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 (c) 2008, 2010, Oracle and/or its affiliates. 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 while (page->cp_parent != NULL)
103 page = page->cp_parent;
108 * Internal version of cl_page_get().
110 * This function can be used to obtain initial reference to previously
111 * unreferenced cached object. It can be called only if concurrent page
112 * reclamation is somehow prevented, e.g., by locking page radix-tree
113 * (cl_object_header::hdr->coh_page_guard), or by keeping a lock on a VM page,
114 * associated with \a page.
116 * Use with care! Not exported.
118 static void cl_page_get_trust(struct cl_page *page)
121 * Checkless version for trusted users.
123 if (cfs_atomic_inc_return(&page->cp_ref) == 1)
124 cfs_atomic_inc(&cl_object_site(page->cp_obj)->cs_pages.cs_busy);
128 * Returns a slice within a page, corresponding to the given layer in the
133 static const struct cl_page_slice *
134 cl_page_at_trusted(const struct cl_page *page,
135 const struct lu_device_type *dtype)
137 const struct cl_page_slice *slice;
139 #ifdef INVARIANT_CHECK
140 struct cl_object_header *ch = cl_object_header(page->cp_obj);
142 if (!cfs_atomic_read(&page->cp_ref))
143 LASSERT_SPIN_LOCKED(&ch->coh_page_guard);
147 page = cl_page_top_trusted((struct cl_page *)page);
149 cfs_list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
150 if (slice->cpl_obj->co_lu.lo_dev->ld_type == dtype)
153 page = page->cp_child;
154 } while (page != NULL);
159 * Returns a page with given index in the given object, or NULL if no page is
160 * found. Acquires a reference on \a page.
162 * Locking: called under cl_object_header::coh_page_guard spin-lock.
164 struct cl_page *cl_page_lookup(struct cl_object_header *hdr, pgoff_t index)
166 struct cl_page *page;
168 LASSERT_SPIN_LOCKED(&hdr->coh_page_guard);
170 page = radix_tree_lookup(&hdr->coh_tree, index);
172 cl_page_get_trust(page);
176 EXPORT_SYMBOL(cl_page_lookup);
179 * Returns a list of pages by a given [start, end] of \a obj.
181 * \param resched If not NULL, then we give up before hogging CPU for too
182 * long and set *resched = 1, in that case caller should implement a retry
185 * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
186 * crucial in the face of [offset, EOF] locks.
188 void cl_page_gang_lookup(const struct lu_env *env, struct cl_object *obj,
189 struct cl_io *io, pgoff_t start, pgoff_t end,
190 struct cl_page_list *queue, int nonblock,
193 struct cl_object_header *hdr;
194 struct cl_page *page;
195 struct cl_page **pvec;
196 const struct cl_page_slice *slice;
197 const struct lu_device_type *dtype;
202 int (*page_own)(const struct lu_env *env,
209 page_own = nonblock ? cl_page_own_try : cl_page_own;
212 hdr = cl_object_header(obj);
213 pvec = cl_env_info(env)->clt_pvec;
214 dtype = cl_object_top(obj)->co_lu.lo_dev->ld_type;
215 cfs_spin_lock(&hdr->coh_page_guard);
216 while ((nr = radix_tree_gang_lookup(&hdr->coh_tree, (void **)pvec,
217 idx, CLT_PVEC_SIZE)) > 0) {
218 idx = pvec[nr - 1]->cp_index + 1;
219 for (i = 0, j = 0; i < nr; ++i) {
222 if (page->cp_index > end)
224 if (page->cp_state == CPS_FREEING)
226 if (page->cp_type == CPT_TRANSIENT) {
227 /* God, we found a transient page!*/
231 slice = cl_page_at_trusted(page, dtype);
233 * Pages for lsm-less file has no underneath sub-page
234 * for osc, in case of ...
236 PASSERT(env, page, slice != NULL);
238 page = slice->cpl_page;
240 * Can safely call cl_page_get_trust() under
241 * radix-tree spin-lock.
243 * XXX not true, because @page is from object another
244 * than @hdr and protected by different tree lock.
246 cl_page_get_trust(page);
247 lu_ref_add_atomic(&page->cp_reference,
248 "page_list", cfs_current());
253 * Here a delicate locking dance is performed. Current thread
254 * holds a reference to a page, but has to own it before it
255 * can be placed into queue. Owning implies waiting, so
256 * radix-tree lock is to be released. After a wait one has to
257 * check that pages weren't truncated (cl_page_own() returns
258 * error in the latter case).
260 cfs_spin_unlock(&hdr->coh_page_guard);
261 for (i = 0; i < j; ++i) {
263 if (page_own(env, io, page) == 0)
264 cl_page_list_add(queue, page);
265 lu_ref_del(&page->cp_reference,
266 "page_list", cfs_current());
267 cl_page_put(env, page);
269 cfs_spin_lock(&hdr->coh_page_guard);
270 if (nr < CLT_PVEC_SIZE)
272 if (resched != NULL && cfs_need_resched()) {
277 cfs_spin_unlock(&hdr->coh_page_guard);
280 EXPORT_SYMBOL(cl_page_gang_lookup);
282 static void cl_page_free(const struct lu_env *env, struct cl_page *page)
284 struct cl_object *obj = page->cp_obj;
285 struct cl_site *site = cl_object_site(obj);
287 PASSERT(env, page, cfs_list_empty(&page->cp_batch));
288 PASSERT(env, page, page->cp_owner == NULL);
289 PASSERT(env, page, page->cp_req == NULL);
290 PASSERT(env, page, page->cp_parent == NULL);
291 PASSERT(env, page, page->cp_state == CPS_FREEING);
295 while (!cfs_list_empty(&page->cp_layers)) {
296 struct cl_page_slice *slice;
298 slice = cfs_list_entry(page->cp_layers.next,
299 struct cl_page_slice, cpl_linkage);
300 cfs_list_del_init(page->cp_layers.next);
301 slice->cpl_ops->cpo_fini(env, slice);
303 cfs_atomic_dec(&site->cs_pages.cs_total);
305 #ifdef LUSTRE_PAGESTATE_TRACKING
306 cfs_atomic_dec(&site->cs_pages_state[page->cp_state]);
308 lu_object_ref_del_at(&obj->co_lu, page->cp_obj_ref, "cl_page", page);
309 cl_object_put(env, obj);
310 lu_ref_fini(&page->cp_reference);
311 OBD_SLAB_FREE_PTR(page, cl_page_kmem);
316 * Helper function updating page state. This is the only place in the code
317 * where cl_page::cp_state field is mutated.
