4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
27 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
30 * Copyright (c) 2011, 2012, Intel Corporation.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
38 * Lustre Lite I/O page cache routines shared by different kernel revs
41 #include <linux/kernel.h>
43 #include <linux/string.h>
44 #include <linux/stat.h>
45 #include <linux/errno.h>
46 #include <linux/unistd.h>
47 #include <linux/writeback.h>
48 #include <linux/uaccess.h>
51 #include <linux/pagemap.h>
52 /* current_is_kswapd() */
53 #include <linux/swap.h>
55 #define DEBUG_SUBSYSTEM S_LLITE
57 #include "../include/lustre_lite.h"
58 #include "../include/obd_cksum.h"
59 #include "llite_internal.h"
60 #include "../include/linux/lustre_compat25.h"
63 * Finalizes cl-data before exiting typical address_space operation. Dual to
66 static void ll_cl_fini(struct ll_cl_context *lcc)
68 struct lu_env *env = lcc->lcc_env;
69 struct cl_io *io = lcc->lcc_io;
70 struct cl_page *page = lcc->lcc_page;
72 LASSERT(lcc->lcc_cookie == current);
76 lu_ref_del(&page->cp_reference, "cl_io", io);
77 cl_page_put(env, page);
80 cl_env_put(env, &lcc->lcc_refcheck);
84 * Initializes common cl-data at the typical address_space operation entry
87 static struct ll_cl_context *ll_cl_init(struct file *file,
88 struct page *vmpage, int create)
90 struct ll_cl_context *lcc;
93 struct cl_object *clob;
99 clob = ll_i2info(vmpage->mapping->host)->lli_clob;
100 LASSERT(clob != NULL);
102 env = cl_env_get(&refcheck);
104 return ERR_CAST(env);
106 lcc = &vvp_env_info(env)->vti_io_ctx;
107 memset(lcc, 0, sizeof(*lcc));
109 lcc->lcc_refcheck = refcheck;
110 lcc->lcc_cookie = current;
112 cio = ccc_env_io(env);
113 io = cio->cui_cl.cis_io;
114 if (io == NULL && create) {
115 struct inode *inode = vmpage->mapping->host;
118 if (mutex_trylock(&inode->i_mutex)) {
119 mutex_unlock(&(inode)->i_mutex);
121 /* this is too bad. Someone is trying to write the
122 * page w/o holding inode mutex. This means we can
123 * add dirty pages into cache during truncate */
124 CERROR("Proc %s is dirtying page w/o inode lock, this will break truncate\n",
128 return ERR_PTR(-EIO);
132 * Loop-back driver calls ->prepare_write().
133 * methods directly, bypassing file system ->write() operation,
134 * so cl_io has to be created here.
136 io = ccc_env_thread_io(env);
137 ll_io_init(io, file, 1);
139 /* No lock at all for this kind of IO - we can't do it because
140 * we have held page lock, it would cause deadlock.
141 * XXX: This causes poor performance to loop device - One page
143 * In order to get better performance, users should use
144 * lloop driver instead.
146 io->ci_lockreq = CILR_NEVER;
148 pos = vmpage->index << PAGE_CACHE_SHIFT;
150 /* Create a temp IO to serve write. */
151 result = cl_io_rw_init(env, io, CIT_WRITE, pos, PAGE_CACHE_SIZE);
153 cio->cui_fd = LUSTRE_FPRIVATE(file);
154 cio->cui_iter = NULL;
155 result = cl_io_iter_init(env, io);
157 result = cl_io_lock(env, io);
159 result = cl_io_start(env, io);
162 result = io->ci_result;
169 struct cl_page *page;
172 LASSERT(io->ci_state == CIS_IO_GOING);
173 LASSERT(cio->cui_fd == LUSTRE_FPRIVATE(file));
174 page = cl_page_find(env, clob, vmpage->index, vmpage,
177 lcc->lcc_page = page;
178 lu_ref_add(&page->cp_reference, "cl_io", io);
181 result = PTR_ERR(page);
185 lcc = ERR_PTR(result);
188 CDEBUG(D_VFSTRACE, "%lu@"DFID" -> %d %p %p\n",
189 vmpage->index, PFID(lu_object_fid(&clob->co_lu)), result,
194 static struct ll_cl_context *ll_cl_get(void)
196 struct ll_cl_context *lcc;
200 env = cl_env_get(&refcheck);
201 LASSERT(!IS_ERR(env));
202 lcc = &vvp_env_info(env)->vti_io_ctx;
203 LASSERT(env == lcc->lcc_env);
204 LASSERT(current == lcc->lcc_cookie);
205 cl_env_put(env, &refcheck);
207 /* env has got in ll_cl_init, so it is still usable. */
212 * ->prepare_write() address space operation called by generic_file_write()
213 * for every page during write.
