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/
30 * Lustre is a trademark of Sun Microsystems, Inc.
34 * Lustre Lite I/O page cache routines shared by different kernel revs
37 #include <linux/kernel.h>
39 #include <linux/string.h>
40 #include <linux/stat.h>
41 #include <linux/errno.h>
42 #include <linux/unistd.h>
43 #include <linux/writeback.h>
44 #include <asm/uaccess.h>
47 #include <linux/file.h>
48 #include <linux/stat.h>
49 #include <asm/uaccess.h>
51 #include <linux/pagemap.h>
52 /* current_is_kswapd() */
53 #include <linux/swap.h>
54 #include <linux/task_io_accounting_ops.h>
56 #define DEBUG_SUBSYSTEM S_LLITE
58 #include <obd_cksum.h>
59 #include "llite_internal.h"
60 #include <lustre_compat.h>
62 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which);
65 * Get readahead pages from the filesystem readahead pool of the client for a
68 * /param sbi superblock for filesystem readahead state ll_ra_info
69 * /param ria per-thread readahead state
70 * /param pages number of pages requested for readahead for the thread.
72 * WARNING: This algorithm is used to reduce contention on sbi->ll_lock.
73 * It should work well if the ra_max_pages is much greater than the single
74 * file's read-ahead window, and not too many threads contending for
75 * these readahead pages.
77 * TODO: There may be a 'global sync problem' if many threads are trying
78 * to get an ra budget that is larger than the remaining readahead pages
79 * and reach here at exactly the same time. They will compute /a ret to
80 * consume the remaining pages, but will fail at atomic_add_return() and
81 * get a zero ra window, although there is still ra space remaining. - Jay */
83 static unsigned long ll_ra_count_get(struct ll_sb_info *sbi,
84 struct ra_io_arg *ria,
86 unsigned long pages_min)
88 struct ll_ra_info *ra = &sbi->ll_ra_info;
92 /* If read-ahead pages left are less than 1M, do not do read-ahead,
93 * otherwise it will form small read RPC(< 1M), which hurt server
94 * performance a lot. */
95 ret = min(ra->ra_max_pages - atomic_read(&ra->ra_cur_pages),
97 if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages))
100 if (atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) {
101 atomic_sub(ret, &ra->ra_cur_pages);
106 if (ret < pages_min) {
107 /* override ra limit for maximum performance */
108 atomic_add(pages_min - ret, &ra->ra_cur_pages);
114 void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long pages)
116 struct ll_ra_info *ra = &sbi->ll_ra_info;
117 atomic_sub(pages, &ra->ra_cur_pages);
120 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which)
122 LASSERTF(which < _NR_RA_STAT, "which: %u\n", which);
123 lprocfs_counter_incr(sbi->ll_ra_stats, which);
126 static inline bool ll_readahead_enabled(struct ll_sb_info *sbi)
128 return sbi->ll_ra_info.ra_max_pages_per_file > 0 &&
129 sbi->ll_ra_info.ra_max_pages > 0;
132 void ll_ra_stats_inc(struct inode *inode, enum ra_stat which)
134 struct ll_sb_info *sbi = ll_i2sbi(inode);
135 ll_ra_stats_inc_sbi(sbi, which);
138 #define RAS_CDEBUG(ras) \
140 "lre %llu cr %lu cb %llu wsi %lu wp %lu nra %lu rpc %lu " \
141 "r %lu csr %lu so %llu sb %llu sl %llu lr %lu\n", \
142 ras->ras_last_read_end_bytes, ras->ras_consecutive_requests, \
143 ras->ras_consecutive_bytes, ras->ras_window_start_idx, \
144 ras->ras_window_pages, ras->ras_next_readahead_idx, \
145 ras->ras_rpc_pages, ras->ras_requests, \
146 ras->ras_consecutive_stride_requests, ras->ras_stride_offset, \
147 ras->ras_stride_bytes, ras->ras_stride_length, \
148 ras->ras_async_last_readpage_idx)
150 static bool pos_in_window(loff_t pos, loff_t point,
151 unsigned long before, unsigned long after)
153 loff_t start = point - before;
154 loff_t end = point + after;
161 return start <= pos && pos <= end;
164 enum ll_ra_page_hint {
165 MAYNEED = 0, /* this page possibly accessed soon */
166 WILLNEED /* this page is gurateed to be needed */
170 * Initiates read-ahead of a page with given index.
172 * \retval +ve: page was already uptodate so it will be skipped
174 * \retval -ve: page wasn't added to \a queue for error;
175 * \retval 0: page was added into \a queue for read ahead.
177 static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io,
178 struct cl_page_list *queue, pgoff_t index,
179 enum ll_ra_page_hint hint)
181 struct cl_object *clob = io->ci_obj;
182 struct inode *inode = vvp_object_inode(clob);
183 struct page *vmpage = NULL;
184 struct cl_page *page;
185 struct vvp_page *vpg;
186 enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */
188 const char *msg = NULL;
194 vmpage = grab_cache_page_nowait(inode->i_mapping, index);
195 if (vmpage == NULL) {
196 which = RA_STAT_FAILED_GRAB_PAGE;
197 msg = "g_c_p_n failed";
198 GOTO(out, rc = -EBUSY);
202 vmpage = find_or_create_page(inode->i_mapping, index,
205 GOTO(out, rc = -ENOMEM);
208 /* should not come here */
209 GOTO(out, rc = -EINVAL);
212 /* Check if vmpage was truncated or reclaimed */
213 if (vmpage->mapping != inode->i_mapping) {
214 which = RA_STAT_WRONG_GRAB_PAGE;
215 msg = "g_c_p_n returned invalid page";
216 GOTO(out, rc = -EBUSY);
219 page = cl_page_find(env, clob, vmpage->index, vmpage, CPT_CACHEABLE);
221 which = RA_STAT_FAILED_GRAB_PAGE;
222 msg = "cl_page_find failed";
223 GOTO(out, rc = PTR_ERR(page));
226 lu_ref_add(&page->cp_reference, "ra", current);
227 cl_page_assume(env, io, page);
228 vpg = cl2vvp_page(cl_object_page_slice(clob, page));
229 if (!vpg->vpg_defer_uptodate && !PageUptodate(vmpage)) {
230 vpg->vpg_defer_uptodate = 1;
231 vpg->vpg_ra_used = 0;
232 cl_page_list_add(queue, page);
234 /* skip completed pages */
235 cl_page_unassume(env, io, page);
236 /* This page is already uptodate, returning a positive number
237 * to tell the callers about this */
241 lu_ref_del(&page->cp_reference, "ra", current);
242 cl_page_put(env, page);
245 if (vmpage != NULL) {
250 if (msg != NULL && hint == MAYNEED) {
251 ll_ra_stats_inc(inode, which);
252 CDEBUG(D_READA, "%s\n", msg);
259 #define RIA_DEBUG(ria) \
260 CDEBUG(D_READA, "rs %lu re %lu ro %llu rl %llu rb %llu\n", \
261 ria->ria_start_idx, ria->ria_end_idx, ria->ria_stoff, \
262 ria->ria_length, ria->ria_bytes)
264 static inline int stride_io_mode(struct ll_readahead_state *ras)
266 return ras->ras_consecutive_stride_requests > 1;
269 /* The function calculates how many bytes will be read in
270 * [off, off + length], in such stride IO area,
271 * stride_offset = st_off, stride_lengh = st_len,
272 * stride_bytes = st_bytes
274 * |------------------|*****|------------------|*****|------------|*****|....
