1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 only,
10 * as published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License version 2 for more details (a copy is included
16 * in the LICENSE file that accompanied this code).
18 * You should have received a copy of the GNU General Public License
19 * version 2 along with this program; If not, see
20 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
29 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
30 * Use is subject to license terms.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
38 * Author: Nikita Danilov <nikita.danilov@sun.com>
41 #define DEBUG_SUBSYSTEM S_CLASS
43 # define EXPORT_SYMTAB
46 #include <libcfs/libcfs.h>
47 #include <obd_class.h>
48 #include <obd_support.h>
49 #include <libcfs/list.h>
51 #include <cl_object.h>
52 #include "cl_internal.h"
54 static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg,
57 static cfs_mem_cache_t *cl_page_kmem = NULL;
59 static struct lu_kmem_descr cl_page_caches[] = {
61 .ckd_cache = &cl_page_kmem,
62 .ckd_name = "cl_page_kmem",
63 .ckd_size = sizeof (struct cl_page)
71 # define PASSERT(env, page, expr) \
73 if (unlikely(!(expr))) { \
74 CL_PAGE_DEBUG(D_ERROR, (env), (page), #expr "\n"); \
78 #else /* !LIBCFS_DEBUG */
79 # define PASSERT(env, page, exp) \
80 ((void)sizeof(env), (void)sizeof(page), (void)sizeof !!(exp))
81 #endif /* !LIBCFS_DEBUG */
83 #ifdef INVARIANT_CHECK
84 # define PINVRNT(env, page, expr) \
86 if (unlikely(!(expr))) { \
87 CL_PAGE_DEBUG(D_ERROR, (env), (page), #expr "\n"); \
91 #else /* !INVARIANT_CHECK */
92 # define PINVRNT(env, page, exp) \
93 ((void)sizeof(env), (void)sizeof(page), (void)sizeof !!(exp))
94 #endif /* !INVARIANT_CHECK */
97 * Internal version of cl_page_top, it should be called with page referenced,
98 * or coh_page_guard held.
100 static struct cl_page *cl_page_top_trusted(struct cl_page *page)
102 LASSERT(cl_is_page(page));
103 while (page->cp_parent != NULL)
104 page = page->cp_parent;
109 * Internal version of cl_page_get().
111 * This function can be used to obtain initial reference to previously
112 * unreferenced cached object. It can be called only if concurrent page
113 * reclamation is somehow prevented, e.g., by locking page radix-tree
114 * (cl_object_header::hdr->coh_page_guard), or by keeping a lock on a VM page,
115 * associated with \a page.
117 * Use with care! Not exported.
119 static void cl_page_get_trust(struct cl_page *page)
121 LASSERT(cl_is_page(page));
123 * Checkless version for trusted users.
125 if (atomic_inc_return(&page->cp_ref) == 1)
126 atomic_inc(&cl_object_site(page->cp_obj)->cs_pages.cs_busy);
130 * Returns a slice within a page, corresponding to the given layer in the
135 static const struct cl_page_slice *
136 cl_page_at_trusted(const struct cl_page *page,
137 const struct lu_device_type *dtype)
139 const struct cl_page_slice *slice;
141 #ifdef INVARIANT_CHECK
142 struct cl_object_header *ch = cl_object_header(page->cp_obj);
144 if (!atomic_read(&page->cp_ref))
145 LASSERT_SPIN_LOCKED(&ch->coh_page_guard);
149 page = cl_page_top_trusted((struct cl_page *)page);
151 list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
152 if (slice->cpl_obj->co_lu.lo_dev->ld_type == dtype)
155 page = page->cp_child;
156 } while (page != NULL);
161 * Returns a page with given index in the given object, or NULL if no page is
162 * found. Acquires a reference on \a page.
164 * Locking: called under cl_object_header::coh_page_guard spin-lock.
166 struct cl_page *cl_page_lookup(struct cl_object_header *hdr, pgoff_t index)
168 struct cl_page *page;
170 LASSERT_SPIN_LOCKED(&hdr->coh_page_guard);
172 page = radix_tree_lookup(&hdr->coh_tree, index);
174 LASSERT(cl_is_page(page));
175 cl_page_get_trust(page);
179 EXPORT_SYMBOL(cl_page_lookup);
182 * Returns a list of pages by a given [start, end] of \a obj.
184 * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
185 * crucial in the face of [offset, EOF] locks.
187 void cl_page_gang_lookup(const struct lu_env *env, struct cl_object *obj,
188 struct cl_io *io, pgoff_t start, pgoff_t end,
189 struct cl_page_list *queue, int nonblock)
191 struct cl_object_header *hdr;
192 struct cl_page *page;
193 struct cl_page **pvec;
194 const struct cl_page_slice *slice;
195 const struct lu_device_type *dtype;
200 int (*page_own)(const struct lu_env *env,
205 page_own = nonblock ? cl_page_own_try : cl_page_own;
208 hdr = cl_object_header(obj);
209 pvec = cl_env_info(env)->clt_pvec;
210 dtype = cl_object_top(obj)->co_lu.lo_dev->ld_type;
211 spin_lock(&hdr->coh_page_guard);
212 while ((nr = radix_tree_gang_lookup(&hdr->coh_tree, (void **)pvec,
213 idx, CLT_PVEC_SIZE)) > 0) {
214 idx = pvec[nr - 1]->cp_index + 1;
215 for (i = 0, j = 0; i < nr; ++i) {
217 PASSERT(env, page, cl_is_page(page));
219 if (page->cp_index > end)
221 if (page->cp_state == CPS_FREEING)
223 if (page->cp_type == CPT_TRANSIENT) {
224 /* God, we found a transient page!*/
228 slice = cl_page_at_trusted(page, dtype);
230 * Pages for lsm-less file has no underneath sub-page
231 * for osc, in case of ...
233 PASSERT(env, page, slice != NULL);
235 page = slice->cpl_page;
237 * Can safely call cl_page_get_trust() under
238 * radix-tree spin-lock.