215 int ll_prepare_write(struct file *file, struct page *vmpage, unsigned from,
218 struct ll_cl_context *lcc;
221 lcc = ll_cl_init(file, vmpage, 1);
223 struct lu_env *env = lcc->lcc_env;
224 struct cl_io *io = lcc->lcc_io;
225 struct cl_page *page = lcc->lcc_page;
227 cl_page_assume(env, io, page);
229 result = cl_io_prepare_write(env, io, page, from, to);
232 * Add a reference, so that page is not evicted from
233 * the cache until ->commit_write() is called.
236 lu_ref_add(&page->cp_reference, "prepare_write",
239 cl_page_unassume(env, io, page);
242 /* returning 0 in prepare assumes commit must be called
245 result = PTR_ERR(lcc);
250 int ll_commit_write(struct file *file, struct page *vmpage, unsigned from,
253 struct ll_cl_context *lcc;
256 struct cl_page *page;
261 page = lcc->lcc_page;
264 LASSERT(cl_page_is_owned(page, io));
266 if (from != to) /* handle short write case. */
267 result = cl_io_commit_write(env, io, page, from, to);
268 if (cl_page_is_owned(page, io))
269 cl_page_unassume(env, io, page);
272 * Release reference acquired by ll_prepare_write().
274 lu_ref_del(&page->cp_reference, "prepare_write", current);
275 cl_page_put(env, page);
280 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which);
283 * Get readahead pages from the filesystem readahead pool of the client for a
286 * /param sbi superblock for filesystem readahead state ll_ra_info
287 * /param ria per-thread readahead state
288 * /param pages number of pages requested for readahead for the thread.
290 * WARNING: This algorithm is used to reduce contention on sbi->ll_lock.
291 * It should work well if the ra_max_pages is much greater than the single
292 * file's read-ahead window, and not too many threads contending for
293 * these readahead pages.
295 * TODO: There may be a 'global sync problem' if many threads are trying
296 * to get an ra budget that is larger than the remaining readahead pages
297 * and reach here at exactly the same time. They will compute /a ret to
298 * consume the remaining pages, but will fail at atomic_add_return() and
299 * get a zero ra window, although there is still ra space remaining. - Jay */
301 static unsigned long ll_ra_count_get(struct ll_sb_info *sbi,
302 struct ra_io_arg *ria,
305 struct ll_ra_info *ra = &sbi->ll_ra_info;
308 /* If read-ahead pages left are less than 1M, do not do read-ahead,
309 * otherwise it will form small read RPC(< 1M), which hurt server
310 * performance a lot. */
311 ret = min(ra->ra_max_pages - atomic_read(&ra->ra_cur_pages), pages);
312 if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages)) {
317 /* If the non-strided (ria_pages == 0) readahead window
318 * (ria_start + ret) has grown across an RPC boundary, then trim
319 * readahead size by the amount beyond the RPC so it ends on an
320 * RPC boundary. If the readahead window is already ending on
321 * an RPC boundary (beyond_rpc == 0), or smaller than a full
322 * RPC (beyond_rpc < ret) the readahead size is unchanged.
323 * The (beyond_rpc != 0) check is skipped since the conditional
324 * branch is more expensive than subtracting zero from the result.
326 * Strided read is left unaligned to avoid small fragments beyond
327 * the RPC boundary from needing an extra read RPC. */
328 if (ria->ria_pages == 0) {
329 long beyond_rpc = (ria->ria_start + ret) % PTLRPC_MAX_BRW_PAGES;
331 if (/* beyond_rpc != 0 && */ beyond_rpc < ret)
335 if (atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) {
336 atomic_sub(ret, &ra->ra_cur_pages);
344 void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len)
346 struct ll_ra_info *ra = &sbi->ll_ra_info;
348 atomic_sub(len, &ra->ra_cur_pages);
351 static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which)
353 LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which);
354 lprocfs_counter_incr(sbi->ll_ra_stats, which);
357 void ll_ra_stats_inc(struct address_space *mapping, enum ra_stat which)
359 struct ll_sb_info *sbi = ll_i2sbi(mapping->host);
361 ll_ra_stats_inc_sbi(sbi, which);
364 #define RAS_CDEBUG(ras) \
366 "lrp %lu cr %lu cp %lu ws %lu wl %lu nra %lu r %lu ri %lu" \
367 "csr %lu sf %lu sp %lu sl %lu \n", \
368 ras->ras_last_readpage, ras->ras_consecutive_requests, \
369 ras->ras_consecutive_pages, ras->ras_window_start, \
370 ras->ras_window_len, ras->ras_next_readahead, \
