linkage) {
+       list_for_each_entry_reverse(scan, layers, lo_linkage) {
                 if (scan->lo_ops->loo_object_start != NULL) {
                         result = scan->lo_ops->loo_object_start(env, scan);
                         if (result != 0) {
@@ -298,19 +343,19 @@ next:
  */
 static void lu_object_free(const struct lu_env *env, struct lu_object *o)
 {
-        struct lu_site_bkt_data *bkt;
-        struct lu_site          *site;
-        struct lu_object        *scan;
-        cfs_list_t              *layers;
-        cfs_list_t               splice;
-
-        site   = o->lo_dev->ld_site;
-        layers = &o->lo_header->loh_layers;
-        bkt    = lu_site_bkt_from_fid(site, &o->lo_header->loh_fid);
+       wait_queue_head_t *wq;
+       struct lu_site          *site;
+       struct lu_object        *scan;
+       struct list_head        *layers;
+       struct list_head         splice;
+
+       site = o->lo_dev->ld_site;
+       layers = &o->lo_header->loh_layers;
+       wq = lu_site_wq_from_fid(site, &o->lo_header->loh_fid);
         /*
          * First call ->loo_object_delete() method to release all resources.
          */
-        cfs_list_for_each_entry_reverse(scan, layers, lo_linkage) {
+       list_for_each_entry_reverse(scan, layers, lo_linkage) {
                 if (scan->lo_ops->loo_object_delete != NULL)
                         scan->lo_ops->loo_object_delete(env, scan);
         }
@@ -321,52 +366,65 @@ static void lu_object_free(const struct lu_env *env, struct lu_object *o)
          * necessary, because lu_object_header is freed together with the
          * top-level slice.
          */
-        CFS_INIT_LIST_HEAD(&splice);
-        cfs_list_splice_init(layers, &splice);
-       while (!cfs_list_empty(&splice)) {
+       INIT_LIST_HEAD(&splice);
+       list_splice_init(layers, &splice);
+       while (!list_empty(&splice)) {
                /*
                 * Free layers in bottom-to-top order, so that object header
                 * lives as long as possible and ->loo_object_free() methods
                 * can look at its contents.
                 */
                o = container_of0(splice.prev, struct lu_object, lo_linkage);
-               cfs_list_del_init(&o->lo_linkage);
+               list_del_init(&o->lo_linkage);
                LASSERT(o->lo_ops->loo_object_free != NULL);
                o->lo_ops->loo_object_free(env, o);
        }
 
-       if (waitqueue_active(&bkt->lsb_marche_funebre))
-               wake_up_all(&bkt->lsb_marche_funebre);
+       if (waitqueue_active(wq))
+               wake_up_all(wq);
 }
 
 /**
  * Free \a nr objects from the cold end of the site LRU list.
+ * if canblock is 0, then don't block awaiting for another
+ * instance of lu_site_purge() to complete
  */
-int lu_site_purge(const struct lu_env *env, struct lu_site *s, int nr)
+int lu_site_purge_objects(const struct lu_env *env, struct lu_site *s,
+                         int nr, int canblock)
 {
         struct lu_object_header *h;
         struct lu_object_header *temp;
         struct lu_site_bkt_data *bkt;
-        cfs_hash_bd_t            bd;
-        cfs_hash_bd_t            bd2;
-        cfs_list_t               dispose;
-        int                      did_sth;
-        int                      start;
+       struct cfs_hash_bd            bd;
+       struct cfs_hash_bd            bd2;
+       struct list_head         dispose;
+       int                      did_sth;
+       unsigned int             start = 0;
         int                      count;
         int                      bnr;
-        int                      i;
+       unsigned int             i;
 
        if (OBD_FAIL_CHECK(OBD_FAIL_OBD_NO_LRU))
                RETURN(0);
 
-        CFS_INIT_LIST_HEAD(&dispose);
+       INIT_LIST_HEAD(&dispose);
         /*
          * Under LRU list lock, scan LRU list and move unreferenced objects to
          * the dispose list, removing them from LRU and hash table.
          */
-        start = s->ls_purge_start;
-        bnr = (nr == ~0) ? -1 : nr / CFS_HASH_NBKT(s->ls_obj_hash) + 1;
+       if (nr != ~0)
+               start = s->ls_purge_start;
+       bnr = (nr == ~0) ? -1 : nr / (int)CFS_HASH_NBKT(s->ls_obj_hash) + 1;
  again:
+       /*
+        * It doesn't make any sense to make purge threads parallel, that can
+        * only bring troubles to us. See LU-5331.
+        */
+       if (canblock != 0)
+               mutex_lock(&s->ls_purge_mutex);
+       else if (mutex_trylock(&s->ls_purge_mutex) == 0)
+               goto out;
+
         did_sth = 0;
         cfs_hash_for_each_bucket(s->ls_obj_hash, &bd, i) {
                 if (i < start)
@@ -375,7 +433,7 @@ int lu_site_purge(const struct lu_env *env, struct lu_site *s, int nr)
                 cfs_hash_bd_lock(s->ls_obj_hash, &bd, 1);
                 bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, &bd);
 
-                cfs_list_for_each_entry_safe(h, temp, &bkt->lsb_lru, loh_lru) {
+               list_for_each_entry_safe(h, temp, &bkt->lsb_lru, loh_lru) {
                        LASSERT(atomic_read(&h->loh_ref) == 0);
 
                         cfs_hash_bd_get(s->ls_obj_hash, &h->loh_fid, &bd2);
@@ -383,7 +441,8 @@ int lu_site_purge(const struct lu_env *env, struct lu_site *s, int nr)
 
                         cfs_hash_bd_del_locked(s->ls_obj_hash,
                                                &bd2, &h->loh_hash);
-                        cfs_list_move(&h->loh_lru, &dispose);
+                       list_move(&h->loh_lru, &dispose);
+                       percpu_counter_dec(&s->ls_lru_len_counter);
                         if (did_sth == 0)
                                 did_sth = 1;
 
@@ -400,17 +459,18 @@ int lu_site_purge(const struct lu_env *env, struct lu_site *s, int nr)
                 * Free everything on the dispose list. This is safe against
                 * races due to the reasons described in lu_object_put().
                 */
-                while (!cfs_list_empty(&dispose)) {
-                        h = container_of0(dispose.next,
-                                          struct lu_object_header, loh_lru);
-                        cfs_list_del_init(&h->loh_lru);
-                        lu_object_free(env, lu_object_top(h));
-                        lprocfs_counter_incr(s->ls_stats, LU_SS_LRU_PURGED);
-                }
+               while (!list_empty(&dispose)) {
+                       h = container_of0(dispose.next,
+                                         struct lu_object_header, loh_lru);
+                       list_del_init(&h->loh_lru);
+                       lu_object_free(env, lu_object_top(h));
+                       lprocfs_counter_incr(s->ls_stats, LU_SS_LRU_PURGED);
+               }
 
                 if (nr == 0)
                         break;
         }
+       mutex_unlock(&s->ls_purge_mutex);
 
         if (nr != 0 && did_sth && start != 0) {
                 start = 0; /* restart from the first bucket */
@@ -419,9 +479,10 @@ int lu_site_purge(const struct lu_env *env, struct lu_site *s, int nr)
         /* race on s->ls_purge_start, but nobody cares */
         s->ls_purge_start = i % CFS_HASH_NBKT(s->ls_obj_hash);
 
+out:
         return nr;
 }
-EXPORT_SYMBOL(lu_site_purge);
+EXPORT_SYMBOL(lu_site_purge_objects);
 
 /*
  * Object printing.
@@ -462,7 +523,7 @@ LU_KEY_INIT_FINI(lu_global, struct lu_cdebug_data);
  * Key, holding temporary buffer. This key is registered very early by
  * lu_global_init().
  */
-struct lu_context_key lu_global_key = {
+static struct lu_context_key lu_global_key = {
        .lct_tags = LCT_MD_THREAD | LCT_DT_THREAD |
                    LCT_MG_THREAD | LCT_CL_THREAD | LCT_LOCAL,
        .lct_init = lu_global_key_init,
@@ -510,13 +571,13 @@ void lu_object_header_print(const struct lu_env *env, void *cookie,
                             lu_printer_t printer,
                             const struct lu_object_header *hdr)
 {
-        (*printer)(env, cookie, "header@%p[%#lx, %d, "DFID"%s%s%s]",
+       (*printer)(env, cookie, "header@%p[%#lx, %d, "DFID"%s%s%s]",
                   hdr, hdr->loh_flags, atomic_read(&hdr->loh_ref),
-                   PFID(&hdr->loh_fid),
-                   cfs_hlist_unhashed(&hdr->loh_hash) ? "" : " hash",
-                   cfs_list_empty((cfs_list_t *)&hdr->loh_lru) ? \
-                   "" : " lru",
-                   hdr->loh_attr & LOHA_EXISTS ? " exist":"");
+                  PFID(&hdr->loh_fid),
+                  hlist_unhashed(&hdr->loh_hash) ? "" : " hash",
+                  list_empty((struct list_head *)&hdr->loh_lru) ? \
+                  "" : " lru",
+                  hdr->loh_attr & LOHA_EXISTS ? " exist" : "");
 }
 EXPORT_SYMBOL(lu_object_header_print);
 
@@ -534,7 +595,7 @@ void lu_object_print(const struct lu_env *env, void *cookie,
        lu_object_header_print(env, cookie, printer, top);
        (*printer)(env, cookie, "{\n");
 
