| /* |
| * GPL HEADER START |
| * |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 only, |
| * as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License version 2 for more details (a copy is included |
| * in the LICENSE file that accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License |
| * version 2 along with this program; If not, see |
| * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| * |
| * GPL HEADER END |
| */ |
| /* |
| * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved. |
| * Use is subject to license terms. |
| * |
| * Copyright (c) 2011, 2015, Intel Corporation. |
| */ |
| /* |
| * This file is part of Lustre, http://www.lustre.org/ |
| * Lustre is a trademark of Sun Microsystems, Inc. |
| * |
| * lustre/llite/rw.c |
| * |
| * Lustre Lite I/O page cache routines shared by different kernel revs |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/string.h> |
| #include <linux/stat.h> |
| #include <linux/errno.h> |
| #include <linux/unistd.h> |
| #include <linux/writeback.h> |
| #include <linux/uaccess.h> |
| |
| #include <linux/fs.h> |
| #include <linux/pagemap.h> |
| /* current_is_kswapd() */ |
| #include <linux/swap.h> |
| |
| #define DEBUG_SUBSYSTEM S_LLITE |
| |
| #include "../include/lustre_lite.h" |
| #include "../include/obd_cksum.h" |
| #include "llite_internal.h" |
| #include "../include/linux/lustre_compat25.h" |
| |
| /** |
| * Finalizes cl-data before exiting typical address_space operation. Dual to |
| * ll_cl_init(). |
| */ |
| void ll_cl_fini(struct ll_cl_context *lcc) |
| { |
| struct lu_env *env = lcc->lcc_env; |
| struct cl_io *io = lcc->lcc_io; |
| struct cl_page *page = lcc->lcc_page; |
| |
| LASSERT(lcc->lcc_cookie == current); |
| LASSERT(env); |
| |
| if (page) { |
| lu_ref_del(&page->cp_reference, "cl_io", io); |
| cl_page_put(env, page); |
| } |
| |
| cl_env_put(env, &lcc->lcc_refcheck); |
| } |
| |
| /** |
| * Initializes common cl-data at the typical address_space operation entry |
| * point. |
| */ |
| struct ll_cl_context *ll_cl_init(struct file *file, struct page *vmpage) |
| { |
| struct ll_cl_context *lcc; |
| struct lu_env *env; |
| struct cl_io *io; |
| struct cl_object *clob; |
| struct vvp_io *vio; |
| |
| int refcheck; |
| int result = 0; |
| |
| clob = ll_i2info(file_inode(file))->lli_clob; |
| LASSERT(clob); |
| |
| env = cl_env_get(&refcheck); |
| if (IS_ERR(env)) |
| return ERR_CAST(env); |
| |
| lcc = &ll_env_info(env)->lti_io_ctx; |
| memset(lcc, 0, sizeof(*lcc)); |
| lcc->lcc_env = env; |
| lcc->lcc_refcheck = refcheck; |
| lcc->lcc_cookie = current; |
| |
| vio = vvp_env_io(env); |
| io = vio->vui_cl.cis_io; |
| lcc->lcc_io = io; |
| if (!io) |
| result = -EIO; |
| |
| if (result == 0 && vmpage) { |
| struct cl_page *page; |
| |
| LASSERT(io->ci_state == CIS_IO_GOING); |
| LASSERT(vio->vui_fd == LUSTRE_FPRIVATE(file)); |
| page = cl_page_find(env, clob, vmpage->index, vmpage, |
| CPT_CACHEABLE); |
| if (!IS_ERR(page)) { |
| lcc->lcc_page = page; |
| lu_ref_add(&page->cp_reference, "cl_io", io); |
| result = 0; |
| } else { |
| result = PTR_ERR(page); |
| } |
| } |
| if (result) { |
| ll_cl_fini(lcc); |
| lcc = ERR_PTR(result); |
| } |
| |
| return lcc; |
| } |
| |
| static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which); |
| |
| /** |
| * Get readahead pages from the filesystem readahead pool of the client for a |
| * thread. |
| * |
| * /param sbi superblock for filesystem readahead state ll_ra_info |
| * /param ria per-thread readahead state |
| * /param pages number of pages requested for readahead for the thread. |
| * |
| * WARNING: This algorithm is used to reduce contention on sbi->ll_lock. |
| * It should work well if the ra_max_pages is much greater than the single |
| * file's read-ahead window, and not too many threads contending for |
| * these readahead pages. |
| * |
| * TODO: There may be a 'global sync problem' if many threads are trying |
| * to get an ra budget that is larger than the remaining readahead pages |
| * and reach here at exactly the same time. They will compute /a ret to |
| * consume the remaining pages, but will fail at atomic_add_return() and |
| * get a zero ra window, although there is still ra space remaining. - Jay |
| */ |
| static unsigned long ll_ra_count_get(struct ll_sb_info *sbi, |
| struct ra_io_arg *ria, |
| unsigned long pages, unsigned long min) |
| { |
| struct ll_ra_info *ra = &sbi->ll_ra_info; |
| long ret; |
| |