371 ras->ras_requests, ras->ras_request_index, \
372 ras->ras_consecutive_stride_requests, ras->ras_stride_offset, \
373 ras->ras_stride_pages, ras->ras_stride_length)
375 static int index_in_window(unsigned long index, unsigned long point,
376 unsigned long before, unsigned long after)
378 unsigned long start = point - before, end = point + after;
385 return start <= index && index <= end;
388 static struct ll_readahead_state *ll_ras_get(struct file *f)
390 struct ll_file_data *fd;
392 fd = LUSTRE_FPRIVATE(f);
396 void ll_ra_read_in(struct file *f, struct ll_ra_read *rar)
398 struct ll_readahead_state *ras;
402 spin_lock(&ras->ras_lock);
404 ras->ras_request_index = 0;
405 ras->ras_consecutive_requests++;
406 rar->lrr_reader = current;
408 list_add(&rar->lrr_linkage, &ras->ras_read_beads);
409 spin_unlock(&ras->ras_lock);
412 void ll_ra_read_ex(struct file *f, struct ll_ra_read *rar)
414 struct ll_readahead_state *ras;
418 spin_lock(&ras->ras_lock);
419 list_del_init(&rar->lrr_linkage);
420 spin_unlock(&ras->ras_lock);
423 static int cl_read_ahead_page(const struct lu_env *env, struct cl_io *io,
424 struct cl_page_list *queue, struct cl_page *page,
431 cl_page_assume(env, io, page);
432 lu_ref_add(&page->cp_reference, "ra", current);
433 cp = cl2ccc_page(cl_page_at(page, &vvp_device_type));
434 if (!cp->cpg_defer_uptodate && !PageUptodate(vmpage)) {
435 rc = cl_page_is_under_lock(env, io, page);
437 cp->cpg_defer_uptodate = 1;
439 cl_page_list_add(queue, page);
442 cl_page_delete(env, page);
446 /* skip completed pages */
447 cl_page_unassume(env, io, page);
449 lu_ref_del(&page->cp_reference, "ra", current);
450 cl_page_put(env, page);
455 * Initiates read-ahead of a page with given index.
457 * \retval +ve: page was added to \a queue.
459 * \retval -ENOLCK: there is no extent lock for this part of a file, stop
462 * \retval -ve, 0: page wasn't added to \a queue for other reason.
464 static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io,
465 struct cl_page_list *queue,
466 pgoff_t index, struct address_space *mapping)
469 struct cl_object *clob = ll_i2info(mapping->host)->lli_clob;
470 struct cl_page *page;
471 enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */
473 const char *msg = NULL;
475 vmpage = grab_cache_page_nowait(mapping, index);
476 if (vmpage != NULL) {
477 /* Check if vmpage was truncated or reclaimed */
478 if (vmpage->mapping == mapping) {
479 page = cl_page_find(env, clob, vmpage->index,
480 vmpage, CPT_CACHEABLE);
482 rc = cl_read_ahead_page(env, io, queue,
485 which = RA_STAT_FAILED_MATCH;
486 msg = "lock match failed";
489 which = RA_STAT_FAILED_GRAB_PAGE;
490 msg = "cl_page_find failed";
493 which = RA_STAT_WRONG_GRAB_PAGE;
494 msg = "g_c_p_n returned invalid page";
498 page_cache_release(vmpage);
500 which = RA_STAT_FAILED_GRAB_PAGE;
501 msg = "g_c_p_n failed";
504 ll_ra_stats_inc(mapping, which);
505 CDEBUG(D_READA, "%s\n", msg);
510 #define RIA_DEBUG(ria) \
511 CDEBUG(D_READA, "rs %lu re %lu ro %lu rl %lu rp %lu\n", \
512 ria->ria_start, ria->ria_end, ria->ria_stoff, ria->ria_length,\
515 /* Limit this to the blocksize instead of PTLRPC_BRW_MAX_SIZE, since we don't
516 * know what the actual RPC size is. If this needs to change, it makes more
517 * sense to tune the i_blkbits value for the file based on the OSTs it is
518 * striped over, rather than having a constant value for all files here. */
520 /* RAS_INCREASE_STEP should be (1UL << (inode->i_blkbits - PAGE_CACHE_SHIFT)).
521 * Temporarily set RAS_INCREASE_STEP to 1MB. After 4MB RPC is enabled
522 * by default, this should be adjusted corresponding with max_read_ahead_mb
523 * and max_read_ahead_per_file_mb otherwise the readahead budget can be used
524 * up quickly which will affect read performance significantly. See LU-2816 */
525 #define RAS_INCREASE_STEP(inode) (ONE_MB_BRW_SIZE >> PAGE_CACHE_SHIFT)
527 static inline int stride_io_mode(struct ll_readahead_state *ras)
529 return ras->ras_consecutive_stride_requests > 1;
532 /* The function calculates how much pages will be read in
533 * [off, off + length], in such stride IO area,
534 * stride_offset = st_off, stride_length = st_len,
535 * stride_pages = st_pgs
537 * |------------------|*****|------------------|*****|------------|*****|....