-       cfs_list_for_each_entry(o, &top->loh_layers, lo_linkage) {
+       list_for_each_entry(o, &top->loh_layers, lo_linkage) {
                /*
                 * print `.' \a depth times followed by type name and address
                 */
@@ -559,82 +620,44 @@ int lu_object_invariant(const struct lu_object *o)
         struct lu_object_header *top;
 
         top = o->lo_header;
-        cfs_list_for_each_entry(o, &top->loh_layers, lo_linkage) {
+       list_for_each_entry(o, &top->loh_layers, lo_linkage) {
                 if (o->lo_ops->loo_object_invariant != NULL &&
                     !o->lo_ops->loo_object_invariant(o))
                         return 0;
         }
         return 1;
 }
-EXPORT_SYMBOL(lu_object_invariant);
 
 static struct lu_object *htable_lookup(struct lu_site *s,
-                                      cfs_hash_bd_t *bd,
+                                      struct cfs_hash_bd *bd,
                                       const struct lu_fid *f,
-                                      wait_queue_t *waiter,
                                       __u64 *version)
 {
-        struct lu_site_bkt_data *bkt;
-        struct lu_object_header *h;
-        cfs_hlist_node_t        *hnode;
-        __u64  ver = cfs_hash_bd_version_get(bd);
+       struct lu_site_bkt_data *bkt;
+       struct lu_object_header *h;
+       struct hlist_node *hnode;
+       __u64 ver = cfs_hash_bd_version_get(bd);
 
-        if (*version == ver)
+       if (*version == ver)
                return ERR_PTR(-ENOENT);
 
-        *version = ver;
-        bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, bd);
+       *version = ver;
+       bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, bd);
        /* cfs_hash_bd_peek_locked is a somehow "internal" function
         * of cfs_hash, it doesn't add refcount on object. */
        hnode = cfs_hash_bd_peek_locked(s->ls_obj_hash, bd, (void *)f);
-        if (hnode == NULL) {
-                lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_MISS);
-               return ERR_PTR(-ENOENT);
-        }
-
-        h = container_of0(hnode, struct lu_object_header, loh_hash);
-        if (likely(!lu_object_is_dying(h))) {
-               cfs_hash_get(s->ls_obj_hash, hnode);
-                lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_HIT);
-                cfs_list_del_init(&h->loh_lru);
-                return lu_object_top(h);
-        }
-
-        /*
-         * Lookup found an object being destroyed this object cannot be
-         * returned (to assure that references to dying objects are eventually
-         * drained), and moreover, lookup has to wait until object is freed.
-         */
-
-       init_waitqueue_entry_current(waiter);
-       add_wait_queue(&bkt->lsb_marche_funebre, waiter);
-       set_current_state(TASK_UNINTERRUPTIBLE);
-       lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_DEATH_RACE);
-       return ERR_PTR(-EAGAIN);
-}
-
-static struct lu_object *htable_lookup_nowait(struct lu_site *s,
-                                             cfs_hash_bd_t *bd,
-                                             const struct lu_fid *f)
-{
-       cfs_hlist_node_t        *hnode;
-       struct lu_object_header *h;
-
-       /* cfs_hash_bd_peek_locked is a somehow "internal" function
-        * of cfs_hash, it doesn't add refcount on object. */
-       hnode = cfs_hash_bd_peek_locked(s->ls_obj_hash, bd, (void *)f);
-       if (hnode == NULL) {
+       if (!hnode) {
                lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_MISS);
                return ERR_PTR(-ENOENT);
        }
 
        h = container_of0(hnode, struct lu_object_header, loh_hash);
-       if (unlikely(lu_object_is_dying(h)))
-               return ERR_PTR(-ENOENT);
-
        cfs_hash_get(s->ls_obj_hash, hnode);
        lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_HIT);
-       cfs_list_del_init(&h->loh_lru);
+       if (!list_empty(&h->loh_lru)) {
+               list_del_init(&h->loh_lru);
+               percpu_counter_dec(&s->ls_lru_len_counter);
+       }
        return lu_object_top(h);
 }
 
@@ -668,119 +691,16 @@ static void lu_object_limit(const struct lu_env *env,
 
        size = cfs_hash_size_get(dev->ld_site->ls_obj_hash);
        nr = (__u64)lu_cache_nr;
-       if (size > nr)
-               lu_site_purge(env, dev->ld_site,
-                             MIN(size - nr, LU_CACHE_NR_MAX_ADJUST));
-
-       return;
-}
-
-static struct lu_object *lu_object_new(const struct lu_env *env,
-                                       struct lu_device *dev,
-                                       const struct lu_fid *f,
-                                       const struct lu_object_conf *conf)
-{
-        struct lu_object        *o;
-        cfs_hash_t              *hs;
-        cfs_hash_bd_t            bd;
-        struct lu_site_bkt_data *bkt;
-
-        o = lu_object_alloc(env, dev, f, conf);
-        if (unlikely(IS_ERR(o)))
-                return o;
-
-        hs = dev->ld_site->ls_obj_hash;
-        cfs_hash_bd_get_and_lock(hs, (void *)f, &bd, 1);
-        bkt = cfs_hash_bd_extra_get(hs, &bd);
-        cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
-        bkt->lsb_busy++;
-        cfs_hash_bd_unlock(hs, &bd, 1);
-
-       lu_object_limit(env, dev);
+       if (size <= nr)
+               return;
 
-        return o;
+       lu_site_purge_objects(env, dev->ld_site,
+                             MIN(size - nr, LU_CACHE_NR_MAX_ADJUST), 0);
 }
 
 /**
  * Core logic of lu_object_find*() functions.
- */
-static struct lu_object *lu_object_find_try(const struct lu_env *env,
-                                           struct lu_device *dev,
-                                           const struct lu_fid *f,
-                                           const struct lu_object_conf *conf,
-                                           wait_queue_t *waiter)
-{
-       struct lu_object      *o;
-       struct lu_object      *shadow;
-       struct lu_site        *s;
-       cfs_hash_t            *hs;
-       cfs_hash_bd_t          bd;
-       __u64                  version = 0;
-
-        /*
-         * This uses standard index maintenance protocol:
-         *
-         *     - search index under lock, and return object if found;
-         *     - otherwise, unlock index, allocate new object;
-         *     - lock index and search again;
-         *     - if nothing is found (usual case), insert newly created
-         *       object into index;
-         *     - otherwise (race: other thread inserted object), free
-         *       object just allocated.
-         *     - unlock index;
-         *     - return object.
-         *
-         * For "LOC_F_NEW" case, we are sure the object is new established.
-         * It is unnecessary to perform lookup-alloc-lookup-insert, instead,
-         * just alloc and insert directly.
-         *
-         * If dying object is found during index search, add @waiter to the
-         * site wait-queue and return ERR_PTR(-EAGAIN).
-         */
-        if (conf != NULL && conf->loc_flags & LOC_F_NEW)
-                return lu_object_new(env, dev, f, conf);
-
-        s  = dev->ld_site;
-        hs = s->ls_obj_hash;
-        cfs_hash_bd_get_and_lock(hs, (void *)f, &bd, 1);
-        o = htable_lookup(s, &bd, f, waiter, &version);
-        cfs_hash_bd_unlock(hs, &bd, 1);
-       if (!IS_ERR(o) || PTR_ERR(o) != -ENOENT)
-                return o;
-
-        /*
-         * Allocate new object. This may result in rather complicated
-         * operations, including fld queries, inode loading, etc.
-         */
-        o = lu_object_alloc(env, dev, f, conf);
-        if (unlikely(IS_ERR(o)))
-                return o;
-
-        LASSERT(lu_fid_eq(lu_object_fid(o), f));
-
-        cfs_hash_bd_lock(hs, &bd, 1);
-
-        shadow = htable_lookup(s, &bd, f, waiter, &version);
-       if (likely(IS_ERR(shadow) && PTR_ERR(shadow) == -ENOENT)) {
-                struct lu_site_bkt_data *bkt;
-
-                bkt = cfs_hash_bd_extra_get(hs, &bd);
-                cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
-                bkt->lsb_busy++;
-                cfs_hash_bd_unlock(hs, &bd, 1);
-
-               lu_object_limit(env, dev);
-
-                return o;
-        }
-
-        lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_RACE);
-        cfs_hash_bd_unlock(hs, &bd, 1);
-        lu_object_free(env, o);
-        return shadow;
-}
-
-/**
+ *
  * Much like lu_object_find(), but top level device of object is specifically
  * \a dev rather than top level device of the site. This interface allows
  * objects of different "stacking" to be created within the same site.
@@ -790,48 +710,73 @@ struct lu_object *lu_object_find_at(const struct lu_env *env,
                                    const struct lu_fid *f,
                                    const struct lu_object_conf *conf)
 {
-       struct lu_site_bkt_data *bkt;
-       struct lu_object        *obj;
-       wait_queue_t           wait;
+       struct lu_object *o;
+       struct lu_object *shadow;
+       struct lu_site *s;
+       struct cfs_hash *hs;
+       struct cfs_hash_bd bd;
+       __u64 version = 0;
 
