4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
27 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
30 * Copyright (c) 2011, 2012, Intel Corporation.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
38 * Lustre Lite I/O page cache routines shared by different kernel revs
41 #include <linux/kernel.h>
43 #include <linux/string.h>
44 #include <linux/stat.h>
45 #include <linux/errno.h>
46 #include <linux/unistd.h>
47 #include <linux/writeback.h>
48 #include <linux/uaccess.h>
51 #include <linux/pagemap.h>
52 /* current_is_kswapd() */
53 #include <linux/swap.h>
55 #define DEBUG_SUBSYSTEM S_LLITE
57 #include "../include/lustre_lite.h"
58 #include "../include/obd_cksum.h"
59 #include "llite_internal.h"
60 #include "../include/linux/lustre_compat25.h"
63 * Finalizes cl-data before exiting typical address_space operation. Dual to
66 static void ll_cl_fini(struct ll_cl_context *lcc)
68 struct lu_env *env = lcc->lcc_env;
69 struct cl_io *io = lcc->lcc_io;
70 struct cl_page *page = lcc->lcc_page;
72 LASSERT(lcc->lcc_cookie == current);
76 lu_ref_del(&page->cp_reference, "cl_io", io);
77 cl_page_put(env, page);
80 cl_env_put(env, &lcc->lcc_refcheck);
84 * Initializes common cl-data at the typical address_space operation entry
87 static struct ll_cl_context *ll_cl_init(struct file *file,
88 struct page *vmpage, int create)
90 struct ll_cl_context *lcc;
93 struct cl_object *clob;
99 clob = ll_i2info(vmpage->mapping->host)->lli_clob;
100 LASSERT(clob != NULL);
102 env = cl_env_get(&refcheck);
104 return ERR_CAST(env);
106 lcc = &vvp_env_info(env)->vti_io_ctx;
107 memset(lcc, 0, sizeof(*lcc));
109 lcc->lcc_refcheck = refcheck;
110 lcc->lcc_cookie = current;
112 cio = ccc_env_io(env);
113 io = cio->cui_cl.cis_io;
114 if (io == NULL && create) {
115 struct inode *inode = vmpage->mapping->host;
118 if (mutex_trylock(&inode->i_mutex)) {
119 mutex_unlock(&(inode)->i_mutex);
121 /* this is too bad. Someone is trying to write the
122 * page w/o holding inode mutex. This means we can
123 * add dirty pages into cache during truncate */
124 CERROR("Proc %s is dirtying page w/o inode lock, this will break truncate\n",
128 return ERR_PTR(-EIO);
132 * Loop-back driver calls ->prepare_write().
133 * methods directly, bypassing file system ->write() operation,
134 * so cl_io has to be created here.
136 io = ccc_env_thread_io(env);
137 ll_io_init(io, file, 1);
139 /* No lock at all for this kind of IO - we can't do it because
140 * we have held page lock, it would cause deadlock.
141 * XXX: This causes poor performance to loop device - One page
143 * In order to get better performance, users should use
144 * lloop driver instead.
146 io->ci_lockreq = CILR_NEVER;
148 pos = vmpage->index << PAGE_CACHE_SHIFT;
150 /* Create a temp IO to serve write. */
151 result = cl_io_rw_init(env, io, CIT_WRITE, pos, PAGE_CACHE_SIZE);
153 cio->cui_fd = LUSTRE_FPRIVATE(file);
154 cio->cui_iter = NULL;
155 result = cl_io_iter_init(env, io);
157 result = cl_io_lock(env, io);
159 result = cl_io_start(env, io);
162 result = io->ci_result;
169 struct cl_page *page;
172 LASSERT(io->ci_state == CIS_IO_GOING);
173 LASSERT(cio->cui_fd == LUSTRE_FPRIVATE(file));
174 page = cl_page_find(env, clob, vmpage->index, vmpage,
177 lcc->lcc_page = page;
178 lu_ref_add(&page->cp_reference, "cl_io", io);
181 result = PTR_ERR(page);
185 lcc = ERR_PTR(result);
188 CDEBUG(D_VFSTRACE, "%lu@"DFID" -> %d %p %p\n",
189 vmpage->index, PFID(lu_object_fid(&clob->co_lu)), result,
194 static struct ll_cl_context *ll_cl_get(void)
196 struct ll_cl_context *lcc;
200 env = cl_env_get(&refcheck);
201 LASSERT(!IS_ERR(env));
202 lcc = &vvp_env_info(env)->vti_io_ctx;
203 LASSERT(env == lcc->lcc_env);
204 LASSERT(current == lcc->lcc_cookie);
205 cl_env_put(env, &refcheck);
207 /* env has got in ll_cl_init, so it is still usable. */
212 * ->prepare_write() address space operation called by generic_file_write()
213 * for every page during write.