240 * XXX not true, because @page is from object another
241 * than @hdr and protected by different tree lock.
243 cl_page_get_trust(page);
244 lu_ref_add_atomic(&page->cp_reference,
245 "page_list", cfs_current());
250 * Here a delicate locking dance is performed. Current thread
251 * holds a reference to a page, but has to own it before it
252 * can be placed into queue. Owning implies waiting, so
253 * radix-tree lock is to be released. After a wait one has to
254 * check that pages weren't truncated (cl_page_own() returns
255 * error in the latter case).
257 spin_unlock(&hdr->coh_page_guard);
258 for (i = 0; i < j; ++i) {
260 if (page_own(env, io, page) == 0)
261 cl_page_list_add(queue, page);
262 lu_ref_del(&page->cp_reference,
263 "page_list", cfs_current());
264 cl_page_put(env, page);
266 spin_lock(&hdr->coh_page_guard);
267 if (nr < CLT_PVEC_SIZE)
270 spin_unlock(&hdr->coh_page_guard);
273 EXPORT_SYMBOL(cl_page_gang_lookup);
275 static void cl_page_free(const struct lu_env *env, struct cl_page *page)
277 struct cl_object *obj = page->cp_obj;
278 struct cl_site *site = cl_object_site(obj);
280 PASSERT(env, page, cl_is_page(page));
281 PASSERT(env, page, list_empty(&page->cp_batch));
282 PASSERT(env, page, page->cp_owner == NULL);
283 PASSERT(env, page, page->cp_req == NULL);
284 PASSERT(env, page, page->cp_parent == NULL);
285 PASSERT(env, page, page->cp_state == CPS_FREEING);
289 while (!list_empty(&page->cp_layers)) {
290 struct cl_page_slice *slice;
292 slice = list_entry(page->cp_layers.next, struct cl_page_slice,
294 list_del_init(page->cp_layers.next);
295 slice->cpl_ops->cpo_fini(env, slice);
297 atomic_dec(&site->cs_pages.cs_total);
298 atomic_dec(&site->cs_pages_state[page->cp_state]);
299 lu_object_ref_del_at(&obj->co_lu, page->cp_obj_ref, "cl_page", page);
300 cl_object_put(env, obj);
301 lu_ref_fini(&page->cp_reference);
302 OBD_SLAB_FREE_PTR(page, cl_page_kmem);
307 * Helper function updating page state. This is the only place in the code
308 * where cl_page::cp_state field is mutated.
310 static inline void cl_page_state_set_trust(struct cl_page *page,
311 enum cl_page_state state)
314 *(enum cl_page_state *)&page->cp_state = state;
317 static int cl_page_alloc(const struct lu_env *env, struct cl_object *o,
318 pgoff_t ind, struct page *vmpage,
319 enum cl_page_type type, struct cl_page **out)
321 struct cl_page *page;
322 struct cl_page *err = NULL;
323 struct lu_object_header *head;
324 struct cl_site *site = cl_object_site(o);
329 OBD_SLAB_ALLOC_PTR_GFP(page, cl_page_kmem, CFS_ALLOC_IO);
331 atomic_set(&page->cp_ref, 1);
334 page->cp_obj_ref = lu_object_ref_add(&o->co_lu,
336 page->cp_index = ind;
337 cl_page_state_set_trust(page, CPS_CACHED);
338 page->cp_type = type;
339 CFS_INIT_LIST_HEAD(&page->cp_layers);
340 CFS_INIT_LIST_HEAD(&page->cp_batch);
341 CFS_INIT_LIST_HEAD(&page->cp_flight);
342 mutex_init(&page->cp_mutex);
343 lu_ref_init(&page->cp_reference);
344 head = o->co_lu.lo_header;
345 list_for_each_entry(o, &head->loh_layers, co_lu.lo_linkage) {
346 if (o->co_ops->coo_page_init != NULL) {
347 err = o->co_ops->coo_page_init(env, o,
350 cl_page_state_set_trust(page,
352 cl_page_free(env, page);
359 atomic_inc(&site->cs_pages.cs_busy);
360 atomic_inc(&site->cs_pages.cs_total);
361 atomic_inc(&site->cs_pages_state[CPS_CACHED]);
362 atomic_inc(&site->cs_pages.cs_created);
366 page = ERR_PTR(-ENOMEM);
372 * Returns a cl_page with index \a idx at the object \a o, and associated with
373 * the VM page \a vmpage.
375 * This is the main entry point into the cl_page caching interface. First, a
376 * cache (implemented as a per-object radix tree) is consulted. If page is
377 * found there, it is returned immediately. Otherwise new page is allocated
378 * and returned. In any case, additional reference to page is acquired.
380 * \see cl_object_find(), cl_lock_find()
382 static struct cl_page *cl_page_find0(const struct lu_env *env,
384 pgoff_t idx, struct page *vmpage,
385 enum cl_page_type type,
386 struct cl_page *parent)
388 struct cl_page *page;
389 struct cl_page *ghost = NULL;
390 struct cl_object_header *hdr;
391 struct cl_site *site = cl_object_site(o);
394 LINVRNT(type == CPT_CACHEABLE || type == CPT_TRANSIENT);
399 hdr = cl_object_header(o);
400 atomic_inc(&site->cs_pages.cs_lookup);
402 CDEBUG(D_PAGE, "%lu@"DFID" %p %lu %i\n",
403 idx, PFID(&hdr->coh_lu.loh_fid), vmpage, vmpage->private, type);
405 if (type == CPT_CACHEABLE) {
407 * cl_vmpage_page() can be called here without any locks as
409 * - "vmpage" is locked (which prevents ->private from
410 * concurrent updates), and
412 * - "o" cannot be destroyed while current thread holds a
415 page = cl_vmpage_page(vmpage, o);
418 cl_page_vmpage(env, page) == vmpage &&
419 (void *)radix_tree_lookup(&hdr->coh_tree,
422 spin_lock(&hdr->coh_page_guard);
423 page = cl_page_lookup(hdr, idx);
424 spin_unlock(&hdr->coh_page_guard);
427 atomic_inc(&site->cs_pages.cs_hit);
431 /* allocate and initialize cl_page */
432 err = cl_page_alloc(env, o, idx, vmpage, type, &page);
436 * XXX optimization: use radix_tree_preload() here, and change tree
437 * gfp mask to GFP_KERNEL in cl_object_header_init().