-       while (1) {
-               obj = lu_object_find_try(env, dev, f, conf, &wait);
-               if (obj != ERR_PTR(-EAGAIN))
-                       return obj;
-               /*
-                * lu_object_find_try() already added waiter into the
-                * wait queue.
-                */
-               waitq_wait(&wait, TASK_UNINTERRUPTIBLE);
-               bkt = lu_site_bkt_from_fid(dev->ld_site, (void *)f);
-               remove_wait_queue(&bkt->lsb_marche_funebre, &wait);
+       /*
+        * This uses standard index maintenance protocol:
+        *
+        *     - search index under lock, and return object if found;
+        *     - otherwise, unlock index, allocate new object;
+        *     - lock index and search again;
+        *     - if nothing is found (usual case), insert newly created
+        *       object into index;
+        *     - otherwise (race: other thread inserted object), free
+        *       object just allocated.
+        *     - unlock index;
+        *     - return object.
+        *
+        * For "LOC_F_NEW" case, we are sure the object is new established.
+        * It is unnecessary to perform lookup-alloc-lookup-insert, instead,
+        * just alloc and insert directly.
+        *
+        */
+       s  = dev->ld_site;
+       hs = s->ls_obj_hash;
+       cfs_hash_bd_get(hs, f, &bd);
+       if (!(conf && conf->loc_flags & LOC_F_NEW)) {
+               cfs_hash_bd_lock(hs, &bd, 1);
+               o = htable_lookup(s, &bd, f, &version);
+               cfs_hash_bd_unlock(hs, &bd, 1);
+
+               if (!IS_ERR(o) || PTR_ERR(o) != -ENOENT)
+                       return o;
        }
-}
-EXPORT_SYMBOL(lu_object_find_at);
+       /*
+        * Allocate new object. This may result in rather complicated
+        * operations, including fld queries, inode loading, etc.
+        */
+       o = lu_object_alloc(env, dev, f, conf);
+       if (IS_ERR(o))
+               return o;
 
-/**
- * Try to find the object in cache without waiting for the dead object
- * to be released nor allocating object if no cached one was found.
- *
- * The found object will be set as LU_OBJECT_HEARD_BANSHEE for purging.
- */
-void lu_object_purge(const struct lu_env *env, struct lu_device *dev,
-                    const struct lu_fid *f)
-{
-       struct lu_site          *s  = dev->ld_site;
-       cfs_hash_t              *hs = s->ls_obj_hash;
-       cfs_hash_bd_t            bd;
-       struct lu_object        *o;
+       LASSERT(lu_fid_eq(lu_object_fid(o), f));
 
-       cfs_hash_bd_get_and_lock(hs, f, &bd, 1);
-       o = htable_lookup_nowait(s, &bd, f);
-       cfs_hash_bd_unlock(hs, &bd, 1);
-       if (!IS_ERR(o)) {
-               set_bit(LU_OBJECT_HEARD_BANSHEE, &o->lo_header->loh_flags);
-               lu_object_put(env, o);
+       cfs_hash_bd_lock(hs, &bd, 1);
+
+       if (conf && conf->loc_flags & LOC_F_NEW)
+               shadow = ERR_PTR(-ENOENT);
+       else
+               shadow = htable_lookup(s, &bd, f, &version);
+       if (likely(PTR_ERR(shadow) == -ENOENT)) {
+               cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
+               cfs_hash_bd_unlock(hs, &bd, 1);
+
+               lu_object_limit(env, dev);
+
+               return o;
        }
+
+       lprocfs_counter_incr(s->ls_stats, LU_SS_CACHE_RACE);
+       cfs_hash_bd_unlock(hs, &bd, 1);
+       lu_object_free(env, o);
+       return shadow;
 }
-EXPORT_SYMBOL(lu_object_purge);
+EXPORT_SYMBOL(lu_object_find_at);
 
 /**
  * Find object with given fid, and return its slice belonging to given device.
@@ -841,49 +786,37 @@ struct lu_object *lu_object_find_slice(const struct lu_env *env,
                                        const struct lu_fid *f,
                                        const struct lu_object_conf *conf)
 {
-        struct lu_object *top;
-        struct lu_object *obj;
+       struct lu_object *top;
+       struct lu_object *obj;
 
-        top = lu_object_find(env, dev, f, conf);
-        if (!IS_ERR(top)) {
-                obj = lu_object_locate(top->lo_header, dev->ld_type);
-                if (obj == NULL)
-                        lu_object_put(env, top);
-        } else
-                obj = top;
-        return obj;
+       top = lu_object_find(env, dev, f, conf);
+       if (IS_ERR(top))
+               return top;
+
+       obj = lu_object_locate(top->lo_header, dev->ld_type);
+       if (unlikely(obj == NULL)) {
+               lu_object_put(env, top);
+               obj = ERR_PTR(-ENOENT);
+       }
+
+       return obj;
 }
 EXPORT_SYMBOL(lu_object_find_slice);
 
-/**
- * Global list of all device types.
- */
-static CFS_LIST_HEAD(lu_device_types);
-
 int lu_device_type_init(struct lu_device_type *ldt)
 {
        int result = 0;
 
        atomic_set(&ldt->ldt_device_nr, 0);
-       INIT_LIST_HEAD(&ldt->ldt_linkage);
        if (ldt->ldt_ops->ldto_init)
                result = ldt->ldt_ops->ldto_init(ldt);
 
-       if (result == 0) {
-               spin_lock(&obd_types_lock);
-               list_add(&ldt->ldt_linkage, &lu_device_types);
-               spin_unlock(&obd_types_lock);
-       }
-
        return result;
 }
 EXPORT_SYMBOL(lu_device_type_init);
 
 void lu_device_type_fini(struct lu_device_type *ldt)
 {
-       spin_lock(&obd_types_lock);
-       list_del_init(&ldt->ldt_linkage);
-       spin_unlock(&obd_types_lock);
        if (ldt->ldt_ops->ldto_fini)
                ldt->ldt_ops->ldto_fini(ldt);
 }
@@ -892,8 +825,8 @@ EXPORT_SYMBOL(lu_device_type_fini);
 /**
  * Global list of all sites on this node
  */
-static CFS_LIST_HEAD(lu_sites);
-static DEFINE_MUTEX(lu_sites_guard);
+static LIST_HEAD(lu_sites);
+static DECLARE_RWSEM(lu_sites_guard);
 
 /**
  * Global environment used by site shrinker.
@@ -907,24 +840,24 @@ struct lu_site_print_arg {
 };
 
 static int
-lu_site_obj_print(cfs_hash_t *hs, cfs_hash_bd_t *bd,
-                  cfs_hlist_node_t *hnode, void *data)
-{
-        struct lu_site_print_arg *arg = (struct lu_site_print_arg *)data;
-        struct lu_object_header  *h;
-
-        h = cfs_hlist_entry(hnode, struct lu_object_header, loh_hash);
-        if (!cfs_list_empty(&h->loh_layers)) {
-                const struct lu_object *o;
-
-                o = lu_object_top(h);
-                lu_object_print(arg->lsp_env, arg->lsp_cookie,
-                                arg->lsp_printer, o);
-        } else {
-                lu_object_header_print(arg->lsp_env, arg->lsp_cookie,
-                                       arg->lsp_printer, h);
-        }
-        return 0;
+lu_site_obj_print(struct cfs_hash *hs, struct cfs_hash_bd *bd,
+                 struct hlist_node *hnode, void *data)
+{
+       struct lu_site_print_arg *arg = (struct lu_site_print_arg *)data;
+       struct lu_object_header  *h;
+
+       h = hlist_entry(hnode, struct lu_object_header, loh_hash);
+       if (!list_empty(&h->loh_layers)) {
+               const struct lu_object *o;
+
+               o = lu_object_top(h);
+               lu_object_print(arg->lsp_env, arg->lsp_cookie,
+                               arg->lsp_printer, o);
+       } else {
+               lu_object_header_print(arg->lsp_env, arg->lsp_cookie,
+                                      arg->lsp_printer, h);
+       }
+       return 0;
 }
 
 /**
@@ -946,10 +879,11 @@ EXPORT_SYMBOL(lu_site_print);
 /**
  * Return desired hash table order.
  */
-static int lu_htable_order(struct lu_device *top)
+static unsigned long lu_htable_order(struct lu_device *top)
 {
-        unsigned long cache_size;
-        int bits;
+       unsigned long cache_size;
+       unsigned long bits;
+       unsigned long bits_max = LU_SITE_BITS_MAX;
 
        /*
         * For ZFS based OSDs the cache should be disabled by default.  This
@@ -963,6 +897,9 @@ static int lu_htable_order(struct lu_device *top)
                return LU_SITE_BITS_MIN;
        }
 
+       if (strcmp(top->ld_type->ldt_name, LUSTRE_VVP_NAME) == 0)
+               bits_max = LU_SITE_BITS_MAX_CL;
+
         /*
          * Calculate hash table size, assuming that we want reasonable
          * performance when 20% of total memory is occupied by cache of
@@ -974,8 +911,8 @@ static int lu_htable_order(struct lu_device *top)
 
 #if BITS_PER_LONG == 32
         /* limit hashtable size for lowmem systems to low RAM */
-       if (cache_size > 1 << (30 - PAGE_CACHE_SHIFT))
-               cache_size = 1 << (30 - PAGE_CACHE_SHIFT) * 3 / 4;
+       if (cache_size > 1 << (30 - PAGE_SHIFT))
+               cache_size = 1 << (30 - PAGE_SHIFT) * 3 / 4;
 #endif
 
         /* clear off unreasonable cache setting. */
@@ -988,15 +925,16 @@ static int lu_htable_order(struct lu_device *top)
                 lu_cache_percent = LU_CACHE_PERCENT_DEFAULT;
         }
         cache_size = cache_size / 100 * lu_cache_percent *
-               (PAGE_CACHE_SIZE / 1024);
+               (PAGE_SIZE / 1024);
 
         for (bits = 1; (1 << bits) < cache_size; ++bits) {
                 ;
         }
-        return bits;
+
+       return clamp_t(typeof(bits), bits, LU_SITE_BITS_MIN, bits_max);
 }
 
