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.gnu.org/licenses/gpl-2.0.html
23 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Use is subject to license terms.
26 * Copyright (c) 2011, 2017, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
33 * Lustre Lite I/O page cache routines shared by different kernel revs
36 #include <linux/kernel.h>
38 #include <linux/string.h>
39 #include <linux/stat.h>
40 #include <linux/errno.h>
41 #include <linux/unistd.h>
42 #include <linux/writeback.h>
43 #include <asm/uaccess.h>
46 #include <linux/file.h>
47 #include <linux/stat.h>
48 #include <asm/uaccess.h>
50 #include <linux/pagemap.h>
51 /* current_is_kswapd() */
52 #include <linux/swap.h>
53 #include <linux/task_io_accounting_ops.h>
55 #define DEBUG_SUBSYSTEM S_LLITE
57 #include <obd_cksum.h>
58 #include "llite_internal.h"
59 #include <lustre_compat.h>
61 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which);
64 * Get readahead pages from the filesystem readahead pool of the client for a
67 * /param sbi superblock for filesystem readahead state ll_ra_info
68 * /param ria per-thread readahead state
69 * /param pages number of pages requested for readahead for the thread.
71 * WARNING: This algorithm is used to reduce contention on sbi->ll_lock.
72 * It should work well if the ra_max_pages is much greater than the single
73 * file's read-ahead window, and not too many threads contending for
74 * these readahead pages.
76 * TODO: There may be a 'global sync problem' if many threads are trying
77 * to get an ra budget that is larger than the remaining readahead pages
78 * and reach here at exactly the same time. They will compute /a ret to
79 * consume the remaining pages, but will fail at atomic_add_return() and
80 * get a zero ra window, although there is still ra space remaining. - Jay */
82 static unsigned long ll_ra_count_get(struct ll_sb_info *sbi,
83 struct ra_io_arg *ria,
85 unsigned long pages_min)
87 struct ll_ra_info *ra = &sbi->ll_ra_info;
92 WARN_ON_ONCE(pages_min > pages);
94 * Don't try readahead aggresively if we are limited
95 * LRU pages, otherwise, it could cause deadlock.
97 pages = min(sbi->ll_cache->ccc_lru_max >> 2, pages);
99 * if this happen, we reserve more pages than needed,
100 * this will make us leak @ra_cur_pages, because
101 * ll_ra_count_put() acutally freed @pages.
103 if (unlikely(pages_min > pages))
107 * If read-ahead pages left are less than 1M, do not do read-ahead,
108 * otherwise it will form small read RPC(< 1M), which hurt server
111 ret = min(ra->ra_max_pages - atomic_read(&ra->ra_cur_pages),
113 if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages))
116 if (atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) {
117 atomic_sub(ret, &ra->ra_cur_pages);
122 if (ret < pages_min) {
123 /* override ra limit for maximum performance */
124 atomic_add(pages_min - ret, &ra->ra_cur_pages);
130 void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long pages)
132 struct ll_ra_info *ra = &sbi->ll_ra_info;
133 atomic_sub(pages, &ra->ra_cur_pages);
136 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which)
138 LASSERTF(which < _NR_RA_STAT, "which: %u\n", which);
139 lprocfs_counter_incr(sbi->ll_ra_stats, which);
142 static inline bool ll_readahead_enabled(struct ll_sb_info *sbi)
144 return sbi->ll_ra_info.ra_max_pages_per_file > 0 &&
145 sbi->ll_ra_info.ra_max_pages > 0;
148 void ll_ra_stats_inc(struct inode *inode, enum ra_stat which)
150 struct ll_sb_info *sbi = ll_i2sbi(inode);
152 ll_ra_stats_inc_sbi(sbi, which);
155 void ll_ra_stats_add(struct inode *inode, enum ra_stat which, long count)
157 struct ll_sb_info *sbi = ll_i2sbi(inode);
159 LASSERTF(which < _NR_RA_STAT, "which: %u\n", which);
160 lprocfs_counter_add(sbi->ll_ra_stats, which, count);
163 #define RAS_CDEBUG(ras) \
165 "lre %llu cr %lu cb %llu wsi %lu wp %lu nra %lu rpc %lu " \
166 "r %lu csr %lu so %llu sb %llu sl %llu lr %lu\n", \
167 ras->ras_last_read_end_bytes, ras->ras_consecutive_requests, \
168 ras->ras_consecutive_bytes, ras->ras_window_start_idx, \
169 ras->ras_window_pages, ras->ras_next_readahead_idx, \
170 ras->ras_rpc_pages, ras->ras_requests, \
171 ras->ras_consecutive_stride_requests, ras->ras_stride_offset, \
172 ras->ras_stride_bytes, ras->ras_stride_length, \
173 ras->ras_async_last_readpage_idx)
175 static bool pos_in_window(loff_t pos, loff_t point,
176 unsigned long before, unsigned long after)
178 loff_t start = point - before;
179 loff_t end = point + after;
186 return start <= pos && pos <= end;
189 enum ll_ra_page_hint {
190 MAYNEED = 0, /* this page possibly accessed soon */
191 WILLNEED /* this page is gurateed to be needed */
195 * Initiates read-ahead of a page with given index.
197 * \retval +ve: page was already uptodate so it will be skipped
199 * \retval -ve: page wasn't added to \a queue for error;
200 * \retval 0: page was added into \a queue for read ahead.
202 static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io,
203 struct cl_page_list *queue, pgoff_t index,
204 enum ll_ra_page_hint hint)
206 struct cl_object *clob = io->ci_obj;
207 struct inode *inode = vvp_object_inode(clob);
208 struct page *vmpage = NULL;
210 enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */
212 const char *msg = NULL;
218 vmpage = grab_cache_page_nowait(inode->i_mapping, index);
219 if (vmpage == NULL) {
220 which = RA_STAT_FAILED_GRAB_PAGE;
221 msg = "g_c_p_n failed";
222 GOTO(out, rc = -EBUSY);
226 vmpage = find_or_create_page(inode->i_mapping, index,
229 GOTO(out, rc = -ENOMEM);
232 /* should not come here */
233 GOTO(out, rc = -EINVAL);
236 /* Check if vmpage was truncated or reclaimed */
237 if (vmpage->mapping != inode->i_mapping) {
238 which = RA_STAT_WRONG_GRAB_PAGE;
239 msg = "g_c_p_n returned invalid page";
240 GOTO(out, rc = -EBUSY);
243 cp = cl_page_find(env, clob, vmpage->index, vmpage, CPT_CACHEABLE);
245 which = RA_STAT_FAILED_GRAB_PAGE;
246 msg = "cl_page_find failed";
247 GOTO(out, rc = PTR_ERR(cp));
250 lu_ref_add(&cp->cp_reference, "ra", current);
251 cl_page_assume(env, io, cp);
253 if (!cp->cp_defer_uptodate && !PageUptodate(vmpage)) {
254 if (hint == MAYNEED) {
255 cp->cp_defer_uptodate = 1;
259 cl_page_list_add(queue, cp, true);
261 /* skip completed pages */
262 cl_page_unassume(env, io, cp);
263 /* This page is already uptodate, returning a positive number
264 * to tell the callers about this */
268 lu_ref_del(&cp->cp_reference, "ra", current);
269 cl_page_put(env, cp);
272 if (vmpage != NULL) {
277 if (msg != NULL && hint == MAYNEED) {
278 ll_ra_stats_inc(inode, which);
279 CDEBUG(D_READA, "%s\n", msg);
286 #define RIA_DEBUG(ria) \
287 CDEBUG(D_READA, "rs %lu re %lu ro %llu rl %llu rb %llu\n", \
288 ria->ria_start_idx, ria->ria_end_idx, ria->ria_stoff, \
289 ria->ria_length, ria->ria_bytes)
291 static inline int stride_io_mode(struct ll_readahead_state *ras)
293 return ras->ras_consecutive_stride_requests > 1;
296 /* The function calculates how many bytes will be read in
297 * [off, off + length], in such stride IO area,
298 * stride_offset = st_off, stride_lengh = st_len,
299 * stride_bytes = st_bytes
301 * |------------------|*****|------------------|*****|------------|*****|....