277 * |----- st_len -----|
279 * How many bytes it should read in such pattern
280 * |-------------------------------------------------------------|
282 * |<------ length ------->|
284 * = |<----->| + |-------------------------------------| + |---|
285 * start_left st_bytes * i end_left
287 static loff_t stride_byte_count(loff_t st_off, loff_t st_len, loff_t st_bytes,
288 loff_t off, loff_t length)
290 u64 start = off > st_off ? off - st_off : 0;
291 u64 end = off + length > st_off ? off + length - st_off : 0;
296 if (st_len == 0 || length == 0 || end == 0)
299 start = div64_u64_rem(start, st_len, &start_left);
300 if (start_left < st_bytes)
301 start_left = st_bytes - start_left;
305 end = div64_u64_rem(end, st_len, &end_left);
306 if (end_left > st_bytes)
309 CDEBUG(D_READA, "start %llu, end %llu start_left %llu end_left %llu\n",
310 start, end, start_left, end_left);
313 bytes_count = end_left - (st_bytes - start_left);
315 bytes_count = start_left +
316 st_bytes * (end - start - 1) + end_left;
319 "st_off %llu, st_len %llu st_bytes %llu off %llu length %llu bytescount %llu\n",
320 st_off, st_len, st_bytes, off, length, bytes_count);
325 static unsigned long ria_page_count(struct ra_io_arg *ria)
327 loff_t length_bytes = ria->ria_end_idx >= ria->ria_start_idx ?
328 (loff_t)(ria->ria_end_idx -
329 ria->ria_start_idx + 1) << PAGE_SHIFT : 0;
332 if (ria->ria_length > ria->ria_bytes && ria->ria_bytes &&
333 (ria->ria_length & ~PAGE_MASK || ria->ria_bytes & ~PAGE_MASK ||
334 ria->ria_stoff & ~PAGE_MASK)) {
335 /* Over-estimate un-aligned page stride read */
336 unsigned long pg_count = ((ria->ria_bytes +
337 PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
338 pg_count *= length_bytes / ria->ria_length + 1;
342 bytes_count = stride_byte_count(ria->ria_stoff, ria->ria_length,
344 (loff_t)ria->ria_start_idx<<PAGE_SHIFT,
346 return (bytes_count + PAGE_SIZE - 1) >> PAGE_SHIFT;
349 static pgoff_t ras_align(struct ll_readahead_state *ras, pgoff_t index)
351 unsigned opt_size = min(ras->ras_window_pages, ras->ras_rpc_pages);
355 return index - (index % opt_size);
358 /* Check whether the index is in the defined ra-window */
359 static bool ras_inside_ra_window(pgoff_t idx, struct ra_io_arg *ria)
361 loff_t pos = (loff_t)idx << PAGE_SHIFT;
363 /* If ria_length == ria_bytes, it means non-stride I/O mode,
364 * idx should always inside read-ahead window in this case
365 * For stride I/O mode, just check whether the idx is inside
368 if (ria->ria_length == 0 || ria->ria_length == ria->ria_bytes)
371 if (pos >= ria->ria_stoff) {
374 div64_u64_rem(pos - ria->ria_stoff, ria->ria_length, &offset);
376 if (offset < ria->ria_bytes ||
377 (ria->ria_length - offset) < PAGE_SIZE)
379 } else if (pos + PAGE_SIZE > ria->ria_stoff) {
387 ll_read_ahead_pages(const struct lu_env *env, struct cl_io *io,
388 struct cl_page_list *queue, struct ll_readahead_state *ras,
389 struct ra_io_arg *ria, pgoff_t *ra_end, pgoff_t skip_index)
391 struct cl_read_ahead ra = { 0 };
392 /* busy page count is per stride */
393 int rc = 0, count = 0, busy_page_count = 0;
396 LASSERT(ria != NULL);
399 for (page_idx = ria->ria_start_idx;
400 page_idx <= ria->ria_end_idx && ria->ria_reserved > 0;
402 if (skip_index && page_idx == skip_index)
404 if (ras_inside_ra_window(page_idx, ria)) {
405 if (ra.cra_end_idx == 0 || ra.cra_end_idx < page_idx) {
409 * Do not shrink ria_end_idx at any case until
410 * the minimum end of current read is covered.
412 * Do not extend read lock accross stripe if
413 * lock contention detected.
415 if (ra.cra_contention &&
416 page_idx > ria->ria_end_idx_min) {
417 ria->ria_end_idx = *ra_end;
421 cl_read_ahead_release(env, &ra);
423 rc = cl_io_read_ahead(env, io, page_idx, &ra);
428 * Only shrink ria_end_idx if the matched
429 * LDLM lock doesn't cover more.
431 if (page_idx > ra.cra_end_idx) {
432 ria->ria_end_idx = ra.cra_end_idx;
436 CDEBUG(D_READA, "idx: %lu, ra: %lu, rpc: %lu\n",
437 page_idx, ra.cra_end_idx,
439 LASSERTF(ra.cra_end_idx >= page_idx,
440 "object: %p, indcies %lu / %lu\n",
441 io->ci_obj, ra.cra_end_idx, page_idx);
442 /* update read ahead RPC size.
443 * NB: it's racy but doesn't matter */
444 if (ras->ras_rpc_pages != ra.cra_rpc_pages &&
445 ra.cra_rpc_pages > 0)
446 ras->ras_rpc_pages = ra.cra_rpc_pages;
448 /* trim it to align with optimal RPC size */
449 end_idx = ras_align(ras, ria->ria_end_idx + 1);
450 if (end_idx > 0 && !ria->ria_eof)
451 ria->ria_end_idx = end_idx - 1;
453 if (ria->ria_end_idx < ria->ria_end_idx_min)
454 ria->ria_end_idx = ria->ria_end_idx_min;
456 if (page_idx > ria->ria_end_idx)
459 /* If the page is inside the read-ahead window */
460 rc = ll_read_ahead_page(env, io, queue, page_idx,
462 if (rc < 0 && rc != -EBUSY)
467 "skip busy page: %lu\n", page_idx);
468 /* For page unaligned readahead the first
469 * last pages of each region can be read by
470 * another reader on the same node, and so
471 * may be busy. So only stop for > 2 busy
473 if (busy_page_count > 2)
478 /* Only subtract from reserve & count the page if we
479 * really did readahead on that page. */
484 } else if (stride_io_mode(ras)) {
485 /* If it is not in the read-ahead window, and it is
486 * read-ahead mode, then check whether it should skip
489 loff_t pos = (loff_t)page_idx << PAGE_SHIFT;
492 div64_u64_rem(pos - ria->ria_stoff, ria->ria_length,