540 * |----- st_len -----|
542 * How many pages it should read in such pattern
543 * |-------------------------------------------------------------|
545 * |<------ length ------->|
547 * = |<----->| + |-------------------------------------| + |---|
548 * start_left st_pgs * i end_left
551 stride_pg_count(pgoff_t st_off, unsigned long st_len, unsigned long st_pgs,
552 unsigned long off, unsigned long length)
554 __u64 start = off > st_off ? off - st_off : 0;
555 __u64 end = off + length > st_off ? off + length - st_off : 0;
556 unsigned long start_left = 0;
557 unsigned long end_left = 0;
558 unsigned long pg_count;
560 if (st_len == 0 || length == 0 || end == 0)
563 start_left = do_div(start, st_len);
564 if (start_left < st_pgs)
565 start_left = st_pgs - start_left;
569 end_left = do_div(end, st_len);
570 if (end_left > st_pgs)
573 CDEBUG(D_READA, "start %llu, end %llu start_left %lu end_left %lu \n",
574 start, end, start_left, end_left);
577 pg_count = end_left - (st_pgs - start_left);
579 pg_count = start_left + st_pgs * (end - start - 1) + end_left;
581 CDEBUG(D_READA, "st_off %lu, st_len %lu st_pgs %lu off %lu length %lu pgcount %lu\n",
582 st_off, st_len, st_pgs, off, length, pg_count);
587 static int ria_page_count(struct ra_io_arg *ria)
589 __u64 length = ria->ria_end >= ria->ria_start ?
590 ria->ria_end - ria->ria_start + 1 : 0;
592 return stride_pg_count(ria->ria_stoff, ria->ria_length,
593 ria->ria_pages, ria->ria_start,
597 /*Check whether the index is in the defined ra-window */
598 static int ras_inside_ra_window(unsigned long idx, struct ra_io_arg *ria)
600 /* If ria_length == ria_pages, it means non-stride I/O mode,
601 * idx should always inside read-ahead window in this case
602 * For stride I/O mode, just check whether the idx is inside
604 return ria->ria_length == 0 || ria->ria_length == ria->ria_pages ||
605 (idx >= ria->ria_stoff && (idx - ria->ria_stoff) %
606 ria->ria_length < ria->ria_pages);
609 static int ll_read_ahead_pages(const struct lu_env *env,
610 struct cl_io *io, struct cl_page_list *queue,
611 struct ra_io_arg *ria,
612 unsigned long *reserved_pages,
613 struct address_space *mapping,
614 unsigned long *ra_end)
616 int rc, count = 0, stride_ria;
617 unsigned long page_idx;
619 LASSERT(ria != NULL);
622 stride_ria = ria->ria_length > ria->ria_pages && ria->ria_pages > 0;
623 for (page_idx = ria->ria_start; page_idx <= ria->ria_end &&
624 *reserved_pages > 0; page_idx++) {
625 if (ras_inside_ra_window(page_idx, ria)) {
626 /* If the page is inside the read-ahead window*/
627 rc = ll_read_ahead_page(env, io, queue,
632 } else if (rc == -ENOLCK)
634 } else if (stride_ria) {
635 /* If it is not in the read-ahead window, and it is
636 * read-ahead mode, then check whether it should skip
639 /* FIXME: This assertion only is valid when it is for
640 * forward read-ahead, it will be fixed when backward
641 * read-ahead is implemented */
642 LASSERTF(page_idx > ria->ria_stoff, "Invalid page_idx %lu rs %lu re %lu ro %lu rl %lu rp %lu\n",
644 ria->ria_start, ria->ria_end, ria->ria_stoff,
645 ria->ria_length, ria->ria_pages);
646 offset = page_idx - ria->ria_stoff;
647 offset = offset % (ria->ria_length);
648 if (offset > ria->ria_pages) {
649 page_idx += ria->ria_length - offset;
650 CDEBUG(D_READA, "i %lu skip %lu \n", page_idx,
651 ria->ria_length - offset);
660 int ll_readahead(const struct lu_env *env, struct cl_io *io,
661 struct ll_readahead_state *ras, struct address_space *mapping,
662 struct cl_page_list *queue, int flags)
664 struct vvp_io *vio = vvp_env_io(env);
665 struct vvp_thread_info *vti = vvp_env_info(env);
666 struct cl_attr *attr = ccc_env_thread_attr(env);
667 unsigned long start = 0, end = 0, reserved;
668 unsigned long ra_end, len;
670 struct ll_ra_read *bead;
671 struct ra_io_arg *ria = &vti->vti_ria;
672 struct ll_inode_info *lli;
673 struct cl_object *clob;
677 inode = mapping->host;
678 lli = ll_i2info(inode);
679 clob = lli->lli_clob;
681 memset(ria, 0, sizeof(*ria));
683 cl_object_attr_lock(clob);
684 ret = cl_object_attr_get(env, clob, attr);
685 cl_object_attr_unlock(clob);
691 ll_ra_stats_inc(mapping, RA_STAT_ZERO_LEN);
695 spin_lock(&ras->ras_lock);
696 if (vio->cui_ra_window_set)
697 bead = &vio->cui_bead;
701 /* Enlarge the RA window to encompass the full read */
702 if (bead != NULL && ras->ras_window_start + ras->ras_window_len <
703 bead->lrr_start + bead->lrr_count) {
704 ras->ras_window_len = bead->lrr_start + bead->lrr_count -
705 ras->ras_window_start;
707 /* Reserve a part of the read-ahead window that we'll be issuing */
708 if (ras->ras_window_len) {
709 start = ras->ras_next_readahead;
710 end = ras->ras_window_start + ras->ras_window_len - 1;
713 unsigned long rpc_boundary;
715 * Align RA window to an optimal boundary.