| /* If read-ahead pages left are less than 1M, do not do read-ahead, |
| * otherwise it will form small read RPC(< 1M), which hurt server |
| * performance a lot. |
| */ |
| ret = min(ra->ra_max_pages - atomic_read(&ra->ra_cur_pages), pages); |
| if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages)) { |
| ret = 0; |
| goto out; |
| } |
| |
| /* If the non-strided (ria_pages == 0) readahead window |
| * (ria_start + ret) has grown across an RPC boundary, then trim |
| * readahead size by the amount beyond the RPC so it ends on an |
| * RPC boundary. If the readahead window is already ending on |
| * an RPC boundary (beyond_rpc == 0), or smaller than a full |
| * RPC (beyond_rpc < ret) the readahead size is unchanged. |
| * The (beyond_rpc != 0) check is skipped since the conditional |
| * branch is more expensive than subtracting zero from the result. |
| * |
| * Strided read is left unaligned to avoid small fragments beyond |
| * the RPC boundary from needing an extra read RPC. |
| */ |
| if (ria->ria_pages == 0) { |
| long beyond_rpc = (ria->ria_start + ret) % PTLRPC_MAX_BRW_PAGES; |
| |
| if (/* beyond_rpc != 0 && */ beyond_rpc < ret) |
| ret -= beyond_rpc; |
| } |
| |
| if (atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) { |
| atomic_sub(ret, &ra->ra_cur_pages); |
| ret = 0; |
| } |
| |
| out: |
| if (ret < min) { |
| /* override ra limit for maximum performance */ |
| atomic_add(min - ret, &ra->ra_cur_pages); |
| ret = min; |
| } |
| return ret; |
| } |
| |
| void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len) |
| { |
| struct ll_ra_info *ra = &sbi->ll_ra_info; |
| |
| atomic_sub(len, &ra->ra_cur_pages); |
| } |
| |
| static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which) |
| { |
| LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which); |
| lprocfs_counter_incr(sbi->ll_ra_stats, which); |
| } |
| |
| void ll_ra_stats_inc(struct inode *inode, enum ra_stat which) |
| { |
| struct ll_sb_info *sbi = ll_i2sbi(inode); |
| |
| ll_ra_stats_inc_sbi(sbi, which); |
| } |
| |
| #define RAS_CDEBUG(ras) \ |
| CDEBUG(D_READA, \ |
| "lrp %lu cr %lu cp %lu ws %lu wl %lu nra %lu r %lu ri %lu" \ |
| "csr %lu sf %lu sp %lu sl %lu\n", \ |
| ras->ras_last_readpage, ras->ras_consecutive_requests, \ |
| ras->ras_consecutive_pages, ras->ras_window_start, \ |
| ras->ras_window_len, ras->ras_next_readahead, \ |
| ras->ras_requests, ras->ras_request_index, \ |
| ras->ras_consecutive_stride_requests, ras->ras_stride_offset, \ |
| ras->ras_stride_pages, ras->ras_stride_length) |
| |
| static int index_in_window(unsigned long index, unsigned long point, |
| unsigned long before, unsigned long after) |
| { |
| unsigned long start = point - before, end = point + after; |
| |
| if (start > point) |
| start = 0; |
| if (end < point) |
| end = ~0; |
| |
| return start <= index && index <= end; |
| } |
| |
| void ll_ras_enter(struct file *f) |
| { |
| struct ll_file_data *fd = LUSTRE_FPRIVATE(f); |
| struct ll_readahead_state *ras = &fd->fd_ras; |
| |
| spin_lock(&ras->ras_lock); |
| ras->ras_requests++; |
| ras->ras_request_index = 0; |
| ras->ras_consecutive_requests++; |
| spin_unlock(&ras->ras_lock); |
| } |
| |
| static int cl_read_ahead_page(const struct lu_env *env, struct cl_io *io, |
| struct cl_page_list *queue, struct cl_page *page, |
| struct cl_object *clob, pgoff_t *max_index) |
| { |
| struct page *vmpage = page->cp_vmpage; |
| struct vvp_page *vpg; |
| int rc; |
| |
| rc = 0; |
| cl_page_assume(env, io, page); |
| lu_ref_add(&page->cp_reference, "ra", current); |
| vpg = cl2vvp_page(cl_object_page_slice(clob, page)); |
| if (!vpg->vpg_defer_uptodate && !PageUptodate(vmpage)) { |
| CDEBUG(D_READA, "page index %lu, max_index: %lu\n", |
| vvp_index(vpg), *max_index); |
| if (*max_index == 0 || vvp_index(vpg) > *max_index) |
| rc = cl_page_is_under_lock(env, io, page, max_index); |
| if (rc == 0) { |
| vpg->vpg_defer_uptodate = 1; |
| vpg->vpg_ra_used = 0; |
| cl_page_list_add(queue, page); |
| rc = 1; |
| } else { |
| cl_page_discard(env, io, page); |
| rc = -ENOLCK; |
| } |
| } else { |
| /* skip completed pages */ |
| cl_page_unassume(env, io, page); |
| } |
| lu_ref_del(&page->cp_reference, "ra", current); |
| cl_page_put(env, page); |
| return rc; |
| } |
| |
| /** |
| * Initiates read-ahead of a page with given index. |
| * |
| * \retval +ve: page was added to \a queue. |
| * |
| * \retval -ENOLCK: there is no extent lock for this part of a file, stop |
| * read-ahead. |
| * |