304 * |----- st_len -----|
306 * How many bytes it should read in such pattern
307 * |-------------------------------------------------------------|
309 * |<------ length ------->|
311 * = |<----->| + |-------------------------------------| + |---|
312 * start_left st_bytes * i end_left
314 static loff_t stride_byte_count(loff_t st_off, loff_t st_len, loff_t st_bytes,
315 loff_t off, loff_t length)
317 u64 start = off > st_off ? off - st_off : 0;
318 u64 end = off + length > st_off ? off + length - st_off : 0;
323 if (st_len == 0 || length == 0 || end == 0)
326 start = div64_u64_rem(start, st_len, &start_left);
327 if (start_left < st_bytes)
328 start_left = st_bytes - start_left;
332 end = div64_u64_rem(end, st_len, &end_left);
333 if (end_left > st_bytes)
336 CDEBUG(D_READA, "start %llu, end %llu start_left %llu end_left %llu\n",
337 start, end, start_left, end_left);
340 bytes_count = end_left - (st_bytes - start_left);
342 bytes_count = start_left +
343 st_bytes * (end - start - 1) + end_left;
346 "st_off %llu, st_len %llu st_bytes %llu off %llu length %llu bytescount %llu\n",
347 st_off, st_len, st_bytes, off, length, bytes_count);
352 static unsigned long ria_page_count(struct ra_io_arg *ria)
354 loff_t length_bytes = ria->ria_end_idx >= ria->ria_start_idx ?
355 (loff_t)(ria->ria_end_idx -
356 ria->ria_start_idx + 1) << PAGE_SHIFT : 0;
359 if (ria->ria_length > ria->ria_bytes && ria->ria_bytes &&
360 (ria->ria_length & ~PAGE_MASK || ria->ria_bytes & ~PAGE_MASK ||
361 ria->ria_stoff & ~PAGE_MASK)) {
362 /* Over-estimate un-aligned page stride read */
363 unsigned long pg_count = ((ria->ria_bytes +
364 PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
365 pg_count *= length_bytes / ria->ria_length + 1;
369 bytes_count = stride_byte_count(ria->ria_stoff, ria->ria_length,
371 (loff_t)ria->ria_start_idx<<PAGE_SHIFT,
373 return (bytes_count + PAGE_SIZE - 1) >> PAGE_SHIFT;
376 static pgoff_t ras_align(struct ll_readahead_state *ras, pgoff_t index)
378 unsigned opt_size = min(ras->ras_window_pages, ras->ras_rpc_pages);
382 return index - (index % opt_size);
385 /* Check whether the index is in the defined ra-window */
386 static bool ras_inside_ra_window(pgoff_t idx, struct ra_io_arg *ria)
388 loff_t pos = (loff_t)idx << PAGE_SHIFT;
390 /* If ria_length == ria_bytes, it means non-stride I/O mode,
391 * idx should always inside read-ahead window in this case
392 * For stride I/O mode, just check whether the idx is inside
395 if (ria->ria_length == 0 || ria->ria_length == ria->ria_bytes)
398 if (pos >= ria->ria_stoff) {
401 div64_u64_rem(pos - ria->ria_stoff, ria->ria_length, &offset);
403 if (offset < ria->ria_bytes ||
404 (ria->ria_length - offset) < PAGE_SIZE)
406 } else if (pos + PAGE_SIZE > ria->ria_stoff) {
414 ll_read_ahead_pages(const struct lu_env *env, struct cl_io *io,
415 struct cl_page_list *queue, struct ll_readahead_state *ras,
416 struct ra_io_arg *ria, pgoff_t *ra_end, pgoff_t skip_index)
418 struct cl_read_ahead ra = { 0 };
419 /* busy page count is per stride */
420 int rc = 0, count = 0, busy_page_count = 0;
423 LASSERT(ria != NULL);
426 for (page_idx = ria->ria_start_idx;
427 page_idx <= ria->ria_end_idx && ria->ria_reserved > 0;
429 if (skip_index && page_idx == skip_index)
431 if (ras_inside_ra_window(page_idx, ria)) {
432 if (ra.cra_end_idx == 0 || ra.cra_end_idx < page_idx) {
436 * Do not shrink ria_end_idx at any case until
437 * the minimum end of current read is covered.
439 * Do not extend read lock accross stripe if
440 * lock contention detected.
442 if (ra.cra_contention &&
443 page_idx > ria->ria_end_idx_min) {
444 ria->ria_end_idx = *ra_end;
448 cl_read_ahead_release(env, &ra);
450 rc = cl_io_read_ahead(env, io, page_idx, &ra);
455 * Only shrink ria_end_idx if the matched
456 * LDLM lock doesn't cover more.
458 if (page_idx > ra.cra_end_idx) {
459 ria->ria_end_idx = ra.cra_end_idx;
463 CDEBUG(D_READA, "idx: %lu, ra: %lu, rpc: %lu\n",
464 page_idx, ra.cra_end_idx,
466 LASSERTF(ra.cra_end_idx >= page_idx,
467 "object: %p, indcies %lu / %lu\n",
468 io->ci_obj, ra.cra_end_idx, page_idx);
469 /* update read ahead RPC size.
470 * NB: it's racy but doesn't matter */
471 if (ras->ras_rpc_pages != ra.cra_rpc_pages &&
472 ra.cra_rpc_pages > 0)
473 ras->ras_rpc_pages = ra.cra_rpc_pages;
475 /* trim it to align with optimal RPC size */
476 end_idx = ras_align(ras, ria->ria_end_idx + 1);
477 if (end_idx > 0 && !ria->ria_eof)
478 ria->ria_end_idx = end_idx - 1;
480 if (ria->ria_end_idx < ria->ria_end_idx_min)
481 ria->ria_end_idx = ria->ria_end_idx_min;
483 if (page_idx > ria->ria_end_idx)
486 /* If the page is inside the read-ahead window */
487 rc = ll_read_ahead_page(env, io, queue, page_idx,
489 if (rc < 0 && rc != -EBUSY)
494 "skip busy page: %lu\n", page_idx);
495 /* For page unaligned readahead the first
496 * last pages of each region can be read by
497 * another reader on the same node, and so
498 * may be busy. So only stop for > 2 busy
500 if (busy_page_count > 2)
505 /* Only subtract from reserve & count the page if we
506 * really did readahead on that page. */
511 } else if (stride_io_mode(ras)) {
512 /* If it is not in the read-ahead window, and it is
513 * read-ahead mode, then check whether it should skip
516 loff_t pos = (loff_t)page_idx << PAGE_SHIFT;
519 div64_u64_rem(pos - ria->ria_stoff, ria->ria_length,
521 if (offset >= ria->ria_bytes) {
522 pos += (ria->ria_length - offset);
523 if ((pos >> PAGE_SHIFT) >= page_idx + 1)
524 page_idx = (pos >> PAGE_SHIFT) - 1;
527 "Stride: jump %llu pages to %lu\n",
528 ria->ria_length - offset, page_idx);
534 cl_read_ahead_release(env, &ra);
537 ll_ra_stats_add(vvp_object_inode(io->ci_obj),
