/* * 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, 2012, Whamcloud, Inc. */ /* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* current_is_kswapd() */ #include #define DEBUG_SUBSYSTEM S_LLITE #include #include #include "llite_internal.h" #include /* this isn't where truncate starts. roughly: * sys_truncate->ll_setattr_raw->vmtruncate->ll_truncate. setattr_raw grabs * DLM lock on [size, EOF], i_mutex, ->lli_size_sem, and WRITE_I_ALLOC_SEM to * avoid races. * * must be called under ->lli_size_sem */ void ll_truncate(struct inode *inode) { ENTRY; CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p) to %llu\n", inode->i_ino, inode->i_generation, inode, i_size_read(inode)); EXIT; return; } /* ll_truncate */ /** * Finalizes cl-data before exiting typical address_space operation. Dual to * ll_cl_init(). */ static 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 != NULL); if (page != NULL) { lu_ref_del(&page->cp_reference, "cl_io", io); cl_page_put(env, page); } if (io && lcc->lcc_created) { cl_io_end(env, io); cl_io_unlock(env, io); cl_io_iter_fini(env, io); cl_io_fini(env, io); } cl_env_put(env, &lcc->lcc_refcheck); } /** * Initializes common cl-data at the typical address_space operation entry * point. */ static struct ll_cl_context *ll_cl_init(struct file *file, struct page *vmpage, int create) { struct ll_cl_context *lcc; struct lu_env *env; struct cl_io *io; struct cl_object *clob; struct ccc_io *cio; int refcheck; int result = 0; clob = ll_i2info(vmpage->mapping->host)->lli_clob; LASSERT(clob != NULL); env = cl_env_get(&refcheck); if (IS_ERR(env)) return ERR_PTR(PTR_ERR(env)); lcc = &vvp_env_info(env)->vti_io_ctx; memset(lcc, 0, sizeof(*lcc)); lcc->lcc_env = env; lcc->lcc_refcheck = refcheck; lcc->lcc_cookie = current; cio = ccc_env_io(env); io = cio->cui_cl.cis_io; if (io == NULL && create) { loff_t pos; /* * Loop-back driver calls ->prepare_write() and ->sendfile() * methods directly, bypassing file system ->write() operation, * so cl_io has to be created here. */ io = ccc_env_thread_io(env); ll_io_init(io, file, 1); /* No lock at all for this kind of IO - we can't do it because * we have held page lock, it would cause deadlock. * XXX: This causes poor performance to loop device - One page * per RPC. * In order to get better performance, users should use * lloop driver instead. */ io->ci_lockreq = CILR_NEVER; pos = (vmpage->index << CFS_PAGE_SHIFT); /* Create a temp IO to serve write. */ result = cl_io_rw_init(env, io, CIT_WRITE, pos, CFS_PAGE_SIZE); if (result == 0) { cio->cui_fd = LUSTRE_FPRIVATE(file); cio->cui_iov = NULL; cio->cui_nrsegs = 0; result = cl_io_iter_init(env, io); if (result == 0) { result = cl_io_lock(env, io); if (result == 0) result = cl_io_start(env, io); } } else result = io->ci_result; lcc->lcc_created = 1; } lcc->lcc_io = io; if (io == NULL) result = -EIO; if (result == 0) { struct cl_page *page; LASSERT(io != NULL); LASSERT(io->ci_state == CIS_IO_GOING); LASSERT(cio->cui_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); } CDEBUG(D_VFSTRACE, "%lu@"DFID" -> %d %p %p\n", vmpage->index, PFID(lu_object_fid(&clob->co_lu)), result, env, io); return lcc; } static struct ll_cl_context *ll_cl_get(void) { struct ll_cl_context *lcc; struct lu_env *env; int refcheck; env = cl_env_get(&refcheck); LASSERT(!IS_ERR(env)); lcc = &vvp_env_info(env)->vti_io_ctx; LASSERT(env == lcc->lcc_env); LASSERT(current == lcc->lcc_cookie); cl_env_put(env, &refcheck); /* env has got in ll_cl_init, so it is still usable. */ return lcc; } /** * ->prepare_write() address space operation called by generic_file_write() * for every page during write. */ int ll_prepare_write(struct file *file, struct page *vmpage, unsigned from, unsigned to) { struct ll_cl_context *lcc; int result; ENTRY; lcc = ll_cl_init(file, vmpage, 1); 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; cl_page_assume(env, io, page); if (cl_io_is_append(io)) { struct cl_object *obj = io->ci_obj; struct inode *inode = ccc_object_inode(obj); /** * In VFS file->page write loop, for