| * \retval -ve, 0: page wasn't added to \a queue for other reason. |
| */ |
| static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io, |
| struct cl_page_list *queue, |
| pgoff_t index, pgoff_t *max_index) |
| { |
| struct cl_object *clob = io->ci_obj; |
| struct inode *inode = vvp_object_inode(clob); |
| struct page *vmpage; |
| struct cl_page *page; |
| enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */ |
| int rc = 0; |
| const char *msg = NULL; |
| |
| vmpage = grab_cache_page_nowait(inode->i_mapping, index); |
| if (vmpage) { |
| /* Check if vmpage was truncated or reclaimed */ |
| if (vmpage->mapping == inode->i_mapping) { |
| page = cl_page_find(env, clob, vmpage->index, |
| vmpage, CPT_CACHEABLE); |
| if (!IS_ERR(page)) { |
| rc = cl_read_ahead_page(env, io, queue, |
| page, clob, max_index); |
| if (rc == -ENOLCK) { |
| which = RA_STAT_FAILED_MATCH; |
| msg = "lock match failed"; |
| } |
| } else { |
| which = RA_STAT_FAILED_GRAB_PAGE; |
| msg = "cl_page_find failed"; |
| } |
| } else { |
| which = RA_STAT_WRONG_GRAB_PAGE; |
| msg = "g_c_p_n returned invalid page"; |
| } |
| if (rc != 1) |
| unlock_page(vmpage); |
| put_page(vmpage); |
| } else { |
| which = RA_STAT_FAILED_GRAB_PAGE; |
| msg = "g_c_p_n failed"; |
| } |
| if (msg) { |
| ll_ra_stats_inc(inode, which); |
| CDEBUG(D_READA, "%s\n", msg); |
| } |
| return rc; |
| } |
| |
| #define RIA_DEBUG(ria) \ |
| CDEBUG(D_READA, "rs %lu re %lu ro %lu rl %lu rp %lu\n", \ |
| ria->ria_start, ria->ria_end, ria->ria_stoff, ria->ria_length,\ |
| ria->ria_pages) |
| |
| /* Limit this to the blocksize instead of PTLRPC_BRW_MAX_SIZE, since we don't |
| * know what the actual RPC size is. If this needs to change, it makes more |
| * sense to tune the i_blkbits value for the file based on the OSTs it is |
| * striped over, rather than having a constant value for all files here. |
| */ |
| |
| /* RAS_INCREASE_STEP should be (1UL << (inode->i_blkbits - PAGE_SHIFT)). |
| * Temporarily set RAS_INCREASE_STEP to 1MB. After 4MB RPC is enabled |
| * by default, this should be adjusted corresponding with max_read_ahead_mb |
| * and max_read_ahead_per_file_mb otherwise the readahead budget can be used |
| * up quickly which will affect read performance significantly. See LU-2816 |
| */ |
| #define RAS_INCREASE_STEP(inode) (ONE_MB_BRW_SIZE >> PAGE_SHIFT) |
| |
| static inline int stride_io_mode(struct ll_readahead_state *ras) |
| { |
| return ras->ras_consecutive_stride_requests > 1; |
| } |
| |
| /* The function calculates how much pages will be read in |
| * [off, off + length], in such stride IO area, |
| * stride_offset = st_off, stride_length = st_len, |
| * stride_pages = st_pgs |
| * |
| * |------------------|*****|------------------|*****|------------|*****|.... |
| * st_off |
| * |--- st_pgs ---| |
| * |----- st_len -----| |
| * |
| * How many pages it should read in such pattern |
| * |-------------------------------------------------------------| |
| * off |
| * |<------ length ------->| |
| * |
| * = |<----->| + |-------------------------------------| + |---| |
| * start_left st_pgs * i end_left |
| */ |
| static unsigned long |
| stride_pg_count(pgoff_t st_off, unsigned long st_len, unsigned long st_pgs, |
| unsigned long off, unsigned long length) |
| { |
| __u64 start = off > st_off ? off - st_off : 0; |
| __u64 end = off + length > st_off ? off + length - st_off : 0; |
| unsigned long start_left = 0; |
| unsigned long end_left = 0; |
| unsigned long pg_count; |
| |
| if (st_len == 0 || length == 0 || end == 0) |
| return length; |
| |
| start_left = do_div(start, st_len); |
| if (start_left < st_pgs) |
| start_left = st_pgs - start_left; |
| else |
| start_left = 0; |
| |
| end_left = do_div(end, st_len); |
| if (end_left > st_pgs) |
| end_left = st_pgs; |
| |
| CDEBUG(D_READA, "start %llu, end %llu start_left %lu end_left %lu\n", |
| start, end, start_left, end_left); |
| |
| if (start == end) |
| pg_count = end_left - (st_pgs - start_left); |
| else |
| pg_count = start_left + st_pgs * (end - start - 1) + end_left; |
| |
| CDEBUG(D_READA, "st_off %lu, st_len %lu st_pgs %lu off %lu length %lu pgcount %lu\n", |
| st_off, st_len, st_pgs, off, length, pg_count); |
| |
| return pg_count; |
| } |
| |
| static int ria_page_count(struct ra_io_arg *ria) |
| { |
| __u64 length = ria->ria_end >= ria->ria_start ? |
| ria->ria_end - ria->ria_start + 1 : 0; |
| |
| return stride_pg_count(ria->ria_stoff, ria->ria_length, |