439 spin_lock(&hdr->coh_page_guard);
440 err = radix_tree_insert(&hdr->coh_tree, idx, page);
444 * Noted by Jay: a lock on \a vmpage protects cl_page_find()
445 * from this race, but
447 * 0. it's better to have cl_page interface "locally
448 * consistent" so that its correctness can be reasoned
449 * about without appealing to the (obscure world of) VM
452 * 1. handling this race allows ->coh_tree to remain
453 * consistent even when VM locking is somehow busted,
454 * which is very useful during diagnosing and debugging.
457 if (err == -EEXIST) {
459 * XXX in case of a lookup for CPT_TRANSIENT page,
460 * nothing protects a CPT_CACHEABLE page from being
461 * concurrently moved into CPS_FREEING state.
463 page = cl_page_lookup(hdr, idx);
464 PASSERT(env, page, page != NULL);
465 if (page->cp_type == CPT_TRANSIENT &&
466 type == CPT_CACHEABLE) {
467 /* XXX: We should make sure that inode sem
468 * keeps being held in the lifetime of
469 * transient pages, so it is impossible to
470 * have conflicting transient pages.
472 spin_unlock(&hdr->coh_page_guard);
473 cl_page_put(env, page);
474 spin_lock(&hdr->coh_page_guard);
475 page = ERR_PTR(-EBUSY);
480 LASSERT(page->cp_parent == NULL);
481 page->cp_parent = parent;
482 parent->cp_child = page;
486 spin_unlock(&hdr->coh_page_guard);
488 if (unlikely(ghost != NULL)) {
489 atomic_dec(&site->cs_pages.cs_busy);
490 cl_page_delete0(env, ghost, 0);
491 cl_page_free(env, ghost);
496 struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *o,
497 pgoff_t idx, struct page *vmpage,
498 enum cl_page_type type)
500 return cl_page_find0(env, o, idx, vmpage, type, NULL);
502 EXPORT_SYMBOL(cl_page_find);
505 struct cl_page *cl_page_find_sub(const struct lu_env *env, struct cl_object *o,
506 pgoff_t idx, struct page *vmpage,
507 struct cl_page *parent)
509 return cl_page_find0(env, o, idx, vmpage, parent->cp_type, parent);
511 EXPORT_SYMBOL(cl_page_find_sub);
513 static inline int cl_page_invariant(const struct cl_page *pg)
515 struct cl_object_header *header;
516 struct cl_page *parent;
517 struct cl_page *child;
520 LASSERT(cl_is_page(pg));
522 * Page invariant is protected by a VM lock.
524 LINVRNT(cl_page_is_vmlocked(NULL, pg));
526 header = cl_object_header(pg->cp_obj);
527 parent = pg->cp_parent;
528 child = pg->cp_child;
529 owner = pg->cp_owner;
531 return atomic_read(&pg->cp_ref) > 0 &&
532 ergo(parent != NULL, parent->cp_child == pg) &&
533 ergo(child != NULL, child->cp_parent == pg) &&
534 ergo(child != NULL, pg->cp_obj != child->cp_obj) &&
535 ergo(parent != NULL, pg->cp_obj != parent->cp_obj) &&
536 ergo(owner != NULL && parent != NULL,
537 parent->cp_owner == pg->cp_owner->ci_parent) &&
538 ergo(owner != NULL && child != NULL,
539 child->cp_owner->ci_parent == owner) &&
541 * Either page is early in initialization (has neither child
542 * nor parent yet), or it is in the object radix tree.
544 ergo(pg->cp_state < CPS_FREEING,
545 (void *)radix_tree_lookup(&header->coh_tree,
546 pg->cp_index) == pg ||
547 (child == NULL && parent == NULL));
550 static void cl_page_state_set0(const struct lu_env *env,
551 struct cl_page *page, enum cl_page_state state)
553 enum cl_page_state old;
554 struct cl_site *site = cl_object_site(page->cp_obj);
557 * Matrix of allowed state transitions [old][new], for sanity
560 static const int allowed_transitions[CPS_NR][CPS_NR] = {
563 [CPS_OWNED] = 1, /* io finds existing cached page */
565 [CPS_PAGEOUT] = 1, /* write-out from the cache */
566 [CPS_FREEING] = 1, /* eviction on the memory pressure */
569 [CPS_CACHED] = 1, /* release to the cache */
571 [CPS_PAGEIN] = 1, /* start read immediately */
572 [CPS_PAGEOUT] = 1, /* start write immediately */
573 [CPS_FREEING] = 1, /* lock invalidation or truncate */
576 [CPS_CACHED] = 1, /* io completion */
583 [CPS_CACHED] = 1, /* io completion */
599 old = page->cp_state;
600 PASSERT(env, page, allowed_transitions[old][state]);
601 CL_PAGE_HEADER(D_TRACE, env, page, "%i -> %i\n", old, state);
602 for (; page != NULL; page = page->cp_child) {
603 PASSERT(env, page, page->cp_state == old);
605 equi(state == CPS_OWNED, page->cp_owner != NULL));
607 atomic_dec(&site->cs_pages_state[page->cp_state]);
608 atomic_inc(&site->cs_pages_state[state]);
609 cl_page_state_set_trust(page, state);
614 static void cl_page_state_set(const struct lu_env *env,
615 struct cl_page *page, enum cl_page_state state)
617 PINVRNT(env, page, cl_page_invariant(page));
618 cl_page_state_set0(env, page, state);
622 * Acquires an additional reference to a page.
624 * This can be called only by caller already possessing a reference to \a
627 * \see cl_object_get(), cl_lock_get().