-static unsigned lu_obj_hop_hash(cfs_hash_t *hs,
+static unsigned lu_obj_hop_hash(struct cfs_hash *hs,
                                const void *key, unsigned mask)
 {
        struct lu_fid  *fid = (struct lu_fid *)key;
@@ -1015,48 +953,41 @@ static unsigned lu_obj_hop_hash(cfs_hash_t *hs,
        return hash & mask;
 }
 
-static void *lu_obj_hop_object(cfs_hlist_node_t *hnode)
+static void *lu_obj_hop_object(struct hlist_node *hnode)
 {
-        return cfs_hlist_entry(hnode, struct lu_object_header, loh_hash);
+       return hlist_entry(hnode, struct lu_object_header, loh_hash);
 }
 
-static void *lu_obj_hop_key(cfs_hlist_node_t *hnode)
+static void *lu_obj_hop_key(struct hlist_node *hnode)
 {
-        struct lu_object_header *h;
+       struct lu_object_header *h;
 
-        h = cfs_hlist_entry(hnode, struct lu_object_header, loh_hash);
-        return &h->loh_fid;
+       h = hlist_entry(hnode, struct lu_object_header, loh_hash);
+       return &h->loh_fid;
 }
 
-static int lu_obj_hop_keycmp(const void *key, cfs_hlist_node_t *hnode)
+static int lu_obj_hop_keycmp(const void *key, struct hlist_node *hnode)
 {
-        struct lu_object_header *h;
+       struct lu_object_header *h;
 
-        h = cfs_hlist_entry(hnode, struct lu_object_header, loh_hash);
-        return lu_fid_eq(&h->loh_fid, (struct lu_fid *)key);
+       h = hlist_entry(hnode, struct lu_object_header, loh_hash);
+       return lu_fid_eq(&h->loh_fid, (struct lu_fid *)key);
 }
 
-static void lu_obj_hop_get(cfs_hash_t *hs, cfs_hlist_node_t *hnode)
+static void lu_obj_hop_get(struct cfs_hash *hs, struct hlist_node *hnode)
 {
-        struct lu_object_header *h;
-
-        h = cfs_hlist_entry(hnode, struct lu_object_header, loh_hash);
-       if (atomic_add_return(1, &h->loh_ref) == 1) {
-                struct lu_site_bkt_data *bkt;
-                cfs_hash_bd_t            bd;
+       struct lu_object_header *h;
 
-                cfs_hash_bd_get(hs, &h->loh_fid, &bd);
-                bkt = cfs_hash_bd_extra_get(hs, &bd);
-                bkt->lsb_busy++;
-        }
+       h = hlist_entry(hnode, struct lu_object_header, loh_hash);
+       atomic_inc(&h->loh_ref);
 }
 
-static void lu_obj_hop_put_locked(cfs_hash_t *hs, cfs_hlist_node_t *hnode)
+static void lu_obj_hop_put_locked(struct cfs_hash *hs, struct hlist_node *hnode)
 {
         LBUG(); /* we should never called it */
 }
 
-cfs_hash_ops_t lu_site_hash_ops = {
+static struct cfs_hash_ops lu_site_hash_ops = {
         .hs_hash        = lu_obj_hop_hash,
         .hs_key         = lu_obj_hop_key,
         .hs_keycmp      = lu_obj_hop_keycmp,
@@ -1068,8 +999,8 @@ cfs_hash_ops_t lu_site_hash_ops = {
 void lu_dev_add_linkage(struct lu_site *s, struct lu_device *d)
 {
        spin_lock(&s->ls_ld_lock);
-       if (cfs_list_empty(&d->ld_linkage))
-               cfs_list_add(&d->ld_linkage, &s->ls_ld_linkage);
+       if (list_empty(&d->ld_linkage))
+               list_add(&d->ld_linkage, &s->ls_ld_linkage);
        spin_unlock(&s->ls_ld_lock);
 }
 EXPORT_SYMBOL(lu_dev_add_linkage);
@@ -1077,7 +1008,7 @@ EXPORT_SYMBOL(lu_dev_add_linkage);
 void lu_dev_del_linkage(struct lu_site *s, struct lu_device *d)
 {
        spin_lock(&s->ls_ld_lock);
-       cfs_list_del_init(&d->ld_linkage);
+       list_del_init(&d->ld_linkage);
        spin_unlock(&s->ls_ld_lock);
 }
 EXPORT_SYMBOL(lu_dev_del_linkage);
@@ -1088,16 +1019,26 @@ EXPORT_SYMBOL(lu_dev_del_linkage);
 int lu_site_init(struct lu_site *s, struct lu_device *top)
 {
        struct lu_site_bkt_data *bkt;
-       cfs_hash_bd_t bd;
+       struct cfs_hash_bd bd;
        char name[16];
-       int bits;
-       int i;
+       unsigned long bits;
+       unsigned int i;
+       int rc;
        ENTRY;
 
        memset(s, 0, sizeof *s);
-       bits = lu_htable_order(top);
-       snprintf(name, 16, "lu_site_%s", top->ld_type->ldt_name);
-       for (bits = min(max(LU_SITE_BITS_MIN, bits), LU_SITE_BITS_MAX);
+       mutex_init(&s->ls_purge_mutex);
+
+#ifdef HAVE_PERCPU_COUNTER_INIT_GFP_FLAG
+       rc = percpu_counter_init(&s->ls_lru_len_counter, 0, GFP_NOFS);
+#else
+       rc = percpu_counter_init(&s->ls_lru_len_counter, 0);
+#endif
+       if (rc)
+               return -ENOMEM;
+
+       snprintf(name, sizeof(name), "lu_site_%s", top->ld_type->ldt_name);
+       for (bits = lu_htable_order(top);
             bits >= LU_SITE_BITS_MIN; bits--) {
                s->ls_obj_hash = cfs_hash_create(name, bits, bits,
                                                 bits - LU_SITE_BKT_BITS,
@@ -1113,13 +1054,13 @@ int lu_site_init(struct lu_site *s, struct lu_device *top)
        }
 
        if (s->ls_obj_hash == NULL) {
-               CERROR("failed to create lu_site hash with bits: %d\n", bits);
+               CERROR("failed to create lu_site hash with bits: %lu\n", bits);
                return -ENOMEM;
        }
 
        cfs_hash_for_each_bucket(s->ls_obj_hash, &bd, i) {
                bkt = cfs_hash_bd_extra_get(s->ls_obj_hash, &bd);
-               CFS_INIT_LIST_HEAD(&bkt->lsb_lru);
+               INIT_LIST_HEAD(&bkt->lsb_lru);
                init_waitqueue_head(&bkt->lsb_marche_funebre);
        }
 
@@ -1143,13 +1084,13 @@ int lu_site_init(struct lu_site *s, struct lu_device *top)
         lprocfs_counter_init(s->ls_stats, LU_SS_LRU_PURGED,
                              0, "lru_purged", "lru_purged");
 
-        CFS_INIT_LIST_HEAD(&s->ls_linkage);
+       INIT_LIST_HEAD(&s->ls_linkage);
         s->ls_top_dev = top;
         top->ld_site = s;
         lu_device_get(top);
         lu_ref_add(&top->ld_reference, "site-top", s);
 
-        CFS_INIT_LIST_HEAD(&s->ls_ld_linkage);
+       INIT_LIST_HEAD(&s->ls_ld_linkage);
        spin_lock_init(&s->ls_ld_lock);
 
        lu_dev_add_linkage(s, top);
@@ -1163,9 +1104,11 @@ EXPORT_SYMBOL(lu_site_init);
  */
 void lu_site_fini(struct lu_site *s)
 {
-       mutex_lock(&lu_sites_guard);
-        cfs_list_del_init(&s->ls_linkage);
-       mutex_unlock(&lu_sites_guard);
+       down_write(&lu_sites_guard);
+       list_del_init(&s->ls_linkage);
+       up_write(&lu_sites_guard);
+
+       percpu_counter_destroy(&s->ls_lru_len_counter);
 
         if (s->ls_obj_hash != NULL) {
                 cfs_hash_putref(s->ls_obj_hash);
@@ -1190,11 +1133,11 @@ EXPORT_SYMBOL(lu_site_fini);
 int lu_site_init_finish(struct lu_site *s)
 {
         int result;
-       mutex_lock(&lu_sites_guard);
+       down_write(&lu_sites_guard);
         result = lu_context_refill(&lu_shrink_env.le_ctx);
         if (result == 0)
-                cfs_list_add(&s->ls_linkage, &lu_sites);
-       mutex_unlock(&lu_sites_guard);
+               list_add(&s->ls_linkage, &lu_sites);
+       up_write(&lu_sites_guard);
         return result;
 }
 EXPORT_SYMBOL(lu_site_init_finish);
@@ -1271,7 +1214,7 @@ int lu_object_init(struct lu_object *o, struct lu_object_header *h,
        o->lo_dev = d;
        lu_device_get(d);
        lu_ref_add_at(&d->ld_reference, &o->lo_dev_ref, "lu_object", o);
-       CFS_INIT_LIST_HEAD(&o->lo_linkage);
+       INIT_LIST_HEAD(&o->lo_linkage);
 
        return 0;
 }
@@ -1284,7 +1227,7 @@ void lu_object_fini(struct lu_object *o)
 {
        struct lu_device *dev = o->lo_dev;
 
-       LASSERT(cfs_list_empty(&o->lo_linkage));
+       LASSERT(list_empty(&o->lo_linkage));
 
        if (dev != NULL) {
                lu_ref_del_at(&dev->ld_reference, &o->lo_dev_ref,
@@ -1303,7 +1246,7 @@ EXPORT_SYMBOL(lu_object_fini);
  */
 void lu_object_add_top(struct lu_object_header *h, struct lu_object *o)
 {
-        cfs_list_move(&o->lo_linkage, &h->loh_layers);
+       list_move(&o->lo_linkage, &h->loh_layers);
 }
 EXPORT_SYMBOL(lu_object_add_top);
 