538 RA_STAT_READAHEAD_PAGES, count);
543 static void ll_readahead_work_free(struct ll_readahead_work *work)
545 fput(work->lrw_file);
549 static void ll_readahead_handle_work(struct work_struct *wq);
550 static void ll_readahead_work_add(struct inode *inode,
551 struct ll_readahead_work *work)
553 INIT_WORK(&work->lrw_readahead_work, ll_readahead_handle_work);
554 queue_work(ll_i2sbi(inode)->ll_ra_info.ll_readahead_wq,
555 &work->lrw_readahead_work);
558 static int ll_readahead_file_kms(const struct lu_env *env,
559 struct cl_io *io, __u64 *kms)
561 struct cl_object *clob;
563 struct cl_attr *attr = vvp_env_thread_attr(env);
567 inode = vvp_object_inode(clob);
569 cl_object_attr_lock(clob);
570 ret = cl_object_attr_get(env, clob, attr);
571 cl_object_attr_unlock(clob);
576 *kms = attr->cat_kms;
580 static void ll_readahead_handle_work(struct work_struct *wq)
582 struct ll_readahead_work *work;
585 struct ra_io_arg *ria;
587 struct ll_file_data *fd;
588 struct ll_readahead_state *ras;
590 struct cl_2queue *queue;
591 pgoff_t ra_end_idx = 0;
592 unsigned long pages, pages_min = 0;
597 struct ll_sb_info *sbi;
599 work = container_of(wq, struct ll_readahead_work,
601 fd = work->lrw_file->private_data;
603 file = work->lrw_file;
604 inode = file_inode(file);
605 sbi = ll_i2sbi(inode);
607 CDEBUG(D_READA|D_IOTRACE,
608 "%s:"DFID": async ra from %lu to %lu triggered by user pid %d\n",
609 file_dentry(file)->d_name.name, PFID(ll_inode2fid(inode)),
610 work->lrw_start_idx, work->lrw_end_idx, work->lrw_user_pid);
612 env = cl_env_alloc(&refcheck, LCT_NOREF);
614 GOTO(out_free_work, rc = PTR_ERR(env));
616 io = vvp_env_thread_io(env);
617 ll_io_init(io, file, CIT_READ, NULL);
619 rc = ll_readahead_file_kms(env, io, &kms);
621 GOTO(out_put_env, rc);
624 ll_ra_stats_inc(inode, RA_STAT_ZERO_LEN);
625 GOTO(out_put_env, rc = 0);
628 ria = &ll_env_info(env)->lti_ria;
629 memset(ria, 0, sizeof(*ria));
631 ria->ria_start_idx = work->lrw_start_idx;
632 /* Truncate RA window to end of file */
633 eof_index = (pgoff_t)(kms - 1) >> PAGE_SHIFT;
634 if (eof_index <= work->lrw_end_idx) {
635 work->lrw_end_idx = eof_index;
638 if (work->lrw_end_idx <= work->lrw_start_idx)
639 GOTO(out_put_env, rc = 0);
641 ria->ria_end_idx = work->lrw_end_idx;
642 pages = ria->ria_end_idx - ria->ria_start_idx + 1;
643 ria->ria_reserved = ll_ra_count_get(sbi, ria,
644 ria_page_count(ria), pages_min);
647 "async reserved pages: %lu/%lu/%lu, ra_cur %d, ra_max %lu\n",
648 ria->ria_reserved, pages, pages_min,
649 atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
650 ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
652 if (ria->ria_reserved < pages) {
653 ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT);
654 if (PAGES_TO_MiB(ria->ria_reserved) < 1) {
655 ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
656 GOTO(out_put_env, rc = 0);
660 rc = cl_io_rw_init(env, io, CIT_READ, ria->ria_start_idx, pages);
662 GOTO(out_put_env, rc);
664 /* overwrite jobid inited in vvp_io_init() */
665 if (strncmp(ll_i2info(inode)->lli_jobid, work->lrw_jobid,
666 sizeof(work->lrw_jobid)))
667 memcpy(ll_i2info(inode)->lli_jobid, work->lrw_jobid,
668 sizeof(work->lrw_jobid));
670 vvp_env_io(env)->vui_fd = fd;
671 io->ci_state = CIS_LOCKED;
672 io->ci_async_readahead = true;
673 rc = cl_io_start(env, io);
675 GOTO(out_io_fini, rc);
677 queue = &io->ci_queue;
678 cl_2queue_init(queue);
680 rc = ll_read_ahead_pages(env, io, &queue->c2_qin, ras, ria,
682 if (ria->ria_reserved != 0)
683 ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
684 if (queue->c2_qin.pl_nr > 0) {
685 int count = queue->c2_qin.pl_nr;
687 rc = cl_io_submit_rw(env, io, CRT_READ, queue);
689 task_io_account_read(PAGE_SIZE * count);
691 if (ria->ria_end_idx == ra_end_idx && ra_end_idx == (kms >> PAGE_SHIFT))
692 ll_ra_stats_inc(inode, RA_STAT_EOF);
694 if (ra_end_idx != ria->ria_end_idx)
695 ll_ra_stats_inc(inode, RA_STAT_FAILED_REACH_END);
697 /* TODO: discard all pages until page reinit route is implemented */
698 cl_page_list_discard(env, io, &queue->c2_qin);
700 /* Unlock unsent read pages in case of error. */
701 cl_page_list_disown(env, &queue->c2_qin);
703 cl_2queue_fini(env, queue);
708 cl_env_put(env, &refcheck);
711 ll_ra_stats_inc_sbi(ll_i2sbi(inode), RA_STAT_ASYNC);
712 atomic_dec(&sbi->ll_ra_info.ra_async_inflight);
713 ll_readahead_work_free(work);
716 static int ll_readahead(const struct lu_env *env, struct cl_io *io,
717 struct cl_page_list *queue,
718 struct ll_readahead_state *ras, bool hit,
719 struct file *file, pgoff_t skip_index,
722 struct vvp_io *vio = vvp_env_io(env);
723 struct ll_thread_info *lti = ll_env_info(env);
724 unsigned long pages, pages_min = 0;
725 pgoff_t ra_end_idx = 0, end_idx = 0;
727 struct ra_io_arg *ria = <i->lti_ria;
728 struct cl_object *clob;
731 struct ll_sb_info *sbi;
732 struct ll_ra_info *ra;
737 inode = vvp_object_inode(clob);
738 sbi = ll_i2sbi(inode);
739 ra = &sbi->ll_ra_info;
742 * In case we have a limited max_cached_mb, readahead
743 * should be stopped if it have run out of all LRU slots.
745 if (atomic_read(&ra->ra_cur_pages) >= sbi->ll_cache->ccc_lru_max) {
746 ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT);
750 memset(ria, 0, sizeof(*ria));
751 ret = ll_readahead_file_kms(env, io, &kms);
756 ll_ra_stats_inc(inode, RA_STAT_ZERO_LEN);
760 spin_lock(&ras->ras_lock);
763 * Note: other thread might rollback the ras_next_readahead_idx,
764 * if it can not get the full size of prepared pages, see the
765 * end of this function. For stride read ahead, it needs to
766 * make sure the offset is no less than ras_stride_offset,
767 * so that stride read ahead can work correctly.