629 void cl_page_get(struct cl_page *page)
632 LASSERT(page->cp_state != CPS_FREEING);
633 cl_page_get_trust(page);
636 EXPORT_SYMBOL(cl_page_get);
639 * Releases a reference to a page.
641 * When last reference is released, page is returned to the cache, unless it
642 * is in cl_page_state::CPS_FREEING state, in which case it is immediately
645 * \see cl_object_put(), cl_lock_put().
647 void cl_page_put(const struct lu_env *env, struct cl_page *page)
649 struct cl_object_header *hdr;
650 struct cl_site *site = cl_object_site(page->cp_obj);
652 PASSERT(env, page, atomic_read(&page->cp_ref) > !!page->cp_parent);
655 CL_PAGE_HEADER(D_TRACE, env, page, "%i\n", atomic_read(&page->cp_ref));
657 hdr = cl_object_header(cl_object_top(page->cp_obj));
658 if (atomic_dec_and_lock(&page->cp_ref, &hdr->coh_page_guard)) {
659 atomic_dec(&site->cs_pages.cs_busy);
660 /* We're going to access the page w/o a reference, but it's
661 * ok because we have grabbed the lock coh_page_guard, which
662 * means nobody is able to free this page behind us.
664 if (page->cp_state == CPS_FREEING) {
665 /* We drop the page reference and check the page state
666 * inside the coh_page_guard. So that if it gets here,
667 * it is the REALLY last reference to this page.
669 spin_unlock(&hdr->coh_page_guard);
671 LASSERT(atomic_read(&page->cp_ref) == 0);
672 PASSERT(env, page, page->cp_owner == NULL);
673 PASSERT(env, page, list_empty(&page->cp_batch));
675 * Page is no longer reachable by other threads. Tear
678 cl_page_free(env, page);
683 spin_unlock(&hdr->coh_page_guard);
688 EXPORT_SYMBOL(cl_page_put);
691 * Returns a VM page associated with a given cl_page.
693 cfs_page_t *cl_page_vmpage(const struct lu_env *env, struct cl_page *page)
695 const struct cl_page_slice *slice;
698 * Find uppermost layer with ->cpo_vmpage() method, and return its
701 page = cl_page_top(page);
703 list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
704 if (slice->cpl_ops->cpo_vmpage != NULL)
705 RETURN(slice->cpl_ops->cpo_vmpage(env, slice));
707 page = page->cp_child;
708 } while (page != NULL);
709 LBUG(); /* ->cpo_vmpage() has to be defined somewhere in the stack */
711 EXPORT_SYMBOL(cl_page_vmpage);
714 * Returns a cl_page associated with a VM page, and given cl_object.
716 struct cl_page *cl_vmpage_page(cfs_page_t *vmpage, struct cl_object *obj)
718 struct cl_page *page;
719 struct cl_object_header *hdr;
722 KLASSERT(PageLocked(vmpage));
725 * NOTE: absence of races and liveness of data are guaranteed by page
726 * lock on a "vmpage". That works because object destruction has
727 * bottom-to-top pass.
731 * This loop assumes that ->private points to the top-most page. This
732 * can be rectified easily.
734 hdr = cl_object_header(cl_object_top(obj));
735 spin_lock(&hdr->coh_page_guard);
736 for (page = (void *)vmpage->private;
737 page != NULL; page = page->cp_child) {
738 if (cl_object_same(page->cp_obj, obj)) {
739 cl_page_get_trust(page);
743 spin_unlock(&hdr->coh_page_guard);
744 LASSERT(ergo(page, cl_is_page(page) && page->cp_type == CPT_CACHEABLE));
747 EXPORT_SYMBOL(cl_vmpage_page);
750 * Returns the top-page for a given page.
752 * \see cl_object_top(), cl_io_top()
754 struct cl_page *cl_page_top(struct cl_page *page)
756 return cl_page_top_trusted(page);
758 EXPORT_SYMBOL(cl_page_top);
761 * Returns true if \a addr is an address of an allocated cl_page. Used in
762 * assertions. This check is optimistically imprecise, i.e., it occasionally
763 * returns true for the incorrect addresses, but if it returns false, then the
764 * address is guaranteed to be incorrect. (Should be named cl_pagep().)
768 int cl_is_page(const void *addr)
770 return cfs_mem_is_in_cache(addr, cl_page_kmem);
772 EXPORT_SYMBOL(cl_is_page);
774 const struct cl_page_slice *cl_page_at(const struct cl_page *page,
775 const struct lu_device_type *dtype)
777 return cl_page_at_trusted(page, dtype);
779 EXPORT_SYMBOL(cl_page_at);
781 #define CL_PAGE_OP(opname) offsetof(struct cl_page_operations, opname)
783 #define CL_PAGE_INVOKE(_env, _page, _op, _proto, ...) \
785 const struct lu_env *__env = (_env); \
786 struct cl_page *__page = (_page); \
787 const struct cl_page_slice *__scan; \
789 ptrdiff_t __op = (_op); \
790 int (*__method)_proto; \
793 __page = cl_page_top(__page); \
795 list_for_each_entry(__scan, &__page->cp_layers, \
797 __method = *(void **)((char *)__scan->cpl_ops + \
799 if (__method != NULL) { \
800 __result = (*__method)(__env, __scan, \
806 __page = __page->cp_child; \
807 } while (__page != NULL && __result == 0); \
813 #define CL_PAGE_INVOID(_env, _page, _op, _proto, ...) \
815 const struct lu_env *__env = (_env); \
816 struct cl_page *__page = (_page); \
817 const struct cl_page_slice *__scan; \
818 ptrdiff_t __op = (_op); \
819 void (*__method)_proto; \
821 __page = cl_page_top(__page); \
823 list_for_each_entry(__scan, &__page->cp_layers, \
825 __method = *(void **)((char *)__scan->cpl_ops + \
827 if (__method != NULL) \
828 (*__method)(__env, __scan, \
831 __page = __page->cp_child; \
832 } while (__page != NULL); \
835 #define CL_PAGE_INVOID_REVERSE(_env, _page, _op, _proto, ...) \
837 const struct lu_env *__env = (_env); \