appending, the * write offset might be reset according to the new * file size before holding i_mutex. So crw_pos should * be reset here. BUG:17711. */ io->u.ci_wr.wr.crw_pos = i_size_read(inode); } result = cl_io_prepare_write(env, io, page, from, to); if (result == 0) { /* * Add a reference, so that page is not evicted from * the cache until ->commit_write() is called. */ cl_page_get(page); lu_ref_add(&page->cp_reference, "prepare_write", cfs_current()); } else { cl_page_unassume(env, io, page); ll_cl_fini(lcc); } /* returning 0 in prepare assumes commit must be called * afterwards */ } else { result = PTR_ERR(lcc); } RETURN(result); } int ll_commit_write(struct file *file, struct page *vmpage, unsigned from, unsigned to) { struct ll_cl_context *lcc; struct lu_env *env; struct cl_io *io; struct cl_page *page; int result = 0; ENTRY; lcc = ll_cl_get(); env = lcc->lcc_env; page = lcc->lcc_page; io = lcc->lcc_io; LASSERT(cl_page_is_owned(page, io)); LASSERT(from <= to); if (from != to) /* handle short write case. */ result = cl_io_commit_write(env, io, page, from, to); if (cl_page_is_owned(page, io)) cl_page_unassume(env, io, page); /* * Release reference acquired by ll_prepare_write(). */ lu_ref_del(&page->cp_reference, "prepare_write", cfs_current()); cl_page_put(env, page); ll_cl_fini(lcc); RETURN(result); } struct obd_capa *cl_capa_lookup(struct inode *inode, enum cl_req_type crt) { __u64 opc; opc = crt == CRT_WRITE ? CAPA_OPC_OSS_WRITE : CAPA_OPC_OSS_RW; return ll_osscapa_get(inode, opc); } 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) { struct ll_ra_info *ra = &sbi->ll_ra_info; long ret; ENTRY; /* 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 - cfs_atomic_read(&ra->ra_cur_pages), pages); if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages)) GOTO(out, ret = 0); /* 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 (cfs_atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) { cfs_atomic_sub(ret, &ra->ra_cur_pages); ret = 0; } out: RETURN(ret); } void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len) { struct ll_ra_info *ra = &sbi->ll_ra_info; cfs_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 address_space *mapping, enum ra_stat which) { struct ll_sb_info *sbi = ll_i2sbi(mapping->host); 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; } static struct ll_readahead_state *ll_ras_get(struct file *f) { struct ll_file_data *fd; fd = LUSTRE_FPRIVATE(f); return &fd->fd_ras; } void ll_ra_read_in(struct file *f, struct ll_ra_read *rar) { struct ll_readahead_state *ras; ras = ll_ras_get(f); cfs_spin_lock(&ras->ras_lock); ras->ras_requests++; ras->ras_request_index = 0; ras->ras_consecutive_requests++; rar->lrr_reader = current; cfs_list_add(&rar->lrr_linkage, &ras->ras_read_beads); cfs_spin_unlock(&ras->ras_lock); } void ll_ra_read_ex(struct file *f, struct ll_ra_read *rar) { struct ll_readahead_state *ras; ras = ll_ras_get(f); cfs_spin_lock(&ras->ras_lock); cfs_list_del_init(&rar->lrr_linkage); cfs_spin_unlock(&ras->ras_lock); } static struct ll_ra_read *ll_ra_read_get_locked(struct ll_readahead_state *ras) { struct ll_ra_read *scan; cfs_list_for_each_entry(scan, &ras->ras_read_beads, lrr_linkage) { if (scan->lrr_reader == current) return scan; } return NULL; } struct ll_ra_read *ll_ra_read_get(struct file *f) { struct ll_readahead_state *ras; struct ll_ra_read *bead; ras = ll_ras_get(f); cfs_spin_lock(&ras->ras_lock); bead = ll_ra_read_get_locked(ras); cfs_spin_unlock(&ras->ras_lock); return bead; } 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 page *vmpage) { struct ccc_page *cp; int rc; ENTRY; rc = 0; cl_page_assume(env, io, page); lu_ref_add(&page->cp_reference, "ra", cfs_current()); cp = cl2ccc_page(cl_page_at(page, &vvp_device_type)); if (!cp->cpg_defer_uptodate && !Page_Uptodate(vmpage)) { rc = cl_page_is_under_lock(env, io, page); if (rc == -EBUSY) { cp->cpg_defer_uptodate = 1; cp->cpg_ra_used = 0; cl_page_list_add(queue, page); rc = 1; } else { cl_page_delete(env, page); rc = -ENOLCK; } } else /* skip completed