717 * XXX This would be better to align to cl_max_pages_per_rpc
718 * instead of PTLRPC_MAX_BRW_PAGES, because the RPC size may
719 * be aligned to the RAID stripe size in the future and that
720 * is more important than the RPC size.
722 /* Note: we only trim the RPC, instead of extending the RPC
723 * to the boundary, so to avoid reading too much pages during
725 rpc_boundary = (end + 1) & (~(PTLRPC_MAX_BRW_PAGES - 1));
726 if (rpc_boundary > 0)
729 if (rpc_boundary > start)
732 /* Truncate RA window to end of file */
733 end = min(end, (unsigned long)((kms - 1) >> PAGE_CACHE_SHIFT));
735 ras->ras_next_readahead = max(end, end + 1);
738 ria->ria_start = start;
740 /* If stride I/O mode is detected, get stride window*/
741 if (stride_io_mode(ras)) {
742 ria->ria_stoff = ras->ras_stride_offset;
743 ria->ria_length = ras->ras_stride_length;
744 ria->ria_pages = ras->ras_stride_pages;
746 spin_unlock(&ras->ras_lock);
749 ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW);
752 len = ria_page_count(ria);
756 reserved = ll_ra_count_get(ll_i2sbi(inode), ria, len);
758 ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT);
760 CDEBUG(D_READA, "reserved page %lu ra_cur %d ra_max %lu\n", reserved,
761 atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
762 ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
764 ret = ll_read_ahead_pages(env, io, queue,
765 ria, &reserved, mapping, &ra_end);
767 LASSERTF(reserved >= 0, "reserved %lu\n", reserved);
769 ll_ra_count_put(ll_i2sbi(inode), reserved);
771 if (ra_end == end + 1 && ra_end == (kms >> PAGE_CACHE_SHIFT))
772 ll_ra_stats_inc(mapping, RA_STAT_EOF);
774 /* if we didn't get to the end of the region we reserved from
775 * the ras we need to go back and update the ras so that the
776 * next read-ahead tries from where we left off. we only do so
777 * if the region we failed to issue read-ahead on is still ahead
778 * of the app and behind the next index to start read-ahead from */
779 CDEBUG(D_READA, "ra_end %lu end %lu stride end %lu \n",
780 ra_end, end, ria->ria_end);
782 if (ra_end != end + 1) {
783 spin_lock(&ras->ras_lock);
784 if (ra_end < ras->ras_next_readahead &&
785 index_in_window(ra_end, ras->ras_window_start, 0,
786 ras->ras_window_len)) {
787 ras->ras_next_readahead = ra_end;
790 spin_unlock(&ras->ras_lock);
796 static void ras_set_start(struct inode *inode, struct ll_readahead_state *ras,
799 ras->ras_window_start = index & (~(RAS_INCREASE_STEP(inode) - 1));
802 /* called with the ras_lock held or from places where it doesn't matter */
803 static void ras_reset(struct inode *inode, struct ll_readahead_state *ras,
806 ras->ras_last_readpage = index;
807 ras->ras_consecutive_requests = 0;
808 ras->ras_consecutive_pages = 0;
809 ras->ras_window_len = 0;
810 ras_set_start(inode, ras, index);
811 ras->ras_next_readahead = max(ras->ras_window_start, index);
816 /* called with the ras_lock held or from places where it doesn't matter */
817 static void ras_stride_reset(struct ll_readahead_state *ras)
819 ras->ras_consecutive_stride_requests = 0;
820 ras->ras_stride_length = 0;
821 ras->ras_stride_pages = 0;
825 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
827 spin_lock_init(&ras->ras_lock);
828 ras_reset(inode, ras, 0);
829 ras->ras_requests = 0;
830 INIT_LIST_HEAD(&ras->ras_read_beads);
834 * Check whether the read request is in the stride window.