| ria->ria_pages, ria->ria_start, |
| length); |
| } |
| |
| /*Check whether the index is in the defined ra-window */ |
| static int ras_inside_ra_window(unsigned long idx, struct ra_io_arg *ria) |
| { |
| /* If ria_length == ria_pages, it means non-stride I/O mode, |
| * idx should always inside read-ahead window in this case |
| * For stride I/O mode, just check whether the idx is inside |
| * the ria_pages. |
| */ |
| return ria->ria_length == 0 || ria->ria_length == ria->ria_pages || |
| (idx >= ria->ria_stoff && (idx - ria->ria_stoff) % |
| ria->ria_length < ria->ria_pages); |
| } |
| |
| static int ll_read_ahead_pages(const struct lu_env *env, |
| struct cl_io *io, struct cl_page_list *queue, |
| struct ra_io_arg *ria, |
| unsigned long *reserved_pages, |
| unsigned long *ra_end) |
| { |
| int rc, count = 0; |
| bool stride_ria; |
| pgoff_t page_idx; |
| pgoff_t max_index = 0; |
| |
| LASSERT(ria); |
| RIA_DEBUG(ria); |
| |
| stride_ria = ria->ria_length > ria->ria_pages && ria->ria_pages > 0; |
| for (page_idx = ria->ria_start; |
| page_idx <= ria->ria_end && *reserved_pages > 0; page_idx++) { |
| if (ras_inside_ra_window(page_idx, ria)) { |
| /* If the page is inside the read-ahead window*/ |
| rc = ll_read_ahead_page(env, io, queue, |
| page_idx, &max_index); |
| if (rc == 1) { |
| (*reserved_pages)--; |
| count++; |
| } else if (rc == -ENOLCK) { |
| break; |
| } |
| } else if (stride_ria) { |
| /* If it is not in the read-ahead window, and it is |
| * read-ahead mode, then check whether it should skip |
| * the stride gap |
| */ |
| pgoff_t offset; |
| /* FIXME: This assertion only is valid when it is for |
| * forward read-ahead, it will be fixed when backward |
| * read-ahead is implemented |
| */ |
| LASSERTF(page_idx > ria->ria_stoff, "Invalid page_idx %lu rs %lu re %lu ro %lu rl %lu rp %lu\n", |
| page_idx, |
| ria->ria_start, ria->ria_end, ria->ria_stoff, |
| ria->ria_length, ria->ria_pages); |
| offset = page_idx - ria->ria_stoff; |
| offset = offset % (ria->ria_length); |
| if (offset > ria->ria_pages) { |
| page_idx += ria->ria_length - offset; |
| CDEBUG(D_READA, "i %lu skip %lu\n", page_idx, |
| ria->ria_length - offset); |
| continue; |
| } |
| } |
| } |
| *ra_end = page_idx; |
| return count; |
| } |
| |
| int ll_readahead(const struct lu_env *env, struct cl_io *io, |
| struct cl_page_list *queue, struct ll_readahead_state *ras, |
| bool hit) |
| { |
| struct vvp_io *vio = vvp_env_io(env); |
| struct ll_thread_info *lti = ll_env_info(env); |
| struct cl_attr *attr = vvp_env_thread_attr(env); |
| unsigned long start = 0, end = 0, reserved; |
| unsigned long ra_end, len, mlen = 0; |
| struct inode *inode; |
| struct ra_io_arg *ria = <i->lti_ria; |
| struct cl_object *clob; |
| int ret = 0; |
| __u64 kms; |
| |
| clob = io->ci_obj; |
| inode = vvp_object_inode(clob); |
| |
| memset(ria, 0, sizeof(*ria)); |
| |
| cl_object_attr_lock(clob); |
| ret = cl_object_attr_get(env, clob, attr); |
| cl_object_attr_unlock(clob); |
| |
| if (ret != 0) |
| return ret; |
| kms = attr->cat_kms; |
| if (kms == 0) { |
| ll_ra_stats_inc(inode, RA_STAT_ZERO_LEN); |
| return 0; |
| } |
| |
| spin_lock(&ras->ras_lock); |
| |
| /* Enlarge the RA window to encompass the full read */ |
| if (vio->vui_ra_valid && |
| ras->ras_window_start + ras->ras_window_len < |
| vio->vui_ra_start + vio->vui_ra_count) { |
| ras->ras_window_len = vio->vui_ra_start + vio->vui_ra_count - |
| ras->ras_window_start; |
| } |
| |
| /* Reserve a part of the read-ahead window that we'll be issuing */ |
| if (ras->ras_window_len) { |
| start = ras->ras_next_readahead; |
| end = ras->ras_window_start + ras->ras_window_len - 1; |
| } |
| if (end != 0) { |
| unsigned long rpc_boundary; |
| /* |
| * Align RA window to an optimal boundary. |
| * |
| * XXX This would be better to align to cl_max_pages_per_rpc |
| * instead of PTLRPC_MAX_BRW_PAGES, because the RPC size may |
| * be aligned to the RAID stripe size in the future and that |
| * is more important than the RPC size. |
| */ |
| /* Note: we only trim the RPC, instead of extending the RPC |
| * to the boundary, so to avoid reading too much pages during |
| * random reading. |
| */ |
| rpc_boundary = (end + 1) & (~(PTLRPC_MAX_BRW_PAGES - 1)); |
| if (rpc_boundary > 0) |
| rpc_boundary--; |
| |
| if (rpc_boundary > start) |
| end = rpc_boundary; |
| |
| /* Truncate RA window to end of file */ |
| end = min(end, (unsigned long)((kms - 1) >> PAGE_SHIFT)); |
| |