215 int ll_prepare_write(struct file *file, struct page *vmpage, unsigned from,
218 struct ll_cl_context *lcc;
221 lcc = ll_cl_init(file, vmpage, 1);
223 struct lu_env *env = lcc->lcc_env;
224 struct cl_io *io = lcc->lcc_io;
225 struct cl_page *page = lcc->lcc_page;
227 cl_page_assume(env, io, page);
229 result = cl_io_prepare_write(env, io, page, from, to);
232 * Add a reference, so that page is not evicted from
233 * the cache until ->commit_write() is called.
236 lu_ref_add(&page->cp_reference, "prepare_write",
239 cl_page_unassume(env, io, page);
242 /* returning 0 in prepare assumes commit must be called
245 result = PTR_ERR(lcc);
250 int ll_commit_write(struct file *file, struct page *vmpage, unsigned from,
253 struct ll_cl_context *lcc;
256 struct cl_page *page;
261 page = lcc->lcc_page;
264 LASSERT(cl_page_is_owned(page, io));
266 if (from != to) /* handle short write case. */
267 result = cl_io_commit_write(env, io, page, from, to);
268 if (cl_page_is_owned(page, io))
269 cl_page_unassume(env, io, page);
272 * Release reference acquired by ll_prepare_write().
274 lu_ref_del(&page->cp_reference, "prepare_write", current);
275 cl_page_put(env, page);
280 struct obd_capa *cl_capa_lookup(struct inode *inode, enum cl_req_type crt)
284 opc = crt == CRT_WRITE ? CAPA_OPC_OSS_WRITE : CAPA_OPC_OSS_RW;
285 return ll_osscapa_get(inode, opc);
288 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which);
291 * Get readahead pages from the filesystem readahead pool of the client for a
294 * /param sbi superblock for filesystem readahead state ll_ra_info
295 * /param ria per-thread readahead state
296 * /param pages number of pages requested for readahead for the thread.
298 * WARNING: This algorithm is used to reduce contention on sbi->ll_lock.
299 * It should work well if the ra_max_pages is much greater than the single
300 * file's read-ahead window, and not too many threads contending for
301 * these readahead pages.
303 * TODO: There may be a 'global sync problem' if many threads are trying
304 * to get an ra budget that is larger than the remaining readahead pages
305 * and reach here at exactly the same time. They will compute /a ret to
306 * consume the remaining pages, but will fail at atomic_add_return() and
307 * get a zero ra window, although there is still ra space remaining. - Jay */
309 static unsigned long ll_ra_count_get(struct ll_sb_info *sbi,
310 struct ra_io_arg *ria,
313 struct ll_ra_info *ra = &sbi->ll_ra_info;
316 /* If read-ahead pages left are less than 1M, do not do read-ahead,
317 * otherwise it will form small read RPC(< 1M), which hurt server
318 * performance a lot. */
319 ret = min(ra->ra_max_pages - atomic_read(&ra->ra_cur_pages), pages);
320 if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages)) {
325 /* If the non-strided (ria_pages == 0) readahead window
326 * (ria_start + ret) has grown across an RPC boundary, then trim
327 * readahead size by the amount beyond the RPC so it ends on an
328 * RPC boundary. If the readahead window is already ending on
329 * an RPC boundary (beyond_rpc == 0), or smaller than a full
330 * RPC (beyond_rpc < ret) the readahead size is unchanged.
331 * The (beyond_rpc != 0) check is skipped since the conditional
332 * branch is more expensive than subtracting zero from the result.