835 * If it is in the stride window, return 1, otherwise return 0.
837 static int index_in_stride_window(struct ll_readahead_state *ras,
840 unsigned long stride_gap;
842 if (ras->ras_stride_length == 0 || ras->ras_stride_pages == 0 ||
843 ras->ras_stride_pages == ras->ras_stride_length)
846 stride_gap = index - ras->ras_last_readpage - 1;
848 /* If it is contiguous read */
850 return ras->ras_consecutive_pages + 1 <= ras->ras_stride_pages;
852 /* Otherwise check the stride by itself */
853 return (ras->ras_stride_length - ras->ras_stride_pages) == stride_gap &&
854 ras->ras_consecutive_pages == ras->ras_stride_pages;
857 static void ras_update_stride_detector(struct ll_readahead_state *ras,
860 unsigned long stride_gap = index - ras->ras_last_readpage - 1;
862 if (!stride_io_mode(ras) && (stride_gap != 0 ||
863 ras->ras_consecutive_stride_requests == 0)) {
864 ras->ras_stride_pages = ras->ras_consecutive_pages;
865 ras->ras_stride_length = stride_gap+ras->ras_consecutive_pages;
867 LASSERT(ras->ras_request_index == 0);
868 LASSERT(ras->ras_consecutive_stride_requests == 0);
870 if (index <= ras->ras_last_readpage) {
871 /*Reset stride window for forward read*/
872 ras_stride_reset(ras);
876 ras->ras_stride_pages = ras->ras_consecutive_pages;
877 ras->ras_stride_length = stride_gap+ras->ras_consecutive_pages;
884 stride_page_count(struct ll_readahead_state *ras, unsigned long len)
886 return stride_pg_count(ras->ras_stride_offset, ras->ras_stride_length,
887 ras->ras_stride_pages, ras->ras_stride_offset,
891 /* Stride Read-ahead window will be increased inc_len according to
892 * stride I/O pattern */
893 static void ras_stride_increase_window(struct ll_readahead_state *ras,
894 struct ll_ra_info *ra,
895 unsigned long inc_len)
897 unsigned long left, step, window_len;
898 unsigned long stride_len;
900 LASSERT(ras->ras_stride_length > 0);
901 LASSERTF(ras->ras_window_start + ras->ras_window_len
902 >= ras->ras_stride_offset, "window_start %lu, window_len %lu stride_offset %lu\n",
903 ras->ras_window_start,
904 ras->ras_window_len, ras->ras_stride_offset);
906 stride_len = ras->ras_window_start + ras->ras_window_len -
907 ras->ras_stride_offset;
909 left = stride_len % ras->ras_stride_length;
910 window_len = ras->ras_window_len - left;
912 if (left < ras->ras_stride_pages)
915 left = ras->ras_stride_pages + inc_len;
917 LASSERT(ras->ras_stride_pages != 0);
919 step = left / ras->ras_stride_pages;
920 left %= ras->ras_stride_pages;
922 window_len += step * ras->ras_stride_length + left;
924 if (stride_page_count(ras, window_len) <= ra->ra_max_pages_per_file)
925 ras->ras_window_len = window_len;
930 static void ras_increase_window(struct inode *inode,
931 struct ll_readahead_state *ras,
932 struct ll_ra_info *ra)
934 /* The stretch of ra-window should be aligned with max rpc_size
935 * but current clio architecture does not support retrieve such
936 * information from lower layer. FIXME later
938 if (stride_io_mode(ras))
939 ras_stride_increase_window(ras, ra, RAS_INCREASE_STEP(inode));
941 ras->ras_window_len = min(ras->ras_window_len +
942 RAS_INCREASE_STEP(inode),
943 ra->ra_max_pages_per_file);
946 void ras_update(struct ll_sb_info *sbi, struct inode *inode,
947 struct ll_readahead_state *ras, unsigned long index,
950 struct ll_ra_info *ra = &sbi->ll_ra_info;
951 int zero = 0, stride_detect = 0, ra_miss = 0;
953 spin_lock(&ras->ras_lock);
955 ll_ra_stats_inc_sbi(sbi, hit ? RA_STAT_HIT : RA_STAT_MISS);
957 /* reset the read-ahead window in two cases. First when the app seeks
958 * or reads to some other part of the file. Secondly if we get a
959 * read-ahead miss that we think we've previously issued. This can
960 * be a symptom of there being so many read-ahead pages that the VM is
961 * reclaiming it before we get to it. */
962 if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) {
964 ll_ra_stats_inc_sbi(sbi, RA_STAT_DISTANT_READPAGE);
965 } else if (!hit && ras->ras_window_len &&
966 index < ras->ras_next_readahead &&
967 index_in_window(index, ras->ras_window_start, 0,
968 ras->ras_window_len)) {
970 ll_ra_stats_inc_sbi(sbi, RA_STAT_MISS_IN_WINDOW);
973 /* On the second access to a file smaller than the tunable
974 * ra_max_read_ahead_whole_pages trigger RA on all pages in the
975 * file up to ra_max_pages_per_file. This is simply a best effort
976 * and only occurs once per open file. Normal RA behavior is reverted
977 * to for subsequent IO. The mmap case does not increment
978 * ras_requests and thus can never trigger this behavior. */