494 if (offset >= ria->ria_bytes) {
495 pos += (ria->ria_length - offset);
496 if ((pos >> PAGE_SHIFT) >= page_idx + 1)
497 page_idx = (pos >> PAGE_SHIFT) - 1;
500 "Stride: jump %llu pages to %lu\n",
501 ria->ria_length - offset, page_idx);
507 cl_read_ahead_release(env, &ra);
512 static void ll_readahead_work_free(struct ll_readahead_work *work)
514 fput(work->lrw_file);
518 static void ll_readahead_handle_work(struct work_struct *wq);
519 static void ll_readahead_work_add(struct inode *inode,
520 struct ll_readahead_work *work)
522 INIT_WORK(&work->lrw_readahead_work, ll_readahead_handle_work);
523 queue_work(ll_i2sbi(inode)->ll_ra_info.ll_readahead_wq,
524 &work->lrw_readahead_work);
527 static int ll_readahead_file_kms(const struct lu_env *env,
528 struct cl_io *io, __u64 *kms)
530 struct cl_object *clob;
532 struct cl_attr *attr = vvp_env_thread_attr(env);
536 inode = vvp_object_inode(clob);
538 cl_object_attr_lock(clob);
539 ret = cl_object_attr_get(env, clob, attr);
540 cl_object_attr_unlock(clob);
545 *kms = attr->cat_kms;
549 static void ll_readahead_handle_work(struct work_struct *wq)
551 struct ll_readahead_work *work;
554 struct ra_io_arg *ria;
556 struct ll_file_data *fd;
557 struct ll_readahead_state *ras;
559 struct cl_2queue *queue;
560 pgoff_t ra_end_idx = 0;
561 unsigned long pages, pages_min = 0;
566 struct ll_sb_info *sbi;
568 work = container_of(wq, struct ll_readahead_work,
570 fd = work->lrw_file->private_data;
572 file = work->lrw_file;
573 inode = file_inode(file);
574 sbi = ll_i2sbi(inode);
576 env = cl_env_alloc(&refcheck, LCT_NOREF);
578 GOTO(out_free_work, rc = PTR_ERR(env));
580 io = vvp_env_thread_io(env);
581 ll_io_init(io, file, CIT_READ, NULL);
583 rc = ll_readahead_file_kms(env, io, &kms);
585 GOTO(out_put_env, rc);
588 ll_ra_stats_inc(inode, RA_STAT_ZERO_LEN);
589 GOTO(out_put_env, rc = 0);
592 ria = &ll_env_info(env)->lti_ria;
593 memset(ria, 0, sizeof(*ria));
595 ria->ria_start_idx = work->lrw_start_idx;
596 /* Truncate RA window to end of file */
597 eof_index = (pgoff_t)(kms - 1) >> PAGE_SHIFT;
598 if (eof_index <= work->lrw_end_idx) {
599 work->lrw_end_idx = eof_index;
602 if (work->lrw_end_idx <= work->lrw_start_idx)
603 GOTO(out_put_env, rc = 0);
605 ria->ria_end_idx = work->lrw_end_idx;
606 pages = ria->ria_end_idx - ria->ria_start_idx + 1;
607 ria->ria_reserved = ll_ra_count_get(sbi, ria,
608 ria_page_count(ria), pages_min);
611 "async reserved pages: %lu/%lu/%lu, ra_cur %d, ra_max %lu\n",
612 ria->ria_reserved, pages, pages_min,
613 atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
614 ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
616 if (ria->ria_reserved < pages) {
617 ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT);
618 if (PAGES_TO_MiB(ria->ria_reserved) < 1) {
619 ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
620 GOTO(out_put_env, rc = 0);
624 rc = cl_io_rw_init(env, io, CIT_READ, ria->ria_start_idx, pages);
626 GOTO(out_put_env, rc);
628 /* overwrite jobid inited in vvp_io_init() */
629 if (strncmp(ll_i2info(inode)->lli_jobid, work->lrw_jobid,
630 sizeof(work->lrw_jobid)))
631 memcpy(ll_i2info(inode)->lli_jobid, work->lrw_jobid,
632 sizeof(work->lrw_jobid));
634 vvp_env_io(env)->vui_fd = fd;
635 io->ci_state = CIS_LOCKED;
636 io->ci_async_readahead = true;
637 rc = cl_io_start(env, io);
639 GOTO(out_io_fini, rc);
641 queue = &io->ci_queue;
642 cl_2queue_init(queue);
644 rc = ll_read_ahead_pages(env, io, &queue->c2_qin, ras, ria,
646 if (ria->ria_reserved != 0)
647 ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
648 if (queue->c2_qin.pl_nr > 0) {
649 int count = queue->c2_qin.pl_nr;
651 rc = cl_io_submit_rw(env, io, CRT_READ, queue);
653 task_io_account_read(PAGE_SIZE * count);
655 if (ria->ria_end_idx == ra_end_idx && ra_end_idx == (kms >> PAGE_SHIFT))
656 ll_ra_stats_inc(inode, RA_STAT_EOF);
658 if (ra_end_idx != ria->ria_end_idx)
659 ll_ra_stats_inc(inode, RA_STAT_FAILED_REACH_END);
661 /* TODO: discard all pages until page reinit route is implemented */
662 cl_page_list_discard(env, io, &queue->c2_qin);
664 /* Unlock unsent read pages in case of error. */
665 cl_page_list_disown(env, io, &queue->c2_qin);
667 cl_2queue_fini(env, queue);
672 cl_env_put(env, &refcheck);
675 ll_ra_stats_inc_sbi(ll_i2sbi(inode), RA_STAT_ASYNC);
676 atomic_dec(&sbi->ll_ra_info.ra_async_inflight);
677 ll_readahead_work_free(work);
680 static int ll_readahead(const struct lu_env *env, struct cl_io *io,
681 struct cl_page_list *queue,
682 struct ll_readahead_state *ras, bool hit,
683 struct file *file, pgoff_t skip_index)
685 struct vvp_io *vio = vvp_env_io(env);
686 struct ll_thread_info *lti = ll_env_info(env);
687 unsigned long pages, pages_min = 0;
688 pgoff_t ra_end_idx = 0, start_idx = 0, end_idx = 0;
690 struct ra_io_arg *ria = <i->lti_ria;
691 struct cl_object *clob;
697 inode = vvp_object_inode(clob);
699 memset(ria, 0, sizeof(*ria));
700 ret = ll_readahead_file_kms(env, io, &kms);
705 ll_ra_stats_inc(inode, RA_STAT_ZERO_LEN);
709 spin_lock(&ras->ras_lock);
712 * Note: other thread might rollback the ras_next_readahead_idx,
713 * if it can not get the full size of prepared pages, see the
714 * end of this function. For stride read ahead, it needs to
715 * make sure the offset is no less than ras_stride_offset,
716 * so that stride read ahead can work correctly.