334 * Strided read is left unaligned to avoid small fragments beyond
335 * the RPC boundary from needing an extra read RPC. */
336 if (ria->ria_pages == 0) {
337 long beyond_rpc = (ria->ria_start + ret) % PTLRPC_MAX_BRW_PAGES;
338 if (/* beyond_rpc != 0 && */ beyond_rpc < ret)
342 if (atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) {
343 atomic_sub(ret, &ra->ra_cur_pages);
351 void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len)
353 struct ll_ra_info *ra = &sbi->ll_ra_info;
354 atomic_sub(len, &ra->ra_cur_pages);
357 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which)
359 LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which);
360 lprocfs_counter_incr(sbi->ll_ra_stats, which);
363 void ll_ra_stats_inc(struct address_space *mapping, enum ra_stat which)
365 struct ll_sb_info *sbi = ll_i2sbi(mapping->host);
366 ll_ra_stats_inc_sbi(sbi, which);
369 #define RAS_CDEBUG(ras) \
371 "lrp %lu cr %lu cp %lu ws %lu wl %lu nra %lu r %lu ri %lu" \
372 "csr %lu sf %lu sp %lu sl %lu \n", \
373 ras->ras_last_readpage, ras->ras_consecutive_requests, \
374 ras->ras_consecutive_pages, ras->ras_window_start, \
375 ras->ras_window_len, ras->ras_next_readahead, \
376 ras->ras_requests, ras->ras_request_index, \
377 ras->ras_consecutive_stride_requests, ras->ras_stride_offset, \
378 ras->ras_stride_pages, ras->ras_stride_length)
380 static int index_in_window(unsigned long index, unsigned long point,
381 unsigned long before, unsigned long after)
383 unsigned long start = point - before, end = point + after;
390 return start <= index && index <= end;
393 static struct ll_readahead_state *ll_ras_get(struct file *f)
395 struct ll_file_data *fd;
397 fd = LUSTRE_FPRIVATE(f);
401 void ll_ra_read_in(struct file *f, struct ll_ra_read *rar)
403 struct ll_readahead_state *ras;
407 spin_lock(&ras->ras_lock);
409 ras->ras_request_index = 0;
410 ras->ras_consecutive_requests++;
411 rar->lrr_reader = current;
413 list_add(&rar->lrr_linkage, &ras->ras_read_beads);
414 spin_unlock(&ras->ras_lock);
417 void ll_ra_read_ex(struct file *f, struct ll_ra_read *rar)
419 struct ll_readahead_state *ras;
423 spin_lock(&ras->ras_lock);
424 list_del_init(&rar->lrr_linkage);
425 spin_unlock(&ras->ras_lock);
428 static struct ll_ra_read *ll_ra_read_get_locked(struct ll_readahead_state *ras)
430 struct ll_ra_read *scan;
432 list_for_each_entry(scan, &ras->ras_read_beads, lrr_linkage) {
433 if (scan->lrr_reader == current)
439 struct ll_ra_read *ll_ra_read_get(struct file *f)
441 struct ll_readahead_state *ras;
442 struct ll_ra_read *bead;
446 spin_lock(&ras->ras_lock);
447 bead = ll_ra_read_get_locked(ras);
448 spin_unlock(&ras->ras_lock);
452 static int cl_read_ahead_page(const struct lu_env *env, struct cl_io *io,
453 struct cl_page_list *queue, struct cl_page *page,
460 cl_page_assume(env, io, page);
461 lu_ref_add(&page->cp_reference, "ra", current);
462 cp = cl2ccc_page(cl_page_at(page, &vvp_device_type));
463 if (!cp->cpg_defer_uptodate && !PageUptodate(vmpage)) {
464 rc = cl_page_is_under_lock(env, io, page);
466 cp->cpg_defer_uptodate = 1;
468 cl_page_list_add(queue, page);
471 cl_page_delete(env, page);
475 /* skip completed pages */
476 cl_page_unassume(env, io, page);
478 lu_ref_del(&page->cp_reference, "ra", current);
479 cl_page_put(env, page);
484 * Initiates read-ahead of a page with given index.
486 * \retval +ve: page was added to \a queue.
488 * \retval -ENOLCK: there is no extent lock for this part of a file, stop
491 * \retval -ve, 0: page wasn't added to \a queue for other reason.
493 static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io,
494 struct cl_page_list *queue,
495 pgoff_t index, struct address_space *mapping)
498 struct cl_object *clob = ll_i2info(mapping->host)->lli_clob;
499 struct cl_page *page;
500 enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */
502 const char *msg = NULL;
504 vmpage = grab_cache_page_nowait(mapping, index);
505 if (vmpage != NULL) {
506 /* Check if vmpage was truncated or reclaimed */
507 if (vmpage->mapping == mapping) {
508 page = cl_page_find(env, clob, vmpage->index,
509 vmpage, CPT_CACHEABLE);
511 rc = cl_read_ahead_page(env, io, queue,
514 which = RA_STAT_FAILED_MATCH;
515 msg = "lock match failed";
518 which = RA_STAT_FAILED_GRAB_PAGE;
519 msg = "cl_page_find failed";
522 which = RA_STAT_WRONG_GRAB_PAGE;
523 msg = "g_c_p_n returned invalid page";
527 page_cache_release(vmpage);
529 which = RA_STAT_FAILED_GRAB_PAGE;
530 msg = "g_c_p_n failed";
533 ll_ra_stats_inc(mapping, which);
534 CDEBUG(D_READA, "%s\n", msg);
539 #define RIA_DEBUG(ria) \
540 CDEBUG(D_READA, "rs %lu re %lu ro %lu rl %lu rp %lu\n", \
541 ria->ria_start, ria->ria_end, ria->ria_stoff, ria->ria_length,\
544 /* Limit this to the blocksize instead of PTLRPC_BRW_MAX_SIZE, since we don't
545 * know what the actual RPC size is. If this needs to change, it makes more
546 * sense to tune the i_blkbits value for the file based on the OSTs it is
547 * striped over, rather than having a constant value for all files here. */
549 /* RAS_INCREASE_STEP should be (1UL << (inode->i_blkbits - PAGE_CACHE_SHIFT)).
