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 * Return at least one page in @queue unless there is no covered page.
190 int cl_page_gang_lookup(const struct lu_env *env, struct cl_object *obj,
191 struct cl_io *io, pgoff_t start, pgoff_t end,
192 struct cl_page_list *queue)
194 struct cl_object_header *hdr;
195 struct cl_page *page;
196 struct cl_page **pvec;
197 const struct cl_page_slice *slice;
198 const struct lu_device_type *dtype;
203 int res = CLP_GANG_OKAY;
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 cfs_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 int end_of_region = 0;
215 idx = pvec[nr - 1]->cp_index + 1;
216 for (i = 0, j = 0; i < nr; ++i) {
220 LASSERT(page->cp_type == CPT_CACHEABLE);
221 if (page->cp_index > end) {
225 if (page->cp_state == CPS_FREEING)
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 cfs_spin_unlock(&hdr->coh_page_guard);
260 for (i = 0; i < j; ++i) {
262 if (res == CLP_GANG_OKAY) {
263 typeof(cl_page_own) *page_own;
265 page_own = queue->pl_nr ?
266 cl_page_own_try : cl_page_own;
267 if (page_own(env, io, page) == 0) {
268 cl_page_list_add(queue, page);
269 } else if (page->cp_state != CPS_FREEING) {
270 /* cl_page_own() won't fail unless
271 * the page is being freed. */
272 LASSERT(queue->pl_nr != 0);
273 res = CLP_GANG_AGAIN;
276 lu_ref_del(&page->cp_reference,
277 "page_list", cfs_current());
278 cl_page_put(env, page);
280 if (nr < CLT_PVEC_SIZE || end_of_region)
283 /* if the number of pages is zero, this will mislead the caller
284 * that there is no page any more. */
285 if (queue->pl_nr && cfs_need_resched())
286 res = CLP_GANG_RESCHED;
287 if (res != CLP_GANG_OKAY)
290 cfs_spin_lock(&hdr->coh_page_guard);
294 cfs_spin_unlock(&hdr->coh_page_guard);
297 EXPORT_SYMBOL(cl_page_gang_lookup);
299 static void cl_page_free(const struct lu_env *env, struct cl_page *page)
301 struct cl_object *obj = page->cp_obj;
302 struct cl_site *site = cl_object_site(obj);
304 PASSERT(env, page, cfs_list_empty(&page->cp_batch));
305 PASSERT(env, page, page->cp_owner == NULL);
306 PASSERT(env, page, page->cp_req == NULL);
307 PASSERT(env, page, page->cp_parent == NULL);
308 PASSERT(env, page, page->cp_state == CPS_FREEING);
312 while (!cfs_list_empty(&page->cp_layers)) {
313 struct cl_page_slice *slice;
315 slice = cfs_list_entry(page->cp_layers.next,
316 struct cl_page_slice, cpl_linkage);
317 cfs_list_del_init(page->cp_layers.next);
318 slice->cpl_ops->cpo_fini(env, slice);
320 cfs_atomic_dec(&site->cs_pages.cs_total);
322 #ifdef LUSTRE_PAGESTATE_TRACKING
323 cfs_atomic_dec(&site->cs_pages_state[page->cp_state]);
325 lu_object_ref_del_at(&obj->co_lu, page->cp_obj_ref, "cl_page", page);
326 cl_object_put(env, obj);
327 lu_ref_fini(&page->cp_reference);
328 OBD_SLAB_FREE_PTR(page, cl_page_kmem);
333 * Helper function updating page state. This is the only place in the code
334 * where cl_page::cp_state field is mutated.
336 static inline void cl_page_state_set_trust(struct cl_page *page,
337 enum cl_page_state state)
340 *(enum cl_page_state *)&page->cp_state = state;
343 static int cl_page_alloc(const struct lu_env *env, struct cl_object *o,
344 pgoff_t ind, struct page *vmpage,
345 enum cl_page_type type, struct cl_page **out)
347 struct cl_page *page;
348 struct cl_page *err = NULL;
349 struct lu_object_header *head;
350 struct cl_site *site = cl_object_site(o);
355 OBD_SLAB_ALLOC_PTR_GFP(page, cl_page_kmem, CFS_ALLOC_IO);
357 cfs_atomic_set(&page->cp_ref, 1);
360 page->cp_obj_ref = lu_object_ref_add(&o->co_lu,
362 page->cp_index = ind;
363 cl_page_state_set_trust(page, CPS_CACHED);
364 page->cp_type = type;
365 CFS_INIT_LIST_HEAD(&page->cp_layers);
366 CFS_INIT_LIST_HEAD(&page->cp_batch);
367 CFS_INIT_LIST_HEAD(&page->cp_flight);
368 cfs_mutex_init(&page->cp_mutex);
369 lu_ref_init(&page->cp_reference);
370 head = o->co_lu.lo_header;
371 cfs_list_for_each_entry(o, &head->loh_layers,
373 if (o->co_ops->coo_page_init != NULL) {
374 err = o->co_ops->coo_page_init(env, o,
377 cl_page_delete0(env, page, 0);
378 cl_page_free(env, page);
385 cfs_atomic_inc(&site->cs_pages.cs_busy);
386 cfs_atomic_inc(&site->cs_pages.cs_total);
388 #ifdef LUSTRE_PAGESTATE_TRACKING
389 cfs_atomic_inc(&site->cs_pages_state[CPS_CACHED]);
391 cfs_atomic_inc(&site->cs_pages.cs_created);
395 page = ERR_PTR(-ENOMEM);
401 * Returns a cl_page with index \a idx at the object \a o, and associated with
402 * the VM page \a vmpage.