319 static inline void cl_page_state_set_trust(struct cl_page *page,
320 enum cl_page_state state)
323 *(enum cl_page_state *)&page->cp_state = state;
326 static int cl_page_alloc(const struct lu_env *env, struct cl_object *o,
327 pgoff_t ind, struct page *vmpage,
328 enum cl_page_type type, struct cl_page **out)
330 struct cl_page *page;
331 struct cl_page *err = NULL;
332 struct lu_object_header *head;
333 struct cl_site *site = cl_object_site(o);
338 OBD_SLAB_ALLOC_PTR_GFP(page, cl_page_kmem, CFS_ALLOC_IO);
340 cfs_atomic_set(&page->cp_ref, 1);
343 page->cp_obj_ref = lu_object_ref_add(&o->co_lu,
345 page->cp_index = ind;
346 cl_page_state_set_trust(page, CPS_CACHED);
347 page->cp_type = type;
348 CFS_INIT_LIST_HEAD(&page->cp_layers);
349 CFS_INIT_LIST_HEAD(&page->cp_batch);
350 CFS_INIT_LIST_HEAD(&page->cp_flight);
351 cfs_mutex_init(&page->cp_mutex);
352 lu_ref_init(&page->cp_reference);
353 head = o->co_lu.lo_header;
354 cfs_list_for_each_entry(o, &head->loh_layers,
356 if (o->co_ops->coo_page_init != NULL) {
357 err = o->co_ops->coo_page_init(env, o,
360 cl_page_state_set_trust(page,
362 cl_page_free(env, page);
369 cfs_atomic_inc(&site->cs_pages.cs_busy);
370 cfs_atomic_inc(&site->cs_pages.cs_total);
372 #ifdef LUSTRE_PAGESTATE_TRACKING
373 cfs_atomic_inc(&site->cs_pages_state[CPS_CACHED]);
375 cfs_atomic_inc(&site->cs_pages.cs_created);
379 page = ERR_PTR(-ENOMEM);
385 * Returns a cl_page with index \a idx at the object \a o, and associated with
386 * the VM page \a vmpage.
388 * This is the main entry point into the cl_page caching interface. First, a
389 * cache (implemented as a per-object radix tree) is consulted. If page is
390 * found there, it is returned immediately. Otherwise new page is allocated
391 * and returned. In any case, additional reference to page is acquired.
393 * \see cl_object_find(), cl_lock_find()
395 static struct cl_page *cl_page_find0(const struct lu_env *env,
397 pgoff_t idx, struct page *vmpage,
398 enum cl_page_type type,
399 struct cl_page *parent)
401 struct cl_page *page;
402 struct cl_page *ghost = NULL;
403 struct cl_object_header *hdr;
404 struct cl_site *site = cl_object_site(o);
407 LINVRNT(type == CPT_CACHEABLE || type == CPT_TRANSIENT);
412 hdr = cl_object_header(o);
413 cfs_atomic_inc(&site->cs_pages.cs_lookup);
415 CDEBUG(D_PAGE, "%lu@"DFID" %p %lu %d\n",
416 idx, PFID(&hdr->coh_lu.loh_fid), vmpage, vmpage->private, type);
418 if (type == CPT_CACHEABLE) {
420 * cl_vmpage_page() can be called here without any locks as
422 * - "vmpage" is locked (which prevents ->private from
423 * concurrent updates), and
425 * - "o" cannot be destroyed while current thread holds a
428 page = cl_vmpage_page(vmpage, o);
431 cl_page_vmpage(env, page) == vmpage &&
432 (void *)radix_tree_lookup(&hdr->coh_tree,
435 cfs_spin_lock(&hdr->coh_page_guard);
436 page = cl_page_lookup(hdr, idx);
437 cfs_spin_unlock(&hdr->coh_page_guard);
440 cfs_atomic_inc(&site->cs_pages.cs_hit);
444 /* allocate and initialize cl_page */
445 err = cl_page_alloc(env, o, idx, vmpage, type, &page);
449 * XXX optimization: use radix_tree_preload() here, and change tree
450 * gfp mask to GFP_KERNEL in cl_object_header_init().
452 cfs_spin_lock(&hdr->coh_page_guard);
453 err = radix_tree_insert(&hdr->coh_tree, idx, page);
457 * Noted by Jay: a lock on \a vmpage protects cl_page_find()
458 * from this race, but
460 * 0. it's better to have cl_page interface "locally
461 * consistent" so that its correctness can be reasoned
462 * about without appealing to the (obscure world of) VM
465 * 1. handling this race allows ->coh_tree to remain
466 * consistent even when VM locking is somehow busted,
467 * which is very useful during diagnosing and debugging.
470 if (err == -EEXIST) {
472 * XXX in case of a lookup for CPT_TRANSIENT page,
473 * nothing protects a CPT_CACHEABLE page from being
474 * concurrently moved into CPS_FREEING state.