718 if (stride_io_mode(ras))
719 start_idx = max_t(pgoff_t, ras->ras_next_readahead_idx,
720 ras->ras_stride_offset >> PAGE_SHIFT);
722 start_idx = ras->ras_next_readahead_idx;
724 if (ras->ras_window_pages > 0)
725 end_idx = ras->ras_window_start_idx + ras->ras_window_pages - 1;
728 end_idx = start_idx + ras->ras_window_pages - 1;
730 /* Enlarge the RA window to encompass the full read */
731 if (vio->vui_ra_valid &&
732 end_idx < vio->vui_ra_start_idx + vio->vui_ra_pages - 1)
733 end_idx = vio->vui_ra_start_idx + vio->vui_ra_pages - 1;
738 /* Truncate RA window to end of file */
739 eof_index = (pgoff_t)((kms - 1) >> PAGE_SHIFT);
740 if (eof_index <= end_idx) {
745 ria->ria_start_idx = start_idx;
746 ria->ria_end_idx = end_idx;
747 /* If stride I/O mode is detected, get stride window*/
748 if (stride_io_mode(ras)) {
749 ria->ria_stoff = ras->ras_stride_offset;
750 ria->ria_length = ras->ras_stride_length;
751 ria->ria_bytes = ras->ras_stride_bytes;
753 spin_unlock(&ras->ras_lock);
756 ll_ra_stats_inc(inode, RA_STAT_ZERO_WINDOW);
759 pages = ria_page_count(ria);
761 ll_ra_stats_inc(inode, RA_STAT_ZERO_WINDOW);
766 CDEBUG(D_READA, DFID": ria: %lu/%lu, bead: %lu/%lu, hit: %d\n",
767 PFID(lu_object_fid(&clob->co_lu)),
768 ria->ria_start_idx, ria->ria_end_idx,
769 vio->vui_ra_valid ? vio->vui_ra_start_idx : 0,
770 vio->vui_ra_valid ? vio->vui_ra_pages : 0,
773 /* at least to extend the readahead window to cover current read */
774 if (!hit && vio->vui_ra_valid &&
775 vio->vui_ra_start_idx + vio->vui_ra_pages > ria->ria_start_idx) {
776 ria->ria_end_idx_min =
777 vio->vui_ra_start_idx + vio->vui_ra_pages - 1;
778 pages_min = vio->vui_ra_start_idx + vio->vui_ra_pages -
781 * For performance reason, exceeding @ra_max_pages
782 * are allowed, but this should be limited with RPC
783 * size in case a large block size read issued. Trim
786 pages_min = min(pages_min, ras->ras_rpc_pages -
787 (ria->ria_start_idx % ras->ras_rpc_pages));
790 /* don't over reserved for mmap range read */
794 ria->ria_reserved = ll_ra_count_get(ll_i2sbi(inode), ria, pages,
796 if (ria->ria_reserved < pages)
797 ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT);
799 CDEBUG(D_READA, "reserved pages: %lu/%lu/%lu, ra_cur %d, ra_max %lu\n",
800 ria->ria_reserved, pages, pages_min,
801 atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
802 ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
804 ret = ll_read_ahead_pages(env, io, queue, ras, ria, &ra_end_idx,
806 if (ria->ria_reserved != 0)
807 ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
809 if (ra_end_idx == end_idx && ra_end_idx == (kms >> PAGE_SHIFT))
810 ll_ra_stats_inc(inode, RA_STAT_EOF);
813 "ra_end_idx = %lu end_idx = %lu stride end = %lu pages = %d\n",
814 ra_end_idx, end_idx, ria->ria_end_idx, ret);
816 if (ra_end_idx != end_idx)
817 ll_ra_stats_inc(inode, RA_STAT_FAILED_REACH_END);
818 if (ra_end_idx > 0) {
819 /* update the ras so that the next read-ahead tries from
820 * where we left off. */
821 spin_lock(&ras->ras_lock);
822 ras->ras_next_readahead_idx = ra_end_idx + 1;
823 spin_unlock(&ras->ras_lock);
830 static int ll_readpages(const struct lu_env *env, struct cl_io *io,
831 struct cl_page_list *queue,
832 pgoff_t start, pgoff_t end)
841 ret = ll_readahead_file_kms(env, io, &kms);
849 unsigned long end_index;
851 end_index = (unsigned long)((kms - 1) >> PAGE_SHIFT);
852 if (end_index <= end)
856 for (page_idx = start; page_idx <= end; page_idx++) {
857 ret= ll_read_ahead_page(env, io, queue, page_idx,
861 else if (ret == 0) /* ret 1 is already uptodate */
865 RETURN(count > 0 ? count : ret);
868 static void ras_set_start(struct ll_readahead_state *ras, pgoff_t index)
870 ras->ras_window_start_idx = ras_align(ras, index);
873 /* called with the ras_lock held or from places where it doesn't matter */
874 static void ras_reset(struct ll_readahead_state *ras, pgoff_t index)
876 ras->ras_consecutive_requests = 0;
877 ras->ras_consecutive_bytes = 0;
878 ras->ras_window_pages = 0;
879 ras_set_start(ras, index);
880 ras->ras_next_readahead_idx = max(ras->ras_window_start_idx, index + 1);
885 /* called with the ras_lock held or from places where it doesn't matter */
886 static void ras_stride_reset(struct ll_readahead_state *ras)
888 ras->ras_consecutive_stride_requests = 0;
889 ras->ras_stride_length = 0;
890 ras->ras_stride_bytes = 0;
894 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
896 spin_lock_init(&ras->ras_lock);
897 ras->ras_rpc_pages = PTLRPC_MAX_BRW_PAGES;
899 ras->ras_last_read_end_bytes = 0;
900 ras->ras_requests = 0;
901 ras->ras_range_min_start_idx = 0;
902 ras->ras_range_max_end_idx = 0;
903 ras->ras_range_requests = 0;
904 ras->ras_last_range_pages = 0;
908 * Check whether the read request is in the stride window.
909 * If it is in the stride window, return true, otherwise return false.
911 static bool read_in_stride_window(struct ll_readahead_state *ras,
912 loff_t pos, loff_t count)
916 if (ras->ras_stride_length == 0 || ras->ras_stride_bytes == 0 ||
917 ras->ras_stride_bytes == ras->ras_stride_length)
920 stride_gap = pos - ras->ras_last_read_end_bytes - 1;
922 /* If it is contiguous read */
924 return ras->ras_consecutive_bytes + count <=
925 ras->ras_stride_bytes;
927 /* Otherwise check the stride by itself */
928 return (ras->ras_stride_length - ras->ras_stride_bytes) == stride_gap &&
929 ras->ras_consecutive_bytes == ras->ras_stride_bytes &&
930 count <= ras->ras_stride_bytes;
933 static void ras_init_stride_detector(struct ll_readahead_state *ras,
934 loff_t pos, loff_t count)
936 loff_t stride_gap = pos - ras->ras_last_read_end_bytes - 1;
938 LASSERT(ras->ras_consecutive_stride_requests == 0);
940 if (pos <= ras->ras_last_read_end_bytes) {
941 /*Reset stride window for forward read*/
942 ras_stride_reset(ras);
946 ras->ras_stride_bytes = ras->ras_consecutive_bytes;
947 ras->ras_stride_length = stride_gap + ras->ras_consecutive_bytes;
948 ras->ras_consecutive_stride_requests++;
949 ras->ras_stride_offset = pos;
955 stride_page_count(struct ll_readahead_state *ras, loff_t len)
958 stride_byte_count(ras->ras_stride_offset,
959 ras->ras_stride_length, ras->ras_stride_bytes,
960 ras->ras_window_start_idx << PAGE_SHIFT, len);
962 return (bytes_count + PAGE_SIZE - 1) >> PAGE_SHIFT;
965 /* Stride Read-ahead window will be increased inc_len according to
966 * stride I/O pattern */
967 static void ras_stride_increase_window(struct ll_readahead_state *ras,
968 struct ll_ra_info *ra, loff_t inc_bytes)
970 loff_t window_bytes, stride_bytes;
975 /* temporarily store in page units to reduce LASSERT() cost below */
976 end = ras->ras_window_start_idx + ras->ras_window_pages;
978 LASSERT(ras->ras_stride_length > 0);
979 LASSERTF(end >= (ras->ras_stride_offset >> PAGE_SHIFT),
980 "window_start_idx %lu, window_pages %lu stride_offset %llu\n",
981 ras->ras_window_start_idx, ras->ras_window_pages,
982 ras->ras_stride_offset);
985 if (end <= ras->ras_stride_offset)
988 stride_bytes = end - ras->ras_stride_offset;
990 div64_u64_rem(stride_bytes, ras->ras_stride_length, &left_bytes);
991 window_bytes = (ras->ras_window_pages << PAGE_SHIFT);
992 if (left_bytes < ras->ras_stride_bytes) {
993 if (ras->ras_stride_bytes - left_bytes >= inc_bytes) {
994 window_bytes += inc_bytes;
997 window_bytes += (ras->ras_stride_bytes - left_bytes);
998 inc_bytes -= (ras->ras_stride_bytes - left_bytes);
1001 window_bytes += (ras->ras_stride_length - left_bytes);
1004 LASSERT(ras->ras_stride_bytes != 0);
1006 step = div64_u64_rem(inc_bytes, ras->ras_stride_bytes, &left_bytes);
1008 window_bytes += step * ras->ras_stride_length + left_bytes;
1009 LASSERT(window_bytes > 0);
1012 if (stride_page_count(ras, window_bytes) <=
1013 ra->ra_max_pages_per_file || ras->ras_window_pages == 0)
1014 ras->ras_window_pages = (window_bytes >> PAGE_SHIFT);
1016 LASSERT(ras->ras_window_pages > 0);
1021 static void ras_increase_window(struct inode *inode,
1022 struct ll_readahead_state *ras,
1023 struct ll_ra_info *ra)
1025 /* The stretch of ra-window should be aligned with max rpc_size
1026 * but current clio architecture does not support retrieve such
1027 * information from lower layer. FIXME later
1029 if (stride_io_mode(ras)) {
1030 ras_stride_increase_window(ras, ra,
1031 (loff_t)ras->ras_rpc_pages << PAGE_SHIFT);
1033 pgoff_t window_pages;
1035 window_pages = min(ras->ras_window_pages + ras->ras_rpc_pages,
1036 ra->ra_max_pages_per_file);
1037 if (window_pages < ras->ras_rpc_pages)
1038 ras->ras_window_pages = window_pages;
1040 ras->ras_window_pages = ras_align(ras, window_pages);
1045 * Seek within 8 pages are considered as sequential read for now.