404 * This is the main entry point into the cl_page caching interface. First, a
405 * cache (implemented as a per-object radix tree) is consulted. If page is
406 * found there, it is returned immediately. Otherwise new page is allocated
407 * and returned. In any case, additional reference to page is acquired.
409 * \see cl_object_find(), cl_lock_find()
411 static struct cl_page *cl_page_find0(const struct lu_env *env,
413 pgoff_t idx, struct page *vmpage,
414 enum cl_page_type type,
415 struct cl_page *parent)
417 struct cl_page *page = NULL;
418 struct cl_page *ghost = NULL;
419 struct cl_object_header *hdr;
420 struct cl_site *site = cl_object_site(o);
423 LINVRNT(type == CPT_CACHEABLE || type == CPT_TRANSIENT);
428 hdr = cl_object_header(o);
429 cfs_atomic_inc(&site->cs_pages.cs_lookup);
431 CDEBUG(D_PAGE, "%lu@"DFID" %p %lx %d\n",
432 idx, PFID(&hdr->coh_lu.loh_fid), vmpage, vmpage->private, type);
434 if (type == CPT_CACHEABLE) {
436 * cl_vmpage_page() can be called here without any locks as
438 * - "vmpage" is locked (which prevents ->private from
439 * concurrent updates), and
441 * - "o" cannot be destroyed while current thread holds a
444 page = cl_vmpage_page(vmpage, o);
447 cl_page_vmpage(env, page) == vmpage &&
448 (void *)radix_tree_lookup(&hdr->coh_tree,
453 cfs_atomic_inc(&site->cs_pages.cs_hit);
457 /* allocate and initialize cl_page */
458 err = cl_page_alloc(env, o, idx, vmpage, type, &page);
462 if (type == CPT_TRANSIENT) {
464 LASSERT(page->cp_parent == NULL);
465 page->cp_parent = parent;
466 parent->cp_child = page;
472 * XXX optimization: use radix_tree_preload() here, and change tree
473 * gfp mask to GFP_KERNEL in cl_object_header_init().
475 cfs_spin_lock(&hdr->coh_page_guard);
476 err = radix_tree_insert(&hdr->coh_tree, idx, page);
480 * Noted by Jay: a lock on \a vmpage protects cl_page_find()
481 * from this race, but
483 * 0. it's better to have cl_page interface "locally
484 * consistent" so that its correctness can be reasoned
485 * about without appealing to the (obscure world of) VM
488 * 1. handling this race allows ->coh_tree to remain
489 * consistent even when VM locking is somehow busted,
490 * which is very useful during diagnosing and debugging.
493 CL_PAGE_DEBUG(D_ERROR, env, ghost,
494 "fail to insert into radix tree: %d\n", err);
497 LASSERT(page->cp_parent == NULL);
498 page->cp_parent = parent;
499 parent->cp_child = page;
503 cfs_spin_unlock(&hdr->coh_page_guard);
505 if (unlikely(ghost != NULL)) {
506 cfs_atomic_dec(&site->cs_pages.cs_busy);
507 cl_page_delete0(env, ghost, 0);
508 cl_page_free(env, ghost);
513 struct cl_page *cl_page_find(const struct lu_env *env, struct cl_object *o,
514 pgoff_t idx, struct page *vmpage,
515 enum cl_page_type type)
517 return cl_page_find0(env, o, idx, vmpage, type, NULL);
519 EXPORT_SYMBOL(cl_page_find);
522 struct cl_page *cl_page_find_sub(const struct lu_env *env, struct cl_object *o,
523 pgoff_t idx, struct page *vmpage,
524 struct cl_page *parent)
526 return cl_page_find0(env, o, idx, vmpage, parent->cp_type, parent);
528 EXPORT_SYMBOL(cl_page_find_sub);
530 static inline int cl_page_invariant(const struct cl_page *pg)
532 struct cl_object_header *header;
533 struct cl_page *parent;
534 struct cl_page *child;
538 * Page invariant is protected by a VM lock.
540 LINVRNT(cl_page_is_vmlocked(NULL, pg));
542 header = cl_object_header(pg->cp_obj);
543 parent = pg->cp_parent;
544 child = pg->cp_child;
545 owner = pg->cp_owner;
547 return cfs_atomic_read(&pg->cp_ref) > 0 &&
548 ergo(parent != NULL, parent->cp_child == pg) &&
549 ergo(child != NULL, child->cp_parent == pg) &&
550 ergo(child != NULL, pg->cp_obj != child->cp_obj) &&
551 ergo(parent != NULL, pg->cp_obj != parent->cp_obj) &&
552 ergo(owner != NULL && parent != NULL,
553 parent->cp_owner == pg->cp_owner->ci_parent) &&
554 ergo(owner != NULL && child != NULL,
555 child->cp_owner->ci_parent == owner) &&
557 * Either page is early in initialization (has neither child
558 * nor parent yet), or it is in the object radix tree.