550 * Temporarily set RAS_INCREASE_STEP to 1MB. After 4MB RPC is enabled
551 * by default, this should be adjusted corresponding with max_read_ahead_mb
552 * and max_read_ahead_per_file_mb otherwise the readahead budget can be used
553 * up quickly which will affect read performance significantly. See LU-2816 */
554 #define RAS_INCREASE_STEP(inode) (ONE_MB_BRW_SIZE >> PAGE_CACHE_SHIFT)
556 static inline int stride_io_mode(struct ll_readahead_state *ras)
558 return ras->ras_consecutive_stride_requests > 1;
560 /* The function calculates how much pages will be read in
561 * [off, off + length], in such stride IO area,
562 * stride_offset = st_off, stride_length = st_len,
563 * stride_pages = st_pgs
565 * |------------------|*****|------------------|*****|------------|*****|....
568 * |----- st_len -----|
570 * How many pages it should read in such pattern
571 * |-------------------------------------------------------------|
573 * |<------ length ------->|
575 * = |<----->| + |-------------------------------------| + |---|
576 * start_left st_pgs * i end_left
579 stride_pg_count(pgoff_t st_off, unsigned long st_len, unsigned long st_pgs,
580 unsigned long off, unsigned long length)
582 __u64 start = off > st_off ? off - st_off : 0;
583 __u64 end = off + length > st_off ? off + length - st_off : 0;
584 unsigned long start_left = 0;
585 unsigned long end_left = 0;
586 unsigned long pg_count;
588 if (st_len == 0 || length == 0 || end == 0)
591 start_left = do_div(start, st_len);
592 if (start_left < st_pgs)
593 start_left = st_pgs - start_left;
597 end_left = do_div(end, st_len);
598 if (end_left > st_pgs)
601 CDEBUG(D_READA, "start %llu, end %llu start_left %lu end_left %lu \n",
602 start, end, start_left, end_left);
605 pg_count = end_left - (st_pgs - start_left);
607 pg_count = start_left + st_pgs * (end - start - 1) + end_left;
609 CDEBUG(D_READA, "st_off %lu, st_len %lu st_pgs %lu off %lu length %lu pgcount %lu\n",
610 st_off, st_len, st_pgs, off, length, pg_count);
615 static int ria_page_count(struct ra_io_arg *ria)
617 __u64 length = ria->ria_end >= ria->ria_start ?
618 ria->ria_end - ria->ria_start + 1 : 0;
620 return stride_pg_count(ria->ria_stoff, ria->ria_length,
621 ria->ria_pages, ria->ria_start,
625 /*Check whether the index is in the defined ra-window */
626 static int ras_inside_ra_window(unsigned long idx, struct ra_io_arg *ria)
628 /* If ria_length == ria_pages, it means non-stride I/O mode,
629 * idx should always inside read-ahead window in this case
630 * For stride I/O mode, just check whether the idx is inside
632 return ria->ria_length == 0 || ria->ria_length == ria->ria_pages ||
633 (idx >= ria->ria_stoff && (idx - ria->ria_stoff) %
634 ria->ria_length < ria->ria_pages);
637 static int ll_read_ahead_pages(const struct lu_env *env,
638 struct cl_io *io, struct cl_page_list *queue,
639 struct ra_io_arg *ria,
640 unsigned long *reserved_pages,
641 struct address_space *mapping,
642 unsigned long *ra_end)
644 int rc, count = 0, stride_ria;
645 unsigned long page_idx;
647 LASSERT(ria != NULL);
650 stride_ria = ria->ria_length > ria->ria_pages && ria->ria_pages > 0;
651 for (page_idx = ria->ria_start; page_idx <= ria->ria_end &&
652 *reserved_pages > 0; page_idx++) {
653 if (ras_inside_ra_window(page_idx, ria)) {
654 /* If the page is inside the read-ahead window*/
655 rc = ll_read_ahead_page(env, io, queue,
660 } else if (rc == -ENOLCK)
662 } else if (stride_ria) {
663 /* If it is not in the read-ahead window, and it is
664 * read-ahead mode, then check whether it should skip
667 /* FIXME: This assertion only is valid when it is for
668 * forward read-ahead, it will be fixed when backward
669 * read-ahead is implemented */
670 LASSERTF(page_idx > ria->ria_stoff, "Invalid page_idx %lu rs %lu re %lu ro %lu rl %lu rp %lu\n",
672 ria->ria_start, ria->ria_end, ria->ria_stoff,
673 ria->ria_length, ria->ria_pages);
674 offset = page_idx - ria->ria_stoff;
675 offset = offset % (ria->ria_length);
676 if (offset > ria->ria_pages) {
677 page_idx += ria->ria_length - offset;
678 CDEBUG(D_READA, "i %lu skip %lu \n", page_idx,
679 ria->ria_length - offset);
688 int ll_readahead(const struct lu_env *env, struct cl_io *io,
689 struct ll_readahead_state *ras, struct address_space *mapping,
690 struct cl_page_list *queue, int flags)
692 struct vvp_io *vio = vvp_env_io(env);
693 struct vvp_thread_info *vti = vvp_env_info(env);
694 struct cl_attr *attr = ccc_env_thread_attr(env);