@@ -1315,7 +1258,7 @@ EXPORT_SYMBOL(lu_object_add_top);
  */
 void lu_object_add(struct lu_object *before, struct lu_object *o)
 {
-        cfs_list_move(&o->lo_linkage, &before->lo_linkage);
+       list_move(&o->lo_linkage, &before->lo_linkage);
 }
 EXPORT_SYMBOL(lu_object_add);
 
@@ -1326,9 +1269,9 @@ int lu_object_header_init(struct lu_object_header *h)
 {
         memset(h, 0, sizeof *h);
        atomic_set(&h->loh_ref, 1);
-        CFS_INIT_HLIST_NODE(&h->loh_hash);
-        CFS_INIT_LIST_HEAD(&h->loh_lru);
-        CFS_INIT_LIST_HEAD(&h->loh_layers);
+       INIT_HLIST_NODE(&h->loh_hash);
+       INIT_LIST_HEAD(&h->loh_lru);
+       INIT_LIST_HEAD(&h->loh_layers);
         lu_ref_init(&h->loh_reference);
         return 0;
 }
@@ -1339,9 +1282,9 @@ EXPORT_SYMBOL(lu_object_header_init);
  */
 void lu_object_header_fini(struct lu_object_header *h)
 {
-        LASSERT(cfs_list_empty(&h->loh_layers));
-        LASSERT(cfs_list_empty(&h->loh_lru));
-        LASSERT(cfs_hlist_unhashed(&h->loh_hash));
+       LASSERT(list_empty(&h->loh_layers));
+       LASSERT(list_empty(&h->loh_lru));
+       LASSERT(hlist_unhashed(&h->loh_hash));
         lu_ref_fini(&h->loh_reference);
 }
 EXPORT_SYMBOL(lu_object_header_fini);
@@ -1353,18 +1296,16 @@ EXPORT_SYMBOL(lu_object_header_fini);
 struct lu_object *lu_object_locate(struct lu_object_header *h,
                                    const struct lu_device_type *dtype)
 {
-        struct lu_object *o;
+       struct lu_object *o;
 
-        cfs_list_for_each_entry(o, &h->loh_layers, lo_linkage) {
-                if (o->lo_dev->ld_type == dtype)
-                        return o;
-        }
-        return NULL;
+       list_for_each_entry(o, &h->loh_layers, lo_linkage) {
+               if (o->lo_dev->ld_type == dtype)
+                       return o;
+       }
+       return NULL;
 }
 EXPORT_SYMBOL(lu_object_locate);
 
-
-
 /**
  * Finalize and free devices in the device stack.
  *
@@ -1400,7 +1341,6 @@ void lu_stack_fini(const struct lu_env *env, struct lu_device *top)
                 }
         }
 }
-EXPORT_SYMBOL(lu_stack_fini);
 
 enum {
         /**
@@ -1411,7 +1351,7 @@ enum {
 
 static struct lu_context_key *lu_keys[LU_CONTEXT_KEY_NR] = { NULL, };
 
-static DEFINE_SPINLOCK(lu_keys_guard);
+static DECLARE_RWSEM(lu_key_initing);
 
 /**
  * Global counter incremented whenever key is registered, unregistered,
@@ -1419,15 +1359,15 @@ static DEFINE_SPINLOCK(lu_keys_guard);
  * lu_context_refill(). No locking is provided, as initialization and shutdown
  * are supposed to be externally serialized.
  */
-static unsigned key_set_version = 0;
+static atomic_t key_set_version = ATOMIC_INIT(0);
 
 /**
  * Register new key.
  */
 int lu_context_key_register(struct lu_context_key *key)
 {
-        int result;
-        int i;
+       int result;
+       unsigned int i;
 
         LASSERT(key->lct_init != NULL);
         LASSERT(key->lct_fini != NULL);
@@ -1435,19 +1375,23 @@ int lu_context_key_register(struct lu_context_key *key)
         LASSERT(key->lct_owner != NULL);
 
         result = -ENFILE;
-       spin_lock(&lu_keys_guard);
+       atomic_set(&key->lct_used, 1);
+       lu_ref_init(&key->lct_reference);
         for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
-                if (lu_keys[i] == NULL) {
-                        key->lct_index = i;
-                       atomic_set(&key->lct_used, 1);
-                        lu_keys[i] = key;
-                        lu_ref_init(&key->lct_reference);
-                        result = 0;
-                        ++key_set_version;
-                        break;
-                }
+               if (lu_keys[i])
+                       continue;
+               key->lct_index = i;
+               if (cmpxchg(&lu_keys[i], NULL, key) != NULL)
+                       continue;
+
+               result = 0;
+               atomic_inc(&key_set_version);
+               break;
         }
-       spin_unlock(&lu_keys_guard);
+       if (result) {
+               lu_ref_fini(&key->lct_reference);
+               atomic_set(&key->lct_used, 0);
+       }
        return result;
 }
 EXPORT_SYMBOL(lu_context_key_register);
@@ -1460,11 +1404,12 @@ static void key_fini(struct lu_context *ctx, int index)
                 key = lu_keys[index];
                 LASSERT(key != NULL);
                 LASSERT(key->lct_fini != NULL);
-               LASSERT(atomic_read(&key->lct_used) > 1);
+               LASSERT(atomic_read(&key->lct_used) > 0);
 
                 key->lct_fini(ctx, key, ctx->lc_value[index]);
                 lu_ref_del(&key->lct_reference, "ctx", ctx);
-               atomic_dec(&key->lct_used);
+               if (atomic_dec_and_test(&key->lct_used))
+                       wake_up_var(&key->lct_used);
 
                LASSERT(key->lct_owner != NULL);
                if ((ctx->lc_tags & LCT_NOREF) == 0) {
@@ -1485,18 +1430,19 @@ void lu_context_key_degister(struct lu_context_key *key)
 
        lu_context_key_quiesce(key);
 
-       ++key_set_version;
-       spin_lock(&lu_keys_guard);
        key_fini(&lu_shrink_env.le_ctx, key->lct_index);
-       if (lu_keys[key->lct_index]) {
-               lu_keys[key->lct_index] = NULL;
+
+       /**
+        * Wait until all transient contexts referencing this key have
+        * run lu_context_key::lct_fini() method.
+        */
+       atomic_dec(&key->lct_used);
+       wait_var_event(&key->lct_used, atomic_read(&key->lct_used) == 0);
+
+       if (!WARN_ON(lu_keys[key->lct_index] == NULL))
                lu_ref_fini(&key->lct_reference);
-       }
-       spin_unlock(&lu_keys_guard);
 
-       LASSERTF(atomic_read(&key->lct_used) == 1,
-                "key has instances: %d\n",
-                atomic_read(&key->lct_used));
+       smp_store_release(&lu_keys[key->lct_index], NULL);
 }
 EXPORT_SYMBOL(lu_context_key_degister);
 
@@ -1597,7 +1543,8 @@ EXPORT_SYMBOL(lu_context_key_get);
 /**
  * List of remembered contexts. XXX document me.
  */
-static CFS_LIST_HEAD(lu_context_remembered);
+static LIST_HEAD(lu_context_remembered);
+static DEFINE_SPINLOCK(lu_context_remembered_guard);
 
 /**
  * Destroy \a key in all remembered contexts. This is used to destroy key
@@ -1606,38 +1553,37 @@ static CFS_LIST_HEAD(lu_context_remembered);
  */
 void lu_context_key_quiesce(struct lu_context_key *key)
 {
-        struct lu_context *ctx;
-        extern unsigned cl_env_cache_purge(unsigned nr);
+       struct lu_context *ctx;
 
-        if (!(key->lct_tags & LCT_QUIESCENT)) {
-                /*
-                 * XXX layering violation.
-                 */
-                cl_env_cache_purge(~0);
-                key->lct_tags |= LCT_QUIESCENT;
+       if (!(key->lct_tags & LCT_QUIESCENT)) {
                 /*
-                 * XXX memory barrier has to go here.
+                * The write-lock on lu_key_initing will ensure that any
+                * keys_fill() which didn't see LCT_QUIESCENT will have
+                * finished before we call key_fini().
                  */
-               spin_lock(&lu_keys_guard);
-               cfs_list_for_each_entry(ctx, &lu_context_remembered,
-                                       lc_remember)
+               down_write(&lu_key_initing);
+               key->lct_tags |= LCT_QUIESCENT;
+               up_write(&lu_key_initing);
+
+               spin_lock(&lu_context_remembered_guard);
+               list_for_each_entry(ctx, &lu_context_remembered, lc_remember) {
+                       spin_until_cond(READ_ONCE(ctx->lc_state) != LCS_LEAVING);
                        key_fini(ctx, key->lct_index);
-               spin_unlock(&lu_keys_guard);
-               ++key_set_version;
+               }
+
+               spin_unlock(&lu_context_remembered_guard);
        }
 }
-EXPORT_SYMBOL(lu_context_key_quiesce);
 
 void lu_context_key_revive(struct lu_context_key *key)
 {
-        key->lct_tags &= ~LCT_QUIESCENT;
-        ++key_set_version;
+       key->lct_tags &= ~LCT_QUIESCENT;
+       atomic_inc(&key_set_version);
 }
-EXPORT_SYMBOL(lu_context_key_revive);
 
 static void keys_fini(struct lu_context *ctx)
 {
-       int     i;
+       unsigned int i;
 
        if (ctx->lc_value == NULL)
                return;
@@ -1651,46 +1597,64 @@ static void keys_fini(struct lu_context *ctx)
 
 static int keys_fill(struct lu_context *ctx)
 {
-        int i;
-
-        LINVRNT(ctx->lc_value != NULL);
-        for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
-                struct lu_context_key *key;
+       unsigned int i;
+       int rc = 0;
 