560 ergo(pg->cp_state < CPS_FREEING,
561 (void *)radix_tree_lookup(&header->coh_tree,
562 pg->cp_index) == pg ||
563 (child == NULL && parent == NULL));
566 static void cl_page_state_set0(const struct lu_env *env,
567 struct cl_page *page, enum cl_page_state state)
569 enum cl_page_state old;
570 #ifdef LUSTRE_PAGESTATE_TRACKING
571 struct cl_site *site = cl_object_site(page->cp_obj);
575 * Matrix of allowed state transitions [old][new], for sanity
578 static const int allowed_transitions[CPS_NR][CPS_NR] = {
581 [CPS_OWNED] = 1, /* io finds existing cached page */
583 [CPS_PAGEOUT] = 1, /* write-out from the cache */
584 [CPS_FREEING] = 1, /* eviction on the memory pressure */
587 [CPS_CACHED] = 1, /* release to the cache */
589 [CPS_PAGEIN] = 1, /* start read immediately */
590 [CPS_PAGEOUT] = 1, /* start write immediately */
591 [CPS_FREEING] = 1, /* lock invalidation or truncate */
594 [CPS_CACHED] = 1, /* io completion */
601 [CPS_CACHED] = 1, /* io completion */
617 old = page->cp_state;
618 PASSERT(env, page, allowed_transitions[old][state]);
619 CL_PAGE_HEADER(D_TRACE, env, page, "%d -> %d\n", old, state);
620 for (; page != NULL; page = page->cp_child) {
621 PASSERT(env, page, page->cp_state == old);
623 equi(state == CPS_OWNED, page->cp_owner != NULL));
625 #ifdef LUSTRE_PAGESTATE_TRACKING
626 cfs_atomic_dec(&site->cs_pages_state[page->cp_state]);
627 cfs_atomic_inc(&site->cs_pages_state[state]);
629 cl_page_state_set_trust(page, state);
634 static void cl_page_state_set(const struct lu_env *env,
635 struct cl_page *page, enum cl_page_state state)
637 PINVRNT(env, page, cl_page_invariant(page));
638 cl_page_state_set0(env, page, state);
642 * Acquires an additional reference to a page.
644 * This can be called only by caller already possessing a reference to \a
647 * \see cl_object_get(), cl_lock_get().
649 void cl_page_get(struct cl_page *page)
652 LASSERT(page->cp_state != CPS_FREEING);
653 cl_page_get_trust(page);
656 EXPORT_SYMBOL(cl_page_get);
659 * Releases a reference to a page.
661 * When last reference is released, page is returned to the cache, unless it
662 * is in cl_page_state::CPS_FREEING state, in which case it is immediately
665 * \see cl_object_put(), cl_lock_put().
667 void cl_page_put(const struct lu_env *env, struct cl_page *page)
669 struct cl_object_header *hdr;
670 struct cl_site *site = cl_object_site(page->cp_obj);
672 PASSERT(env, page, cfs_atomic_read(&page->cp_ref) > !!page->cp_parent);
675 CL_PAGE_HEADER(D_TRACE, env, page, "%d\n",
676 cfs_atomic_read(&page->cp_ref));
678 hdr = cl_object_header(cl_object_top(page->cp_obj));
679 if (cfs_atomic_dec_and_lock(&page->cp_ref, &hdr->coh_page_guard)) {
680 cfs_atomic_dec(&site->cs_pages.cs_busy);
681 /* We're going to access the page w/o a reference, but it's
682 * ok because we have grabbed the lock coh_page_guard, which
683 * means nobody is able to free this page behind us.
685 if (page->cp_state == CPS_FREEING) {
686 /* We drop the page reference and check the page state
687 * inside the coh_page_guard. So that if it gets here,
688 * it is the REALLY last reference to this page.
690 cfs_spin_unlock(&hdr->coh_page_guard);
692 LASSERT(cfs_atomic_read(&page->cp_ref) == 0);
693 PASSERT(env, page, page->cp_owner == NULL);
694 PASSERT(env, page, cfs_list_empty(&page->cp_batch));
696 * Page is no longer reachable by other threads. Tear
699 cl_page_free(env, page);
704 cfs_spin_unlock(&hdr->coh_page_guard);
709 EXPORT_SYMBOL(cl_page_put);
712 * Returns a VM page associated with a given cl_page.
714 cfs_page_t *cl_page_vmpage(const struct lu_env *env, struct cl_page *page)
716 const struct cl_page_slice *slice;
719 * Find uppermost layer with ->cpo_vmpage() method, and return its
722 page = cl_page_top(page);
724 cfs_list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
725 if (slice->cpl_ops->cpo_vmpage != NULL)
726 RETURN(slice->cpl_ops->cpo_vmpage(env, slice));
728 page = page->cp_child;
729 } while (page != NULL);
730 LBUG(); /* ->cpo_vmpage() has to be defined somewhere in the stack */
732 EXPORT_SYMBOL(cl_page_vmpage);
735 * Returns a cl_page associated with a VM page, and given cl_object.
737 struct cl_page *cl_vmpage_page(cfs_page_t *vmpage, struct cl_object *obj)
739 struct cl_page *page;
740 struct cl_object_header *hdr;
743 KLASSERT(PageLocked(vmpage));
746 * NOTE: absence of races and liveness of data are guaranteed by page
747 * lock on a "vmpage". That works because object destruction has
748 * bottom-to-top pass.
752 * This loop assumes that ->private points to the top-most page. This
753 * can be rectified easily.
755 hdr = cl_object_header(cl_object_top(obj));
756 cfs_spin_lock(&hdr->coh_page_guard);
757 for (page = (void *)vmpage->private;
758 page != NULL; page = page->cp_child) {
759 if (cl_object_same(page->cp_obj, obj)) {
760 cl_page_get_trust(page);
764 cfs_spin_unlock(&hdr->coh_page_guard);
765 LASSERT(ergo(page, page->cp_type == CPT_CACHEABLE));
768 EXPORT_SYMBOL(cl_vmpage_page);
771 * Returns the top-page for a given page.