476 page = cl_page_lookup(hdr, idx);
477 PASSERT(env, page, page != NULL);
478 if (page->cp_type == CPT_TRANSIENT &&
479 type == CPT_CACHEABLE) {
480 /* XXX: We should make sure that inode sem
481 * keeps being held in the lifetime of
482 * transient pages, so it is impossible to
483 * have conflicting transient pages.
485 cfs_spin_unlock(&hdr->coh_page_guard);
486 cl_page_put(env, page);
487 cfs_spin_lock(&hdr->coh_page_guard);
488 page = ERR_PTR(-EBUSY);
493 LASSERT(page->cp_parent == NULL);
494 page->cp_parent = parent;
495 parent->cp_child = page;
499 cfs_spin_unlock(&hdr->coh_page_guard);
501 if (unlikely(ghost != NULL)) {
502 cfs_atomic_dec(&site->cs_pages.cs_busy);
503 cl_page_delete0(env, ghost, 0);
504 cl_page_free(env, ghost);
509 struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *o,
510 pgoff_t idx, struct page *vmpage,
511 enum cl_page_type type)
513 return cl_page_find0(env, o, idx, vmpage, type, NULL);
515 EXPORT_SYMBOL(cl_page_find);
518 struct cl_page *cl_page_find_sub(const struct lu_env *env, struct cl_object *o,
519 pgoff_t idx, struct page *vmpage,
520 struct cl_page *parent)
522 return cl_page_find0(env, o, idx, vmpage, parent->cp_type, parent);
524 EXPORT_SYMBOL(cl_page_find_sub);
526 static inline int cl_page_invariant(const struct cl_page *pg)
528 struct cl_object_header *header;
529 struct cl_page *parent;
530 struct cl_page *child;
534 * Page invariant is protected by a VM lock.
536 LINVRNT(cl_page_is_vmlocked(NULL, pg));
538 header = cl_object_header(pg->cp_obj);
539 parent = pg->cp_parent;
540 child = pg->cp_child;
541 owner = pg->cp_owner;
543 return cfs_atomic_read(&pg->cp_ref) > 0 &&
544 ergo(parent != NULL, parent->cp_child == pg) &&
545 ergo(child != NULL, child->cp_parent == pg) &&
546 ergo(child != NULL, pg->cp_obj != child->cp_obj) &&
547 ergo(parent != NULL, pg->cp_obj != parent->cp_obj) &&
548 ergo(owner != NULL && parent != NULL,
549 parent->cp_owner == pg->cp_owner->ci_parent) &&
550 ergo(owner != NULL && child != NULL,
551 child->cp_owner->ci_parent == owner) &&
553 * Either page is early in initialization (has neither child
554 * nor parent yet), or it is in the object radix tree.
556 ergo(pg->cp_state < CPS_FREEING,
557 (void *)radix_tree_lookup(&header->coh_tree,
558 pg->cp_index) == pg ||
559 (child == NULL && parent == NULL));
562 static void cl_page_state_set0(const struct lu_env *env,
563 struct cl_page *page, enum cl_page_state state)
565 enum cl_page_state old;
566 #ifdef LUSTRE_PAGESTATE_TRACKING
567 struct cl_site *site = cl_object_site(page->cp_obj);
571 * Matrix of allowed state transitions [old][new], for sanity
574 static const int allowed_transitions[CPS_NR][CPS_NR] = {
577 [CPS_OWNED] = 1, /* io finds existing cached page */
579 [CPS_PAGEOUT] = 1, /* write-out from the cache */
580 [CPS_FREEING] = 1, /* eviction on the memory pressure */
583 [CPS_CACHED] = 1, /* release to the cache */
585 [CPS_PAGEIN] = 1, /* start read immediately */
586 [CPS_PAGEOUT] = 1, /* start write immediately */
587 [CPS_FREEING] = 1, /* lock invalidation or truncate */
590 [CPS_CACHED] = 1, /* io completion */
597 [CPS_CACHED] = 1, /* io completion */
613 old = page->cp_state;
614 PASSERT(env, page, allowed_transitions[old][state]);
615 CL_PAGE_HEADER(D_TRACE, env, page, "%d -> %d\n", old, state);
616 for (; page != NULL; page = page->cp_child) {
617 PASSERT(env, page, page->cp_state == old);
619 equi(state == CPS_OWNED, page->cp_owner != NULL));
621 #ifdef LUSTRE_PAGESTATE_TRACKING
622 cfs_atomic_dec(&site->cs_pages_state[page->cp_state]);
623 cfs_atomic_inc(&site->cs_pages_state[state]);
625 cl_page_state_set_trust(page, state);
630 static void cl_page_state_set(const struct lu_env *env,
631 struct cl_page *page, enum cl_page_state state)
633 PINVRNT(env, page, cl_page_invariant(page));
634 cl_page_state_set0(env, page, state);
638 * Acquires an additional reference to a page.
640 * This can be called only by caller already possessing a reference to \a
643 * \see cl_object_get(), cl_lock_get().
645 void cl_page_get(struct cl_page *page)
648 LASSERT(page->cp_state != CPS_FREEING);
649 cl_page_get_trust(page);
652 EXPORT_SYMBOL(cl_page_get);
655 * Releases a reference to a page.
657 * When last reference is released, page is returned to the cache, unless it
658 * is in cl_page_state::CPS_FREEING state, in which case it is immediately
661 * \see cl_object_put(), cl_lock_put().