695 unsigned long start = 0, end = 0, reserved;
696 unsigned long ra_end, len;
698 struct ll_ra_read *bead;
699 struct ra_io_arg *ria = &vti->vti_ria;
700 struct ll_inode_info *lli;
701 struct cl_object *clob;
705 inode = mapping->host;
706 lli = ll_i2info(inode);
707 clob = lli->lli_clob;
709 memset(ria, 0, sizeof(*ria));
711 cl_object_attr_lock(clob);
712 ret = cl_object_attr_get(env, clob, attr);
713 cl_object_attr_unlock(clob);
719 ll_ra_stats_inc(mapping, RA_STAT_ZERO_LEN);
723 spin_lock(&ras->ras_lock);
724 if (vio->cui_ra_window_set)
725 bead = &vio->cui_bead;
729 /* Enlarge the RA window to encompass the full read */
730 if (bead != NULL && ras->ras_window_start + ras->ras_window_len <
731 bead->lrr_start + bead->lrr_count) {
732 ras->ras_window_len = bead->lrr_start + bead->lrr_count -
733 ras->ras_window_start;
735 /* Reserve a part of the read-ahead window that we'll be issuing */
736 if (ras->ras_window_len) {
737 start = ras->ras_next_readahead;
738 end = ras->ras_window_start + ras->ras_window_len - 1;
741 unsigned long rpc_boundary;
743 * Align RA window to an optimal boundary.
745 * XXX This would be better to align to cl_max_pages_per_rpc
746 * instead of PTLRPC_MAX_BRW_PAGES, because the RPC size may
747 * be aligned to the RAID stripe size in the future and that
748 * is more important than the RPC size.
750 /* Note: we only trim the RPC, instead of extending the RPC
751 * to the boundary, so to avoid reading too much pages during
753 rpc_boundary = (end + 1) & (~(PTLRPC_MAX_BRW_PAGES - 1));
754 if (rpc_boundary > 0)
757 if (rpc_boundary > start)
760 /* Truncate RA window to end of file */
761 end = min(end, (unsigned long)((kms - 1) >> PAGE_CACHE_SHIFT));
763 ras->ras_next_readahead = max(end, end + 1);
766 ria->ria_start = start;
768 /* If stride I/O mode is detected, get stride window*/
769 if (stride_io_mode(ras)) {
770 ria->ria_stoff = ras->ras_stride_offset;
771 ria->ria_length = ras->ras_stride_length;
772 ria->ria_pages = ras->ras_stride_pages;
774 spin_unlock(&ras->ras_lock);
777 ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW);
780 len = ria_page_count(ria);
784 reserved = ll_ra_count_get(ll_i2sbi(inode), ria, len);
786 ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT);
788 CDEBUG(D_READA, "reserved page %lu ra_cur %d ra_max %lu\n", reserved,
789 atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
790 ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
792 ret = ll_read_ahead_pages(env, io, queue,
793 ria, &reserved, mapping, &ra_end);
795 LASSERTF(reserved >= 0, "reserved %lu\n", reserved);
797 ll_ra_count_put(ll_i2sbi(inode), reserved);
799 if (ra_end == end + 1 && ra_end == (kms >> PAGE_CACHE_SHIFT))
800 ll_ra_stats_inc(mapping, RA_STAT_EOF);
802 /* if we didn't get to the end of the region we reserved from
803 * the ras we need to go back and update the ras so that the
804 * next read-ahead tries from where we left off. we only do so
805 * if the region we failed to issue read-ahead on is still ahead
806 * of the app and behind the next index to start read-ahead from */
807 CDEBUG(D_READA, "ra_end %lu end %lu stride end %lu \n",
808 ra_end, end, ria->ria_end);
810 if (ra_end != end + 1) {
811 spin_lock(&ras->ras_lock);
812 if (ra_end < ras->ras_next_readahead &&
813 index_in_window(ra_end, ras->ras_window_start, 0,
814 ras->ras_window_len)) {
815 ras->ras_next_readahead = ra_end;
818 spin_unlock(&ras->ras_lock);
824 static void ras_set_start(struct inode *inode, struct ll_readahead_state *ras,
827 ras->ras_window_start = index & (~(RAS_INCREASE_STEP(inode) - 1));
830 /* called with the ras_lock held or from places where it doesn't matter */
831 static void ras_reset(struct inode *inode, struct ll_readahead_state *ras,
834 ras->ras_last_readpage = index;
835 ras->ras_consecutive_requests = 0;
836 ras->ras_consecutive_pages = 0;
837 ras->ras_window_len = 0;
838 ras_set_start(inode, ras, index);
839 ras->ras_next_readahead = max(ras->ras_window_start, index);
844 /* called with the ras_lock held or from places where it doesn't matter */
845 static void ras_stride_reset(struct ll_readahead_state *ras)
847 ras->ras_consecutive_stride_requests = 0;
848 ras->ras_stride_length = 0;
849 ras->ras_stride_pages = 0;
853 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
855 spin_lock_init(&ras->ras_lock);
856 ras_reset(inode, ras, 0);
857 ras->ras_requests = 0;
858 INIT_LIST_HEAD(&ras->ras_read_beads);
862 * Check whether the read request is in the stride window.