773 * \see cl_object_top(), cl_io_top()
775 struct cl_page *cl_page_top(struct cl_page *page)
777 return cl_page_top_trusted(page);
779 EXPORT_SYMBOL(cl_page_top);
781 const struct cl_page_slice *cl_page_at(const struct cl_page *page,
782 const struct lu_device_type *dtype)
784 return cl_page_at_trusted(page, dtype);
786 EXPORT_SYMBOL(cl_page_at);
788 #define CL_PAGE_OP(opname) offsetof(struct cl_page_operations, opname)
790 #define CL_PAGE_INVOKE(_env, _page, _op, _proto, ...) \
792 const struct lu_env *__env = (_env); \
793 struct cl_page *__page = (_page); \
794 const struct cl_page_slice *__scan; \
796 ptrdiff_t __op = (_op); \
797 int (*__method)_proto; \
800 __page = cl_page_top(__page); \
802 cfs_list_for_each_entry(__scan, &__page->cp_layers, \
804 __method = *(void **)((char *)__scan->cpl_ops + \
806 if (__method != NULL) { \
807 __result = (*__method)(__env, __scan, \
813 __page = __page->cp_child; \
814 } while (__page != NULL && __result == 0); \
820 #define CL_PAGE_INVOID(_env, _page, _op, _proto, ...) \
822 const struct lu_env *__env = (_env); \
823 struct cl_page *__page = (_page); \
824 const struct cl_page_slice *__scan; \
825 ptrdiff_t __op = (_op); \
826 void (*__method)_proto; \
828 __page = cl_page_top(__page); \
830 cfs_list_for_each_entry(__scan, &__page->cp_layers, \
832 __method = *(void **)((char *)__scan->cpl_ops + \
834 if (__method != NULL) \
835 (*__method)(__env, __scan, \
838 __page = __page->cp_child; \
839 } while (__page != NULL); \
842 #define CL_PAGE_INVOID_REVERSE(_env, _page, _op, _proto, ...) \
844 const struct lu_env *__env = (_env); \
845 struct cl_page *__page = (_page); \
846 const struct cl_page_slice *__scan; \
847 ptrdiff_t __op = (_op); \
848 void (*__method)_proto; \
850 /* get to the bottom page. */ \
851 while (__page->cp_child != NULL) \
852 __page = __page->cp_child; \
854 cfs_list_for_each_entry_reverse(__scan, &__page->cp_layers, \
856 __method = *(void **)((char *)__scan->cpl_ops + \
858 if (__method != NULL) \
859 (*__method)(__env, __scan, \
862 __page = __page->cp_parent; \
863 } while (__page != NULL); \
866 static int cl_page_invoke(const struct lu_env *env,
867 struct cl_io *io, struct cl_page *page, ptrdiff_t op)
870 PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
872 RETURN(CL_PAGE_INVOKE(env, page, op,
873 (const struct lu_env *,
874 const struct cl_page_slice *, struct cl_io *),
878 static void cl_page_invoid(const struct lu_env *env,
879 struct cl_io *io, struct cl_page *page, ptrdiff_t op)
882 PINVRNT(env, page, cl_object_same(page->cp_obj, io->ci_obj));
884 CL_PAGE_INVOID(env, page, op,
885 (const struct lu_env *,
886 const struct cl_page_slice *, struct cl_io *), io);
890 static void cl_page_owner_clear(struct cl_page *page)
893 for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
894 if (page->cp_owner != NULL) {
895 LASSERT(page->cp_owner->ci_owned_nr > 0);
896 page->cp_owner->ci_owned_nr--;
897 page->cp_owner = NULL;
898 page->cp_task = NULL;
904 static void cl_page_owner_set(struct cl_page *page)
907 for (page = cl_page_top(page); page != NULL; page = page->cp_child) {
908 LASSERT(page->cp_owner != NULL);
909 page->cp_owner->ci_owned_nr++;
914 void cl_page_disown0(const struct lu_env *env,
915 struct cl_io *io, struct cl_page *pg)
917 enum cl_page_state state;
920 state = pg->cp_state;
921 PINVRNT(env, pg, state == CPS_OWNED || state == CPS_FREEING);
922 PINVRNT(env, pg, cl_page_invariant(pg));
923 cl_page_owner_clear(pg);
925 if (state == CPS_OWNED)
926 cl_page_state_set(env, pg, CPS_CACHED);
928 * Completion call-backs are executed in the bottom-up order, so that
929 * uppermost layer (llite), responsible for VFS/VM interaction runs
930 * last and can release locks safely.
932 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_disown),
933 (const struct lu_env *,
934 const struct cl_page_slice *, struct cl_io *),
940 * returns true, iff page is owned by the given io.
942 int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io)
944 LINVRNT(cl_object_same(pg->cp_obj, io->ci_obj));
946 RETURN(pg->cp_state == CPS_OWNED && pg->cp_owner == io);
948 EXPORT_SYMBOL(cl_page_is_owned);
951 * Try to own a page by IO.
953 * Waits until page is in cl_page_state::CPS_CACHED state, and then switch it
954 * into cl_page_state::CPS_OWNED state.