769 if (stride_io_mode(ras))
770 *start_idx = max_t(pgoff_t, ras->ras_next_readahead_idx,
771 ras->ras_stride_offset >> PAGE_SHIFT);
773 *start_idx = ras->ras_next_readahead_idx;
775 if (ras->ras_window_pages > 0)
776 end_idx = ras->ras_window_start_idx + ras->ras_window_pages - 1;
779 end_idx = *start_idx + ras->ras_window_pages - 1;
781 /* Enlarge the RA window to encompass the full read */
782 if (vio->vui_ra_valid &&
783 end_idx < vio->vui_ra_start_idx + vio->vui_ra_pages - 1)
784 end_idx = vio->vui_ra_start_idx + vio->vui_ra_pages - 1;
789 /* Truncate RA window to end of file */
790 eof_index = (pgoff_t)((kms - 1) >> PAGE_SHIFT);
791 if (eof_index <= end_idx) {
796 ria->ria_start_idx = *start_idx;
797 ria->ria_end_idx = end_idx;
798 /* If stride I/O mode is detected, get stride window*/
799 if (stride_io_mode(ras)) {
800 ria->ria_stoff = ras->ras_stride_offset;
801 ria->ria_length = ras->ras_stride_length;
802 ria->ria_bytes = ras->ras_stride_bytes;
804 spin_unlock(&ras->ras_lock);
807 ll_ra_stats_inc(inode, RA_STAT_ZERO_WINDOW);
810 pages = ria_page_count(ria);
812 ll_ra_stats_inc(inode, RA_STAT_ZERO_WINDOW);
817 CDEBUG(D_READA, DFID": ria: %lu/%lu, bead: %lu/%lu, hit: %d\n",
818 PFID(lu_object_fid(&clob->co_lu)),
819 ria->ria_start_idx, ria->ria_end_idx,
820 vio->vui_ra_valid ? vio->vui_ra_start_idx : 0,
821 vio->vui_ra_valid ? vio->vui_ra_pages : 0,
824 /* at least to extend the readahead window to cover current read */
825 if (!hit && vio->vui_ra_valid &&
826 vio->vui_ra_start_idx + vio->vui_ra_pages > ria->ria_start_idx) {
827 ria->ria_end_idx_min =
828 vio->vui_ra_start_idx + vio->vui_ra_pages - 1;
829 pages_min = vio->vui_ra_start_idx + vio->vui_ra_pages -
832 * For performance reason, exceeding @ra_max_pages
833 * are allowed, but this should be limited with RPC
834 * size in case a large block size read issued. Trim
837 pages_min = min(pages_min, ras->ras_rpc_pages -
838 (ria->ria_start_idx % ras->ras_rpc_pages));
841 /* don't over reserved for mmap range read */
844 if (pages_min > pages)
846 ria->ria_reserved = ll_ra_count_get(ll_i2sbi(inode), ria, pages,
848 if (ria->ria_reserved < pages)
849 ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT);
851 CDEBUG(D_READA, "reserved pages: %lu/%lu/%lu, ra_cur %d, ra_max %lu\n",
852 ria->ria_reserved, pages, pages_min,
853 atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
854 ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
856 ret = ll_read_ahead_pages(env, io, queue, ras, ria, &ra_end_idx,
858 if (ria->ria_reserved != 0)
859 ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
861 if (ra_end_idx == end_idx && ra_end_idx == (kms >> PAGE_SHIFT))
862 ll_ra_stats_inc(inode, RA_STAT_EOF);
865 "ra_end_idx = %lu end_idx = %lu stride end = %lu pages = %d\n",
866 ra_end_idx, end_idx, ria->ria_end_idx, ret);
868 if (ra_end_idx != end_idx)
869 ll_ra_stats_inc(inode, RA_STAT_FAILED_REACH_END);
870 if (ra_end_idx > 0) {
871 /* update the ras so that the next read-ahead tries from
872 * where we left off. */
873 spin_lock(&ras->ras_lock);
874 ras->ras_next_readahead_idx = ra_end_idx + 1;
875 spin_unlock(&ras->ras_lock);
882 static int ll_readpages(const struct lu_env *env, struct cl_io *io,
883 struct cl_page_list *queue,
884 pgoff_t start, pgoff_t end)
893 ret = ll_readahead_file_kms(env, io, &kms);
901 unsigned long end_index;
903 end_index = (unsigned long)((kms - 1) >> PAGE_SHIFT);
904 if (end_index <= end)
908 for (page_idx = start; page_idx <= end; page_idx++) {
909 ret= ll_read_ahead_page(env, io, queue, page_idx,
913 else if (ret == 0) /* ret 1 is already uptodate */
917 RETURN(count > 0 ? count : ret);
920 static void ras_set_start(struct ll_readahead_state *ras, pgoff_t index)
922 ras->ras_window_start_idx = ras_align(ras, index);
925 /* called with the ras_lock held or from places where it doesn't matter */
926 static void ras_reset(struct ll_readahead_state *ras, pgoff_t index)
928 ras->ras_consecutive_requests = 0;
929 ras->ras_consecutive_bytes = 0;
930 ras->ras_window_pages = 0;
931 ras_set_start(ras, index);
932 ras->ras_next_readahead_idx = max(ras->ras_window_start_idx, index + 1);
937 /* called with the ras_lock held or from places where it doesn't matter */
938 static void ras_stride_reset(struct ll_readahead_state *ras)
940 ras->ras_consecutive_stride_requests = 0;
941 ras->ras_stride_length = 0;
942 ras->ras_stride_bytes = 0;
946 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
948 spin_lock_init(&ras->ras_lock);
949 ras->ras_rpc_pages = PTLRPC_MAX_BRW_PAGES;
951 ras->ras_last_read_end_bytes = 0;
952 ras->ras_requests = 0;
953 ras->ras_range_min_start_idx = 0;
954 ras->ras_range_max_end_idx = 0;
955 ras->ras_range_requests = 0;
956 ras->ras_last_range_pages = 0;
960 * Check whether the read request is in the stride window.
961 * If it is in the stride window, return true, otherwise return false.
963 static bool read_in_stride_window(struct ll_readahead_state *ras,
964 loff_t pos, loff_t count)
968 if (ras->ras_stride_length == 0 || ras->ras_stride_bytes == 0 ||
969 ras->ras_stride_bytes == ras->ras_stride_length)
972 stride_gap = pos - ras->ras_last_read_end_bytes - 1;
974 /* If it is contiguous read */
976 return ras->ras_consecutive_bytes + count <=
977 ras->ras_stride_bytes;
979 /* Otherwise check the stride by itself */
980 return (ras->ras_stride_length - ras->ras_stride_bytes) == stride_gap &&
981 ras->ras_consecutive_bytes == ras->ras_stride_bytes &&
982 count <= ras->ras_stride_bytes;
985 static void ras_init_stride_detector(struct ll_readahead_state *ras,
986 loff_t pos, loff_t count)
988 loff_t stride_gap = pos - ras->ras_last_read_end_bytes - 1;
990 LASSERT(ras->ras_consecutive_stride_requests == 0);
992 if (pos <= ras->ras_last_read_end_bytes) {
993 /*Reset stride window for forward read*/
994 ras_stride_reset(ras);
998 ras->ras_stride_bytes = ras->ras_consecutive_bytes;
999 ras->ras_stride_length = stride_gap + ras->ras_consecutive_bytes;
1000 ras->ras_consecutive_stride_requests++;
1001 ras->ras_stride_offset = pos;
1006 static unsigned long
1007 stride_page_count(struct ll_readahead_state *ras, loff_t len)
1009 loff_t bytes_count =
1010 stride_byte_count(ras->ras_stride_offset,
1011 ras->ras_stride_length, ras->ras_stride_bytes,
1012 ras->ras_window_start_idx << PAGE_SHIFT, len);
1014 return (bytes_count + PAGE_SIZE - 1) >> PAGE_SHIFT;
1017 /* Stride Read-ahead window will be increased inc_len according to
1018 * stride I/O pattern */
1019 static void ras_stride_increase_window(struct ll_readahead_state *ras,
1020 struct ll_ra_info *ra, loff_t inc_bytes)
1022 loff_t window_bytes, stride_bytes;
1027 /* temporarily store in page units to reduce LASSERT() cost below */
1028 end = ras->ras_window_start_idx + ras->ras_window_pages;
1030 LASSERT(ras->ras_stride_length > 0);
1031 LASSERTF(end >= (ras->ras_stride_offset >> PAGE_SHIFT),
1032 "window_start_idx %lu, window_pages %lu stride_offset %llu\n",
1033 ras->ras_window_start_idx, ras->ras_window_pages,
1034 ras->ras_stride_offset);
1037 if (end <= ras->ras_stride_offset)
1040 stride_bytes = end - ras->ras_stride_offset;
1042 div64_u64_rem(stride_bytes, ras->ras_stride_length, &left_bytes);
1043 window_bytes = (ras->ras_window_pages << PAGE_SHIFT);
1044 if (left_bytes < ras->ras_stride_bytes) {
1045 if (ras->ras_stride_bytes - left_bytes >= inc_bytes) {
1046 window_bytes += inc_bytes;
1049 window_bytes += (ras->ras_stride_bytes - left_bytes);
1050 inc_bytes -= (ras->ras_stride_bytes - left_bytes);
1053 window_bytes += (ras->ras_stride_length - left_bytes);
1056 LASSERT(ras->ras_stride_bytes != 0);
1058 step = div64_u64_rem(inc_bytes, ras->ras_stride_bytes, &left_bytes);
1060 window_bytes += step * ras->ras_stride_length + left_bytes;
1061 LASSERT(window_bytes > 0);
1064 if (stride_page_count(ras, window_bytes) <=
1065 ra->ra_max_pages_per_file || ras->ras_window_pages == 0)
1066 ras->ras_window_pages = (window_bytes >> PAGE_SHIFT);
1068 LASSERT(ras->ras_window_pages > 0);
1073 static void ras_increase_window(struct inode *inode,
1074 struct ll_readahead_state *ras,
1075 struct ll_ra_info *ra)
1077 /* The stretch of ra-window should be aligned with max rpc_size
1078 * but current clio architecture does not support retrieve such
1079 * information from lower layer. FIXME later
1081 if (stride_io_mode(ras)) {
1082 ras_stride_increase_window(ras, ra,
1083 (loff_t)ras->ras_rpc_pages << PAGE_SHIFT);
1085 pgoff_t window_pages;
1087 window_pages = min(ras->ras_window_pages + ras->ras_rpc_pages,
1088 ra->ra_max_pages_per_file);
1089 if (window_pages < ras->ras_rpc_pages)
1090 ras->ras_window_pages = window_pages;
1092 ras->ras_window_pages = ras_align(ras, window_pages);
1097 * Seek within 8 pages are considered as sequential read for now.