-                key = lu_keys[i];
-                if (ctx->lc_value[i] == NULL && key != NULL &&
-                    (key->lct_tags & ctx->lc_tags) &&
-                    /*
-                     * Don't create values for a LCT_QUIESCENT key, as this
-                     * will pin module owning a key.
-                     */
-                    !(key->lct_tags & LCT_QUIESCENT)) {
-                        void *value;
-
-                        LINVRNT(key->lct_init != NULL);
-                        LINVRNT(key->lct_index == i);
-
-                        value = key->lct_init(ctx, key);
-                        if (unlikely(IS_ERR(value)))
-                                return PTR_ERR(value);
+       /*
+        * A serialisation with lu_context_key_quiesce() is needed, to
+        * ensure we see LCT_QUIESCENT and don't allocate a new value
+        * after it freed one.  The rwsem provides this.  As down_read()
+        * does optimistic spinning while the writer is active, this is
+        * unlikely to ever sleep.
+        */
+       down_read(&lu_key_initing);
+       ctx->lc_version = atomic_read(&key_set_version);
+
+       LINVRNT(ctx->lc_value);
+       for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
+               struct lu_context_key *key;
+
+               key = lu_keys[i];
+               if (!ctx->lc_value[i] && key &&
+                   (key->lct_tags & ctx->lc_tags) &&
+                   /*
+                    * Don't create values for a LCT_QUIESCENT key, as this
+                    * will pin module owning a key.
+                    */
+                   !(key->lct_tags & LCT_QUIESCENT)) {
+                       void *value;
+
+                       LINVRNT(key->lct_init != NULL);
+                       LINVRNT(key->lct_index == i);
 
                        LASSERT(key->lct_owner != NULL);
-                       if (!(ctx->lc_tags & LCT_NOREF))
-                               try_module_get(key->lct_owner);
+                       if (!(ctx->lc_tags & LCT_NOREF) &&
+                           try_module_get(key->lct_owner) == 0) {
+                               /* module is unloading, skip this key */
+                               continue;
+                       }
+
+                       value = key->lct_init(ctx, key);
+                       if (unlikely(IS_ERR(value))) {
+                               rc = PTR_ERR(value);
+                               break;
+                       }
+
                        lu_ref_add_atomic(&key->lct_reference, "ctx", ctx);
                        atomic_inc(&key->lct_used);
-                        /*
-                         * This is the only place in the code, where an
-                         * element of ctx->lc_value[] array is set to non-NULL
-                         * value.
-                         */
-                        ctx->lc_value[i] = value;
-                        if (key->lct_exit != NULL)
-                                ctx->lc_tags |= LCT_HAS_EXIT;
-                }
-                ctx->lc_version = key_set_version;
-        }
-        return 0;
+                       /*
+                        * This is the only place in the code, where an
+                        * element of ctx->lc_value[] array is set to non-NULL
+                        * value.
+                        */
+                       ctx->lc_value[i] = value;
+                       if (key->lct_exit != NULL)
+                               ctx->lc_tags |= LCT_HAS_EXIT;
+               }
+       }
+
+       up_read(&lu_key_initing);
+       return rc;
 }
 
 static int keys_init(struct lu_context *ctx)
@@ -1713,11 +1677,11 @@ int lu_context_init(struct lu_context *ctx, __u32 tags)
        ctx->lc_state = LCS_INITIALIZED;
        ctx->lc_tags = tags;
        if (tags & LCT_REMEMBER) {
-               spin_lock(&lu_keys_guard);
-               cfs_list_add(&ctx->lc_remember, &lu_context_remembered);
-               spin_unlock(&lu_keys_guard);
+               spin_lock(&lu_context_remembered_guard);
+               list_add(&ctx->lc_remember, &lu_context_remembered);
+               spin_unlock(&lu_context_remembered_guard);
        } else {
-               CFS_INIT_LIST_HEAD(&ctx->lc_remember);
+               INIT_LIST_HEAD(&ctx->lc_remember);
        }
 
        rc = keys_init(ctx);
@@ -1737,15 +1701,14 @@ void lu_context_fini(struct lu_context *ctx)
        ctx->lc_state = LCS_FINALIZED;
 
        if ((ctx->lc_tags & LCT_REMEMBER) == 0) {
-               LASSERT(cfs_list_empty(&ctx->lc_remember));
-               keys_fini(ctx);
-
-       } else { /* could race with key degister */
-               spin_lock(&lu_keys_guard);
-               keys_fini(ctx);
-               cfs_list_del_init(&ctx->lc_remember);
-               spin_unlock(&lu_keys_guard);
+               LASSERT(list_empty(&ctx->lc_remember));
+       } else {
+               /* could race with key degister */
+               spin_lock(&lu_context_remembered_guard);
+               list_del_init(&ctx->lc_remember);
+               spin_unlock(&lu_context_remembered_guard);
        }
+       keys_fini(ctx);
 }
 EXPORT_SYMBOL(lu_context_fini);
 
@@ -1764,23 +1727,37 @@ EXPORT_SYMBOL(lu_context_enter);
  */
 void lu_context_exit(struct lu_context *ctx)
 {
-        int i;
+       unsigned int i;
 
-        LINVRNT(ctx->lc_state == LCS_ENTERED);
-        ctx->lc_state = LCS_LEFT;
-        if (ctx->lc_tags & LCT_HAS_EXIT && ctx->lc_value != NULL) {
+       LINVRNT(ctx->lc_state == LCS_ENTERED);
+       /*
+        * Disable preempt to ensure we get a warning if
+        * any lct_exit ever tries to sleep.  That would hurt
+        * lu_context_key_quiesce() which spins waiting for us.
+        * This also ensure we aren't preempted while the state
+        * is LCS_LEAVING, as that too would cause problems for
+        * lu_context_key_quiesce().
+        */
+       preempt_disable();
+       /*
+        * Ensure lu_context_key_quiesce() sees LCS_LEAVING
+        * or we see LCT_QUIESCENT
+        */
+       smp_store_mb(ctx->lc_state, LCS_LEAVING);
+       if (ctx->lc_tags & LCT_HAS_EXIT && ctx->lc_value) {
                 for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
-                        if (ctx->lc_value[i] != NULL) {
-                                struct lu_context_key *key;
-
-                                key = lu_keys[i];
-                                LASSERT(key != NULL);
-                                if (key->lct_exit != NULL)
-                                        key->lct_exit(ctx,
-                                                      key, ctx->lc_value[i]);
-                        }
-                }
+                       struct lu_context_key *key;
+
+                       key = lu_keys[i];
+                       if (ctx->lc_value[i] &&
+                           !(key->lct_tags & LCT_QUIESCENT) &&
+                           key->lct_exit)
+                               key->lct_exit(ctx, key, ctx->lc_value[i]);
+               }
         }
+
+       smp_store_release(&ctx->lc_state, LCS_LEFT);
+       preempt_enable();
 }
 EXPORT_SYMBOL(lu_context_exit);
 
@@ -1791,9 +1768,11 @@ EXPORT_SYMBOL(lu_context_exit);
  */
 int lu_context_refill(struct lu_context *ctx)
 {
-        return likely(ctx->lc_version == key_set_version) ? 0 : keys_fill(ctx);
+       if (likely(ctx->lc_version == atomic_read(&key_set_version)))
+               return 0;
+
+       return keys_fill(ctx);
 }
-EXPORT_SYMBOL(lu_context_refill);
 
 /**
  * lu_ctx_tags/lu_ses_tags will be updated if there are new types of
@@ -1802,44 +1781,46 @@ EXPORT_SYMBOL(lu_context_refill);
  * predefined when the lu_device type are registered, during the module probe
  * phase.
  */
-__u32 lu_context_tags_default = 0;
-__u32 lu_session_tags_default = 0;
+u32 lu_context_tags_default;
+u32 lu_session_tags_default;
 
+#ifdef HAVE_SERVER_SUPPORT
 void lu_context_tags_update(__u32 tags)
 {
-       spin_lock(&lu_keys_guard);
+       spin_lock(&lu_context_remembered_guard);
        lu_context_tags_default |= tags;
-       key_set_version++;
-       spin_unlock(&lu_keys_guard);
+       atomic_inc(&key_set_version);
+       spin_unlock(&lu_context_remembered_guard);
 }
 EXPORT_SYMBOL(lu_context_tags_update);
 
 void lu_context_tags_clear(__u32 tags)
 {
-       spin_lock(&lu_keys_guard);
+       spin_lock(&lu_context_remembered_guard);
        lu_context_tags_default &= ~tags;
-       key_set_version++;
-       spin_unlock(&lu_keys_guard);
+       atomic_inc(&key_set_version);
+       spin_unlock(&lu_context_remembered_guard);
 }
 EXPORT_SYMBOL(lu_context_tags_clear);
 
 void lu_session_tags_update(__u32 tags)
 {
-       spin_lock(&lu_keys_guard);
+       spin_lock(&lu_context_remembered_guard);
        lu_session_tags_default |= tags;
-       key_set_version++;
-       spin_unlock(&lu_keys_guard);
+       atomic_inc(&key_set_version);
+       spin_unlock(&lu_context_remembered_guard);
 }
 EXPORT_SYMBOL(lu_session_tags_update);
 
 void lu_session_tags_clear(__u32 tags)
 {
-       spin_lock(&lu_keys_guard);
+       spin_lock(&lu_context_remembered_guard);
        lu_session_tags_default &= ~tags;
-       key_set_version++;
-       spin_unlock(&lu_keys_guard);
+       atomic_inc(&key_set_version);
+       spin_unlock(&lu_context_remembered_guard);
 }
 EXPORT_SYMBOL(lu_session_tags_clear);
+#endif /* HAVE_SERVER_SUPPORT */
 
 int lu_env_init(struct lu_env *env, __u32 tags)
 {
@@ -1900,6 +1881,101 @@ int lu_env_refill_by_tags(struct lu_env *env, __u32 ctags,
 }
 EXPORT_SYMBOL(lu_env_refill_by_tags);
 