956 * \pre !cl_page_is_owned(pg, io)
957 * \post result == 0 iff cl_page_is_owned(pg, io)
961 * \retval -ve failure, e.g., page was destroyed (and landed in
962 * cl_page_state::CPS_FREEING instead of cl_page_state::CPS_CACHED).
963 * or, page was owned by another thread, or in IO.
965 * \see cl_page_disown()
966 * \see cl_page_operations::cpo_own()
967 * \see cl_page_own_try()
970 static int cl_page_own0(const struct lu_env *env, struct cl_io *io,
971 struct cl_page *pg, int nonblock)
975 PINVRNT(env, pg, !cl_page_is_owned(pg, io));
978 pg = cl_page_top(pg);
981 if (pg->cp_state == CPS_FREEING) {
984 result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(cpo_own),
985 (const struct lu_env *,
986 const struct cl_page_slice *,
987 struct cl_io *, int),
990 PASSERT(env, pg, pg->cp_owner == NULL);
991 PASSERT(env, pg, pg->cp_req == NULL);
993 pg->cp_task = current;
994 cl_page_owner_set(pg);
995 if (pg->cp_state != CPS_FREEING) {
996 cl_page_state_set(env, pg, CPS_OWNED);
998 cl_page_disown0(env, io, pg);
1003 PINVRNT(env, pg, ergo(result == 0, cl_page_invariant(pg)));
1008 * Own a page, might be blocked.
1010 * \see cl_page_own0()
1012 int cl_page_own(const struct lu_env *env, struct cl_io *io, struct cl_page *pg)
1014 return cl_page_own0(env, io, pg, 0);
1016 EXPORT_SYMBOL(cl_page_own);
1019 * Nonblock version of cl_page_own().
1021 * \see cl_page_own0()
1023 int cl_page_own_try(const struct lu_env *env, struct cl_io *io,
1026 return cl_page_own0(env, io, pg, 1);
1028 EXPORT_SYMBOL(cl_page_own_try);
1032 * Assume page ownership.
1034 * Called when page is already locked by the hosting VM.
1036 * \pre !cl_page_is_owned(pg, io)
1037 * \post cl_page_is_owned(pg, io)
1039 * \see cl_page_operations::cpo_assume()
1041 void cl_page_assume(const struct lu_env *env,
1042 struct cl_io *io, struct cl_page *pg)
1044 PASSERT(env, pg, pg->cp_state < CPS_OWNED);
1045 PASSERT(env, pg, pg->cp_owner == NULL);
1046 PINVRNT(env, pg, cl_object_same(pg->cp_obj, io->ci_obj));
1047 PINVRNT(env, pg, cl_page_invariant(pg));
1050 pg = cl_page_top(pg);
1053 cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_assume));
1055 pg->cp_task = current;
1056 cl_page_owner_set(pg);
1057 cl_page_state_set(env, pg, CPS_OWNED);
1060 EXPORT_SYMBOL(cl_page_assume);
1063 * Releases page ownership without unlocking the page.
1065 * Moves page into cl_page_state::CPS_CACHED without releasing a lock on the
1066 * underlying VM page (as VM is supposed to do this itself).
1068 * \pre cl_page_is_owned(pg, io)
1069 * \post !cl_page_is_owned(pg, io)
1071 * \see cl_page_assume()
1073 void cl_page_unassume(const struct lu_env *env,
1074 struct cl_io *io, struct cl_page *pg)
1076 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1077 PINVRNT(env, pg, cl_page_invariant(pg));
1080 pg = cl_page_top(pg);
1082 cl_page_owner_clear(pg);
1083 cl_page_state_set(env, pg, CPS_CACHED);
1084 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(cpo_unassume),
1085 (const struct lu_env *,
1086 const struct cl_page_slice *, struct cl_io *),
1090 EXPORT_SYMBOL(cl_page_unassume);
1093 * Releases page ownership.
1095 * Moves page into cl_page_state::CPS_CACHED.
1097 * \pre cl_page_is_owned(pg, io)
1098 * \post !cl_page_is_owned(pg, io)
1100 * \see cl_page_own()
1101 * \see cl_page_operations::cpo_disown()
1103 void cl_page_disown(const struct lu_env *env,
1104 struct cl_io *io, struct cl_page *pg)
1106 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1109 pg = cl_page_top(pg);
1111 cl_page_disown0(env, io, pg);
1114 EXPORT_SYMBOL(cl_page_disown);
1117 * Called when page is to be removed from the object, e.g., as a result of
1120 * Calls cl_page_operations::cpo_discard() top-to-bottom.
1122 * \pre cl_page_is_owned(pg, io)
1124 * \see cl_page_operations::cpo_discard()
1126 void cl_page_discard(const struct lu_env *env,
1127 struct cl_io *io, struct cl_page *pg)
1129 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1130 PINVRNT(env, pg, cl_page_invariant(pg));
1132 cl_page_invoid(env, io, pg, CL_PAGE_OP(cpo_discard));
1134 EXPORT_SYMBOL(cl_page_discard);
1137 * Version of cl_page_delete() that can be called for not fully constructed
1138 * pages, e.g,. in a error handling cl_page_find()->cl_page_delete0()
1139 * path. Doesn't check page invariant.
1141 static void cl_page_delete0(const struct lu_env *env, struct cl_page *pg,
1144 struct cl_page *tmp = pg;
1147 PASSERT(env, pg, pg == cl_page_top(pg));
1148 PASSERT(env, pg, pg->cp_state != CPS_FREEING);
1151 * Severe all ways to obtain new pointers to @pg.