838 struct cl_page *__page = (_page); \
839 const struct cl_page_slice *__scan; \
840 ptrdiff_t __op = (_op); \
841 void (*__method)_proto; \
843 /* get to the bottom page. */ \
844 while (__page->cp_child != NULL) \
845 __page = __page->cp_child; \
847 list_for_each_entry_reverse(__scan, &__page->cp_layers, \
849 __method = *(void **)((char *)__scan->cpl_ops + \
851 if (__method != NULL) \
852 (*__method)(__env, __scan, \
855 __page = __page->cp_parent; \
856 } while (__page != NULL); \
859 static int cl_page_invoke(const struct lu_env *env,
860 struct cl_io *io, struct cl_page *page, ptrdiff_t op)
863 PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
865 RETURN(CL_PAGE_INVOKE(env, page, op,
866 (const struct lu_env *,
867 const struct cl_page_slice *, struct cl_io *),
871 static void cl_page_invoid(const struct lu_env *env,
872 struct cl_io *io, struct cl_page *page, ptrdiff_t op)
875 PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
877 CL_PAGE_INVOID(env, page, op,
878 (const struct lu_env *,
879 const struct cl_page_slice *, struct cl_io *), io);
883 static void cl_page_owner_clear(struct cl_page *page)
886 for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
887 if (page->cp_owner != NULL) {
888 LASSERT(page->cp_owner->ci_owned_nr > 0);
889 page->cp_owner->ci_owned_nr--;
890 page->cp_owner = NULL;
891 page->cp_task = NULL;
897 static void cl_page_owner_set(struct cl_page *page)
900 for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
901 LASSERT(page->cp_owner != NULL);
902 page->cp_owner->ci_owned_nr++;
907 void cl_page_disown0(const struct lu_env *env,
908 struct cl_io *io, struct cl_page *pg)
910 enum cl_page_state state;
913 state = pg->cp_state;
914 PINVRNT(env, pg, state == CPS_OWNED || state == CPS_FREEING);
915 PINVRNT(env, pg, cl_page_invariant(pg));
916 cl_page_owner_clear(pg);
918 if (state == CPS_OWNED)
919 cl_page_state_set(env, pg, CPS_CACHED);
921 * Completion call-backs are executed in the bottom-up order, so that
922 * uppermost layer (llite), responsible for VFS/VM interaction runs
923 * last and can release locks safely.
925 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_disown),
926 (const struct lu_env *,
927 const struct cl_page_slice *, struct cl_io *),
933 * returns true, iff page is owned by the given io.
935 int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io)
937 LINVRNT(cl_object_same(pg->cp_obj, io->ci_obj));
939 RETURN(pg->cp_state == CPS_OWNED && pg->cp_owner == io);
941 EXPORT_SYMBOL(cl_page_is_owned);
944 * Try to own a page by IO.
946 * Waits until page is in cl_page_state::CPS_CACHED state, and then switch it
947 * into cl_page_state::CPS_OWNED state.
949 * \pre !cl_page_is_owned(pg, io)
950 * \post result == 0 iff cl_page_is_owned(pg, io)
954 * \retval -ve failure, e.g., page was destroyed (and landed in
955 * cl_page_state::CPS_FREEING instead of cl_page_state::CPS_CACHED).
956 * or, page was owned by another thread, or in IO.
958 * \see cl_page_disown()
959 * \see cl_page_operations::cpo_own()
960 * \see cl_page_own_try()
963 static int cl_page_own0(const struct lu_env *env, struct cl_io *io,
964 struct cl_page *pg, int nonblock)
968 PINVRNT(env, pg, !cl_page_is_owned(pg, io));
971 pg = cl_page_top(pg);
974 if (pg->cp_state == CPS_FREEING) {
977 result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(cpo_own),
978 (const struct lu_env *,
979 const struct cl_page_slice *,
980 struct cl_io *, int),
983 PASSERT(env, pg, pg->cp_owner == NULL);
984 PASSERT(env, pg, pg->cp_req == NULL);
986 pg->cp_task = current;
987 cl_page_owner_set(pg);
988 if (pg->cp_state != CPS_FREEING) {
989 cl_page_state_set(env, pg, CPS_OWNED);
991 cl_page_disown0(env, io, pg);
996 PINVRNT(env, pg, ergo(result == 0, cl_page_invariant(pg)));
1001 * Own a page, might be blocked.
1003 * \see cl_page_own0()
1005 int cl_page_own(const struct lu_env *env, struct cl_io *io, struct cl_page *pg)
1007 return cl_page_own0(env, io, pg, 0);
1009 EXPORT_SYMBOL(cl_page_own);
1012 * Nonblock version of cl_page_own().
1014 * \see cl_page_own0()
1016 int cl_page_own_try(const struct lu_env *env, struct cl_io *io,
1019 return cl_page_own0(env, io, pg, 1);
1021 EXPORT_SYMBOL(cl_page_own_try);
1025 * Assume page ownership.
1027 * Called when page is already locked by the hosting VM.
1029 * \pre !cl_page_is_owned(pg, io)
1030 * \post cl_page_is_owned(pg, io)
1032 * \see cl_page_operations::cpo_assume()
1034 void cl_page_assume(const struct lu_env *env,
1035 struct cl_io *io, struct cl_page *pg)
1037 PASSERT(env, pg, pg->cp_state < CPS_OWNED);
1038 PASSERT(env, pg, pg->cp_owner == NULL);
1039 PINVRNT(env, pg, cl_object_same(pg->cp_obj, io->ci_obj));
1040 PINVRNT(env, pg, cl_page_invariant(pg));
1043 pg = cl_page_top(pg);
1046 cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_assume));
1048 pg->cp_task = current;
1049 cl_page_owner_set(pg);
1050 cl_page_state_set(env, pg, CPS_OWNED);
1053 EXPORT_SYMBOL(cl_page_assume);
1056 * Releases page ownership without unlocking the page.
1058 * Moves page into cl_page_state::CPS_CACHED without releasing a lock on the
1059 * underlying VM page (as VM is supposed to do this itself).