| ras->ras_next_readahead = max(end, end + 1); |
| RAS_CDEBUG(ras); |
| } |
| ria->ria_start = start; |
| ria->ria_end = end; |
| /* If stride I/O mode is detected, get stride window*/ |
| if (stride_io_mode(ras)) { |
| ria->ria_stoff = ras->ras_stride_offset; |
| ria->ria_length = ras->ras_stride_length; |
| ria->ria_pages = ras->ras_stride_pages; |
| } |
| spin_unlock(&ras->ras_lock); |
| |
| if (end == 0) { |
| ll_ra_stats_inc(inode, RA_STAT_ZERO_WINDOW); |
| return 0; |
| } |
| len = ria_page_count(ria); |
| if (len == 0) { |
| ll_ra_stats_inc(inode, RA_STAT_ZERO_WINDOW); |
| return 0; |
| } |
| |
| CDEBUG(D_READA, DFID ": ria: %lu/%lu, bead: %lu/%lu, hit: %d\n", |
| PFID(lu_object_fid(&clob->co_lu)), |
| ria->ria_start, ria->ria_end, |
| vio->vui_ra_valid ? vio->vui_ra_start : 0, |
| vio->vui_ra_valid ? vio->vui_ra_count : 0, |
| hit); |
| |
| /* at least to extend the readahead window to cover current read */ |
| if (!hit && vio->vui_ra_valid && |
| vio->vui_ra_start + vio->vui_ra_count > ria->ria_start) { |
| /* to the end of current read window. */ |
| mlen = vio->vui_ra_start + vio->vui_ra_count - ria->ria_start; |
| /* trim to RPC boundary */ |
| start = ria->ria_start & (PTLRPC_MAX_BRW_PAGES - 1); |
| mlen = min(mlen, PTLRPC_MAX_BRW_PAGES - start); |
| } |
| |
| reserved = ll_ra_count_get(ll_i2sbi(inode), ria, len, mlen); |
| if (reserved < len) |
| ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT); |
| |
| CDEBUG(D_READA, "reserved pages %lu/%lu/%lu, ra_cur %d, ra_max %lu\n", |
| reserved, len, mlen, |
| atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages), |
| ll_i2sbi(inode)->ll_ra_info.ra_max_pages); |
| |
| ret = ll_read_ahead_pages(env, io, queue, ria, &reserved, &ra_end); |
| |
| if (reserved != 0) |
| ll_ra_count_put(ll_i2sbi(inode), reserved); |
| |
| if (ra_end == end + 1 && ra_end == (kms >> PAGE_SHIFT)) |
| ll_ra_stats_inc(inode, RA_STAT_EOF); |
| |
| /* if we didn't get to the end of the region we reserved from |
| * the ras we need to go back and update the ras so that the |
| * next read-ahead tries from where we left off. we only do so |
| * if the region we failed to issue read-ahead on is still ahead |
| * of the app and behind the next index to start read-ahead from |
| */ |
| CDEBUG(D_READA, "ra_end %lu end %lu stride end %lu\n", |
| ra_end, end, ria->ria_end); |
| |
| if (ra_end != end + 1) { |
| ll_ra_stats_inc(inode, RA_STAT_FAILED_REACH_END); |
| spin_lock(&ras->ras_lock); |
| if (ra_end < ras->ras_next_readahead && |
| index_in_window(ra_end, ras->ras_window_start, 0, |
| ras->ras_window_len)) { |
| ras->ras_next_readahead = ra_end; |
| RAS_CDEBUG(ras); |
| } |
| spin_unlock(&ras->ras_lock); |
| } |
| |
| return ret; |
| } |
| |
| static void ras_set_start(struct inode *inode, struct ll_readahead_state *ras, |
| unsigned long index) |
| { |
| ras->ras_window_start = index & (~(RAS_INCREASE_STEP(inode) - 1)); |
| } |
| |
| /* called with the ras_lock held or from places where it doesn't matter */ |
| static void ras_reset(struct inode *inode, struct ll_readahead_state *ras, |
| unsigned long index) |
| { |
| ras->ras_last_readpage = index; |
| ras->ras_consecutive_requests = 0; |
| ras->ras_consecutive_pages = 0; |
| ras->ras_window_len = 0; |
| ras_set_start(inode, ras, index); |
| ras->ras_next_readahead = max(ras->ras_window_start, index); |
| |
| RAS_CDEBUG(ras); |
| } |
| |
| /* called with the ras_lock held or from places where it doesn't matter */ |
| static void ras_stride_reset(struct ll_readahead_state *ras) |
| { |
| ras->ras_consecutive_stride_requests = 0; |
| ras->ras_stride_length = 0; |
| ras->ras_stride_pages = 0; |
| RAS_CDEBUG(ras); |
| } |
| |
| void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras) |
| { |
| spin_lock_init(&ras->ras_lock); |
| ras_reset(inode, ras, 0); |
| ras->ras_requests = 0; |
| } |
| |
| /* |
| * Check whether the read request is in the stride window. |
| * If it is in the stride window, return 1, otherwise return 0. |
| */ |
| static int index_in_stride_window(struct ll_readahead_state *ras, |
| unsigned long index) |
| { |
| unsigned long stride_gap; |
| |
| if (ras->ras_stride_length == 0 || ras->ras_stride_pages == 0 || |
| ras->ras_stride_pages == ras->ras_stride_length) |
| return 0; |
| |
| stride_gap = index - ras->ras_last_readpage - 1; |
| |
| /* If it is contiguous read */ |
| if (stride_gap == 0) |
| return ras->ras_consecutive_pages + 1 <= ras->ras_stride_pages; |
| |