1153 cl_page_owner_clear(pg);
1156 * unexport the page firstly before freeing it so that
1157 * the page content is considered to be invalid.
1158 * We have to do this because a CPS_FREEING cl_page may
1159 * be NOT under the protection of a cl_lock.
1160 * Afterwards, if this page is found by other threads, then this
1161 * page will be forced to reread.
1163 cl_page_export(env, pg, 0);
1164 cl_page_state_set0(env, pg, CPS_FREEING);
1166 if (tmp->cp_type == CPT_CACHEABLE) {
1168 /* !radix means that @pg is not yet in the radix tree,
1172 for (; tmp != NULL; tmp = tmp->cp_child) {
1174 struct cl_object_header *hdr;
1176 hdr = cl_object_header(tmp->cp_obj);
1177 cfs_spin_lock(&hdr->coh_page_guard);
1178 value = radix_tree_delete(&hdr->coh_tree,
1180 PASSERT(env, tmp, value == tmp);
1181 PASSERT(env, tmp, hdr->coh_pages > 0);
1183 cfs_spin_unlock(&hdr->coh_page_guard);
1187 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_delete),
1188 (const struct lu_env *, const struct cl_page_slice *));
1193 * Called when a decision is made to throw page out of memory.
1195 * Notifies all layers about page destruction by calling
1196 * cl_page_operations::cpo_delete() method top-to-bottom.
1198 * Moves page into cl_page_state::CPS_FREEING state (this is the only place
1199 * where transition to this state happens).
1201 * Eliminates all venues through which new references to the page can be
1204 * - removes page from the radix trees,
1206 * - breaks linkage from VM page to cl_page.
1208 * Once page reaches cl_page_state::CPS_FREEING, all remaining references will
1209 * drain after some time, at which point page will be recycled.
1211 * \pre pg == cl_page_top(pg)
1212 * \pre VM page is locked
1213 * \post pg->cp_state == CPS_FREEING
1215 * \see cl_page_operations::cpo_delete()
1217 void cl_page_delete(const struct lu_env *env, struct cl_page *pg)
1219 PINVRNT(env, pg, cl_page_invariant(pg));
1221 cl_page_delete0(env, pg, 1);
1224 EXPORT_SYMBOL(cl_page_delete);
1227 * Unmaps page from user virtual memory.
1229 * Calls cl_page_operations::cpo_unmap() through all layers top-to-bottom. The
1230 * layer responsible for VM interaction has to unmap page from user space
1233 * \see cl_page_operations::cpo_unmap()
1235 int cl_page_unmap(const struct lu_env *env,
1236 struct cl_io *io, struct cl_page *pg)
1238 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1239 PINVRNT(env, pg, cl_page_invariant(pg));
1241 return cl_page_invoke(env, io, pg, CL_PAGE_OP(cpo_unmap));
1243 EXPORT_SYMBOL(cl_page_unmap);
1246 * Marks page up-to-date.
1248 * Call cl_page_operations::cpo_export() through all layers top-to-bottom. The
1249 * layer responsible for VM interaction has to mark/clear page as up-to-date
1250 * by the \a uptodate argument.
1252 * \see cl_page_operations::cpo_export()
1254 void cl_page_export(const struct lu_env *env, struct cl_page *pg, int uptodate)
1256 PINVRNT(env, pg, cl_page_invariant(pg));
1257 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_export),
1258 (const struct lu_env *,
1259 const struct cl_page_slice *, int), uptodate);
1261 EXPORT_SYMBOL(cl_page_export);
1264 * Returns true, iff \a pg is VM locked in a suitable sense by the calling
1267 int cl_page_is_vmlocked(const struct lu_env *env, const struct cl_page *pg)
1270 const struct cl_page_slice *slice;
1273 pg = cl_page_top_trusted((struct cl_page *)pg);
1274 slice = container_of(pg->cp_layers.next,
1275 const struct cl_page_slice, cpl_linkage);
1276 PASSERT(env, pg, slice->cpl_ops->cpo_is_vmlocked != NULL);
1278 * Call ->cpo_is_vmlocked() directly instead of going through
1279 * CL_PAGE_INVOKE(), because cl_page_is_vmlocked() is used by
1280 * cl_page_invariant().
1282 result = slice->cpl_ops->cpo_is_vmlocked(env, slice);
1283 PASSERT(env, pg, result == -EBUSY || result == -ENODATA);
1284 RETURN(result == -EBUSY);
1286 EXPORT_SYMBOL(cl_page_is_vmlocked);
1288 static enum cl_page_state cl_req_type_state(enum cl_req_type crt)
1291 RETURN(crt == CRT_WRITE ? CPS_PAGEOUT : CPS_PAGEIN);
1294 static void cl_page_io_start(const struct lu_env *env,
1295 struct cl_page *pg, enum cl_req_type crt)
1298 * Page is queued for IO, change its state.
1301 cl_page_owner_clear(pg);
1302 cl_page_state_set(env, pg, cl_req_type_state(crt));
1307 * Prepares page for immediate transfer. cl_page_operations::cpo_prep() is
1308 * called top-to-bottom. Every layer either agrees to submit this page (by
1309 * returning 0), or requests to omit this page (by returning -EALREADY). Layer
1310 * handling interactions with the VM also has to inform VM that page is under
1313 int cl_page_prep(const struct lu_env *env, struct cl_io *io,
1314 struct cl_page *pg, enum cl_req_type crt)
1318 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1319 PINVRNT(env, pg, cl_page_invariant(pg));
1320 PINVRNT(env, pg, crt < CRT_NR);
1323 * XXX this has to be called bottom-to-top, so that llite can set up
1324 * PG_writeback without risking other layers deciding to skip this
1327 result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_prep));
1329 cl_page_io_start(env, pg, crt);
1331 KLASSERT(ergo(crt == CRT_WRITE && pg->cp_type == CPT_CACHEABLE,
1333 PageWriteback(cl_page_vmpage(env, pg)))));
1334 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
1337 EXPORT_SYMBOL(cl_page_prep);
1340 * Notify layers about transfer completion.