1061 * \pre cl_page_is_owned(pg, io)
1062 * \post !cl_page_is_owned(pg, io)
1064 * \see cl_page_assume()
1066 void cl_page_unassume(const struct lu_env *env,
1067 struct cl_io *io, struct cl_page *pg)
1069 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1070 PINVRNT(env, pg, cl_page_invariant(pg));
1073 pg = cl_page_top(pg);
1075 cl_page_owner_clear(pg);
1076 cl_page_state_set(env, pg, CPS_CACHED);
1077 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_unassume),
1078 (const struct lu_env *,
1079 const struct cl_page_slice *, struct cl_io *),
1083 EXPORT_SYMBOL(cl_page_unassume);
1086 * Releases page ownership.
1088 * Moves page into cl_page_state::CPS_CACHED.
1090 * \pre cl_page_is_owned(pg, io)
1091 * \post !cl_page_is_owned(pg, io)
1093 * \see cl_page_own()
1094 * \see cl_page_operations::cpo_disown()
1096 void cl_page_disown(const struct lu_env *env,
1097 struct cl_io *io, struct cl_page *pg)
1099 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1102 pg = cl_page_top(pg);
1104 cl_page_disown0(env, io, pg);
1107 EXPORT_SYMBOL(cl_page_disown);
1110 * Called when page is to be removed from the object, e.g., as a result of
1113 * Calls cl_page_operations::cpo_discard() top-to-bottom.
1115 * \pre cl_page_is_owned(pg, io)
1117 * \see cl_page_operations::cpo_discard()
1119 void cl_page_discard(const struct lu_env *env,
1120 struct cl_io *io, struct cl_page *pg)
1122 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1123 PINVRNT(env, pg, cl_page_invariant(pg));
1125 cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_discard));
1127 EXPORT_SYMBOL(cl_page_discard);
1130 * Version of cl_page_delete() that can be called for not fully constructed
1131 * pages, e.g,. in a error handling cl_page_find()->cl_page_delete0()
1132 * path. Doesn't check page invariant.
1134 static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg,
1137 struct cl_page *tmp = pg;
1140 PASSERT(env, pg, pg == cl_page_top(pg));
1141 PASSERT(env, pg, pg->cp_state != CPS_FREEING);
1144 * Severe all ways to obtain new pointers to @pg.
1146 cl_page_owner_clear(pg);
1149 * unexport the page firstly before freeing it so that
1150 * the page content is considered to be invalid.
1151 * We have to do this because a CPS_FREEING cl_page may
1152 * be NOT under the protection of a cl_lock.
1153 * Afterwards, if this page is found by other threads, then this
1154 * page will be forced to reread.
1156 cl_page_export(env, pg, 0);
1157 cl_page_state_set0(env, pg, CPS_FREEING);
1161 * !radix means that @pg is not yet in the radix tree, skip
1165 for (; tmp != NULL; tmp = tmp->cp_child) {
1167 struct cl_object_header *hdr;
1169 hdr = cl_object_header(tmp->cp_obj);
1170 spin_lock(&hdr->coh_page_guard);
1171 value = radix_tree_delete(&hdr->coh_tree, tmp->cp_index);
1172 PASSERT(env, tmp, value == tmp);
1173 PASSERT(env, tmp, hdr->coh_pages > 0);
1175 spin_unlock(&hdr->coh_page_guard);
1178 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_delete),
1179 (const struct lu_env *, const struct cl_page_slice *));
1184 * Called when a decision is made to throw page out of memory.
1186 * Notifies all layers about page destruction by calling
1187 * cl_page_operations::cpo_delete() method top-to-bottom.
1189 * Moves page into cl_page_state::CPS_FREEING state (this is the only place
1190 * where transition to this state happens).
1192 * Eliminates all venues through which new references to the page can be
1195 * - removes page from the radix trees,
1197 * - breaks linkage from VM page to cl_page.
1199 * Once page reaches cl_page_state::CPS_FREEING, all remaining references will
1200 * drain after some time, at which point page will be recycled.
1202 * \pre pg == cl_page_top(pg)
1203 * \pre VM page is locked
1204 * \post pg->cp_state == CPS_FREEING
1206 * \see cl_page_operations::cpo_delete()
1208 void cl_page_delete(const struct lu_env *env, struct cl_page *pg)
1210 PINVRNT(env, pg, cl_page_invariant(pg));
1212 cl_page_delete0(env, pg, 1);
1215 EXPORT_SYMBOL(cl_page_delete);
1218 * Unmaps page from user virtual memory.
1220 * Calls cl_page_operations::cpo_unmap() through all layers top-to-bottom. The
1221 * layer responsible for VM interaction has to unmap page from user space
1224 * \see cl_page_operations::cpo_unmap()
1226 int cl_page_unmap(const struct lu_env *env,
1227 struct cl_io *io, struct cl_page *pg)
1229 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1230 PINVRNT(env, pg, cl_page_invariant(pg));
1232 return cl_page_invoke(env, io, pg, CL_PAGE_OP(cpo_unmap));
1234 EXPORT_SYMBOL(cl_page_unmap);
1237 * Marks page up-to-date.
1239 * Call cl_page_operations::cpo_export() through all layers top-to-bottom. The
1240 * layer responsible for VM interaction has to mark/clear page as up-to-date
1241 * by the \a uptodate argument.
1243 * \see cl_page_operations::cpo_export()
1245 void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate)
1247 PINVRNT(env, pg, cl_page_invariant(pg));
1248 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_export),
1249 (const struct lu_env *,
1250 const struct cl_page_slice *, int), uptodate);
1252 EXPORT_SYMBOL(cl_page_export);
1255 * Returns true, iff \a pg is VM locked in a suitable sense by the calling
1258 int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg)
1261 const struct cl_page_slice *slice;
1264 pg = cl_page_top_trusted((struct cl_page *)pg);
1265 slice = container_of(pg->cp_layers.next,
1266 const struct cl_page_slice, cpl_linkage);
1267 PASSERT(env, pg, slice->cpl_ops->cpo_is_vmlocked != NULL);
1269 * Call ->cpo_is_vmlocked() directly instead of going through
1270 * CL_PAGE_INVOKE(), because cl_page_is_vmlocked() is used by
1271 * cl_page_invariant().