663 void cl_page_put(const struct lu_env *env, struct cl_page *page)
665 struct cl_object_header *hdr;
666 struct cl_site *site = cl_object_site(page->cp_obj);
668 PASSERT(env, page, cfs_atomic_read(&page->cp_ref) > !!page->cp_parent);
671 CL_PAGE_HEADER(D_TRACE, env, page, "%d\n",
672 cfs_atomic_read(&page->cp_ref));
674 hdr = cl_object_header(cl_object_top(page->cp_obj));
675 if (cfs_atomic_dec_and_lock(&page->cp_ref, &hdr->coh_page_guard)) {
676 cfs_atomic_dec(&site->cs_pages.cs_busy);
677 /* We're going to access the page w/o a reference, but it's
678 * ok because we have grabbed the lock coh_page_guard, which
679 * means nobody is able to free this page behind us.
681 if (page->cp_state == CPS_FREEING) {
682 /* We drop the page reference and check the page state
683 * inside the coh_page_guard. So that if it gets here,
684 * it is the REALLY last reference to this page.
686 cfs_spin_unlock(&hdr->coh_page_guard);
688 LASSERT(cfs_atomic_read(&page->cp_ref) == 0);
689 PASSERT(env, page, page->cp_owner == NULL);
690 PASSERT(env, page, cfs_list_empty(&page->cp_batch));
692 * Page is no longer reachable by other threads. Tear
695 cl_page_free(env, page);
700 cfs_spin_unlock(&hdr->coh_page_guard);
705 EXPORT_SYMBOL(cl_page_put);
708 * Returns a VM page associated with a given cl_page.
710 cfs_page_t *cl_page_vmpage(const struct lu_env *env, struct cl_page *page)
712 const struct cl_page_slice *slice;
715 * Find uppermost layer with ->cpo_vmpage() method, and return its
718 page = cl_page_top(page);
720 cfs_list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
721 if (slice->cpl_ops->cpo_vmpage != NULL)
722 RETURN(slice->cpl_ops->cpo_vmpage(env, slice));
724 page = page->cp_child;
725 } while (page != NULL);
726 LBUG(); /* ->cpo_vmpage() has to be defined somewhere in the stack */
728 EXPORT_SYMBOL(cl_page_vmpage);
731 * Returns a cl_page associated with a VM page, and given cl_object.
733 struct cl_page *cl_vmpage_page(cfs_page_t *vmpage, struct cl_object *obj)
735 struct cl_page *page;
736 struct cl_object_header *hdr;
739 KLASSERT(PageLocked(vmpage));
742 * NOTE: absence of races and liveness of data are guaranteed by page
743 * lock on a "vmpage". That works because object destruction has
744 * bottom-to-top pass.
748 * This loop assumes that ->private points to the top-most page. This
749 * can be rectified easily.
751 hdr = cl_object_header(cl_object_top(obj));
752 cfs_spin_lock(&hdr->coh_page_guard);
753 for (page = (void *)vmpage->private;
754 page != NULL; page = page->cp_child) {
755 if (cl_object_same(page->cp_obj, obj)) {
756 cl_page_get_trust(page);
760 cfs_spin_unlock(&hdr->coh_page_guard);
761 LASSERT(ergo(page, page->cp_type == CPT_CACHEABLE));
764 EXPORT_SYMBOL(cl_vmpage_page);
767 * Returns the top-page for a given page.
769 * \see cl_object_top(), cl_io_top()
771 struct cl_page *cl_page_top(struct cl_page *page)
773 return cl_page_top_trusted(page);
775 EXPORT_SYMBOL(cl_page_top);
777 const struct cl_page_slice *cl_page_at(const struct cl_page *page,
778 const struct lu_device_type *dtype)
780 return cl_page_at_trusted(page, dtype);
782 EXPORT_SYMBOL(cl_page_at);
784 #define CL_PAGE_OP(opname) offsetof(struct cl_page_operations, opname)
786 #define CL_PAGE_INVOKE(_env, _page, _op, _proto, ...) \
788 const struct lu_env *__env = (_env); \
789 struct cl_page *__page = (_page); \
790 const struct cl_page_slice *__scan; \
792 ptrdiff_t __op = (_op); \
793 int (*__method)_proto; \
796 __page = cl_page_top(__page); \
798 cfs_list_for_each_entry(__scan, &__page->cp_layers, \
800 __method = *(void **)((char *)__scan->cpl_ops + \
802 if (__method != NULL) { \
803 __result = (*__method)(__env, __scan, \
809 __page = __page->cp_child; \
810 } while (__page != NULL && __result == 0); \
816 #define CL_PAGE_INVOID(_env, _page, _op, _proto, ...) \
818 const struct lu_env *__env = (_env); \
819 struct cl_page *__page = (_page); \
820 const struct cl_page_slice *__scan; \
821 ptrdiff_t __op = (_op); \
822 void (*__method)_proto; \
824 __page = cl_page_top(__page); \
826 cfs_list_for_each_entry(__scan, &__page->cp_layers, \
828 __method = *(void **)((char *)__scan->cpl_ops + \
830 if (__method != NULL) \
831 (*__method)(__env, __scan, \
834 __page = __page->cp_child; \
835 } while (__page != NULL); \
838 #define CL_PAGE_INVOID_REVERSE(_env, _page, _op, _proto, ...) \
840 const struct lu_env *__env = (_env); \
841 struct cl_page *__page = (_page); \
842 const struct cl_page_slice *__scan; \
843 ptrdiff_t __op = (_op); \
844 void (*__method)_proto; \
846 /* get to the bottom page. */ \
847 while (__page->cp_child != NULL) \
848 __page = __page->cp_child; \
850 cfs_list_for_each_entry_reverse(__scan, &__page->cp_layers, \
852 __method = *(void **)((char *)__scan->cpl_ops + \
854 if (__method != NULL) \
855 (*__method)(__env, __scan, \
858 __page = __page->cp_parent; \
859 } while (__page != NULL); \
862 static int cl_page_invoke(const struct lu_env *env,
863 struct cl_io *io, struct cl_page *page, ptrdiff_t op)
866 PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
868 RETURN(CL_PAGE_INVOKE(env, page, op,
869 (const struct lu_env *,
870 const struct cl_page_slice *, struct cl_io *),
874 static void cl_page_invoid(const struct lu_env *env,
875 struct cl_io *io, struct cl_page *page, ptrdiff_t op)
878 PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
880 CL_PAGE_INVOID(env, page, op,
881 (const struct lu_env *,
882 const struct cl_page_slice *, struct cl_io *), io);
886 static void cl_page_owner_clear(struct cl_page *page)
889 for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
890 if (page->cp_owner != NULL) {
891 LASSERT(page->cp_owner->ci_owned_nr > 0);
892 page->cp_owner->ci_owned_nr--;
893 page->cp_owner = NULL;
894 page->cp_task = NULL;
900 static void cl_page_owner_set(struct cl_page *page)
903 for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
904 LASSERT(page->cp_owner != NULL);
905 page->cp_owner->ci_owned_nr++;
910 void cl_page_disown0(const struct lu_env *env,
911 struct cl_io *io, struct cl_page *pg)
913 enum cl_page_state state;
916 state = pg->cp_state;
917 PINVRNT(env, pg, state == CPS_OWNED || state == CPS_FREEING);
918 PINVRNT(env, pg, cl_page_invariant(pg));
919 cl_page_owner_clear(pg);
921 if (state == CPS_OWNED)
922 cl_page_state_set(env, pg, CPS_CACHED);
924 * Completion call-backs are executed in the bottom-up order, so that
925 * uppermost layer (llite), responsible for VFS/VM interaction runs
926 * last and can release locks safely.