1047 static inline bool is_loose_seq_read(struct ll_readahead_state *ras, loff_t pos)
1049 return pos_in_window(pos, ras->ras_last_read_end_bytes,
1050 8UL << PAGE_SHIFT, 8UL << PAGE_SHIFT);
1053 static inline bool is_loose_mmap_read(struct ll_sb_info *sbi,
1054 struct ll_readahead_state *ras,
1057 unsigned long range_pages = sbi->ll_ra_info.ra_range_pages;
1059 return pos_in_window(pos, ras->ras_last_read_end_bytes,
1060 range_pages << PAGE_SHIFT,
1061 range_pages << PAGE_SHIFT);
1065 * We have observed slow mmap read performances for some
1066 * applications. The problem is if access pattern is neither
1067 * sequential nor stride, but could be still adjacent in a
1068 * small range and then seek a random position.
1070 * So the pattern could be something like this:
1072 * [1M data] [hole] [0.5M data] [hole] [0.7M data] [1M data]
1075 * Every time an application reads mmap data, it may not only
1076 * read a single 4KB page, but aslo a cluster of nearby pages in
1077 * a range(e.g. 1MB) of the first page after a cache miss.
1079 * The readahead engine is modified to track the range size of
1080 * a cluster of mmap reads, so that after a seek and/or cache miss,
1081 * the range size is used to efficiently prefetch multiple pages
1082 * in a single RPC rather than many small RPCs.
1084 static void ras_detect_cluster_range(struct ll_readahead_state *ras,
1085 struct ll_sb_info *sbi,
1086 unsigned long pos, unsigned long count)
1088 pgoff_t last_pages, pages;
1089 pgoff_t end_idx = (pos + count - 1) >> PAGE_SHIFT;
1091 last_pages = ras->ras_range_max_end_idx -
1092 ras->ras_range_min_start_idx + 1;
1093 /* First time come here */
1094 if (!ras->ras_range_max_end_idx)
1097 /* Random or Stride read */
1098 if (!is_loose_mmap_read(sbi, ras, pos))
1101 ras->ras_range_requests++;
1102 if (ras->ras_range_max_end_idx < end_idx)
1103 ras->ras_range_max_end_idx = end_idx;
1105 if (ras->ras_range_min_start_idx > (pos >> PAGE_SHIFT))
1106 ras->ras_range_min_start_idx = pos >> PAGE_SHIFT;
1108 /* Out of range, consider it as random or stride */
1109 pages = ras->ras_range_max_end_idx -
1110 ras->ras_range_min_start_idx + 1;
1111 if (pages <= sbi->ll_ra_info.ra_range_pages)
1114 ras->ras_last_range_pages = last_pages;
1115 ras->ras_range_requests = 0;
1116 ras->ras_range_min_start_idx = pos >> PAGE_SHIFT;
1117 ras->ras_range_max_end_idx = end_idx;
1120 static void ras_detect_read_pattern(struct ll_readahead_state *ras,
1121 struct ll_sb_info *sbi,
1122 loff_t pos, size_t count, bool mmap)
1124 bool stride_detect = false;
1125 pgoff_t index = pos >> PAGE_SHIFT;
1128 * Reset the read-ahead window in two cases. First when the app seeks
1129 * or reads to some other part of the file. Secondly if we get a
1130 * read-ahead miss that we think we've previously issued. This can
1131 * be a symptom of there being so many read-ahead pages that the VM
1132 * is reclaiming it before we get to it.
1134 if (!is_loose_seq_read(ras, pos)) {
1135 /* Check whether it is in stride I/O mode */
1136 if (!read_in_stride_window(ras, pos, count)) {
1137 if (ras->ras_consecutive_stride_requests == 0)
1138 ras_init_stride_detector(ras, pos, count);
1140 ras_stride_reset(ras);
1141 ras->ras_consecutive_bytes = 0;
1142 ras_reset(ras, index);
1144 ras->ras_consecutive_bytes = 0;
1145 ras->ras_consecutive_requests = 0;
1146 if (++ras->ras_consecutive_stride_requests > 1)
1147 stride_detect = true;
1150 ll_ra_stats_inc_sbi(sbi, RA_STAT_DISTANT_READPAGE);
1151 } else if (stride_io_mode(ras)) {
1153 * If this is contiguous read but in stride I/O mode
1154 * currently, check whether stride step still is valid,
1155 * if invalid, it will reset the stride ra window to
1158 if (!read_in_stride_window(ras, pos, count)) {
1159 ras_stride_reset(ras);
1160 ras->ras_window_pages = 0;
1161 ras->ras_next_readahead_idx = index;
1165 ras->ras_consecutive_bytes += count;
1167 pgoff_t idx = ras->ras_consecutive_bytes >> PAGE_SHIFT;
1168 unsigned long ra_range_pages =
1169 max_t(unsigned long, RA_MIN_MMAP_RANGE_PAGES,
1170 sbi->ll_ra_info.ra_range_pages);
1172 if ((idx >= ra_range_pages &&
1173 idx % ra_range_pages == 0) || stride_detect)
1174 ras->ras_need_increase_window = true;
1175 } else if ((ras->ras_consecutive_requests > 1 || stride_detect)) {
1176 ras->ras_need_increase_window = true;
1179 ras->ras_last_read_end_bytes = pos + count - 1;
1182 void ll_ras_enter(struct file *f, loff_t pos, size_t count)
1184 struct ll_file_data *fd = f->private_data;
1185 struct ll_readahead_state *ras = &fd->fd_ras;
1186 struct inode *inode = file_inode(f);
1187 unsigned long index = pos >> PAGE_SHIFT;
1188 struct ll_sb_info *sbi = ll_i2sbi(inode);
1190 spin_lock(&ras->ras_lock);
1191 ras->ras_requests++;
1192 ras->ras_consecutive_requests++;
1193 ras->ras_need_increase_window = false;
1194 ras->ras_no_miss_check = false;
1196 * On the second access to a file smaller than the tunable
1197 * ra_max_read_ahead_whole_pages trigger RA on all pages in the
1198 * file up to ra_max_pages_per_file. This is simply a best effort
1199 * and only occurs once per open file. Normal RA behavior is reverted
1200 * to for subsequent IO.