+
+struct lu_env_item {
+       struct task_struct *lei_task;   /* rhashtable key */
+       struct rhash_head lei_linkage;
+       struct lu_env *lei_env;
+};
+
+static const struct rhashtable_params lu_env_rhash_params = {
+       .key_len     = sizeof(struct task_struct *),
+       .key_offset  = offsetof(struct lu_env_item, lei_task),
+       .head_offset = offsetof(struct lu_env_item, lei_linkage),
+    };
+
+struct rhashtable lu_env_rhash;
+
+struct lu_env_percpu {
+       struct task_struct *lep_task;
+       struct lu_env *lep_env ____cacheline_aligned_in_smp;
+};
+
+static struct lu_env_percpu lu_env_percpu[NR_CPUS];
+
+int lu_env_add(struct lu_env *env)
+{
+       struct lu_env_item *lei, *old;
+
+       LASSERT(env);
+
+       OBD_ALLOC_PTR(lei);
+       if (!lei)
+               return -ENOMEM;
+
+       lei->lei_task = current;
+       lei->lei_env = env;
+
+       old = rhashtable_lookup_get_insert_fast(&lu_env_rhash,
+                                               &lei->lei_linkage,
+                                               lu_env_rhash_params);
+       LASSERT(!old);
+
+       return 0;
+}
+EXPORT_SYMBOL(lu_env_add);
+
+void lu_env_remove(struct lu_env *env)
+{
+       struct lu_env_item *lei;
+       const void *task = current;
+       int i;
+
+       for_each_possible_cpu(i) {
+               if (lu_env_percpu[i].lep_env == env) {
+                       LASSERT(lu_env_percpu[i].lep_task == task);
+                       lu_env_percpu[i].lep_task = NULL;
+                       lu_env_percpu[i].lep_env = NULL;
+               }
+       }
+
+       rcu_read_lock();
+       lei = rhashtable_lookup_fast(&lu_env_rhash, &task,
+                                    lu_env_rhash_params);
+       if (lei && rhashtable_remove_fast(&lu_env_rhash, &lei->lei_linkage,
+                                         lu_env_rhash_params) == 0)
+               OBD_FREE_PTR(lei);
+       rcu_read_unlock();
+}
+EXPORT_SYMBOL(lu_env_remove);
+
+struct lu_env *lu_env_find(void)
+{
+       struct lu_env *env = NULL;
+       struct lu_env_item *lei;
+       const void *task = current;
+       int i = get_cpu();
+
+       if (lu_env_percpu[i].lep_task == current) {
+               env = lu_env_percpu[i].lep_env;
+               put_cpu();
+               LASSERT(env);
+               return env;
+       }
+
+       lei = rhashtable_lookup_fast(&lu_env_rhash, &task,
+                                    lu_env_rhash_params);
+       if (lei) {
+               env = lei->lei_env;
+               lu_env_percpu[i].lep_task = current;
+               lu_env_percpu[i].lep_env = env;
+       }
+       put_cpu();
+
+       return env;
+}
+EXPORT_SYMBOL(lu_env_find);
+
 static struct shrinker *lu_site_shrinker;
 
 typedef struct lu_site_stats{
@@ -1909,18 +1985,24 @@ typedef struct lu_site_stats{
         unsigned        lss_busy;
 } lu_site_stats_t;
 
-static void lu_site_stats_get(cfs_hash_t *hs,
+static void lu_site_stats_get(const struct lu_site *s,
                               lu_site_stats_t *stats, int populated)
 {
-        cfs_hash_bd_t bd;
-        int           i;
+       struct cfs_hash *hs = s->ls_obj_hash;
+       struct cfs_hash_bd bd;
+       unsigned int i;
+       /*
+        * percpu_counter_sum_positive() won't accept a const pointer
+        * as it does modify the struct by taking a spinlock
+        */
+       struct lu_site *s2 = (struct lu_site *)s;
 
+       stats->lss_busy += cfs_hash_size_get(hs) -
+               percpu_counter_sum_positive(&s2->ls_lru_len_counter);
         cfs_hash_for_each_bucket(hs, &bd, i) {
-                struct lu_site_bkt_data *bkt = cfs_hash_bd_extra_get(hs, &bd);
-                cfs_hlist_head_t        *hhead;
+               struct hlist_head *hhead;
 
                 cfs_hash_bd_lock(hs, &bd, 1);
-                stats->lss_busy  += bkt->lsb_busy;
                 stats->lss_total += cfs_hash_bd_count_get(&bd);
                 stats->lss_max_search = max((int)stats->lss_max_search,
                                             cfs_hash_bd_depmax_get(&bd));
@@ -1930,19 +2012,33 @@ static void lu_site_stats_get(cfs_hash_t *hs,
                 }
 
                 cfs_hash_bd_for_each_hlist(hs, &bd, hhead) {
-                        if (!cfs_hlist_empty(hhead))
+                       if (!hlist_empty(hhead))
                                 stats->lss_populated++;
                 }
                 cfs_hash_bd_unlock(hs, &bd, 1);
         }
 }
 
-#ifdef __KERNEL__
 
+/*
+ * lu_cache_shrink_count() returns an approximate number of cached objects
+ * that can be freed by shrink_slab(). A counter, which tracks the
+ * number of items in the site's lru, is maintained in a percpu_counter
+ * for each site. The percpu values are incremented and decremented as
+ * objects are added or removed from the lru. The percpu values are summed
+ * and saved whenever a percpu value exceeds a threshold. Thus the saved,
+ * summed value at any given time may not accurately reflect the current
+ * lru length. But this value is sufficiently accurate for the needs of
+ * a shrinker.
+ *
+ * Using a per cpu counter is a compromise solution to concurrent access:
+ * lu_object_put() can update the counter without locking the site and
+ * lu_cache_shrink_count can sum the counters without locking each
+ * ls_obj_hash bucket.
+ */
 static unsigned long lu_cache_shrink_count(struct shrinker *sk,
                                           struct shrink_control *sc)
 {
-       lu_site_stats_t stats;
        struct lu_site *s;
        struct lu_site *tmp;
        unsigned long cached = 0;
@@ -1950,16 +2046,15 @@ static unsigned long lu_cache_shrink_count(struct shrinker *sk,
        if (!(sc->gfp_mask & __GFP_FS))
                return 0;
 
-       mutex_lock(&lu_sites_guard);
-       list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage) {
-               memset(&stats, 0, sizeof(stats));
-               lu_site_stats_get(s->ls_obj_hash, &stats, 0);
-               cached += stats.lss_total - stats.lss_busy;
-       }
-       mutex_unlock(&lu_sites_guard);
+       down_read(&lu_sites_guard);
+       list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage)
+               cached += percpu_counter_read_positive(&s->ls_lru_len_counter);
+       up_read(&lu_sites_guard);
 
        cached = (cached / 100) * sysctl_vfs_cache_pressure;
-       CDEBUG(D_INODE, "%ld objects cached\n", cached);
+       CDEBUG(D_INODE, "%ld objects cached, cache pressure %d\n",
+              cached, sysctl_vfs_cache_pressure);
+
        return cached;
 }
 
@@ -1985,7 +2080,7 @@ static unsigned long lu_cache_shrink_scan(struct shrinker *sk,
                 */
                return SHRINK_STOP;
 
-       mutex_lock(&lu_sites_guard);
+       down_write(&lu_sites_guard);
        list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage) {
                remain = lu_site_purge(&lu_shrink_env, s, remain);
                /*
@@ -1995,7 +2090,7 @@ static unsigned long lu_cache_shrink_scan(struct shrinker *sk,
                list_move_tail(&s->ls_linkage, &splice);
        }
        list_splice(&splice, lu_sites.prev);
-       mutex_unlock(&lu_sites_guard);
+       up_write(&lu_sites_guard);
 
        return sc->nr_to_scan - remain;
 }
@@ -2016,7 +2111,7 @@ static unsigned long lu_cache_shrink_scan(struct shrinker *sk,
  * is safe to take the lu_sites_guard lock.
  *
  * Ideally we should accurately return the remaining number of cached
- * objects without taking the  lu_sites_guard lock, but this is not
+ * objects without taking the lu_sites_guard lock, but this is not
  * possible in the current implementation.
  */
 static int lu_cache_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
@@ -2033,11 +2128,10 @@ static int lu_cache_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
 
        CDEBUG(D_INODE, "Shrink %lu objects\n", scv.nr_to_scan);
 
-       lu_cache_shrink_scan(shrinker, &scv);
+       if (scv.nr_to_scan != 0)
+               lu_cache_shrink_scan(shrinker, &scv);
 
        cached = lu_cache_shrink_count(shrinker, &scv);
-       if (scv.nr_to_scan == 0)
-               CDEBUG(D_INODE, "%d objects cached\n", cached);
        return cached;
 }
 
@@ -2051,13 +2145,13 @@ static int lu_cache_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
 /**
  * Environment to be used in debugger, contains all tags.
  */
-struct lu_env lu_debugging_env;
+static struct lu_env lu_debugging_env;
 