1099 static inline bool is_loose_seq_read(struct ll_readahead_state *ras, loff_t pos)
1101 return pos_in_window(pos, ras->ras_last_read_end_bytes,
1102 8UL << PAGE_SHIFT, 8UL << PAGE_SHIFT);
1105 static inline bool is_loose_mmap_read(struct ll_sb_info *sbi,
1106 struct ll_readahead_state *ras,
1109 unsigned long range_pages = sbi->ll_ra_info.ra_range_pages;
1111 return pos_in_window(pos, ras->ras_last_read_end_bytes,
1112 range_pages << PAGE_SHIFT,
1113 range_pages << PAGE_SHIFT);
1117 * We have observed slow mmap read performances for some
1118 * applications. The problem is if access pattern is neither
1119 * sequential nor stride, but could be still adjacent in a
1120 * small range and then seek a random position.
1122 * So the pattern could be something like this:
1124 * [1M data] [hole] [0.5M data] [hole] [0.7M data] [1M data]
1127 * Every time an application reads mmap data, it may not only
1128 * read a single 4KB page, but aslo a cluster of nearby pages in
1129 * a range(e.g. 1MB) of the first page after a cache miss.
1131 * The readahead engine is modified to track the range size of
1132 * a cluster of mmap reads, so that after a seek and/or cache miss,
1133 * the range size is used to efficiently prefetch multiple pages
1134 * in a single RPC rather than many small RPCs.
1136 static void ras_detect_cluster_range(struct ll_readahead_state *ras,
1137 struct ll_sb_info *sbi,
1138 unsigned long pos, unsigned long count)
1140 pgoff_t last_pages, pages;
1141 pgoff_t end_idx = (pos + count - 1) >> PAGE_SHIFT;
1143 last_pages = ras->ras_range_max_end_idx -
1144 ras->ras_range_min_start_idx + 1;
1145 /* First time come here */
1146 if (!ras->ras_range_max_end_idx)
1149 /* Random or Stride read */
1150 if (!is_loose_mmap_read(sbi, ras, pos))
1153 ras->ras_range_requests++;
1154 if (ras->ras_range_max_end_idx < end_idx)
1155 ras->ras_range_max_end_idx = end_idx;
1157 if (ras->ras_range_min_start_idx > (pos >> PAGE_SHIFT))
1158 ras->ras_range_min_start_idx = pos >> PAGE_SHIFT;
1160 /* Out of range, consider it as random or stride */
1161 pages = ras->ras_range_max_end_idx -
1162 ras->ras_range_min_start_idx + 1;
1163 if (pages <= sbi->ll_ra_info.ra_range_pages)
1166 ras->ras_last_range_pages = last_pages;
1167 ras->ras_range_requests = 0;
1168 ras->ras_range_min_start_idx = pos >> PAGE_SHIFT;
1169 ras->ras_range_max_end_idx = end_idx;
1172 static void ras_detect_read_pattern(struct ll_readahead_state *ras,
1173 struct ll_sb_info *sbi,
1174 loff_t pos, size_t count, bool mmap)
1176 bool stride_detect = false;
1177 pgoff_t index = pos >> PAGE_SHIFT;
1180 * Reset the read-ahead window in two cases. First when the app seeks
1181 * or reads to some other part of the file. Secondly if we get a
1182 * read-ahead miss that we think we've previously issued. This can
1183 * be a symptom of there being so many read-ahead pages that the VM
1184 * is reclaiming it before we get to it.
1186 if (!is_loose_seq_read(ras, pos)) {
1187 /* Check whether it is in stride I/O mode */
1188 if (!read_in_stride_window(ras, pos, count)) {
1189 if (ras->ras_consecutive_stride_requests == 0)
1190 ras_init_stride_detector(ras, pos, count);
1192 ras_stride_reset(ras);
1193 ras->ras_consecutive_bytes = 0;
1194 ras_reset(ras, index);
1196 ras->ras_consecutive_bytes = 0;
1197 ras->ras_consecutive_requests = 0;
1198 if (++ras->ras_consecutive_stride_requests > 1)
1199 stride_detect = true;
1202 ll_ra_stats_inc_sbi(sbi, RA_STAT_DISTANT_READPAGE);
1203 } else if (stride_io_mode(ras)) {
1205 * If this is contiguous read but in stride I/O mode
1206 * currently, check whether stride step still is valid,
1207 * if invalid, it will reset the stride ra window to
1210 if (!read_in_stride_window(ras, pos, count)) {
1211 ras_stride_reset(ras);
1212 ras->ras_window_pages = 0;
1213 ras->ras_next_readahead_idx = index;
1217 ras->ras_consecutive_bytes += count;
1219 pgoff_t idx = ras->ras_consecutive_bytes >> PAGE_SHIFT;
1220 unsigned long ra_range_pages =
1221 max_t(unsigned long, RA_MIN_MMAP_RANGE_PAGES,
1222 sbi->ll_ra_info.ra_range_pages);
1224 if ((idx >= ra_range_pages &&
1225 idx % ra_range_pages == 0) || stride_detect)
1226 ras->ras_need_increase_window = true;
1227 } else if ((ras->ras_consecutive_requests > 1 || stride_detect)) {
1228 ras->ras_need_increase_window = true;
1231 ras->ras_last_read_end_bytes = pos + count - 1;
1234 void ll_ras_enter(struct file *f, loff_t pos, size_t count)
1236 struct ll_file_data *fd = f->private_data;
1237 struct ll_readahead_state *ras = &fd->fd_ras;
1238 struct inode *inode = file_inode(f);
1239 unsigned long index = pos >> PAGE_SHIFT;
1240 struct ll_sb_info *sbi = ll_i2sbi(inode);
1242 spin_lock(&ras->ras_lock);
1243 ras->ras_requests++;
1244 ras->ras_consecutive_requests++;
1245 ras->ras_need_increase_window = false;
1246 ras->ras_no_miss_check = false;
1248 * On the second access to a file smaller than the tunable
1249 * ra_max_read_ahead_whole_pages trigger RA on all pages in the
1250 * file up to ra_max_pages_per_file. This is simply a best effort
1251 * and only occurs once per open file. Normal RA behavior is reverted
1252 * to for subsequent IO.