| /* Otherwise check the stride by itself */ |
| return (ras->ras_stride_length - ras->ras_stride_pages) == stride_gap && |
| ras->ras_consecutive_pages == ras->ras_stride_pages; |
| } |
| |
| static void ras_update_stride_detector(struct ll_readahead_state *ras, |
| unsigned long index) |
| { |
| unsigned long stride_gap = index - ras->ras_last_readpage - 1; |
| |
| if (!stride_io_mode(ras) && (stride_gap != 0 || |
| ras->ras_consecutive_stride_requests == 0)) { |
| ras->ras_stride_pages = ras->ras_consecutive_pages; |
| ras->ras_stride_length = stride_gap+ras->ras_consecutive_pages; |
| } |
| LASSERT(ras->ras_request_index == 0); |
| LASSERT(ras->ras_consecutive_stride_requests == 0); |
| |
| if (index <= ras->ras_last_readpage) { |
| /*Reset stride window for forward read*/ |
| ras_stride_reset(ras); |
| return; |
| } |
| |
| ras->ras_stride_pages = ras->ras_consecutive_pages; |
| ras->ras_stride_length = stride_gap+ras->ras_consecutive_pages; |
| |
| RAS_CDEBUG(ras); |
| return; |
| } |
| |
| /* Stride Read-ahead window will be increased inc_len according to |
| * stride I/O pattern |
| */ |
| static void ras_stride_increase_window(struct ll_readahead_state *ras, |
| struct ll_ra_info *ra, |
| unsigned long inc_len) |
| { |
| unsigned long left, step, window_len; |
| unsigned long stride_len; |
| |
| LASSERT(ras->ras_stride_length > 0); |
| LASSERTF(ras->ras_window_start + ras->ras_window_len |
| >= ras->ras_stride_offset, "window_start %lu, window_len %lu stride_offset %lu\n", |
| ras->ras_window_start, |
| ras->ras_window_len, ras->ras_stride_offset); |
| |
| stride_len = ras->ras_window_start + ras->ras_window_len - |
| ras->ras_stride_offset; |
| |
| left = stride_len % ras->ras_stride_length; |
| window_len = ras->ras_window_len - left; |
| |
| if (left < ras->ras_stride_pages) |
| left += inc_len; |
| else |
| left = ras->ras_stride_pages + inc_len; |
| |
| LASSERT(ras->ras_stride_pages != 0); |
| |
| step = left / ras->ras_stride_pages; |
| left %= ras->ras_stride_pages; |
| |
| window_len += step * ras->ras_stride_length + left; |
| |
| if (stride_pg_count(ras->ras_stride_offset, ras->ras_stride_length, |
| ras->ras_stride_pages, ras->ras_stride_offset, |
| window_len) <= ra->ra_max_pages_per_file) |
| ras->ras_window_len = window_len; |
| |
| RAS_CDEBUG(ras); |
| } |
| |
| static void ras_increase_window(struct inode *inode, |
| struct ll_readahead_state *ras, |
| struct ll_ra_info *ra) |
| { |
| /* The stretch of ra-window should be aligned with max rpc_size |
| * but current clio architecture does not support retrieve such |
| * information from lower layer. FIXME later |
| */ |
| if (stride_io_mode(ras)) |
| ras_stride_increase_window(ras, ra, RAS_INCREASE_STEP(inode)); |
| else |
| ras->ras_window_len = min(ras->ras_window_len + |
| RAS_INCREASE_STEP(inode), |
| ra->ra_max_pages_per_file); |
| } |
| |
| void ras_update(struct ll_sb_info *sbi, struct inode *inode, |
| struct ll_readahead_state *ras, unsigned long index, |
| unsigned hit) |
| { |
| struct ll_ra_info *ra = &sbi->ll_ra_info; |
| int zero = 0, stride_detect = 0, ra_miss = 0; |
| |
| spin_lock(&ras->ras_lock); |
| |
| ll_ra_stats_inc_sbi(sbi, hit ? RA_STAT_HIT : RA_STAT_MISS); |
| |
| /* reset the read-ahead window in two cases. First when the app seeks |
| * or reads to some other part of the file. Secondly if we get a |
| * read-ahead miss that we think we've previously issued. This can |
| * be a symptom of there being so many read-ahead pages that the VM is |
| * reclaiming it before we get to it. |
| */ |
| if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) { |
| zero = 1; |
| ll_ra_stats_inc_sbi(sbi, RA_STAT_DISTANT_READPAGE); |
| } else if (!hit && ras->ras_window_len && |
| index < ras->ras_next_readahead && |
| index_in_window(index, ras->ras_window_start, 0, |
| ras->ras_window_len)) { |
| ra_miss = 1; |
| ll_ra_stats_inc_sbi(sbi, RA_STAT_MISS_IN_WINDOW); |
| } |
| |
| /* On the second access to a file smaller than the tunable |
| * ra_max_read_ahead_whole_pages trigger RA on all pages in the |
| * file up to ra_max_pages_per_file. This is simply a best effort |
| * and only occurs once per open file. Normal RA behavior is reverted |
| * to for subsequent IO. The mmap case does not increment |
| * ras_requests and thus can never trigger this behavior. |
| */ |
| if (ras->ras_requests == 2 && !ras->ras_request_index) { |
| __u64 kms_pages; |
| |
| kms_pages = (i_size_read(inode) + PAGE_SIZE - 1) >> |
| PAGE_SHIFT; |