1202 if (ras->ras_requests >= 2) {
1204 struct ll_ra_info *ra = &sbi->ll_ra_info;
1206 kms_pages = (i_size_read(inode) + PAGE_SIZE - 1) >>
1209 CDEBUG(D_READA, "kmsp %llu mwp %lu mp %lu\n", kms_pages,
1210 ra->ra_max_read_ahead_whole_pages,
1211 ra->ra_max_pages_per_file);
1214 kms_pages <= ra->ra_max_read_ahead_whole_pages) {
1215 ras->ras_window_start_idx = 0;
1216 ras->ras_next_readahead_idx = index + 1;
1217 ras->ras_window_pages = min(ra->ra_max_pages_per_file,
1218 ra->ra_max_read_ahead_whole_pages);
1219 ras->ras_no_miss_check = true;
1220 GOTO(out_unlock, 0);
1223 ras_detect_read_pattern(ras, sbi, pos, count, false);
1225 spin_unlock(&ras->ras_lock);
1228 static bool index_in_stride_window(struct ll_readahead_state *ras,
1231 loff_t pos = (loff_t)index << PAGE_SHIFT;
1233 if (ras->ras_stride_length == 0 || ras->ras_stride_bytes == 0 ||
1234 ras->ras_stride_bytes == ras->ras_stride_length)
1237 if (pos >= ras->ras_stride_offset) {
1240 div64_u64_rem(pos - ras->ras_stride_offset,
1241 ras->ras_stride_length, &offset);
1242 if (offset < ras->ras_stride_bytes ||
1243 ras->ras_stride_length - offset < PAGE_SIZE)
1245 } else if (ras->ras_stride_offset - pos < PAGE_SIZE) {
1253 * ll_ras_enter() is used to detect read pattern according to pos and count.
1255 * ras_update() is used to detect cache miss and
1256 * reset window or increase window accordingly
1258 static void ras_update(struct ll_sb_info *sbi, struct inode *inode,
1259 struct ll_readahead_state *ras, pgoff_t index,
1260 enum ras_update_flags flags, struct cl_io *io)
1262 struct ll_ra_info *ra = &sbi->ll_ra_info;
1263 bool hit = flags & LL_RAS_HIT;
1266 spin_lock(&ras->ras_lock);
1269 CDEBUG(D_READA, DFID " pages at %lu miss.\n",
1270 PFID(ll_inode2fid(inode)), index);
1271 ll_ra_stats_inc_sbi(sbi, hit ? RA_STAT_HIT : RA_STAT_MISS);
1274 * The readahead window has been expanded to cover whole
1275 * file size, we don't care whether ra miss happen or not.
1276 * Because we will read whole file to page cache even if
1277 * some pages missed.
1279 if (ras->ras_no_miss_check)
1280 GOTO(out_unlock, 0);
1282 if (io && io->ci_rand_read)
1283 GOTO(out_unlock, 0);
1285 if (io && io->ci_seq_read) {
1287 /* to avoid many small read RPC here */
1288 ras->ras_window_pages = sbi->ll_ra_info.ra_range_pages;
1289 ll_ra_stats_inc_sbi(sbi, RA_STAT_MMAP_RANGE_READ);
1294 if (flags & LL_RAS_MMAP) {
1295 unsigned long ra_pages;
1297 ras_detect_cluster_range(ras, sbi, index << PAGE_SHIFT,
1299 ras_detect_read_pattern(ras, sbi, (loff_t)index << PAGE_SHIFT,
1302 /* we did not detect anything but we could prefetch */
1303 if (!ras->ras_need_increase_window &&
1304 ras->ras_window_pages <= sbi->ll_ra_info.ra_range_pages &&
1305 ras->ras_range_requests >= 2) {
1307 ra_pages = max_t(unsigned long,
1308 RA_MIN_MMAP_RANGE_PAGES,
1309 ras->ras_last_range_pages);
1310 if (index < ra_pages / 2)
1313 index -= ra_pages / 2;
1314 ras->ras_window_pages = ra_pages;
1315 ll_ra_stats_inc_sbi(sbi,
1316 RA_STAT_MMAP_RANGE_READ);
1318 ras->ras_window_pages = 0;
1324 if (!hit && ras->ras_window_pages &&
1325 index < ras->ras_next_readahead_idx &&
1326 pos_in_window(index, ras->ras_window_start_idx, 0,
1327 ras->ras_window_pages)) {
1328 ll_ra_stats_inc_sbi(sbi, RA_STAT_MISS_IN_WINDOW);
1329 ras->ras_need_increase_window = false;
1331 if (index_in_stride_window(ras, index) &&
1332 stride_io_mode(ras)) {
1334 * if (index != ras->ras_last_readpage + 1)
1335 * ras->ras_consecutive_pages = 0;
1337 ras_reset(ras, index);
1340 * If stride-RA hit cache miss, the stride
1341 * detector will not be reset to avoid the
1342 * overhead of redetecting read-ahead mode,
1343 * but on the condition that the stride window
1344 * is still intersect with normal sequential
1345 * read-ahead window.
1347 if (ras->ras_window_start_idx < ras->ras_stride_offset)
1348 ras_stride_reset(ras);
1352 * Reset both stride window and normal RA
1355 ras_reset(ras, index);
1356 /* ras->ras_consecutive_pages++; */
1357 ras->ras_consecutive_bytes = 0;
1358 ras_stride_reset(ras);
1359 GOTO(out_unlock, 0);
1364 ras_set_start(ras, index);
1366 if (stride_io_mode(ras)) {
1367 /* Since stride readahead is sentivite to the offset
1368 * of read-ahead, so we use original offset here,
1369 * instead of ras_window_start_idx, which is RPC aligned.
1371 ras->ras_next_readahead_idx = max(index + 1,
1372 ras->ras_next_readahead_idx);
1373 ras->ras_window_start_idx =
1374 max_t(pgoff_t, ras->ras_window_start_idx,
1375 ras->ras_stride_offset >> PAGE_SHIFT);
1377 if (ras->ras_next_readahead_idx < ras->ras_window_start_idx)
1378 ras->ras_next_readahead_idx = ras->ras_window_start_idx;
1380 ras->ras_next_readahead_idx = index + 1;
1383 if (ras->ras_need_increase_window) {
1384 ras_increase_window(inode, ras, ra);
1385 ras->ras_need_increase_window = false;
1390 spin_unlock(&ras->ras_lock);
1393 int ll_writepage(struct page *vmpage, struct writeback_control *wbc)
1395 struct inode *inode = vmpage->mapping->host;
1396 struct ll_inode_info *lli = ll_i2info(inode);
1399 struct cl_page *page;
1400 struct cl_object *clob;
1401 bool redirtied = false;
1402 bool unlocked = false;
1407 LASSERT(PageLocked(vmpage));
1408 LASSERT(!PageWriteback(vmpage));
1410 LASSERT(ll_i2dtexp(inode) != NULL);
1412 env = cl_env_get(&refcheck);
1414 GOTO(out, result = PTR_ERR(env));
1416 clob = ll_i2info(inode)->lli_clob;
1417 LASSERT(clob != NULL);
1419 io = vvp_env_thread_io(env);
1421 io->ci_ignore_layout = 1;
1422 result = cl_io_init(env, io, CIT_MISC, clob);
1424 page = cl_page_find(env, clob, vmpage->index,
1425 vmpage, CPT_CACHEABLE);
1426 if (!IS_ERR(page)) {
1427 lu_ref_add(&page->cp_reference, "writepage",
1429 cl_page_assume(env, io, page);
1430 result = cl_page_flush(env, io, page);
1433 * Re-dirty page on error so it retries write,
1434 * but not in case when IO has actually
1435 * occurred and completed with an error.