928 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_disown),
929 (const struct lu_env *,
930 const struct cl_page_slice *, struct cl_io *),
936 * returns true, iff page is owned by the given io.
938 int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io)
940 LINVRNT(cl_object_same(pg->cp_obj, io->ci_obj));
942 RETURN(pg->cp_state == CPS_OWNED && pg->cp_owner == io);
944 EXPORT_SYMBOL(cl_page_is_owned);
947 * Try to own a page by IO.
949 * Waits until page is in cl_page_state::CPS_CACHED state, and then switch it
950 * into cl_page_state::CPS_OWNED state.
952 * \pre !cl_page_is_owned(pg, io)
953 * \post result == 0 iff cl_page_is_owned(pg, io)
957 * \retval -ve failure, e.g., page was destroyed (and landed in
958 * cl_page_state::CPS_FREEING instead of cl_page_state::CPS_CACHED).
959 * or, page was owned by another thread, or in IO.
961 * \see cl_page_disown()
962 * \see cl_page_operations::cpo_own()
963 * \see cl_page_own_try()
966 static int cl_page_own0(const struct lu_env *env, struct cl_io *io,
967 struct cl_page *pg, int nonblock)
971 PINVRNT(env, pg, !cl_page_is_owned(pg, io));
974 pg = cl_page_top(pg);
977 if (pg->cp_state == CPS_FREEING) {
980 result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(cpo_own),
981 (const struct lu_env *,
982 const struct cl_page_slice *,
983 struct cl_io *, int),
986 PASSERT(env, pg, pg->cp_owner == NULL);
987 PASSERT(env, pg, pg->cp_req == NULL);
989 pg->cp_task = current;
990 cl_page_owner_set(pg);
991 if (pg->cp_state != CPS_FREEING) {
992 cl_page_state_set(env, pg, CPS_OWNED);
994 cl_page_disown0(env, io, pg);
999 PINVRNT(env, pg, ergo(result == 0, cl_page_invariant(pg)));
1004 * Own a page, might be blocked.
1006 * \see cl_page_own0()
1008 int cl_page_own(const struct lu_env *env, struct cl_io *io, struct cl_page *pg)
1010 return cl_page_own0(env, io, pg, 0);
1012 EXPORT_SYMBOL(cl_page_own);
1015 * Nonblock version of cl_page_own().
1017 * \see cl_page_own0()
1019 int cl_page_own_try(const struct lu_env *env, struct cl_io *io,
1022 return cl_page_own0(env, io, pg, 1);
1024 EXPORT_SYMBOL(cl_page_own_try);
1028 * Assume page ownership.
1030 * Called when page is already locked by the hosting VM.
1032 * \pre !cl_page_is_owned(pg, io)
1033 * \post cl_page_is_owned(pg, io)
1035 * \see cl_page_operations::cpo_assume()
1037 void cl_page_assume(const struct lu_env *env,
1038 struct cl_io *io, struct cl_page *pg)
1040 PASSERT(env, pg, pg->cp_state < CPS_OWNED);
1041 PASSERT(env, pg, pg->cp_owner == NULL);
1042 PINVRNT(env, pg, cl_object_same(pg->cp_obj, io->ci_obj));
1043 PINVRNT(env, pg, cl_page_invariant(pg));
1046 pg = cl_page_top(pg);
1049 cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_assume));
1051 pg->cp_task = current;
1052 cl_page_owner_set(pg);
1053 cl_page_state_set(env, pg, CPS_OWNED);
1056 EXPORT_SYMBOL(cl_page_assume);
1059 * Releases page ownership without unlocking the page.
1061 * Moves page into cl_page_state::CPS_CACHED without releasing a lock on the
1062 * underlying VM page (as VM is supposed to do this itself).
1064 * \pre cl_page_is_owned(pg, io)
1065 * \post !cl_page_is_owned(pg, io)
1067 * \see cl_page_assume()
1069 void cl_page_unassume(const struct lu_env *env,
1070 struct cl_io *io, struct cl_page *pg)
1072 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1073 PINVRNT(env, pg, cl_page_invariant(pg));
1076 pg = cl_page_top(pg);
1078 cl_page_owner_clear(pg);
1079 cl_page_state_set(env, pg, CPS_CACHED);
1080 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_unassume),
1081 (const struct lu_env *,
1082 const struct cl_page_slice *, struct cl_io *),
1086 EXPORT_SYMBOL(cl_page_unassume);
1089 * Releases page ownership.