1254 if (ras->ras_requests >= 2) {
1256 struct ll_ra_info *ra = &sbi->ll_ra_info;
1258 kms_pages = (i_size_read(inode) + PAGE_SIZE - 1) >>
1261 CDEBUG(D_READA, "kmsp %llu mwp %lu mp %lu\n", kms_pages,
1262 ra->ra_max_read_ahead_whole_pages,
1263 ra->ra_max_pages_per_file);
1266 kms_pages <= ra->ra_max_read_ahead_whole_pages) {
1267 ras->ras_window_start_idx = 0;
1268 ras->ras_next_readahead_idx = index + 1;
1269 ras->ras_window_pages = min(ra->ra_max_pages_per_file,
1270 ra->ra_max_read_ahead_whole_pages);
1271 ras->ras_no_miss_check = true;
1272 GOTO(out_unlock, 0);
1275 ras_detect_read_pattern(ras, sbi, pos, count, false);
1277 spin_unlock(&ras->ras_lock);
1280 static bool index_in_stride_window(struct ll_readahead_state *ras,
1283 loff_t pos = (loff_t)index << PAGE_SHIFT;
1285 if (ras->ras_stride_length == 0 || ras->ras_stride_bytes == 0 ||
1286 ras->ras_stride_bytes == ras->ras_stride_length)
1289 if (pos >= ras->ras_stride_offset) {
1292 div64_u64_rem(pos - ras->ras_stride_offset,
1293 ras->ras_stride_length, &offset);
1294 if (offset < ras->ras_stride_bytes ||
1295 ras->ras_stride_length - offset < PAGE_SIZE)
1297 } else if (ras->ras_stride_offset - pos < PAGE_SIZE) {
1305 * ll_ras_enter() is used to detect read pattern according to pos and count.
1307 * ras_update() is used to detect cache miss and
1308 * reset window or increase window accordingly
1310 static void ras_update(struct ll_sb_info *sbi, struct inode *inode,
1311 struct ll_readahead_state *ras, pgoff_t index,
1312 enum ras_update_flags flags, struct cl_io *io)
1314 struct ll_ra_info *ra = &sbi->ll_ra_info;
1315 bool hit = flags & LL_RAS_HIT;
1318 spin_lock(&ras->ras_lock);
1321 CDEBUG(D_READA|D_IOTRACE, DFID " pages at %lu miss.\n",
1322 PFID(ll_inode2fid(inode)), index);
1323 ll_ra_stats_inc_sbi(sbi, hit ? RA_STAT_HIT : RA_STAT_MISS);
1326 * The readahead window has been expanded to cover whole
1327 * file size, we don't care whether ra miss happen or not.
1328 * Because we will read whole file to page cache even if
1329 * some pages missed.
1331 if (ras->ras_no_miss_check)
1332 GOTO(out_unlock, 0);
1334 if (io && io->ci_rand_read)
1335 GOTO(out_unlock, 0);
1337 if (io && io->ci_seq_read) {
1339 /* to avoid many small read RPC here */
1340 ras->ras_window_pages = sbi->ll_ra_info.ra_range_pages;
1341 ll_ra_stats_inc_sbi(sbi, RA_STAT_MMAP_RANGE_READ);
1346 if (flags & LL_RAS_MMAP) {
1347 unsigned long ra_pages;
1349 ras_detect_cluster_range(ras, sbi, index << PAGE_SHIFT,
1351 ras_detect_read_pattern(ras, sbi, (loff_t)index << PAGE_SHIFT,
1354 /* we did not detect anything but we could prefetch */
1355 if (!ras->ras_need_increase_window &&
1356 ras->ras_window_pages <= sbi->ll_ra_info.ra_range_pages &&
1357 ras->ras_range_requests >= 2) {
1359 ra_pages = max_t(unsigned long,
1360 RA_MIN_MMAP_RANGE_PAGES,
1361 ras->ras_last_range_pages);
1362 if (index < ra_pages / 2)
1365 index -= ra_pages / 2;
1366 ras->ras_window_pages = ra_pages;
1367 ll_ra_stats_inc_sbi(sbi,
1368 RA_STAT_MMAP_RANGE_READ);
1370 ras->ras_window_pages = 0;
1376 if (!hit && ras->ras_window_pages &&
1377 index < ras->ras_next_readahead_idx &&
1378 pos_in_window(index, ras->ras_window_start_idx, 0,
1379 ras->ras_window_pages)) {
1380 ll_ra_stats_inc_sbi(sbi, RA_STAT_MISS_IN_WINDOW);
1381 ras->ras_need_increase_window = false;
1383 if (index_in_stride_window(ras, index) &&
1384 stride_io_mode(ras)) {
1386 * if (index != ras->ras_last_readpage + 1)
1387 * ras->ras_consecutive_pages = 0;
1389 ras_reset(ras, index);
1392 * If stride-RA hit cache miss, the stride
1393 * detector will not be reset to avoid the
1394 * overhead of redetecting read-ahead mode,
1395 * but on the condition that the stride window
1396 * is still intersect with normal sequential
1397 * read-ahead window.
1399 if (ras->ras_window_start_idx < ras->ras_stride_offset)
1400 ras_stride_reset(ras);
1404 * Reset both stride window and normal RA
1407 ras_reset(ras, index);
1408 /* ras->ras_consecutive_pages++; */
1409 ras->ras_consecutive_bytes = 0;
1410 ras_stride_reset(ras);
1411 GOTO(out_unlock, 0);
1416 ras_set_start(ras, index);
1418 if (stride_io_mode(ras)) {
1419 /* Since stride readahead is sentivite to the offset
1420 * of read-ahead, so we use original offset here,
1421 * instead of ras_window_start_idx, which is RPC aligned.
1423 ras->ras_next_readahead_idx = max(index + 1,
1424 ras->ras_next_readahead_idx);
1425 ras->ras_window_start_idx =
1426 max_t(pgoff_t, ras->ras_window_start_idx,
1427 ras->ras_stride_offset >> PAGE_SHIFT);
1429 if (ras->ras_next_readahead_idx < ras->ras_window_start_idx)
1430 ras->ras_next_readahead_idx = ras->ras_window_start_idx;
1432 ras->ras_next_readahead_idx = index + 1;
1435 if (ras->ras_need_increase_window) {
1436 ras_increase_window(inode, ras, ra);
1437 ras->ras_need_increase_window = false;
1442 spin_unlock(&ras->ras_lock);
1445 int ll_writepage(struct page *vmpage, struct writeback_control *wbc)
1447 struct inode *inode = vmpage->mapping->host;
1448 struct ll_inode_info *lli = ll_i2info(inode);
1451 struct cl_page *page;
1452 struct cl_object *clob;
1453 bool redirtied = false;
1454 bool unlocked = false;
1459 LASSERT(PageLocked(vmpage));
1460 LASSERT(!PageWriteback(vmpage));
1462 LASSERT(ll_i2dtexp(inode) != NULL);
1464 env = cl_env_get(&refcheck);
1466 GOTO(out, result = PTR_ERR(env));
1468 clob = ll_i2info(inode)->lli_clob;
1469 LASSERT(clob != NULL);
1471 io = vvp_env_thread_io(env);
1473 io->ci_ignore_layout = 1;
1474 result = cl_io_init(env, io, CIT_MISC, clob);
1476 page = cl_page_find(env, clob, vmpage->index,
1477 vmpage, CPT_CACHEABLE);
1478 if (!IS_ERR(page)) {
1479 lu_ref_add(&page->cp_reference, "writepage",
1481 cl_page_assume(env, io, page);
1482 result = cl_page_flush(env, io, page);
1485 * Re-dirty page on error so it retries write,
1486 * but not in case when IO has actually
1487 * occurred and completed with an error.