863 * If it is in the stride window, return 1, otherwise return 0.
865 static int index_in_stride_window(struct ll_readahead_state *ras,
868 unsigned long stride_gap;
870 if (ras->ras_stride_length == 0 || ras->ras_stride_pages == 0 ||
871 ras->ras_stride_pages == ras->ras_stride_length)
874 stride_gap = index - ras->ras_last_readpage - 1;
876 /* If it is contiguous read */
878 return ras->ras_consecutive_pages + 1 <= ras->ras_stride_pages;
880 /* Otherwise check the stride by itself */
881 return (ras->ras_stride_length - ras->ras_stride_pages) == stride_gap &&
882 ras->ras_consecutive_pages == ras->ras_stride_pages;
885 static void ras_update_stride_detector(struct ll_readahead_state *ras,
888 unsigned long stride_gap = index - ras->ras_last_readpage - 1;
890 if (!stride_io_mode(ras) && (stride_gap != 0 ||
891 ras->ras_consecutive_stride_requests == 0)) {
892 ras->ras_stride_pages = ras->ras_consecutive_pages;
893 ras->ras_stride_length = stride_gap +ras->ras_consecutive_pages;
895 LASSERT(ras->ras_request_index == 0);
896 LASSERT(ras->ras_consecutive_stride_requests == 0);
898 if (index <= ras->ras_last_readpage) {
899 /*Reset stride window for forward read*/
900 ras_stride_reset(ras);
904 ras->ras_stride_pages = ras->ras_consecutive_pages;
905 ras->ras_stride_length = stride_gap +ras->ras_consecutive_pages;
912 stride_page_count(struct ll_readahead_state *ras, unsigned long len)
914 return stride_pg_count(ras->ras_stride_offset, ras->ras_stride_length,
915 ras->ras_stride_pages, ras->ras_stride_offset,
919 /* Stride Read-ahead window will be increased inc_len according to
920 * stride I/O pattern */
921 static void ras_stride_increase_window(struct ll_readahead_state *ras,
922 struct ll_ra_info *ra,
923 unsigned long inc_len)
925 unsigned long left, step, window_len;
926 unsigned long stride_len;
928 LASSERT(ras->ras_stride_length > 0);
929 LASSERTF(ras->ras_window_start + ras->ras_window_len
930 >= ras->ras_stride_offset, "window_start %lu, window_len %lu stride_offset %lu\n",
931 ras->ras_window_start,
932 ras->ras_window_len, ras->ras_stride_offset);
934 stride_len = ras->ras_window_start + ras->ras_window_len -
935 ras->ras_stride_offset;
937 left = stride_len % ras->ras_stride_length;
938 window_len = ras->ras_window_len - left;
940 if (left < ras->ras_stride_pages)
943 left = ras->ras_stride_pages + inc_len;
945 LASSERT(ras->ras_stride_pages != 0);
947 step = left / ras->ras_stride_pages;
948 left %= ras->ras_stride_pages;
950 window_len += step * ras->ras_stride_length + left;
952 if (stride_page_count(ras, window_len) <= ra->ra_max_pages_per_file)
953 ras->ras_window_len = window_len;
958 static void ras_increase_window(struct inode *inode,
959 struct ll_readahead_state *ras,
960 struct ll_ra_info *ra)
962 /* The stretch of ra-window should be aligned with max rpc_size
963 * but current clio architecture does not support retrieve such
964 * information from lower layer. FIXME later
966 if (stride_io_mode(ras))
967 ras_stride_increase_window(ras, ra, RAS_INCREASE_STEP(inode));
969 ras->ras_window_len = min(ras->ras_window_len +
970 RAS_INCREASE_STEP(inode),
971 ra->ra_max_pages_per_file);
974 void ras_update(struct ll_sb_info *sbi, struct inode *inode,
975 struct ll_readahead_state *ras, unsigned long index,
978 struct ll_ra_info *ra = &sbi->ll_ra_info;
979 int zero = 0, stride_detect = 0, ra_miss = 0;
981 spin_lock(&ras->ras_lock);
983 ll_ra_stats_inc_sbi(sbi, hit ? RA_STAT_HIT : RA_STAT_MISS);
985 /* reset the read-ahead window in two cases. First when the app seeks
986 * or reads to some other part of the file. Secondly if we get a
987 * read-ahead miss that we think we've previously issued. This can
988 * be a symptom of there being so many read-ahead pages that the VM is
989 * reclaiming it before we get to it. */
990 if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) {
992 ll_ra_stats_inc_sbi(sbi, RA_STAT_DISTANT_READPAGE);