979 if (ras->ras_requests == 2 && !ras->ras_request_index) {
982 kms_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
985 CDEBUG(D_READA, "kmsp %llu mwp %lu mp %lu\n", kms_pages,
986 ra->ra_max_read_ahead_whole_pages, ra->ra_max_pages_per_file);
989 kms_pages <= ra->ra_max_read_ahead_whole_pages) {
990 ras->ras_window_start = 0;
991 ras->ras_last_readpage = 0;
992 ras->ras_next_readahead = 0;
993 ras->ras_window_len = min(ra->ra_max_pages_per_file,
994 ra->ra_max_read_ahead_whole_pages);
999 /* check whether it is in stride I/O mode*/
1000 if (!index_in_stride_window(ras, index)) {
1001 if (ras->ras_consecutive_stride_requests == 0 &&
1002 ras->ras_request_index == 0) {
1003 ras_update_stride_detector(ras, index);
1004 ras->ras_consecutive_stride_requests++;
1006 ras_stride_reset(ras);
1008 ras_reset(inode, ras, index);
1009 ras->ras_consecutive_pages++;
1012 ras->ras_consecutive_pages = 0;
1013 ras->ras_consecutive_requests = 0;
1014 if (++ras->ras_consecutive_stride_requests > 1)
1020 if (index_in_stride_window(ras, index) &&
1021 stride_io_mode(ras)) {
1022 /*If stride-RA hit cache miss, the stride dector
1023 *will not be reset to avoid the overhead of
1024 *redetecting read-ahead mode */
1025 if (index != ras->ras_last_readpage + 1)
1026 ras->ras_consecutive_pages = 0;
1027 ras_reset(inode, ras, index);
1030 /* Reset both stride window and normal RA
1032 ras_reset(inode, ras, index);
1033 ras->ras_consecutive_pages++;
1034 ras_stride_reset(ras);
1037 } else if (stride_io_mode(ras)) {
1038 /* If this is contiguous read but in stride I/O mode
1039 * currently, check whether stride step still is valid,
1040 * if invalid, it will reset the stride ra window*/
1041 if (!index_in_stride_window(ras, index)) {
1042 /* Shrink stride read-ahead window to be zero */
1043 ras_stride_reset(ras);
1044 ras->ras_window_len = 0;
1045 ras->ras_next_readahead = index;
1049 ras->ras_consecutive_pages++;
1050 ras->ras_last_readpage = index;
1051 ras_set_start(inode, ras, index);
1053 if (stride_io_mode(ras))
1054 /* Since stride readahead is sensitive to the offset
1055 * of read-ahead, so we use original offset here,
1056 * instead of ras_window_start, which is RPC aligned */
1057 ras->ras_next_readahead = max(index, ras->ras_next_readahead);
1059 ras->ras_next_readahead = max(ras->ras_window_start,
1060 ras->ras_next_readahead);
1063 /* Trigger RA in the mmap case where ras_consecutive_requests
1064 * is not incremented and thus can't be used to trigger RA */
1065 if (!ras->ras_window_len && ras->ras_consecutive_pages == 4) {
1066 ras->ras_window_len = RAS_INCREASE_STEP(inode);
1070 /* Initially reset the stride window offset to next_readahead*/
1071 if (ras->ras_consecutive_stride_requests == 2 && stride_detect) {
1073 * Once stride IO mode is detected, next_readahead should be
1074 * reset to make sure next_readahead > stride offset
1076 ras->ras_next_readahead = max(index, ras->ras_next_readahead);
1077 ras->ras_stride_offset = index;
1078 ras->ras_window_len = RAS_INCREASE_STEP(inode);
1081 /* The initial ras_window_len is set to the request size. To avoid
1082 * uselessly reading and discarding pages for random IO the window is
1083 * only increased once per consecutive request received. */
1084 if ((ras->ras_consecutive_requests > 1 || stride_detect) &&
1085 !ras->ras_request_index)
1086 ras_increase_window(inode, ras, ra);
1089 ras->ras_request_index++;
1090 spin_unlock(&ras->ras_lock);
1094 int ll_writepage(struct page *vmpage, struct writeback_control *wbc)
1096 struct inode *inode = vmpage->mapping->host;
1097 struct ll_inode_info *lli = ll_i2info(inode);
1100 struct cl_page *page;
1101 struct cl_object *clob;
1102 struct cl_env_nest nest;
1103 bool redirtied = false;
1104 bool unlocked = false;
1107 LASSERT(PageLocked(vmpage));
1108 LASSERT(!PageWriteback(vmpage));
1110 LASSERT(ll_i2dtexp(inode) != NULL);
1112 env = cl_env_nested_get(&nest);
1114 result = PTR_ERR(env);
1118 clob = ll_i2info(inode)->lli_clob;
1119 LASSERT(clob != NULL);
1121 io = ccc_env_thread_io(env);
1123 io->ci_ignore_layout = 1;
1124 result = cl_io_init(env, io, CIT_MISC, clob);
1126 page = cl_page_find(env, clob, vmpage->index,
1127 vmpage, CPT_CACHEABLE);
1128 if (!IS_ERR(page)) {
1129 lu_ref_add(&page->cp_reference, "writepage",
1131 cl_page_assume(env, io, page);
1132 result = cl_page_flush(env, io, page);
1135 * Re-dirty page on error so it retries write,
1136 * but not in case when IO has actually
1137 * occurred and completed with an error.