pages */ cl_page_unassume(env, io, page); lu_ref_del(&page->cp_reference, "ra", cfs_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, struct address_space *mapping) { struct page *vmpage; struct cl_object *clob = ll_i2info(mapping->host)->lli_clob; struct cl_page *page; enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */ unsigned int gfp_mask; int rc = 0; const char *msg = NULL; ENTRY; gfp_mask = GFP_HIGHUSER & ~__GFP_WAIT; #ifdef __GFP_NOWARN gfp_mask |= __GFP_NOWARN; #endif vmpage = grab_cache_page_nowait(mapping, index); if (vmpage != NULL) { /* Check if vmpage was truncated or reclaimed */ if (vmpage->mapping == 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, vmpage); 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); page_cache_release(vmpage); } else { which = RA_STAT_FAILED_GRAB_PAGE; msg = "g_c_p_n failed"; } if (msg != NULL) { ll_ra_stats_inc(mapping, 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) #define RAS_INCREASE_STEP PTLRPC_MAX_BRW_PAGES 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_lengh = 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 "LPU64", end "LPU64" 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, struct address_space *mapping, unsigned long *ra_end) { int rc, count = 0, stride_ria; unsigned long page_idx; LASSERT(ria != NULL); 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, mapping); 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 ll_readahead_state *ras, struct address_space *mapping, struct cl_page_list *queue, int flags) { struct vvp_io *vio = vvp_env_io(env); struct vvp_thread_info *vti = vvp_env_info(env); struct cl_attr *attr = ccc_env_thread_attr(env); unsigned long start = 0, end = 0, reserved; unsigned long ra_end, len; struct inode *inode; struct ll_ra_read *bead; struct ra_io_arg *ria = &vti->vti_ria; struct ll_inode_info *lli; struct cl_object *clob; int ret = 0; __u64 kms; ENTRY; inode = mapping->host; lli = ll_i2info(inode); clob = lli->lli_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(mapping, RA_STAT_ZERO_LEN); RETURN(0); } cfs_spin_lock(&ras->ras_lock); if (vio->cui_ra_window_set) bead = &vio->cui_bead; else bead = NULL; /* Enlarge the RA window to encompass the full read */ if (bead != NULL && ras->ras_window_start + ras->ras_window_len < bead->lrr_start + bead->lrr_count) { ras->ras_window_len = bead->lrr_start + bead->lrr_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) >> CFS_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; } cfs_spin_unlock(&ras->ras_lock); if (end == 0) { ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW); RETURN(0); } len = ria_page_count(ria); if (len == 0) RETURN(0); reserved = ll_ra_count_get(ll_i2sbi(inode), ria, len); if (reserved < len) ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT); CDEBUG(D_READA, "reserved page %lu ra_cur %d ra_max %lu\n", reserved, cfs_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, mapping, &ra_end); LASSERTF(reserved >= 0, "reserved %lu\n", reserved); if (reserved != 0) ll_ra_count_put(ll_i2sbi(inode), reserved); if (ra_end == end + 1 && ra_end == (kms >> CFS_PAGE_SHIFT)) ll_ra_stats_inc(mapping, 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) { cfs_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); } cfs_spin_unlock(&ras->ras_lock); } RETURN(ret); } static void ras_set_start(struct ll_readahead_state *ras, unsigned long index) { ras->ras_window_start = index & (~(RAS_INCREASE_STEP - 1)); } /* called with the ras_lock held or from places where it doesn't matter */ static void ras_reset(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(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) { cfs_spin_lock_init(&ras->ras_lock); ras_reset(ras, 0); ras->ras_requests = 0; CFS_INIT_LIST_HEAD(&ras->ras_read_beads); } /* * 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(unsigned long index, struct ll_readahead_state *ras, struct inode *inode) { unsigned long stride_gap = index - ras->ras_last_readpage - 1; if (ras->ras_stride_length == 0 || ras->ras_stride_pages == 0 || ras->ras_stride_pages == ras->ras_stride_length) return 0; /* 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; } static unsigned long stride_page_count(struct ll_readahead_state *ras, unsigned long len) { return stride_pg_count(ras->ras_stride_offset, ras->ras_stride_length, ras->ras_stride_pages, ras->ras_stride_offset, len); } /* 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_page_count(ras, window_len) <= ra->ra_max_pages_per_file) ras->ras_window_len = window_len; RAS_CDEBUG(ras); } static void ras_increase_window(struct ll_readahead_state *ras, struct ll_ra_info *ra, struct inode *inode) { /* 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); else ras->ras_window_len = min(ras->ras_window_len + RAS_INCREASE_STEP, 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; ENTRY; cfs_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) + CFS_PAGE_SIZE - 1) >> CFS_PAGE_SHIFT; CDEBUG(D_READA, "kmsp "LPU64" 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, 0); } } if (zero) { /* check whether it is in stride I/O mode*/ if (!index_in_stride_window(index, ras, inode)) { 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(ras, index); ras->ras_consecutive_pages++; GOTO(out_unlock, 0); } 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(index, ras, inode) && 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(ras, index); RAS_CDEBUG(ras); } else { /* Reset both stride window and normal RA * window */ ras_reset(ras, index); ras->ras_consecutive_pages++; ras_stride_reset(ras); GOTO(out_unlock, 0); } } 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(index, ras, inode)) { /* 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(ras, index); if (stride_io_mode(ras)) /* Since stride readahead is sentivite to the offset * of read-ahead, so we use original offset here, * instead of ras_window_start, which is 1M aligned*/ ras->ras_next_readahead = max(index, ras->ras_next_readahead); else ras->ras_next_readahead = max(ras->ras_window_start, ras->ras_next_readahead); 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; GOTO(out_unlock, 0); } /* 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; } /* 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(ras, ra, inode); EXIT; out_unlock: RAS_CDEBUG(ras); ras->ras_request_index++; cfs_spin_unlock(&ras->ras_lock); return; } int ll_writepage(struct page *vmpage, struct writeback_control *wbc) { struct inode *inode = vmpage->mapping->host; struct lu_env *env; struct cl_io *io; struct cl_page *page; struct cl_object *clob; struct cl_2queue *queue; struct cl_env_nest nest; int result; ENTRY; LASSERT(PageLocked(vmpage)); LASSERT(!PageWriteback(vmpage)); if (ll_i2dtexp(inode) == NULL) RETURN(-EINVAL); env = cl_env_nested_get(&nest); if (IS_ERR(env)) RETURN(PTR_ERR(env)); queue = &vvp_env_info(env)->vti_queue; clob = ll_i2info(inode)->lli_clob; LASSERT(clob != NULL); io = ccc_env_thread_io(env); io->ci_obj = clob; 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", cfs_current()); cl_page_assume(env, io, page); /* * Mark page dirty, because this is what * ->vio_submit()->cpo_prep_write() assumes. * * XXX better solution is to detect this from within * cl_io_submit_rw() somehow. */ set_page_dirty(vmpage); cl_2queue_init_page(queue, page); result = cl_io_submit_rw(env, io, CRT_WRITE, queue, CRP_NORMAL); 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; } } cl_page_list_disown(env, io, &queue->c2_qin); LASSERT(!cl_page_is_owned(page, io)); lu_ref_del(&page->cp_reference, "writepage", cfs_current()); cl_page_put(env, page); cl_2queue_fini(env, queue); } } cl_io_fini(env, io); cl_env_nested_put(&nest, env); RETURN(result); } int ll_readpage(struct file *file, struct page *vmpage) { struct ll_cl_context *lcc; int result; ENTRY; lcc = ll_cl_init(file, vmpage, 0); 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. */ LASSERT(!ll_i2info(vmpage->mapping->host)->lli_smd); unlock_page(vmpage); result = 0; } ll_cl_fini(lcc); } else { unlock_page(vmpage); result = PTR_ERR(lcc); } RETURN(result); }