993 } else if (!hit && ras->ras_window_len &&
994 index < ras->ras_next_readahead &&
995 index_in_window(index, ras->ras_window_start, 0,
996 ras->ras_window_len)) {
998 ll_ra_stats_inc_sbi(sbi, RA_STAT_MISS_IN_WINDOW);
1001 /* On the second access to a file smaller than the tunable
1002 * ra_max_read_ahead_whole_pages trigger RA on all pages in the
1003 * file up to ra_max_pages_per_file. This is simply a best effort
1004 * and only occurs once per open file. Normal RA behavior is reverted
1005 * to for subsequent IO. The mmap case does not increment
1006 * ras_requests and thus can never trigger this behavior. */
1007 if (ras->ras_requests == 2 && !ras->ras_request_index) {
1010 kms_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
1013 CDEBUG(D_READA, "kmsp %llu mwp %lu mp %lu\n", kms_pages,
1014 ra->ra_max_read_ahead_whole_pages, ra->ra_max_pages_per_file);
1017 kms_pages <= ra->ra_max_read_ahead_whole_pages) {
1018 ras->ras_window_start = 0;
1019 ras->ras_last_readpage = 0;
1020 ras->ras_next_readahead = 0;
1021 ras->ras_window_len = min(ra->ra_max_pages_per_file,
1022 ra->ra_max_read_ahead_whole_pages);
1027 /* check whether it is in stride I/O mode*/
1028 if (!index_in_stride_window(ras, index)) {
1029 if (ras->ras_consecutive_stride_requests == 0 &&
1030 ras->ras_request_index == 0) {
1031 ras_update_stride_detector(ras, index);
1032 ras->ras_consecutive_stride_requests++;
1034 ras_stride_reset(ras);
1036 ras_reset(inode, ras, index);
1037 ras->ras_consecutive_pages++;
1040 ras->ras_consecutive_pages = 0;
1041 ras->ras_consecutive_requests = 0;
1042 if (++ras->ras_consecutive_stride_requests > 1)
1048 if (index_in_stride_window(ras, index) &&
1049 stride_io_mode(ras)) {
1050 /*If stride-RA hit cache miss, the stride dector
1051 *will not be reset to avoid the overhead of
1052 *redetecting read-ahead mode */
1053 if (index != ras->ras_last_readpage + 1)
1054 ras->ras_consecutive_pages = 0;
1055 ras_reset(inode, ras, index);
1058 /* Reset both stride window and normal RA
1060 ras_reset(inode, ras, index);
1061 ras->ras_consecutive_pages++;
1062 ras_stride_reset(ras);
1065 } else if (stride_io_mode(ras)) {
1066 /* If this is contiguous read but in stride I/O mode
1067 * currently, check whether stride step still is valid,
1068 * if invalid, it will reset the stride ra window*/
1069 if (!index_in_stride_window(ras, index)) {
1070 /* Shrink stride read-ahead window to be zero */
1071 ras_stride_reset(ras);
1072 ras->ras_window_len = 0;
1073 ras->ras_next_readahead = index;
1077 ras->ras_consecutive_pages++;
1078 ras->ras_last_readpage = index;
1079 ras_set_start(inode, ras, index);
1081 if (stride_io_mode(ras))
1082 /* Since stride readahead is sensitive to the offset
1083 * of read-ahead, so we use original offset here,
1084 * instead of ras_window_start, which is RPC aligned */
1085 ras->ras_next_readahead = max(index, ras->ras_next_readahead);
1087 ras->ras_next_readahead = max(ras->ras_window_start,
1088 ras->ras_next_readahead);
1091 /* Trigger RA in the mmap case where ras_consecutive_requests
1092 * is not incremented and thus can't be used to trigger RA */
1093 if (!ras->ras_window_len && ras->ras_consecutive_pages == 4) {
1094 ras->ras_window_len = RAS_INCREASE_STEP(inode);
1098 /* Initially reset the stride window offset to next_readahead*/
1099 if (ras->ras_consecutive_stride_requests == 2 && stride_detect) {
1101 * Once stride IO mode is detected, next_readahead should be
1102 * reset to make sure next_readahead > stride offset
1104 ras->ras_next_readahead = max(index, ras->ras_next_readahead);
1105 ras->ras_stride_offset = index;
1106 ras->ras_window_len = RAS_INCREASE_STEP(inode);
1109 /* The initial ras_window_len is set to the request size. To avoid
1110 * uselessly reading and discarding pages for random IO the window is
1111 * only increased once per consecutive request received. */