1139 if (!PageError(vmpage)) {
1140 redirty_page_for_writepage(wbc, vmpage);
1145 cl_page_disown(env, io, page);
1147 lu_ref_del(&page->cp_reference,
1148 "writepage", current);
1149 cl_page_put(env, page);
1151 result = PTR_ERR(page);
1154 cl_io_fini(env, io);
1156 if (redirtied && wbc->sync_mode == WB_SYNC_ALL) {
1157 loff_t offset = cl_offset(clob, vmpage->index);
1159 /* Flush page failed because the extent is being written out.
1160 * Wait for the write of extent to be finished to avoid
1161 * breaking kernel which assumes ->writepage should mark
1162 * PageWriteback or clean the page. */
1163 result = cl_sync_file_range(inode, offset,
1164 offset + PAGE_CACHE_SIZE - 1,
1167 /* actually we may have written more than one page.
1168 * decreasing this page because the caller will count
1170 wbc->nr_to_write -= result - 1;
1175 cl_env_nested_put(&nest, env);
1180 if (!lli->lli_async_rc)
1181 lli->lli_async_rc = result;
1182 SetPageError(vmpage);
1184 unlock_page(vmpage);
1189 int ll_writepages(struct address_space *mapping, struct writeback_control *wbc)
1191 struct inode *inode = mapping->host;
1192 struct ll_sb_info *sbi = ll_i2sbi(inode);
1195 enum cl_fsync_mode mode;
1196 int range_whole = 0;
1198 int ignore_layout = 0;
1200 if (wbc->range_cyclic) {
1201 start = mapping->writeback_index << PAGE_CACHE_SHIFT;
1202 end = OBD_OBJECT_EOF;
1204 start = wbc->range_start;
1205 end = wbc->range_end;
1206 if (end == LLONG_MAX) {
1207 end = OBD_OBJECT_EOF;
1208 range_whole = start == 0;
1212 mode = CL_FSYNC_NONE;
1213 if (wbc->sync_mode == WB_SYNC_ALL)
1214 mode = CL_FSYNC_LOCAL;
1216 if (sbi->ll_umounting)
1217 /* if the mountpoint is being umounted, all pages have to be
1218 * evicted to avoid hitting LBUG when truncate_inode_pages()
1219 * is called later on. */
1221 result = cl_sync_file_range(inode, start, end, mode, ignore_layout);
1223 wbc->nr_to_write -= result;
1227 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) {
1228 if (end == OBD_OBJECT_EOF)
1229 end = i_size_read(inode);
1230 mapping->writeback_index = (end >> PAGE_CACHE_SHIFT) + 1;
1235 int ll_readpage(struct file *file, struct page *vmpage)
1237 struct ll_cl_context *lcc;
1240 lcc = ll_cl_init(file, vmpage, 0);
1242 struct lu_env *env = lcc->lcc_env;
1243 struct cl_io *io = lcc->lcc_io;
1244 struct cl_page *page = lcc->lcc_page;
1246 LASSERT(page->cp_type == CPT_CACHEABLE);
1247 if (likely(!PageUptodate(vmpage))) {
1248 cl_page_assume(env, io, page);
1249 result = cl_io_read_page(env, io, page);
1251 /* Page from a non-object file. */
1252 unlock_page(vmpage);
1257 unlock_page(vmpage);
1258 result = PTR_ERR(lcc);