1437 if (!PageError(vmpage)) {
1438 redirty_page_for_writepage(wbc, vmpage);
1443 cl_page_disown(env, io, page);
1445 lu_ref_del(&page->cp_reference,
1446 "writepage", current);
1447 cl_page_put(env, page);
1449 result = PTR_ERR(page);
1452 cl_io_fini(env, io);
1454 if (redirtied && wbc->sync_mode == WB_SYNC_ALL) {
1455 loff_t offset = cl_offset(clob, vmpage->index);
1457 /* Flush page failed because the extent is being written out.
1458 * Wait for the write of extent to be finished to avoid
1459 * breaking kernel which assumes ->writepage should mark
1460 * PageWriteback or clean the page. */
1461 result = cl_sync_file_range(inode, offset,
1462 offset + PAGE_SIZE - 1,
1465 /* actually we may have written more than one page.
1466 * decreasing this page because the caller will count
1468 wbc->nr_to_write -= result - 1;
1473 cl_env_put(env, &refcheck);
1478 if (!lli->lli_async_rc)
1479 lli->lli_async_rc = result;
1480 SetPageError(vmpage);
1482 unlock_page(vmpage);
1487 int ll_writepages(struct address_space *mapping, struct writeback_control *wbc)
1489 struct inode *inode = mapping->host;
1492 enum cl_fsync_mode mode;
1493 int range_whole = 0;
1497 if (wbc->range_cyclic) {
1498 start = (loff_t)mapping->writeback_index << PAGE_SHIFT;
1499 end = OBD_OBJECT_EOF;
1501 start = wbc->range_start;
1502 end = wbc->range_end;
1503 if (end == LLONG_MAX) {
1504 end = OBD_OBJECT_EOF;
1505 range_whole = start == 0;
1509 mode = CL_FSYNC_NONE;
1510 if (wbc->sync_mode == WB_SYNC_ALL)
1511 mode = CL_FSYNC_LOCAL;
1513 if (ll_i2info(inode)->lli_clob == NULL)
1516 /* for directio, it would call writepages() to evict cached pages
1517 * inside the IO context of write, which will cause deadlock at
1518 * layout_conf since it waits for active IOs to complete. */
1519 result = cl_sync_file_range(inode, start, end, mode, 1);
1521 wbc->nr_to_write -= result;
1525 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) {
1526 if (end == OBD_OBJECT_EOF)
1527 mapping->writeback_index = 0;
1529 mapping->writeback_index = (end >> PAGE_SHIFT) + 1;
1534 struct ll_cl_context *ll_cl_find(struct file *file)
1536 struct ll_file_data *fd = file->private_data;
1537 struct ll_cl_context *lcc;
1538 struct ll_cl_context *found = NULL;
1540 read_lock(&fd->fd_lock);
1541 list_for_each_entry(lcc, &fd->fd_lccs, lcc_list) {
1542 if (lcc->lcc_cookie == current) {
1547 read_unlock(&fd->fd_lock);
1552 void ll_cl_add(struct file *file, const struct lu_env *env, struct cl_io *io,
1555 struct ll_file_data *fd = file->private_data;
1556 struct ll_cl_context *lcc = &ll_env_info(env)->lti_io_ctx;
1558 memset(lcc, 0, sizeof(*lcc));
1559 INIT_LIST_HEAD(&lcc->lcc_list);
1560 lcc->lcc_cookie = current;
1563 lcc->lcc_type = type;
1565 write_lock(&fd->fd_lock);
1566 list_add(&lcc->lcc_list, &fd->fd_lccs);
1567 write_unlock(&fd->fd_lock);
1570 void ll_cl_remove(struct file *file, const struct lu_env *env)
1572 struct ll_file_data *fd = file->private_data;
1573 struct ll_cl_context *lcc = &ll_env_info(env)->lti_io_ctx;
1575 write_lock(&fd->fd_lock);
1576 list_del_init(&lcc->lcc_list);
1577 write_unlock(&fd->fd_lock);
1580 int ll_io_read_page(const struct lu_env *env, struct cl_io *io,
1581 struct cl_page *page, struct file *file)
1583 struct inode *inode = vvp_object_inode(page->cp_obj);
1584 struct ll_sb_info *sbi = ll_i2sbi(inode);
1585 struct ll_file_data *fd = NULL;
1586 struct ll_readahead_state *ras = NULL;
1587 struct cl_2queue *queue = &io->ci_queue;
1588 struct cl_sync_io *anchor = NULL;
1589 struct vvp_page *vpg;
1590 int rc = 0, rc2 = 0;
1592 pgoff_t io_start_index;
1593 pgoff_t io_end_index;
1597 fd = file->private_data;
1601 vpg = cl2vvp_page(cl_object_page_slice(page->cp_obj, page));
1602 uptodate = vpg->vpg_defer_uptodate;
1604 if (ll_readahead_enabled(sbi) && !vpg->vpg_ra_updated && ras) {
1605 struct vvp_io *vio = vvp_env_io(env);
1606 enum ras_update_flags flags = 0;
1609 flags |= LL_RAS_HIT;
1610 if (!vio->vui_ra_valid)
1611 flags |= LL_RAS_MMAP;
1612 ras_update(sbi, inode, ras, vvp_index(vpg), flags, io);
1615 cl_2queue_init(queue);
1617 vpg->vpg_ra_used = 1;
1618 cl_page_export(env, page, 1);
1619 cl_page_disown(env, io, page);
1621 anchor = &vvp_env_info(env)->vti_anchor;
1622 cl_sync_io_init(anchor, 1);
1623 page->cp_sync_io = anchor;
1625 cl_2queue_add(queue, page);
1628 io_start_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos);
1629 io_end_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos +
1630 io->u.ci_rw.crw_count - 1);
1631 if (ll_readahead_enabled(sbi) && ras && !io->ci_rand_read) {
1632 pgoff_t skip_index = 0;
1634 if (ras->ras_next_readahead_idx < vvp_index(vpg))
1635 skip_index = vvp_index(vpg);
1636 rc2 = ll_readahead(env, io, &queue->c2_qin, ras,
1637 uptodate, file, skip_index);
1638 CDEBUG(D_READA, DFID " %d pages read ahead at %lu\n",
1639 PFID(ll_inode2fid(inode)), rc2, vvp_index(vpg));
1640 } else if (vvp_index(vpg) == io_start_index &&
1641 io_end_index - io_start_index > 0) {
1642 rc2 = ll_readpages(env, io, &queue->c2_qin, io_start_index + 1,
1644 CDEBUG(D_READA, DFID " %d pages read at %lu\n",
1645 PFID(ll_inode2fid(inode)), rc2, vvp_index(vpg));
1648 if (queue->c2_qin.pl_nr > 0) {
1649 int count = queue->c2_qin.pl_nr;
1650 rc = cl_io_submit_rw(env, io, CRT_READ, queue);
1652 task_io_account_read(PAGE_SIZE * count);
1656 if (anchor != NULL && !cl_page_is_owned(page, io)) { /* have sent */
1657 rc = cl_sync_io_wait(env, anchor, 0);
1659 cl_page_assume(env, io, page);
1660 cl_page_list_del(env, &queue->c2_qout, page);
1662 if (!PageUptodate(cl_page_vmpage(page))) {
1663 /* Failed to read a mirror, discard this page so that
1664 * new page can be created with new mirror.