1112 if ((ras->ras_consecutive_requests > 1 || stride_detect) &&
1113 !ras->ras_request_index)
1114 ras_increase_window(inode, ras, ra);
1117 ras->ras_request_index++;
1118 spin_unlock(&ras->ras_lock);
1122 int ll_writepage(struct page *vmpage, struct writeback_control *wbc)
1124 struct inode *inode = vmpage->mapping->host;
1125 struct ll_inode_info *lli = ll_i2info(inode);
1128 struct cl_page *page;
1129 struct cl_object *clob;
1130 struct cl_env_nest nest;
1131 bool redirtied = false;
1132 bool unlocked = false;
1135 LASSERT(PageLocked(vmpage));
1136 LASSERT(!PageWriteback(vmpage));
1138 LASSERT(ll_i2dtexp(inode) != NULL);
1140 env = cl_env_nested_get(&nest);
1142 result = PTR_ERR(env);
1146 clob = ll_i2info(inode)->lli_clob;
1147 LASSERT(clob != NULL);
1149 io = ccc_env_thread_io(env);
1151 io->ci_ignore_layout = 1;
1152 result = cl_io_init(env, io, CIT_MISC, clob);
1154 page = cl_page_find(env, clob, vmpage->index,
1155 vmpage, CPT_CACHEABLE);
1156 if (!IS_ERR(page)) {
1157 lu_ref_add(&page->cp_reference, "writepage",
1159 cl_page_assume(env, io, page);
1160 result = cl_page_flush(env, io, page);
1163 * Re-dirty page on error so it retries write,
1164 * but not in case when IO has actually
1165 * occurred and completed with an error.
1167 if (!PageError(vmpage)) {
1168 redirty_page_for_writepage(wbc, vmpage);
1173 cl_page_disown(env, io, page);
1175 lu_ref_del(&page->cp_reference,
1176 "writepage", current);
1177 cl_page_put(env, page);
1179 result = PTR_ERR(page);
1182 cl_io_fini(env, io);
1184 if (redirtied && wbc->sync_mode == WB_SYNC_ALL) {
1185 loff_t offset = cl_offset(clob, vmpage->index);
1187 /* Flush page failed because the extent is being written out.
1188 * Wait for the write of extent to be finished to avoid
1189 * breaking kernel which assumes ->writepage should mark
1190 * PageWriteback or clean the page. */
1191 result = cl_sync_file_range(inode, offset,
1192 offset + PAGE_CACHE_SIZE - 1,
1195 /* actually we may have written more than one page.
1196 * decreasing this page because the caller will count
1198 wbc->nr_to_write -= result - 1;
1203 cl_env_nested_put(&nest, env);
1208 if (!lli->lli_async_rc)
1209 lli->lli_async_rc = result;
1210 SetPageError(vmpage);
1212 unlock_page(vmpage);
1217 int ll_writepages(struct address_space *mapping, struct writeback_control *wbc)
1219 struct inode *inode = mapping->host;
1220 struct ll_sb_info *sbi = ll_i2sbi(inode);
1223 enum cl_fsync_mode mode;
1224 int range_whole = 0;
1226 int ignore_layout = 0;
1228 if (wbc->range_cyclic) {
1229 start = mapping->writeback_index << PAGE_CACHE_SHIFT;
1230 end = OBD_OBJECT_EOF;
1232 start = wbc->range_start;
1233 end = wbc->range_end;
1234 if (end == LLONG_MAX) {
1235 end = OBD_OBJECT_EOF;
1236 range_whole = start == 0;
1240 mode = CL_FSYNC_NONE;
1241 if (wbc->sync_mode == WB_SYNC_ALL)
1242 mode = CL_FSYNC_LOCAL;
1244 if (sbi->ll_umounting)
1245 /* if the mountpoint is being umounted, all pages have to be
1246 * evicted to avoid hitting LBUG when truncate_inode_pages()
1247 * is called later on. */
1249 result = cl_sync_file_range(inode, start, end, mode, ignore_layout);
1251 wbc->nr_to_write -= result;
1255 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) {
1256 if (end == OBD_OBJECT_EOF)
1257 end = i_size_read(inode);
1258 mapping->writeback_index = (end >> PAGE_CACHE_SHIFT) + 1;
1263 int ll_readpage(struct file *file, struct page *vmpage)
1265 struct ll_cl_context *lcc;
1268 lcc = ll_cl_init(file, vmpage, 0);
1270 struct lu_env *env = lcc->lcc_env;
1271 struct cl_io *io = lcc->lcc_io;
1272 struct cl_page *page = lcc->lcc_page;
1274 LASSERT(page->cp_type == CPT_CACHEABLE);
1275 if (likely(!PageUptodate(vmpage))) {
1276 cl_page_assume(env, io, page);
1277 result = cl_io_read_page(env, io, page);
1279 /* Page from a non-object file. */
1280 unlock_page(vmpage);
1285 unlock_page(vmpage);
1286 result = PTR_ERR(lcc);