1489 if (!PageError(vmpage)) {
1490 redirty_page_for_writepage(wbc, vmpage);
1495 cl_page_disown(env, io, page);
1497 lu_ref_del(&page->cp_reference,
1498 "writepage", current);
1499 cl_page_put(env, page);
1501 result = PTR_ERR(page);
1504 cl_io_fini(env, io);
1506 if (redirtied && wbc->sync_mode == WB_SYNC_ALL) {
1507 loff_t offset = cl_offset(clob, vmpage->index);
1509 /* Flush page failed because the extent is being written out.
1510 * Wait for the write of extent to be finished to avoid
1511 * breaking kernel which assumes ->writepage should mark
1512 * PageWriteback or clean the page. */
1513 result = cl_sync_file_range(inode, offset,
1514 offset + PAGE_SIZE - 1,
1517 /* actually we may have written more than one page.
1518 * decreasing this page because the caller will count
1520 wbc->nr_to_write -= result - 1;
1525 cl_env_put(env, &refcheck);
1530 if (!lli->lli_async_rc)
1531 lli->lli_async_rc = result;
1532 SetPageError(vmpage);
1534 unlock_page(vmpage);
1539 int ll_writepages(struct address_space *mapping, struct writeback_control *wbc)
1541 struct inode *inode = mapping->host;
1544 enum cl_fsync_mode mode;
1545 int range_whole = 0;
1549 if (wbc->range_cyclic) {
1550 start = (loff_t)mapping->writeback_index << PAGE_SHIFT;
1551 end = OBD_OBJECT_EOF;
1553 start = wbc->range_start;
1554 end = wbc->range_end;
1555 if (end == LLONG_MAX) {
1556 end = OBD_OBJECT_EOF;
1557 range_whole = start == 0;
1561 mode = CL_FSYNC_NONE;
1562 if (wbc->sync_mode == WB_SYNC_ALL)
1563 mode = CL_FSYNC_LOCAL;
1565 if (ll_i2info(inode)->lli_clob == NULL)
1568 /* for directio, it would call writepages() to evict cached pages
1569 * inside the IO context of write, which will cause deadlock at
1570 * layout_conf since it waits for active IOs to complete. */
1571 result = cl_sync_file_range(inode, start, end, mode, 1);
1573 wbc->nr_to_write -= result;
1577 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) {
1578 if (end == OBD_OBJECT_EOF)
1579 mapping->writeback_index = 0;
1581 mapping->writeback_index = (end >> PAGE_SHIFT) + 1;
1586 struct ll_cl_context *ll_cl_find(struct inode *inode)
1588 struct ll_inode_info *lli = ll_i2info(inode);
1589 struct ll_cl_context *lcc;
1590 struct ll_cl_context *found = NULL;
1592 read_lock(&lli->lli_lock);
1593 list_for_each_entry(lcc, &lli->lli_lccs, lcc_list) {
1594 if (lcc->lcc_cookie == current) {
1599 read_unlock(&lli->lli_lock);
1604 void ll_cl_add(struct inode *inode, const struct lu_env *env, struct cl_io *io,
1607 struct ll_inode_info *lli = ll_i2info(inode);
1608 struct ll_cl_context *lcc = &ll_env_info(env)->lti_io_ctx;
1610 memset(lcc, 0, sizeof(*lcc));
1611 INIT_LIST_HEAD(&lcc->lcc_list);
1612 lcc->lcc_cookie = current;
1615 lcc->lcc_type = type;
1617 write_lock(&lli->lli_lock);
1618 list_add(&lcc->lcc_list, &lli->lli_lccs);
1619 write_unlock(&lli->lli_lock);
1622 void ll_cl_remove(struct inode *inode, const struct lu_env *env)
1624 struct ll_inode_info *lli = ll_i2info(inode);
1625 struct ll_cl_context *lcc = &ll_env_info(env)->lti_io_ctx;
1627 write_lock(&lli->lli_lock);
1628 list_del_init(&lcc->lcc_list);
1629 write_unlock(&lli->lli_lock);
1632 int ll_io_read_page(const struct lu_env *env, struct cl_io *io,
1633 struct cl_page *page, struct file *file)
1635 struct inode *inode = vvp_object_inode(page->cp_obj);
1636 struct ll_sb_info *sbi = ll_i2sbi(inode);
1637 struct ll_file_data *fd = NULL;
1638 struct ll_readahead_state *ras = NULL;
1639 struct cl_2queue *queue = &io->ci_queue;
1640 struct cl_sync_io *anchor = NULL;
1641 int rc = 0, rc2 = 0;
1643 struct vvp_io *vio = vvp_env_io(env);
1644 bool mmap = !vio->vui_ra_valid;
1645 pgoff_t ra_start_index = 0;
1646 pgoff_t io_start_index;
1647 pgoff_t io_end_index;
1648 bool unlockpage = true;
1652 fd = file->private_data;
1656 /* PagePrivate2 is set in ll_io_zero_page() to tell us the vmpage
1657 * must not be unlocked after processing.
1659 if (page->cp_vmpage && PagePrivate2(page->cp_vmpage))
1662 uptodate = page->cp_defer_uptodate;
1664 if (ll_readahead_enabled(sbi) && !page->cp_ra_updated && ras) {
1665 enum ras_update_flags flags = 0;
1668 flags |= LL_RAS_HIT;
1670 flags |= LL_RAS_MMAP;
1671 ras_update(sbi, inode, ras, cl_page_index(page), flags, io);
1674 cl_2queue_init(queue);
1676 page->cp_ra_used = 1;
1677 SetPageUptodate(page->cp_vmpage);
1678 cl_page_disown(env, io, page);
1680 anchor = &vvp_env_info(env)->vti_anchor;
1681 cl_sync_io_init(anchor, 1);
1682 page->cp_sync_io = anchor;
1684 cl_page_list_add(&queue->c2_qin, page, true);
1687 /* mmap does not set the ci_rw fields */
1689 io_start_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos);
1690 io_end_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos +
1691 io->u.ci_rw.crw_count - 1);
1693 io_start_index = cl_page_index(page);
1694 io_end_index = cl_page_index(page);
1697 if (ll_readahead_enabled(sbi) && ras && !io->ci_rand_read) {
1698 pgoff_t skip_index = 0;
1700 if (ras->ras_next_readahead_idx < cl_page_index(page))
1701 skip_index = cl_page_index(page);
1702 rc2 = ll_readahead(env, io, &queue->c2_qin, ras,
1703 uptodate, file, skip_index,
1705 /* to keep iotrace clean, we only print here if we actually
1708 CDEBUG(D_READA | (rc2 ? D_IOTRACE : 0),
1709 DFID " %d pages read ahead at %lu, triggered by user read at %lu, stride offset %lld, stride length %lld, stride bytes %lld\n",
1710 PFID(ll_inode2fid(inode)), rc2, ra_start_index,
1711 cl_page_index(page), ras->ras_stride_offset,
1712 ras->ras_stride_length, ras->ras_stride_bytes);
1714 } else if (cl_page_index(page) == io_start_index &&
1715 io_end_index - io_start_index > 0) {
1716 rc2 = ll_readpages(env, io, &queue->c2_qin, io_start_index + 1,
1718 CDEBUG(D_READA, DFID " %d pages read at %lu\n",
1719 PFID(ll_inode2fid(inode)), rc2, cl_page_index(page));
1722 if (queue->c2_qin.pl_nr > 0) {
1723 int count = queue->c2_qin.pl_nr;
1724 rc = cl_io_submit_rw(env, io, CRT_READ, queue);
1726 task_io_account_read(PAGE_SIZE * count);
1730 if (anchor != NULL && !cl_page_is_owned(page, io)) { /* have sent */
1731 rc = cl_sync_io_wait(env, anchor, 0);
1733 cl_page_assume(env, io, page);
1734 cl_page_list_del(env, &queue->c2_qout, page);
1736 if (!PageUptodate(cl_page_vmpage(page))) {
1737 /* Failed to read a mirror, discard this page so that
1738 * new page can be created with new mirror.