 /**
  * Debugging printer function using printk().
  */
 int lu_printk_printer(const struct lu_env *env,
-                      void *unused, const char *format, ...)
+                     void *unused, const char *format, ...)
 {
         va_list args;
 
@@ -2074,7 +2168,7 @@ int lu_debugging_setup(void)
 
 void lu_context_keys_dump(void)
 {
-        int i;
+       unsigned int i;
 
         for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
                 struct lu_context_key *key;
@@ -2091,15 +2185,13 @@ void lu_context_keys_dump(void)
                 }
         }
 }
-EXPORT_SYMBOL(lu_context_keys_dump);
-#endif /* __KERNEL__ */
 
 /**
  * Initialization of global lu_* data.
  */
 int lu_global_init(void)
 {
-        int result;
+       int result;
        DEF_SHRINKER_VAR(shvar, lu_cache_shrink,
                         lu_cache_shrink_count, lu_cache_shrink_scan);
 
@@ -2119,9 +2211,9 @@ int lu_global_init(void)
          * conservatively. This should not be too bad, because this
          * environment is global.
          */
-       mutex_lock(&lu_sites_guard);
+       down_write(&lu_sites_guard);
         result = lu_env_init(&lu_shrink_env, LCT_SHRINKER);
-       mutex_unlock(&lu_sites_guard);
+       up_write(&lu_sites_guard);
         if (result != 0)
                 return result;
 
@@ -2134,6 +2226,8 @@ int lu_global_init(void)
         if (lu_site_shrinker == NULL)
                 return -ENOMEM;
 
+       result = rhashtable_init(&lu_env_rhash, &lu_env_rhash_params);
+
         return result;
 }
 
@@ -2153,22 +2247,24 @@ void lu_global_fini(void)
          * Tear shrinker environment down _after_ de-registering
          * lu_global_key, because the latter has a value in the former.
          */
-       mutex_lock(&lu_sites_guard);
+       down_write(&lu_sites_guard);
         lu_env_fini(&lu_shrink_env);
-       mutex_unlock(&lu_sites_guard);
+       up_write(&lu_sites_guard);
+
+       rhashtable_destroy(&lu_env_rhash);
 
         lu_ref_global_fini();
 }
 
 static __u32 ls_stats_read(struct lprocfs_stats *stats, int idx)
 {
-#ifdef LPROCFS
-        struct lprocfs_counter ret;
+#ifdef CONFIG_PROC_FS
+       struct lprocfs_counter ret;
 
-        lprocfs_stats_collect(stats, idx, &ret);
-        return (__u32)ret.lc_count;
+       lprocfs_stats_collect(stats, idx, &ret);
+       return (__u32)ret.lc_count;
 #else
-        return 0;
+       return 0;
 #endif
 }
 
@@ -2181,45 +2277,24 @@ int lu_site_stats_seq_print(const struct lu_site *s, struct seq_file *m)
        lu_site_stats_t stats;
 
        memset(&stats, 0, sizeof(stats));
-       lu_site_stats_get(s->ls_obj_hash, &stats, 1);
-
-       return seq_printf(m, "%d/%d %d/%d %d %d %d %d %d %d %d\n",
-                         stats.lss_busy,
-                         stats.lss_total,
-                         stats.lss_populated,
-                         CFS_HASH_NHLIST(s->ls_obj_hash),
-                         stats.lss_max_search,
-                         ls_stats_read(s->ls_stats, LU_SS_CREATED),
-                         ls_stats_read(s->ls_stats, LU_SS_CACHE_HIT),
-                         ls_stats_read(s->ls_stats, LU_SS_CACHE_MISS),
-                         ls_stats_read(s->ls_stats, LU_SS_CACHE_RACE),
-                         ls_stats_read(s->ls_stats, LU_SS_CACHE_DEATH_RACE),
-                         ls_stats_read(s->ls_stats, LU_SS_LRU_PURGED));
+       lu_site_stats_get(s, &stats, 1);
+
+       seq_printf(m, "%d/%d %d/%d %d %d %d %d %d %d %d\n",
+                  stats.lss_busy,
+                  stats.lss_total,
+                  stats.lss_populated,
+                  CFS_HASH_NHLIST(s->ls_obj_hash),
+                  stats.lss_max_search,
+                  ls_stats_read(s->ls_stats, LU_SS_CREATED),
+                  ls_stats_read(s->ls_stats, LU_SS_CACHE_HIT),
+                  ls_stats_read(s->ls_stats, LU_SS_CACHE_MISS),
+                  ls_stats_read(s->ls_stats, LU_SS_CACHE_RACE),
+                  ls_stats_read(s->ls_stats, LU_SS_CACHE_DEATH_RACE),
+                  ls_stats_read(s->ls_stats, LU_SS_LRU_PURGED));
+       return 0;
 }
 EXPORT_SYMBOL(lu_site_stats_seq_print);
 
-int lu_site_stats_print(const struct lu_site *s, char *page, int count)
-{
-        lu_site_stats_t stats;
-
-        memset(&stats, 0, sizeof(stats));
-        lu_site_stats_get(s->ls_obj_hash, &stats, 1);
-
-        return snprintf(page, count, "%d/%d %d/%d %d %d %d %d %d %d %d\n",
-                        stats.lss_busy,
-                        stats.lss_total,
-                        stats.lss_populated,
-                        CFS_HASH_NHLIST(s->ls_obj_hash),
-                        stats.lss_max_search,
-                        ls_stats_read(s->ls_stats, LU_SS_CREATED),
-                        ls_stats_read(s->ls_stats, LU_SS_CACHE_HIT),
-                        ls_stats_read(s->ls_stats, LU_SS_CACHE_MISS),
-                        ls_stats_read(s->ls_stats, LU_SS_CACHE_RACE),
-                        ls_stats_read(s->ls_stats, LU_SS_CACHE_DEATH_RACE),
-                        ls_stats_read(s->ls_stats, LU_SS_LRU_PURGED));
-}
-EXPORT_SYMBOL(lu_site_stats_print);
-
 /**
  * Helper function to initialize a number of kmem slab caches at once.
  */
@@ -2267,24 +2342,26 @@ void lu_object_assign_fid(const struct lu_env *env, struct lu_object *o,
 {
        struct lu_site          *s = o->lo_dev->ld_site;
        struct lu_fid           *old = &o->lo_header->loh_fid;
-       struct lu_site_bkt_data *bkt;
-       struct lu_object        *shadow;
-       wait_queue_t             waiter;
-       cfs_hash_t              *hs;
-       cfs_hash_bd_t            bd;
-       __u64                    version = 0;
+       struct cfs_hash         *hs;
+       struct cfs_hash_bd       bd;
 
        LASSERT(fid_is_zero(old));
 
+       /* supposed to be unique */
        hs = s->ls_obj_hash;
        cfs_hash_bd_get_and_lock(hs, (void *)fid, &bd, 1);
-       shadow = htable_lookup(s, &bd, fid, &waiter, &version);
-       /* supposed to be unique */
-       LASSERT(IS_ERR(shadow) && PTR_ERR(shadow) == -ENOENT);
+#ifdef CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK
+       {
+               __u64 version = 0;
+               struct lu_object *shadow;
+
+               shadow = htable_lookup(s, &bd, fid, &version);
+               /* supposed to be unique */
+               LASSERT(IS_ERR(shadow) && PTR_ERR(shadow) == -ENOENT);
+       }
+#endif
        *old = *fid;
-       bkt = cfs_hash_bd_extra_get(hs, &bd);
        cfs_hash_bd_add_locked(hs, &bd, &o->lo_header->loh_hash);
-       bkt->lsb_busy++;
        cfs_hash_bd_unlock(hs, &bd, 1);
 }
 EXPORT_SYMBOL(lu_object_assign_fid);
@@ -2326,7 +2403,7 @@ void lu_buf_free(struct lu_buf *buf)
 }
 EXPORT_SYMBOL(lu_buf_free);
 
-void lu_buf_alloc(struct lu_buf *buf, int size)
+void lu_buf_alloc(struct lu_buf *buf, size_t size)
 {
        LASSERT(buf);
        LASSERT(buf->lb_buf == NULL);
@@ -2337,14 +2414,14 @@ void lu_buf_alloc(struct lu_buf *buf, int size)
 }
 EXPORT_SYMBOL(lu_buf_alloc);
 
-void lu_buf_realloc(struct lu_buf *buf, int size)
+void lu_buf_realloc(struct lu_buf *buf, size_t size)
 {
        lu_buf_free(buf);
        lu_buf_alloc(buf, size);
 }
 EXPORT_SYMBOL(lu_buf_realloc);
 
-struct lu_buf *lu_buf_check_and_alloc(struct lu_buf *buf, int len)
+struct lu_buf *lu_buf_check_and_alloc(struct lu_buf *buf, size_t len)
 {
        if (buf->lb_buf == NULL && buf->lb_len == 0)
                lu_buf_alloc(buf, len);
@@ -2362,7 +2439,7 @@ EXPORT_SYMBOL(lu_buf_check_and_alloc);
  * old buffer remains unchanged on error
  * \retval 0 or -ENOMEM
  */
-int lu_buf_check_and_grow(struct lu_buf *buf, int len)
+int lu_buf_check_and_grow(struct lu_buf *buf, size_t len)
 {
        char *ptr;
 
@@ -2384,4 +2461,3 @@ int lu_buf_check_and_grow(struct lu_buf *buf, int len)
        return 0;
 }
 EXPORT_SYMBOL(lu_buf_check_and_grow);
-