| |
| CDEBUG(D_READA, "kmsp %llu mwp %lu mp %lu\n", kms_pages, |
| ra->ra_max_read_ahead_whole_pages, ra->ra_max_pages_per_file); |
| |
| if (kms_pages && |
| kms_pages <= ra->ra_max_read_ahead_whole_pages) { |
| ras->ras_window_start = 0; |
| ras->ras_last_readpage = 0; |
| ras->ras_next_readahead = 0; |
| ras->ras_window_len = min(ra->ra_max_pages_per_file, |
| ra->ra_max_read_ahead_whole_pages); |
| goto out_unlock; |
| } |
| } |
| if (zero) { |
| /* check whether it is in stride I/O mode*/ |
| if (!index_in_stride_window(ras, index)) { |
| if (ras->ras_consecutive_stride_requests == 0 && |
| ras->ras_request_index == 0) { |
| ras_update_stride_detector(ras, index); |
| ras->ras_consecutive_stride_requests++; |
| } else { |
| ras_stride_reset(ras); |
| } |
| ras_reset(inode, ras, index); |
| ras->ras_consecutive_pages++; |
| goto out_unlock; |
| } else { |
| ras->ras_consecutive_pages = 0; |
| ras->ras_consecutive_requests = 0; |
| if (++ras->ras_consecutive_stride_requests > 1) |
| stride_detect = 1; |
| RAS_CDEBUG(ras); |
| } |
| } else { |
| if (ra_miss) { |
| if (index_in_stride_window(ras, index) && |
| stride_io_mode(ras)) { |
| /*If stride-RA hit cache miss, the stride dector |
| *will not be reset to avoid the overhead of |
| *redetecting read-ahead mode |
| */ |
| if (index != ras->ras_last_readpage + 1) |
| ras->ras_consecutive_pages = 0; |
| ras_reset(inode, ras, index); |
| RAS_CDEBUG(ras); |
| } else { |
| /* Reset both stride window and normal RA |
| * window |
| */ |
| ras_reset(inode, ras, index); |
| ras->ras_consecutive_pages++; |
| ras_stride_reset(ras); |
| goto out_unlock; |
| } |
| } else if (stride_io_mode(ras)) { |
| /* If this is contiguous read but in stride I/O mode |
| * currently, check whether stride step still is valid, |
| * if invalid, it will reset the stride ra window |
| */ |
| if (!index_in_stride_window(ras, index)) { |
| /* Shrink stride read-ahead window to be zero */ |
| ras_stride_reset(ras); |
| ras->ras_window_len = 0; |
| ras->ras_next_readahead = index; |
| } |
| } |
| } |
| ras->ras_consecutive_pages++; |
| ras->ras_last_readpage = index; |
| ras_set_start(inode, ras, index); |
| |
| if (stride_io_mode(ras)) { |
| /* Since stride readahead is sensitive to the offset |
| * of read-ahead, so we use original offset here, |
| * instead of ras_window_start, which is RPC aligned |
| */ |
| ras->ras_next_readahead = max(index, ras->ras_next_readahead); |
| } else { |
| if (ras->ras_next_readahead < ras->ras_window_start) |
| ras->ras_next_readahead = ras->ras_window_start; |
| if (!hit) |
| ras->ras_next_readahead = index + 1; |
| } |
| RAS_CDEBUG(ras); |
| |
| /* Trigger RA in the mmap case where ras_consecutive_requests |
| * is not incremented and thus can't be used to trigger RA |
| */ |
| if (!ras->ras_window_len && ras->ras_consecutive_pages == 4) { |
| ras->ras_window_len = RAS_INCREASE_STEP(inode); |
| goto out_unlock; |
| } |
| |
| /* Initially reset the stride window offset to next_readahead*/ |
| if (ras->ras_consecutive_stride_requests == 2 && stride_detect) { |
| /** |
| * Once stride IO mode is detected, next_readahead should be |
| * reset to make sure next_readahead > stride offset |
| */ |
| ras->ras_next_readahead = max(index, ras->ras_next_readahead); |
| ras->ras_stride_offset = index; |
| ras->ras_window_len = RAS_INCREASE_STEP(inode); |
| } |
| |
| /* The initial ras_window_len is set to the request size. To avoid |
| * uselessly reading and discarding pages for random IO the window is |
| * only increased once per consecutive request received. */ |
| if ((ras->ras_consecutive_requests > 1 || stride_detect) && |
| !ras->ras_request_index) |
| ras_increase_window(inode, ras, ra); |
| out_unlock: |
| RAS_CDEBUG(ras); |
| ras->ras_request_index++; |
| spin_unlock(&ras->ras_lock); |
| return; |
| } |
| |
| int ll_writepage(struct page *vmpage, struct writeback_control *wbc) |
| { |
| struct inode *inode = vmpage->mapping->host; |
| struct ll_inode_info *lli = ll_i2info(inode); |
| struct lu_env *env; |
| struct cl_io *io; |
| struct cl_page *page; |
| struct cl_object *clob; |
| struct cl_env_nest nest; |
| bool redirtied = false; |
| bool unlocked = false; |
| int result; |
| |
| LASSERT(PageLocked(vmpage)); |
| LASSERT(!PageWriteback(vmpage)); |
| |
| LASSERT(ll_i2dtexp(inode)); |
| |
| env = cl_env_nested_get(&nest); |
| if (IS_ERR(env)) { |
| result = PTR_ERR(env); |
| goto out; |
| } |
| |
| clob = ll_i2info(inode)->lli_clob; |