1342 * Invoked by transfer sub-system (which is a part of osc) to notify layers
1343 * that a transfer, of which this page is a part of has completed.
1345 * Completion call-backs are executed in the bottom-up order, so that
1346 * uppermost layer (llite), responsible for the VFS/VM interaction runs last
1347 * and can release locks safely.
1349 * \pre pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
1350 * \post pg->cp_state == CPS_CACHED
1352 * \see cl_page_operations::cpo_completion()
1354 void cl_page_completion(const struct lu_env *env,
1355 struct cl_page *pg, enum cl_req_type crt, int ioret)
1357 struct cl_sync_io *anchor = pg->cp_sync_io;
1359 PASSERT(env, pg, crt < CRT_NR);
1360 /* cl_page::cp_req already cleared by the caller (osc_completion()) */
1361 PASSERT(env, pg, pg->cp_req == NULL);
1362 PASSERT(env, pg, pg->cp_state == cl_req_type_state(crt));
1363 PINVRNT(env, pg, cl_page_invariant(pg));
1366 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, ioret);
1367 if (crt == CRT_READ && ioret == 0) {
1368 PASSERT(env, pg, !(pg->cp_flags & CPF_READ_COMPLETED));
1369 pg->cp_flags |= CPF_READ_COMPLETED;
1372 cl_page_state_set(env, pg, CPS_CACHED);
1373 CL_PAGE_INVOID_REVERSE(env, pg, CL_PAGE_OP(io[crt].cpo_completion),
1374 (const struct lu_env *,
1375 const struct cl_page_slice *, int), ioret);
1377 LASSERT(pg->cp_sync_io == anchor);
1378 pg->cp_sync_io = NULL;
1379 cl_sync_io_note(anchor, ioret);
1382 /* Don't assert the page writeback bit here because the lustre file
1383 * may be as a backend of swap space. in this case, the page writeback
1384 * is set by VM, and obvious we shouldn't clear it at all. Fortunately
1385 * this type of pages are all TRANSIENT pages. */
1386 KLASSERT(ergo(pg->cp_type == CPT_CACHEABLE,
1387 !PageWriteback(cl_page_vmpage(env, pg))));
1390 EXPORT_SYMBOL(cl_page_completion);
1393 * Notify layers that transfer formation engine decided to yank this page from
1394 * the cache and to make it a part of a transfer.
1396 * \pre pg->cp_state == CPS_CACHED
1397 * \post pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT
1399 * \see cl_page_operations::cpo_make_ready()
1401 int cl_page_make_ready(const struct lu_env *env, struct cl_page *pg,
1402 enum cl_req_type crt)
1406 PINVRNT(env, pg, crt < CRT_NR);
1409 result = CL_PAGE_INVOKE(env, pg, CL_PAGE_OP(io[crt].cpo_make_ready),
1410 (const struct lu_env *,
1411 const struct cl_page_slice *));
1413 PASSERT(env, pg, pg->cp_state == CPS_CACHED);
1414 cl_page_io_start(env, pg, crt);
1416 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
1419 EXPORT_SYMBOL(cl_page_make_ready);
1422 * Notify layers that high level io decided to place this page into a cache
1423 * for future transfer.
1425 * The layer implementing transfer engine (osc) has to register this page in
1428 * \pre cl_page_is_owned(pg, io)
1429 * \post ergo(result == 0,
1430 * pg->cp_state == CPS_PAGEIN || pg->cp_state == CPS_PAGEOUT)
1432 * \see cl_page_operations::cpo_cache_add()
1434 int cl_page_cache_add(const struct lu_env *env, struct cl_io *io,
1435 struct cl_page *pg, enum cl_req_type crt)
1439 PINVRNT(env, pg, crt < CRT_NR);
1440 PINVRNT(env, pg, cl_page_is_owned(pg, io));
1441 PINVRNT(env, pg, cl_page_invariant(pg));
1444 result = cl_page_invoke(env, io, pg, CL_PAGE_OP(io[crt].cpo_cache_add));
1446 cl_page_owner_clear(pg);
1447 cl_page_state_set(env, pg, CPS_CACHED);
1449 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", crt, result);
1452 EXPORT_SYMBOL(cl_page_cache_add);
1455 * Checks whether page is protected by any extent lock is at least required
1458 * \return the same as in cl_page_operations::cpo_is_under_lock() method.
1459 * \see cl_page_operations::cpo_is_under_lock()
1461 int cl_page_is_under_lock(const struct lu_env *env, struct cl_io *io,
1462 struct cl_page *page)
1466 PINVRNT(env, page, cl_page_invariant(page));
1469 rc = CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_is_under_lock),
1470 (const struct lu_env *,
1471 const struct cl_page_slice *, struct cl_io *),
1473 PASSERT(env, page, rc != 0);
1476 EXPORT_SYMBOL(cl_page_is_under_lock);
1479 * Purges all cached pages belonging to the object \a obj.