1740 * TODO: this is not needed after page reinit
1741 * route is implemented */
1742 cl_page_discard(env, io, page);
1745 cl_page_disown(env, io, page);
1748 /* TODO: discard all pages until page reinit route is implemented */
1749 cl_page_list_discard(env, io, &queue->c2_qin);
1751 /* Unlock unsent read pages in case of error. */
1752 cl_page_list_disown(env, &queue->c2_qin);
1754 cl_2queue_fini(env, queue);
1760 * Possible return value:
1761 * 0 no async readahead triggered and fast read could not be used.
1762 * 1 no async readahead, but fast read could be used.
1763 * 2 async readahead triggered and fast read could be used too.
1766 static int kickoff_async_readahead(struct file *file, unsigned long pages)
1768 struct ll_readahead_work *lrw;
1769 struct inode *inode = file_inode(file);
1770 struct ll_sb_info *sbi = ll_i2sbi(inode);
1771 struct ll_file_data *fd = file->private_data;
1772 struct ll_readahead_state *ras = &fd->fd_ras;
1773 struct ll_ra_info *ra = &sbi->ll_ra_info;
1774 unsigned long throttle;
1775 pgoff_t start_idx = ras_align(ras, ras->ras_next_readahead_idx);
1776 pgoff_t end_idx = start_idx + pages - 1;
1779 * In case we have a limited max_cached_mb, readahead
1780 * should be stopped if it have run out of all LRU slots.
1782 if (atomic_read(&ra->ra_cur_pages) >= sbi->ll_cache->ccc_lru_max) {
1783 ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT);
1787 throttle = min(ra->ra_async_pages_per_file_threshold,
1788 ra->ra_max_pages_per_file);
1790 * If this is strided i/o or the window is smaller than the
1791 * throttle limit, we do not do async readahead. Otherwise,
1792 * we do async readahead, allowing the user thread to do fast i/o.
1794 if (stride_io_mode(ras) || !throttle ||
1795 ras->ras_window_pages < throttle ||
1796 atomic_read(&ra->ra_async_inflight) > ra->ra_async_max_active)
1799 if ((atomic_read(&ra->ra_cur_pages) + pages) > ra->ra_max_pages)
1802 if (ras->ras_async_last_readpage_idx == start_idx)
1805 /* ll_readahead_work_free() free it */
1808 atomic_inc(&sbi->ll_ra_info.ra_async_inflight);
1809 lrw->lrw_file = get_file(file);
1810 lrw->lrw_start_idx = start_idx;
1811 lrw->lrw_end_idx = end_idx;
1812 lrw->lrw_user_pid = current->pid;
1813 spin_lock(&ras->ras_lock);
1814 ras->ras_next_readahead_idx = end_idx + 1;
1815 ras->ras_async_last_readpage_idx = start_idx;
1816 spin_unlock(&ras->ras_lock);
1817 memcpy(lrw->lrw_jobid, ll_i2info(inode)->lli_jobid,
1818 sizeof(lrw->lrw_jobid));
1819 ll_readahead_work_add(inode, lrw);
1828 * Check if we can issue a readahead RPC, if that is
1829 * the case, we can't do fast IO because we will need
1830 * a cl_io to issue the RPC.
1832 static bool ll_use_fast_io(struct file *file,
1833 struct ll_readahead_state *ras, pgoff_t index)
1835 unsigned long fast_read_pages =
1836 max(RA_REMAIN_WINDOW_MIN, ras->ras_rpc_pages);
1838 loff_t stride_bytes = ras->ras_stride_bytes;
1840 if (stride_io_mode(ras) && stride_bytes) {
1841 skip_pages = (ras->ras_stride_length +
1842 ras->ras_stride_bytes - 1) / stride_bytes;
1843 skip_pages *= fast_read_pages;
1845 skip_pages = fast_read_pages;
1848 if (ras->ras_window_start_idx + ras->ras_window_pages <
1849 ras->ras_next_readahead_idx + skip_pages ||
1850 kickoff_async_readahead(file, fast_read_pages) > 0)
1856 int ll_readpage(struct file *file, struct page *vmpage)
1858 struct inode *inode = file_inode(file);
1859 struct cl_object *clob = ll_i2info(inode)->lli_clob;
1860 struct ll_cl_context *lcc;
1861 const struct lu_env *env = NULL;
1862 struct cl_io *io = NULL;
1863 struct cl_page *page;
1864 struct ll_sb_info *sbi = ll_i2sbi(inode);
1868 lcc = ll_cl_find(inode);
1874 if (io == NULL) { /* fast read */
1875 struct inode *inode = file_inode(file);
1876 struct ll_file_data *fd = file->private_data;
1877 struct ll_readahead_state *ras = &fd->fd_ras;
1878 struct lu_env *local_env = NULL;
1882 /* TODO: need to verify the layout version to make sure
1883 * the page is not invalid due to layout change. */
1884 page = cl_vmpage_page(vmpage, clob);
1886 unlock_page(vmpage);
1887 ll_ra_stats_inc_sbi(sbi, RA_STAT_FAILED_FAST_READ);
1891 if (page->cp_defer_uptodate) {
1892 enum ras_update_flags flags = LL_RAS_HIT;
1894 if (lcc && lcc->lcc_type == LCC_MMAP)
1895 flags |= LL_RAS_MMAP;
1897 /* For fast read, it updates read ahead state only
1898 * if the page is hit in cache because non cache page
1899 * case will be handled by slow read later. */
1900 ras_update(sbi, inode, ras, cl_page_index(page), flags, io);
1901 /* avoid duplicate ras_update() call */
1902 page->cp_ra_updated = 1;
1904 if (ll_use_fast_io(file, ras, cl_page_index(page)))
1909 local_env = cl_env_percpu_get();
1913 /* export the page and skip io stack */
1915 page->cp_ra_used = 1;
1916 SetPageUptodate(vmpage);
1918 ll_ra_stats_inc_sbi(sbi, RA_STAT_FAILED_FAST_READ);
1921 /* release page refcount before unlocking the page to ensure
1922 * the object won't be destroyed in the calling path of
1923 * cl_page_put(). Please see comment in ll_releasepage(). */
1924 cl_page_put(env, page);
1925 unlock_page(vmpage);
1927 cl_env_percpu_put(local_env);
1933 * Direct read can fall back to buffered read, but DIO is done
1934 * with lockless i/o, and buffered requires LDLM locking, so in
1935 * this case we must restart without lockless.
1937 if (file->f_flags & O_DIRECT &&
1938 lcc && lcc->lcc_type == LCC_RW &&
1940 unlock_page(vmpage);
1941 io->ci_dio_lock = 1;
1942 io->ci_need_restart = 1;
1946 LASSERT(io->ci_state == CIS_IO_GOING);
1947 page = cl_page_find(env, clob, vmpage->index, vmpage, CPT_CACHEABLE);
1948 if (!IS_ERR(page)) {
1949 LASSERT(page->cp_type == CPT_CACHEABLE);
1950 if (likely(!PageUptodate(vmpage))) {
1951 cl_page_assume(env, io, page);
1953 result = ll_io_read_page(env, io, page, file);
1955 /* Page from a non-object file. */
1956 unlock_page(vmpage);
1959 cl_page_put(env, page);
1961 unlock_page(vmpage);
1962 result = PTR_ERR(page);