1273 result = slice->cpl_ops->cpo_is_vmlocked(env, slice);
1274 PASSERT(env, pg, result == -EBUSY || result == -ENODATA);
1275 RETURN(result == -EBUSY);
1277 EXPORT_SYMBOL(cl_page_is_vmlocked);
1279 static enum cl_page_state cl_req_type_state(enum cl_req_type crt)
1282 RETURN(crt == CRT_WRITE ? CPS_PAGEOUT : CPS_PAGEIN);
1285 static void cl_page_io_start(const struct lu_env *env,
1286 struct cl_page *pg, enum cl_req_type crt)
1289 * Page is queued for IO, change its state.
1292 cl_page_owner_clear(pg);
1293 cl_page_state_set(env, pg, cl_req_type_state(crt));
1298 * Prepares page for immediate transfer. cl_page_operations::cpo_prep() is
1299 * called top-to-bottom. Every layer either agrees to submit this page (by
1300 * returning 0), or requests to omit this page (by returning -EALREADY). Layer
1301 * handling interactions with the VM also has to inform VM that page is under
1304 int cl_page_prep(const struct lu_env *env, struct cl_io *io,
1305 struct cl_page *pg, enum cl_req_type crt)
1309 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1310 PINVRNT(env, pg, cl_page_invariant(pg));
1311 PINVRNT(env, pg, crt < CRT_NR);
1314 * XXX this has to be called bottom-to-top, so that llite can set up
1315 * PG_writeback without risking other layers deciding to skip this
1318 result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_prep));
1320 cl_page_io_start(env, pg, crt);
1322 KLASSERT(ergo(crt == CRT_WRITE && pg->cp_type == CPT_CACHEABLE,
1324 PageWriteback(cl_page_vmpage(env, pg)))));
1325 CL_PAGE_HEADER(D_TRACE, env, pg, "%i %i\n", crt, result);
1328 EXPORT_SYMBOL(cl_page_prep);
1331 * Notify layers about transfer completion.
1333 * Invoked by transfer sub-system (which is a part of osc) to notify layers
1334 * that a transfer, of which this page is a part of has completed.
1336 * Completion call-backs are executed in the bottom-up order, so that
1337 * uppermost layer (llite), responsible for the VFS/VM interaction runs last
1338 * and can release locks safely.
1340 * \pre pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
1341 * \post pg->cp_state == CPS_CACHED
1343 * \see cl_page_operations::cpo_completion()
1345 void cl_page_completion(const struct lu_env *env,
1346 struct cl_page *pg, enum cl_req_type crt, int ioret)
1348 struct cl_sync_io *anchor = pg->cp_sync_io;
1350 PASSERT(env, pg, crt < CRT_NR);
1351 /* cl_page::cp_req already cleared by the caller (osc_completion()) */
1352 PASSERT(env, pg, pg->cp_req == NULL);
1353 PASSERT(env, pg, pg->cp_state == cl_req_type_state(crt));
1354 PINVRNT(env, pg, cl_page_invariant(pg));
1357 CL_PAGE_HEADER(D_TRACE, env, pg, "%i %i\n", crt, ioret);
1358 if (crt == CRT_READ && ioret == 0) {
1359 PASSERT(env, pg, !(pg->cp_flags & CPF_READ_COMPLETED));
1360 pg->cp_flags |= CPF_READ_COMPLETED;
1363 cl_page_state_set(env, pg, CPS_CACHED);
1364 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(io[crt].cpo_completion),
1365 (const struct lu_env *,
1366 const struct cl_page_slice *, int), ioret);
1368 LASSERT(pg->cp_sync_io == anchor);
1369 pg->cp_sync_io = NULL;
1370 cl_sync_io_note(anchor, ioret);
1373 /* Don't assert the page writeback bit here because the lustre file
1374 * may be as a backend of swap space. in this case, the page writeback
1375 * is set by VM, and obvious we shouldn't clear it at all. Fortunately
1376 * this type of pages are all TRANSIENT pages. */
1377 KLASSERT(ergo(pg->cp_type == CPT_CACHEABLE,
1378 !PageWriteback(cl_page_vmpage(env, pg))));
1381 EXPORT_SYMBOL(cl_page_completion);
1384 * Notify layers that transfer formation engine decided to yank this page from
1385 * the cache and to make it a part of a transfer.
1387 * \pre pg->cp_state == CPS_CACHED
1388 * \post pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
1390 * \see cl_page_operations::cpo_make_ready()
1392 int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg,
1393 enum cl_req_type crt)
1397 PINVRNT(env, pg, crt < CRT_NR);
1400 result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(io[crt].cpo_make_ready),
1401 (const struct lu_env *,
1402 const struct cl_page_slice *));
1404 PASSERT(env, pg, pg->cp_state == CPS_CACHED);
1405 cl_page_io_start(env, pg, crt);
1407 CL_PAGE_HEADER(D_TRACE, env, pg, "%i %i\n", crt, result);
1410 EXPORT_SYMBOL(cl_page_make_ready);
1413 * Notify layers that high level io decided to place this page into a cache
1414 * for future transfer.
1416 * The layer implementing transfer engine (osc) has to register this page in
1419 * \pre cl_page_is_owned(pg, io)
1420 * \post ergo(result == 0,
1421 * pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT)
1423 * \see cl_page_operations::cpo_cache_add()
1425 int cl_page_cache_add(const struct lu_env *env, struct cl_io *io,
1426 struct cl_page *pg, enum cl_req_type crt)
1430 PINVRNT(env, pg, crt < CRT_NR);
1431 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1432 PINVRNT(env, pg, cl_page_invariant(pg));
1435 result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_cache_add));
1437 cl_page_owner_clear(pg);
1438 cl_page_state_set(env, pg, CPS_CACHED);
1440 CL_PAGE_HEADER(D_TRACE, env, pg, "%i %i\n", crt, result);
1443 EXPORT_SYMBOL(cl_page_cache_add);
1446 * Checks whether page is protected by any extent lock is at least required
1449 * \return the same as in cl_page_operations::cpo_is_under_lock() method.