1091 * Moves page into cl_page_state::CPS_CACHED.
1093 * \pre cl_page_is_owned(pg, io)
1094 * \post !cl_page_is_owned(pg, io)
1096 * \see cl_page_own()
1097 * \see cl_page_operations::cpo_disown()
1099 void cl_page_disown(const struct lu_env *env,
1100 struct cl_io *io, struct cl_page *pg)
1102 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1105 pg = cl_page_top(pg);
1107 cl_page_disown0(env, io, pg);
1110 EXPORT_SYMBOL(cl_page_disown);
1113 * Called when page is to be removed from the object, e.g., as a result of
1116 * Calls cl_page_operations::cpo_discard() top-to-bottom.
1118 * \pre cl_page_is_owned(pg, io)
1120 * \see cl_page_operations::cpo_discard()
1122 void cl_page_discard(const struct lu_env *env,
1123 struct cl_io *io, struct cl_page *pg)
1125 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1126 PINVRNT(env, pg, cl_page_invariant(pg));
1128 cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_discard));
1130 EXPORT_SYMBOL(cl_page_discard);
1133 * Version of cl_page_delete() that can be called for not fully constructed
1134 * pages, e.g,. in a error handling cl_page_find()->cl_page_delete0()
1135 * path. Doesn't check page invariant.
1137 static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg,
1140 struct cl_page *tmp = pg;
1143 PASSERT(env, pg, pg == cl_page_top(pg));
1144 PASSERT(env, pg, pg->cp_state != CPS_FREEING);
1147 * Severe all ways to obtain new pointers to @pg.
1149 cl_page_owner_clear(pg);
1152 * unexport the page firstly before freeing it so that
1153 * the page content is considered to be invalid.
1154 * We have to do this because a CPS_FREEING cl_page may
1155 * be NOT under the protection of a cl_lock.
1156 * Afterwards, if this page is found by other threads, then this
1157 * page will be forced to reread.
1159 cl_page_export(env, pg, 0);
1160 cl_page_state_set0(env, pg, CPS_FREEING);
1164 * !radix means that @pg is not yet in the radix tree, skip
1168 for (; tmp != NULL; tmp = tmp->cp_child) {
1170 struct cl_object_header *hdr;
1172 hdr = cl_object_header(tmp->cp_obj);
1173 cfs_spin_lock(&hdr->coh_page_guard);
1174 value = radix_tree_delete(&hdr->coh_tree, tmp->cp_index);
1175 PASSERT(env, tmp, value == tmp);
1176 PASSERT(env, tmp, hdr->coh_pages > 0);
1178 cfs_spin_unlock(&hdr->coh_page_guard);
1181 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_delete),
1182 (const struct lu_env *, const struct cl_page_slice *));
1187 * Called when a decision is made to throw page out of memory.
1189 * Notifies all layers about page destruction by calling
1190 * cl_page_operations::cpo_delete() method top-to-bottom.
1192 * Moves page into cl_page_state::CPS_FREEING state (this is the only place
1193 * where transition to this state happens).
1195 * Eliminates all venues through which new references to the page can be
1198 * - removes page from the radix trees,
1200 * - breaks linkage from VM page to cl_page.
1202 * Once page reaches cl_page_state::CPS_FREEING, all remaining references will
1203 * drain after some time, at which point page will be recycled.
1205 * \pre pg == cl_page_top(pg)
1206 * \pre VM page is locked
1207 * \post pg->cp_state == CPS_FREEING
1209 * \see cl_page_operations::cpo_delete()
1211 void cl_page_delete(const struct lu_env *env, struct cl_page *pg)
1213 PINVRNT(env, pg, cl_page_invariant(pg));
1215 cl_page_delete0(env, pg, 1);
1218 EXPORT_SYMBOL(cl_page_delete);
1221 * Unmaps page from user virtual memory.
1223 * Calls cl_page_operations::cpo_unmap() through all layers top-to-bottom. The
1224 * layer responsible for VM interaction has to unmap page from user space
1227 * \see cl_page_operations::cpo_unmap()
1229 int cl_page_unmap(const struct lu_env *env,
1230 struct cl_io *io, struct cl_page *pg)
1232 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1233 PINVRNT(env, pg, cl_page_invariant(pg));
1235 return cl_page_invoke(env, io, pg, CL_PAGE_OP(cpo_unmap));
1237 EXPORT_SYMBOL(cl_page_unmap);
1240 * Marks page up-to-date.
1242 * Call cl_page_operations::cpo_export() through all layers top-to-bottom. The
1243 * layer responsible for VM interaction has to mark/clear page as up-to-date
1244 * by the \a uptodate argument.
1246 * \see cl_page_operations::cpo_export()
1248 void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate)
1250 PINVRNT(env, pg, cl_page_invariant(pg));
1251 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_export),
1252 (const struct lu_env *,
1253 const struct cl_page_slice *, int), uptodate);
1255 EXPORT_SYMBOL(cl_page_export);
1258 * Returns true, iff \a pg is VM locked in a suitable sense by the calling
1261 int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg)
1264 const struct cl_page_slice *slice;
1267 pg = cl_page_top_trusted((struct cl_page *)pg);
1268 slice = container_of(pg->cp_layers.next,
1269 const struct cl_page_slice, cpl_linkage);
1270 PASSERT(env, pg, slice->cpl_ops->cpo_is_vmlocked != NULL);
1272 * Call ->cpo_is_vmlocked() directly instead of going through
1273 * CL_PAGE_INVOKE(), because cl_page_is_vmlocked() is used by
1274 * cl_page_invariant().