1666 * TODO: this is not needed after page reinit
1667 * route is implemented */
1668 cl_page_discard(env, io, page);
1670 cl_page_disown(env, io, page);
1673 /* TODO: discard all pages until page reinit route is implemented */
1674 cl_page_list_discard(env, io, &queue->c2_qin);
1676 /* Unlock unsent read pages in case of error. */
1677 cl_page_list_disown(env, io, &queue->c2_qin);
1679 cl_2queue_fini(env, queue);
1685 * Possible return value:
1686 * 0 no async readahead triggered and fast read could not be used.
1687 * 1 no async readahead, but fast read could be used.
1688 * 2 async readahead triggered and fast read could be used too.
1691 static int kickoff_async_readahead(struct file *file, unsigned long pages)
1693 struct ll_readahead_work *lrw;
1694 struct inode *inode = file_inode(file);
1695 struct ll_sb_info *sbi = ll_i2sbi(inode);
1696 struct ll_file_data *fd = file->private_data;
1697 struct ll_readahead_state *ras = &fd->fd_ras;
1698 struct ll_ra_info *ra = &sbi->ll_ra_info;
1699 unsigned long throttle;
1700 pgoff_t start_idx = ras_align(ras, ras->ras_next_readahead_idx);
1701 pgoff_t end_idx = start_idx + pages - 1;
1703 throttle = min(ra->ra_async_pages_per_file_threshold,
1704 ra->ra_max_pages_per_file);
1706 * If this is strided i/o or the window is smaller than the
1707 * throttle limit, we do not do async readahead. Otherwise,
1708 * we do async readahead, allowing the user thread to do fast i/o.
1710 if (stride_io_mode(ras) || !throttle ||
1711 ras->ras_window_pages < throttle ||
1712 atomic_read(&ra->ra_async_inflight) > ra->ra_async_max_active)
1715 if ((atomic_read(&ra->ra_cur_pages) + pages) > ra->ra_max_pages)
1718 if (ras->ras_async_last_readpage_idx == start_idx)
1721 /* ll_readahead_work_free() free it */
1724 atomic_inc(&sbi->ll_ra_info.ra_async_inflight);
1725 lrw->lrw_file = get_file(file);
1726 lrw->lrw_start_idx = start_idx;
1727 lrw->lrw_end_idx = end_idx;
1728 spin_lock(&ras->ras_lock);
1729 ras->ras_next_readahead_idx = end_idx + 1;
1730 ras->ras_async_last_readpage_idx = start_idx;
1731 spin_unlock(&ras->ras_lock);
1732 memcpy(lrw->lrw_jobid, ll_i2info(inode)->lli_jobid,
1733 sizeof(lrw->lrw_jobid));
1734 ll_readahead_work_add(inode, lrw);
1743 * Check if we can issue a readahead RPC, if that is
1744 * the case, we can't do fast IO because we will need
1745 * a cl_io to issue the RPC.
1747 static bool ll_use_fast_io(struct file *file,
1748 struct ll_readahead_state *ras, pgoff_t index)
1750 unsigned long fast_read_pages =
1751 max(RA_REMAIN_WINDOW_MIN, ras->ras_rpc_pages);
1753 loff_t stride_bytes = ras->ras_stride_bytes;
1755 if (stride_io_mode(ras) && stride_bytes) {
1756 skip_pages = (ras->ras_stride_length +
1757 ras->ras_stride_bytes - 1) / stride_bytes;
1758 skip_pages *= fast_read_pages;
1760 skip_pages = fast_read_pages;
1763 if (ras->ras_window_start_idx + ras->ras_window_pages <
1764 ras->ras_next_readahead_idx + skip_pages ||
1765 kickoff_async_readahead(file, fast_read_pages) > 0)
1771 int ll_readpage(struct file *file, struct page *vmpage)
1773 struct inode *inode = file_inode(file);
1774 struct cl_object *clob = ll_i2info(inode)->lli_clob;
1775 struct ll_cl_context *lcc;
1776 const struct lu_env *env = NULL;
1777 struct cl_io *io = NULL;
1778 struct cl_page *page;
1779 struct ll_sb_info *sbi = ll_i2sbi(inode);
1783 lcc = ll_cl_find(file);
1789 if (io == NULL) { /* fast read */
1790 struct inode *inode = file_inode(file);
1791 struct ll_file_data *fd = file->private_data;
1792 struct ll_readahead_state *ras = &fd->fd_ras;
1793 struct lu_env *local_env = NULL;
1794 struct vvp_page *vpg;
1798 /* TODO: need to verify the layout version to make sure
1799 * the page is not invalid due to layout change. */
1800 page = cl_vmpage_page(vmpage, clob);
1802 unlock_page(vmpage);
1803 ll_ra_stats_inc_sbi(sbi, RA_STAT_FAILED_FAST_READ);
1807 vpg = cl2vvp_page(cl_object_page_slice(page->cp_obj, page));
1808 if (vpg->vpg_defer_uptodate) {
1809 enum ras_update_flags flags = LL_RAS_HIT;
1811 if (lcc && lcc->lcc_type == LCC_MMAP)
1812 flags |= LL_RAS_MMAP;
1814 /* For fast read, it updates read ahead state only
1815 * if the page is hit in cache because non cache page
1816 * case will be handled by slow read later. */
1817 ras_update(sbi, inode, ras, vvp_index(vpg), flags, io);
1818 /* avoid duplicate ras_update() call */
1819 vpg->vpg_ra_updated = 1;
1821 if (ll_use_fast_io(file, ras, vvp_index(vpg)))
1826 local_env = cl_env_percpu_get();
1830 /* export the page and skip io stack */
1832 vpg->vpg_ra_used = 1;
1833 cl_page_export(env, page, 1);
1835 ll_ra_stats_inc_sbi(sbi, RA_STAT_FAILED_FAST_READ);
1837 /* release page refcount before unlocking the page to ensure
1838 * the object won't be destroyed in the calling path of
1839 * cl_page_put(). Please see comment in ll_releasepage(). */
1840 cl_page_put(env, page);
1841 unlock_page(vmpage);
1843 cl_env_percpu_put(local_env);
1849 * Direct read can fall back to buffered read, but DIO is done
1850 * with lockless i/o, and buffered requires LDLM locking, so in
1851 * this case we must restart without lockless.
1853 if (file->f_flags & O_DIRECT &&
1854 lcc && lcc->lcc_type == LCC_RW &&
1856 unlock_page(vmpage);
1857 io->ci_dio_lock = 1;
1858 io->ci_need_restart = 1;
1862 LASSERT(io->ci_state == CIS_IO_GOING);
1863 page = cl_page_find(env, clob, vmpage->index, vmpage, CPT_CACHEABLE);
1864 if (!IS_ERR(page)) {
1865 LASSERT(page->cp_type == CPT_CACHEABLE);
1866 if (likely(!PageUptodate(vmpage))) {
1867 cl_page_assume(env, io, page);
1869 result = ll_io_read_page(env, io, page, file);
1871 /* Page from a non-object file. */
1872 unlock_page(vmpage);
1875 cl_page_put(env, page);
1877 unlock_page(vmpage);
1878 result = PTR_ERR(page);