1450 * \see cl_page_operations::cpo_is_under_lock()
1452 int cl_page_is_under_lock(const struct lu_env *env, struct cl_io *io,
1453 struct cl_page *page)
1457 PINVRNT(env, page, cl_page_invariant(page));
1460 rc = CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_is_under_lock),
1461 (const struct lu_env *,
1462 const struct cl_page_slice *, struct cl_io *),
1464 PASSERT(env, page, rc != 0);
1467 EXPORT_SYMBOL(cl_page_is_under_lock);
1470 * Purges all cached pages belonging to the object \a obj.
1472 int cl_pages_prune(const struct lu_env *env, struct cl_object *clobj)
1474 struct cl_thread_info *info;
1475 struct cl_object *obj = cl_object_top(clobj);
1477 struct cl_page_list *plist;
1481 info = cl_env_info(env);
1482 plist = &info->clt_list;
1486 * initialize the io. This is ugly since we never do IO in this
1487 * function, we just make cl_page_list functions happy. -jay
1490 result = cl_io_init(env, io, CIT_MISC, obj);
1492 cl_io_fini(env, io);
1493 RETURN(io->ci_result);
1496 cl_page_list_init(plist);
1497 cl_page_gang_lookup(env, obj, io, 0, CL_PAGE_EOF, plist, 0);
1499 * Since we're purging the pages of an object, we don't care
1500 * the possible outcomes of the following functions.
1502 cl_page_list_unmap(env, io, plist);
1503 cl_page_list_discard(env, io, plist);
1504 cl_page_list_disown(env, io, plist);
1505 cl_page_list_fini(env, plist);
1507 cl_io_fini(env, io);
1510 EXPORT_SYMBOL(cl_pages_prune);
1513 * Tells transfer engine that only part of a page is to be transmitted.
1515 * \see cl_page_operations::cpo_clip()
1517 void cl_page_clip(const struct lu_env *env, struct cl_page *pg,
1520 PINVRNT(env, pg, cl_page_invariant(pg));
1522 CL_PAGE_HEADER(D_TRACE, env, pg, "%i %i\n", from, to);
1523 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_clip),
1524 (const struct lu_env *,
1525 const struct cl_page_slice *,int, int),
1528 EXPORT_SYMBOL(cl_page_clip);
1531 * Prints human readable representation of \a pg to the \a f.
1533 void cl_page_header_print(const struct lu_env *env, void *cookie,
1534 lu_printer_t printer, const struct cl_page *pg)
1536 (*printer)(env, cookie,
1537 "page@%p[%d %p:%lu ^%p_%p %d %d %d %p %p %#x]\n",
1538 pg, atomic_read(&pg->cp_ref), pg->cp_obj,
1539 pg->cp_index, pg->cp_parent, pg->cp_child,
1540 pg->cp_state, pg->cp_error, pg->cp_type,
1541 pg->cp_owner, pg->cp_req, pg->cp_flags);
1543 EXPORT_SYMBOL(cl_page_header_print);
1546 * Prints human readable representation of \a pg to the \a f.
1548 void cl_page_print(const struct lu_env *env, void *cookie,
1549 lu_printer_t printer, const struct cl_page *pg)
1551 struct cl_page *scan;
1553 for (scan = cl_page_top((struct cl_page *)pg);
1554 scan != NULL; scan = scan->cp_child)
1555 cl_page_header_print(env, cookie, printer, scan);
1556 CL_PAGE_INVOKE(env, (struct cl_page *)pg, CL_PAGE_OP(cpo_print),
1557 (const struct lu_env *env,
1558 const struct cl_page_slice *slice,
1559 void *cookie, lu_printer_t p), cookie, printer);
1560 (*printer)(env, cookie, "end page@%p\n", pg);
1562 EXPORT_SYMBOL(cl_page_print);
1565 * Cancel a page which is still in a transfer.
1567 int cl_page_cancel(const struct lu_env *env, struct cl_page *page)
1569 return CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_cancel),
1570 (const struct lu_env *,
1571 const struct cl_page_slice *));
1573 EXPORT_SYMBOL(cl_page_cancel);
1576 * Converts a byte offset within object \a obj into a page index.
1578 loff_t cl_offset(const struct cl_object *obj, pgoff_t idx)
1583 return (loff_t)idx << CFS_PAGE_SHIFT;
1585 EXPORT_SYMBOL(cl_offset);
1588 * Converts a page index into a byte offset within object \a obj.
1590 pgoff_t cl_index(const struct cl_object *obj, loff_t offset)
1595 return offset >> CFS_PAGE_SHIFT;
1597 EXPORT_SYMBOL(cl_index);
1599 int cl_page_size(const struct cl_object *obj)
1601 return 1 << CFS_PAGE_SHIFT;
1603 EXPORT_SYMBOL(cl_page_size);
1606 * Adds page slice to the compound page.
1608 * This is called by cl_object_operations::coo_page_init() methods to add a
1609 * per-layer state to the page. New state is added at the end of
1610 * cl_page::cp_layers list, that is, it is at the bottom of the stack.
1612 * \see cl_lock_slice_add(), cl_req_slice_add(), cl_io_slice_add()
1614 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
1615 struct cl_object *obj,
1616 const struct cl_page_operations *ops)
1619 list_add_tail(&slice->cpl_linkage, &page->cp_layers);
1620 slice->cpl_obj = obj;
1621 slice->cpl_ops = ops;
1622 slice->cpl_page = page;
1625 EXPORT_SYMBOL(cl_page_slice_add);
1627 int cl_page_init(void)
1629 return lu_kmem_init(cl_page_caches);
1632 void cl_page_fini(void)
1634 lu_kmem_fini(cl_page_caches);