1276 result = slice->cpl_ops->cpo_is_vmlocked(env, slice);
1277 PASSERT(env, pg, result == -EBUSY || result == -ENODATA);
1278 RETURN(result == -EBUSY);
1280 EXPORT_SYMBOL(cl_page_is_vmlocked);
1282 static enum cl_page_state cl_req_type_state(enum cl_req_type crt)
1285 RETURN(crt == CRT_WRITE ? CPS_PAGEOUT : CPS_PAGEIN);
1288 static void cl_page_io_start(const struct lu_env *env,
1289 struct cl_page *pg, enum cl_req_type crt)
1292 * Page is queued for IO, change its state.
1295 cl_page_owner_clear(pg);
1296 cl_page_state_set(env, pg, cl_req_type_state(crt));
1301 * Prepares page for immediate transfer. cl_page_operations::cpo_prep() is
1302 * called top-to-bottom. Every layer either agrees to submit this page (by
1303 * returning 0), or requests to omit this page (by returning -EALREADY). Layer
1304 * handling interactions with the VM also has to inform VM that page is under
1307 int cl_page_prep(const struct lu_env *env, struct cl_io *io,
1308 struct cl_page *pg, enum cl_req_type crt)
1312 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1313 PINVRNT(env, pg, cl_page_invariant(pg));
1314 PINVRNT(env, pg, crt < CRT_NR);
1317 * XXX this has to be called bottom-to-top, so that llite can set up
1318 * PG_writeback without risking other layers deciding to skip this
1321 result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_prep));
1323 cl_page_io_start(env, pg, crt);
1325 KLASSERT(ergo(crt == CRT_WRITE && pg->cp_type == CPT_CACHEABLE,
1327 PageWriteback(cl_page_vmpage(env, pg)))));
1328 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
1331 EXPORT_SYMBOL(cl_page_prep);
1334 * Notify layers about transfer completion.
1336 * Invoked by transfer sub-system (which is a part of osc) to notify layers
1337 * that a transfer, of which this page is a part of has completed.
1339 * Completion call-backs are executed in the bottom-up order, so that
1340 * uppermost layer (llite), responsible for the VFS/VM interaction runs last
1341 * and can release locks safely.
1343 * \pre pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
1344 * \post pg->cp_state == CPS_CACHED
1346 * \see cl_page_operations::cpo_completion()
1348 void cl_page_completion(const struct lu_env *env,
1349 struct cl_page *pg, enum cl_req_type crt, int ioret)
1351 struct cl_sync_io *anchor = pg->cp_sync_io;
1353 PASSERT(env, pg, crt < CRT_NR);
1354 /* cl_page::cp_req already cleared by the caller (osc_completion()) */
1355 PASSERT(env, pg, pg->cp_req == NULL);
1356 PASSERT(env, pg, pg->cp_state == cl_req_type_state(crt));
1357 PINVRNT(env, pg, cl_page_invariant(pg));
1360 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, ioret);
1361 if (crt == CRT_READ && ioret == 0) {
1362 PASSERT(env, pg, !(pg->cp_flags & CPF_READ_COMPLETED));
1363 pg->cp_flags |= CPF_READ_COMPLETED;
1366 cl_page_state_set(env, pg, CPS_CACHED);
1367 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(io[crt].cpo_completion),
1368 (const struct lu_env *,
1369 const struct cl_page_slice *, int), ioret);
1371 LASSERT(pg->cp_sync_io == anchor);
1372 pg->cp_sync_io = NULL;
1373 cl_sync_io_note(anchor, ioret);
1376 /* Don't assert the page writeback bit here because the lustre file
1377 * may be as a backend of swap space. in this case, the page writeback
1378 * is set by VM, and obvious we shouldn't clear it at all. Fortunately
1379 * this type of pages are all TRANSIENT pages. */
1380 KLASSERT(ergo(pg->cp_type == CPT_CACHEABLE,
1381 !PageWriteback(cl_page_vmpage(env, pg))));
1384 EXPORT_SYMBOL(cl_page_completion);
1387 * Notify layers that transfer formation engine decided to yank this page from
1388 * the cache and to make it a part of a transfer.
1390 * \pre pg->cp_state == CPS_CACHED
1391 * \post pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
1393 * \see cl_page_operations::cpo_make_ready()
1395 int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg,
1396 enum cl_req_type crt)
1400 PINVRNT(env, pg, crt < CRT_NR);
1403 result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(io[crt].cpo_make_ready),
1404 (const struct lu_env *,
1405 const struct cl_page_slice *));
1407 PASSERT(env, pg, pg->cp_state == CPS_CACHED);
1408 cl_page_io_start(env, pg, crt);
1410 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
1413 EXPORT_SYMBOL(cl_page_make_ready);
1416 * Notify layers that high level io decided to place this page into a cache
1417 * for future transfer.
1419 * The layer implementing transfer engine (osc) has to register this page in
1422 * \pre cl_page_is_owned(pg, io)
1423 * \post ergo(result == 0,
1424 * pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT)
1426 * \see cl_page_operations::cpo_cache_add()
1428 int cl_page_cache_add(const struct lu_env *env, struct cl_io *io,
1429 struct cl_page *pg, enum cl_req_type crt)
1433 PINVRNT(env, pg, crt < CRT_NR);
1434 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1435 PINVRNT(env, pg, cl_page_invariant(pg));
1438 result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_cache_add));
1440 cl_page_owner_clear(pg);
1441 cl_page_state_set(env, pg, CPS_CACHED);
1443 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
1446 EXPORT_SYMBOL(cl_page_cache_add);
1449 * Checks whether page is protected by any extent lock is at least required
1452 * \return the same as in cl_page_operations::cpo_is_under_lock() method.