| LASSERT(clob); |
| |
| io = vvp_env_thread_io(env); |
| io->ci_obj = clob; |
| io->ci_ignore_layout = 1; |
| result = cl_io_init(env, io, CIT_MISC, clob); |
| if (result == 0) { |
| page = cl_page_find(env, clob, vmpage->index, |
| vmpage, CPT_CACHEABLE); |
| if (!IS_ERR(page)) { |
| lu_ref_add(&page->cp_reference, "writepage", |
| current); |
| cl_page_assume(env, io, page); |
| result = cl_page_flush(env, io, page); |
| if (result != 0) { |
| /* |
| * Re-dirty page on error so it retries write, |
| * but not in case when IO has actually |
| * occurred and completed with an error. |
| */ |
| if (!PageError(vmpage)) { |
| redirty_page_for_writepage(wbc, vmpage); |
| result = 0; |
| redirtied = true; |
| } |
| } |
| cl_page_disown(env, io, page); |
| unlocked = true; |
| lu_ref_del(&page->cp_reference, |
| "writepage", current); |
| cl_page_put(env, page); |
| } else { |
| result = PTR_ERR(page); |
| } |
| } |
| cl_io_fini(env, io); |
| |
| if (redirtied && wbc->sync_mode == WB_SYNC_ALL) { |
| loff_t offset = cl_offset(clob, vmpage->index); |
| |
| /* Flush page failed because the extent is being written out. |
| * Wait for the write of extent to be finished to avoid |
| * breaking kernel which assumes ->writepage should mark |
| * PageWriteback or clean the page. |
| */ |
| result = cl_sync_file_range(inode, offset, |
| offset + PAGE_SIZE - 1, |
| CL_FSYNC_LOCAL, 1); |
| if (result > 0) { |
| /* actually we may have written more than one page. |
| * decreasing this page because the caller will count |
| * it. |
| */ |
| wbc->nr_to_write -= result - 1; |
| result = 0; |
| } |
| } |
| |
| cl_env_nested_put(&nest, env); |
| goto out; |
| |
| out: |
| if (result < 0) { |
| if (!lli->lli_async_rc) |
| lli->lli_async_rc = result; |
| SetPageError(vmpage); |
| if (!unlocked) |
| unlock_page(vmpage); |
| } |
| return result; |
| } |
| |
| int ll_writepages(struct address_space *mapping, struct writeback_control *wbc) |
| { |
| struct inode *inode = mapping->host; |
| struct ll_sb_info *sbi = ll_i2sbi(inode); |
| loff_t start; |
| loff_t end; |
| enum cl_fsync_mode mode; |
| int range_whole = 0; |
| int result; |
| int ignore_layout = 0; |
| |
| if (wbc->range_cyclic) { |
| start = mapping->writeback_index << PAGE_SHIFT; |
| end = OBD_OBJECT_EOF; |
| } else { |
| start = wbc->range_start; |
| end = wbc->range_end; |
| if (end == LLONG_MAX) { |
| end = OBD_OBJECT_EOF; |
| range_whole = start == 0; |
| } |
| } |
| |
| mode = CL_FSYNC_NONE; |
| if (wbc->sync_mode == WB_SYNC_ALL) |
| mode = CL_FSYNC_LOCAL; |
| |
| if (sbi->ll_umounting) |
| /* if the mountpoint is being umounted, all pages have to be |
| * evicted to avoid hitting LBUG when truncate_inode_pages() |
| * is called later on. |
| */ |
| ignore_layout = 1; |
| result = cl_sync_file_range(inode, start, end, mode, ignore_layout); |
| if (result > 0) { |
| wbc->nr_to_write -= result; |
| result = 0; |
| } |
| |
| if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) { |
| if (end == OBD_OBJECT_EOF) |
| mapping->writeback_index = 0; |
| else |
| mapping->writeback_index = (end >> PAGE_SHIFT) + 1; |
| } |
| return result; |
| } |
| |
| int ll_readpage(struct file *file, struct page *vmpage) |
| { |
| struct ll_cl_context *lcc; |
| int result; |
| |
| lcc = ll_cl_init(file, vmpage); |
| if (!IS_ERR(lcc)) { |
| struct lu_env *env = lcc->lcc_env; |
| struct cl_io *io = lcc->lcc_io; |
| struct cl_page *page = lcc->lcc_page; |
| |
| LASSERT(page->cp_type == CPT_CACHEABLE); |
| if (likely(!PageUptodate(vmpage))) { |
| cl_page_assume(env, io, page); |
| result = cl_io_read_page(env, io, page); |
| } else { |
| /* Page from a non-object file. */ |
| unlock_page(vmpage); |
| result = 0; |
| } |
| ll_cl_fini(lcc); |
| } else { |
| unlock_page(vmpage); |
| result = PTR_ERR(lcc); |
| } |
| return result; |
| } |
| |
| int ll_page_sync_io(const struct lu_env *env, struct cl_io *io, |
| struct cl_page *page, enum cl_req_type crt) |
| { |
| struct cl_2queue *queue; |
| int result; |
| |
| LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE); |
| |
| queue = &io->ci_queue; |
| cl_2queue_init_page(queue, page); |
| |
| result = cl_io_submit_sync(env, io, crt, queue, 0); |
| LASSERT(cl_page_is_owned(page, io)); |
| |
| if (crt == CRT_READ) |
| /* |
| * in CRT_WRITE case page is left locked even in case of |
| * error. |
| */ |
| cl_page_list_disown(env, io, &queue->c2_qin); |
| cl_2queue_fini(env, queue); |
| |
| return result; |
| } |