1481 int cl_pages_prune(const struct lu_env *env, struct cl_object *clobj)
1483 struct cl_thread_info *info;
1484 struct cl_object *obj = cl_object_top(clobj);
1486 struct cl_page_list *plist;
1490 info = cl_env_info(env);
1491 plist = &info->clt_list;
1495 * initialize the io. This is ugly since we never do IO in this
1496 * function, we just make cl_page_list functions happy. -jay
1499 result = cl_io_init(env, io, CIT_MISC, obj);
1501 cl_io_fini(env, io);
1502 RETURN(io->ci_result);
1506 cl_page_list_init(plist);
1507 result = cl_page_gang_lookup(env, obj, io, 0, CL_PAGE_EOF,
1510 * Since we're purging the pages of an object, we don't care
1511 * the possible outcomes of the following functions.
1513 cl_page_list_unmap(env, io, plist);
1514 cl_page_list_discard(env, io, plist);
1515 cl_page_list_disown(env, io, plist);
1516 cl_page_list_fini(env, plist);
1518 if (result == CLP_GANG_RESCHED)
1520 } while (result != CLP_GANG_OKAY);
1522 cl_io_fini(env, io);
1525 EXPORT_SYMBOL(cl_pages_prune);
1528 * Tells transfer engine that only part of a page is to be transmitted.
1530 * \see cl_page_operations::cpo_clip()
1532 void cl_page_clip(const struct lu_env *env, struct cl_page *pg,
1535 PINVRNT(env, pg, cl_page_invariant(pg));
1537 CL_PAGE_HEADER(D_TRACE, env, pg, "%d %d\n", from, to);
1538 CL_PAGE_INVOID(env, pg, CL_PAGE_OP(cpo_clip),
1539 (const struct lu_env *,
1540 const struct cl_page_slice *,int, int),
1543 EXPORT_SYMBOL(cl_page_clip);
1546 * Prints human readable representation of \a pg to the \a f.
1548 void cl_page_header_print(const struct lu_env *env, void *cookie,
1549 lu_printer_t printer, const struct cl_page *pg)
1551 (*printer)(env, cookie,
1552 "page@%p[%d %p:%lu ^%p_%p %d %d %d %p %p %#x]\n",
1553 pg, cfs_atomic_read(&pg->cp_ref), pg->cp_obj,
1554 pg->cp_index, pg->cp_parent, pg->cp_child,
1555 pg->cp_state, pg->cp_error, pg->cp_type,
1556 pg->cp_owner, pg->cp_req, pg->cp_flags);
1558 EXPORT_SYMBOL(cl_page_header_print);
1561 * Prints human readable representation of \a pg to the \a f.
1563 void cl_page_print(const struct lu_env *env, void *cookie,
1564 lu_printer_t printer, const struct cl_page *pg)
1566 struct cl_page *scan;
1568 for (scan = cl_page_top((struct cl_page *)pg);
1569 scan != NULL; scan = scan->cp_child)
1570 cl_page_header_print(env, cookie, printer, scan);
1571 CL_PAGE_INVOKE(env, (struct cl_page *)pg, CL_PAGE_OP(cpo_print),
1572 (const struct lu_env *env,
1573 const struct cl_page_slice *slice,
1574 void *cookie, lu_printer_t p), cookie, printer);
1575 (*printer)(env, cookie, "end page@%p\n", pg);
1577 EXPORT_SYMBOL(cl_page_print);
1580 * Cancel a page which is still in a transfer.
1582 int cl_page_cancel(const struct lu_env *env, struct cl_page *page)
1584 return CL_PAGE_INVOKE(env, page, CL_PAGE_OP(cpo_cancel),
1585 (const struct lu_env *,
1586 const struct cl_page_slice *));
1588 EXPORT_SYMBOL(cl_page_cancel);
1591 * Converts a byte offset within object \a obj into a page index.
1593 loff_t cl_offset(const struct cl_object *obj, pgoff_t idx)
1598 return (loff_t)idx << CFS_PAGE_SHIFT;
1600 EXPORT_SYMBOL(cl_offset);
1603 * Converts a page index into a byte offset within object \a obj.
1605 pgoff_t cl_index(const struct cl_object *obj, loff_t offset)
1610 return offset >> CFS_PAGE_SHIFT;
1612 EXPORT_SYMBOL(cl_index);
1614 int cl_page_size(const struct cl_object *obj)
1616 return 1 << CFS_PAGE_SHIFT;
1618 EXPORT_SYMBOL(cl_page_size);
1621 * Adds page slice to the compound page.
1623 * This is called by cl_object_operations::coo_page_init() methods to add a
1624 * per-layer state to the page. New state is added at the end of
1625 * cl_page::cp_layers list, that is, it is at the bottom of the stack.
1627 * \see cl_lock_slice_add(), cl_req_slice_add(), cl_io_slice_add()
1629 void cl_page_slice_add(struct cl_page *page, struct cl_page_slice *slice,
1630 struct cl_object *obj,
1631 const struct cl_page_operations *ops)
1634 cfs_list_add_tail(&slice->cpl_linkage, &page->cp_layers);
1635 slice->cpl_obj = obj;
1636 slice->cpl_ops = ops;
1637 slice->cpl_page = page;
1640 EXPORT_SYMBOL(cl_page_slice_add);
1642 int cl_page_init(void)
1644 return lu_kmem_init(cl_page_caches);
1647 void cl_page_fini(void)
1649 lu_kmem_fini(cl_page_caches);