1453 * \see cl_page_operations::cpo_is_under_lock()
1455 int cl_page_is_under_lock(const struct lu_env *env, struct cl_io *io,
1456 struct cl_page *page)
1460 PINVRNT(env, page, cl_page_invariant(page));
1463 rc = CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_is_under_lock),
1464 (const struct lu_env *,
1465 const struct cl_page_slice *, struct cl_io *),
1467 PASSERT(env, page, rc != 0);
1470 EXPORT_SYMBOL(cl_page_is_under_lock);
1473 * Purges all cached pages belonging to the object \a obj.
1475 int cl_pages_prune(const struct lu_env *env, struct cl_object *clobj)
1477 struct cl_thread_info *info;
1478 struct cl_object *obj = cl_object_top(clobj);
1480 struct cl_page_list *plist;
1485 info = cl_env_info(env);
1486 plist = &info->clt_list;
1490 * initialize the io. This is ugly since we never do IO in this
1491 * function, we just make cl_page_list functions happy. -jay
1494 result = cl_io_init(env, io, CIT_MISC, obj);
1496 cl_io_fini(env, io);
1497 RETURN(io->ci_result);
1501 cl_page_list_init(plist);
1502 cl_page_gang_lookup(env, obj, io, 0, CL_PAGE_EOF, plist, 0,
1505 * Since we're purging the pages of an object, we don't care
1506 * the possible outcomes of the following functions.
1508 cl_page_list_unmap(env, io, plist);
1509 cl_page_list_discard(env, io, plist);
1510 cl_page_list_disown(env, io, plist);
1511 cl_page_list_fini(env, plist);
1517 cl_io_fini(env, io);
1520 EXPORT_SYMBOL(cl_pages_prune);
1523 * Tells transfer engine that only part of a page is to be transmitted.
1525 * \see cl_page_operations::cpo_clip()
1527 void cl_page_clip(const struct lu_env *env, struct cl_page *pg,
1530 PINVRNT(env, pg, cl_page_invariant(pg));
1532 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", from, to);
1533 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_clip),
1534 (const struct lu_env *,
1535 const struct cl_page_slice *,int, int),
1538 EXPORT_SYMBOL(cl_page_clip);
1541 * Prints human readable representation of \a pg to the \a f.
1543 void cl_page_header_print(const struct lu_env *env, void *cookie,
1544 lu_printer_t printer, const struct cl_page *pg)
1546 (*printer)(env, cookie,
1547 "page@%p[%d %p:%lu ^%p_%p %d %d %d %p %p %#x]\n",
1548 pg, cfs_atomic_read(&pg->cp_ref), pg->cp_obj,
1549 pg->cp_index, pg->cp_parent, pg->cp_child,
1550 pg->cp_state, pg->cp_error, pg->cp_type,
1551 pg->cp_owner, pg->cp_req, pg->cp_flags);
1553 EXPORT_SYMBOL(cl_page_header_print);
1556 * Prints human readable representation of \a pg to the \a f.
1558 void cl_page_print(const struct lu_env *env, void *cookie,
1559 lu_printer_t printer, const struct cl_page *pg)
1561 struct cl_page *scan;
1563 for (scan = cl_page_top((struct cl_page *)pg);
1564 scan != NULL; scan = scan->cp_child)
1565 cl_page_header_print(env, cookie, printer, scan);
1566 CL_PAGE_INVOKE(env, (struct cl_page *)pg, CL_PAGE_OP(cpo_print),
1567 (const struct lu_env *env,
1568 const struct cl_page_slice *slice,
1569 void *cookie, lu_printer_t p), cookie, printer);
1570 (*printer)(env, cookie, "end page@%p\n", pg);
1572 EXPORT_SYMBOL(cl_page_print);
1575 * Cancel a page which is still in a transfer.
1577 int cl_page_cancel(const struct lu_env *env, struct cl_page *page)
1579 return CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_cancel),
1580 (const struct lu_env *,
1581 const struct cl_page_slice *));
1583 EXPORT_SYMBOL(cl_page_cancel);
1586 * Converts a byte offset within object \a obj into a page index.
1588 loff_t cl_offset(const struct cl_object *obj, pgoff_t idx)
1593 return (loff_t)idx << CFS_PAGE_SHIFT;
1595 EXPORT_SYMBOL(cl_offset);
1598 * Converts a page index into a byte offset within object \a obj.
1600 pgoff_t cl_index(const struct cl_object *obj, loff_t offset)
1605 return offset >> CFS_PAGE_SHIFT;
1607 EXPORT_SYMBOL(cl_index);
1609 int cl_page_size(const struct cl_object *obj)
1611 return 1 << CFS_PAGE_SHIFT;
1613 EXPORT_SYMBOL(cl_page_size);
1616 * Adds page slice to the compound page.
1618 * This is called by cl_object_operations::coo_page_init() methods to add a
1619 * per-layer state to the page. New state is added at the end of
1620 * cl_page::cp_layers list, that is, it is at the bottom of the stack.
1622 * \see cl_lock_slice_add(), cl_req_slice_add(), cl_io_slice_add()
1624 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
1625 struct cl_object *obj,
1626 const struct cl_page_operations *ops)
1629 cfs_list_add_tail(&slice->cpl_linkage, &page->cp_layers);
1630 slice->cpl_obj = obj;
1631 slice->cpl_ops = ops;
1632 slice->cpl_page = page;
1635 EXPORT_SYMBOL(cl_page_slice_add);
1637 int cl_page_init(void)
1639 return lu_kmem_init(cl_page_caches);
1642 void cl_page_fini(void)
1644 lu_kmem_fini(cl_page_caches);