X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fllite%2Frw.c;h=3d69fecf9a7c57f255a0e26bf42c4e04fc61b320;hp=da9e04c8792f8953ec8ec5f6c6af95cdc61616b6;hb=1e4d10af3909452b0eee1f99010d80aeb01d42a7;hpb=7e8efb339b0958146eb294fc9d961688f5d16079 diff --git a/lustre/llite/rw.c b/lustre/llite/rw.c index da9e04c..3d69fec 100644 --- a/lustre/llite/rw.c +++ b/lustre/llite/rw.c @@ -27,7 +27,6 @@ */ /* * This file is part of Lustre, http://www.lustre.org/ - * Lustre is a trademark of Sun Microsystems, Inc. * * lustre/llite/rw.c * @@ -85,17 +84,34 @@ static unsigned long ll_ra_count_get(struct ll_sb_info *sbi, unsigned long pages, unsigned long pages_min) { - struct ll_ra_info *ra = &sbi->ll_ra_info; - long ret; + 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. */ + WARN_ON_ONCE(pages_min > pages); + /** + * Don't try readahead aggresively if we are limited + * LRU pages, otherwise, it could cause deadlock. + */ + pages = min(sbi->ll_cache->ccc_lru_max >> 2, pages); + /** + * if this happen, we reserve more pages than needed, + * this will make us leak @ra_cur_pages, because + * ll_ra_count_put() acutally freed @pages. + */ + if (unlikely(pages_min > pages)) + pages_min = pages; + + /* + * 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)) - GOTO(out, ret = 0); + if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages)) + GOTO(out, ret = 0); if (atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) { atomic_sub(ret, &ra->ra_cur_pages); @@ -227,9 +243,11 @@ static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io, cl_page_assume(env, io, page); vpg = cl2vvp_page(cl_object_page_slice(clob, page)); if (!vpg->vpg_defer_uptodate && !PageUptodate(vmpage)) { - vpg->vpg_defer_uptodate = 1; - vpg->vpg_ra_used = 0; - cl_page_list_add(queue, page); + if (hint == MAYNEED) { + vpg->vpg_defer_uptodate = 1; + vpg->vpg_ra_used = 0; + } + cl_page_list_add(queue, page, true); } else { /* skip completed pages */ cl_page_unassume(env, io, page); @@ -348,7 +366,11 @@ static unsigned long ria_page_count(struct ra_io_arg *ria) static pgoff_t ras_align(struct ll_readahead_state *ras, pgoff_t index) { - return index - (index % ras->ras_rpc_pages); + unsigned opt_size = min(ras->ras_window_pages, ras->ras_rpc_pages); + + if (opt_size == 0) + opt_size = 1; + return index - (index % opt_size); } /* Check whether the index is in the defined ra-window */ @@ -382,7 +404,7 @@ static bool ras_inside_ra_window(pgoff_t idx, struct ra_io_arg *ria) static unsigned long ll_read_ahead_pages(const struct lu_env *env, struct cl_io *io, struct cl_page_list *queue, struct ll_readahead_state *ras, - struct ra_io_arg *ria, pgoff_t *ra_end) + struct ra_io_arg *ria, pgoff_t *ra_end, pgoff_t skip_index) { struct cl_read_ahead ra = { 0 }; /* busy page count is per stride */ @@ -395,6 +417,8 @@ ll_read_ahead_pages(const struct lu_env *env, struct cl_io *io, for (page_idx = ria->ria_start_idx; page_idx <= ria->ria_end_idx && ria->ria_reserved > 0; page_idx++) { + if (skip_index && page_idx == skip_index) + continue; if (ras_inside_ra_window(page_idx, ria)) { if (ra.cra_end_idx == 0 || ra.cra_end_idx < page_idx) { pgoff_t end_idx; @@ -438,10 +462,12 @@ ll_read_ahead_pages(const struct lu_env *env, struct cl_io *io, if (ras->ras_rpc_pages != ra.cra_rpc_pages && ra.cra_rpc_pages > 0) ras->ras_rpc_pages = ra.cra_rpc_pages; - /* trim it to align with optimal RPC size */ - end_idx = ras_align(ras, ria->ria_end_idx + 1); - if (end_idx > 0 && !ria->ria_eof) - ria->ria_end_idx = end_idx - 1; + if (!skip_index) { + /* trim it to align with optimal RPC size */ + end_idx = ras_align(ras, ria->ria_end_idx + 1); + if (end_idx > 0 && !ria->ria_eof) + ria->ria_end_idx = end_idx - 1; + } if (ria->ria_end_idx < ria->ria_end_idx_min) ria->ria_end_idx = ria->ria_end_idx_min; } @@ -617,7 +643,12 @@ static void ll_readahead_handle_work(struct work_struct *wq) if (rc) GOTO(out_put_env, rc); - vvp_env_io(env)->vui_io_subtype = IO_NORMAL; + /* overwrite jobid inited in vvp_io_init() */ + if (strncmp(ll_i2info(inode)->lli_jobid, work->lrw_jobid, + sizeof(work->lrw_jobid))) + memcpy(ll_i2info(inode)->lli_jobid, work->lrw_jobid, + sizeof(work->lrw_jobid)); + vvp_env_io(env)->vui_fd = fd; io->ci_state = CIS_LOCKED; io->ci_async_readahead = true; @@ -629,7 +660,7 @@ static void ll_readahead_handle_work(struct work_struct *wq) cl_2queue_init(queue); rc = ll_read_ahead_pages(env, io, &queue->c2_qin, ras, ria, - &ra_end_idx); + &ra_end_idx, 0); if (ria->ria_reserved != 0) ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved); if (queue->c2_qin.pl_nr > 0) { @@ -667,7 +698,7 @@ out_free_work: static 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 file *file) + struct file *file, pgoff_t skip_index) { struct vvp_io *vio = vvp_env_io(env); struct ll_thread_info *lti = ll_env_info(env); @@ -678,10 +709,26 @@ static int ll_readahead(const struct lu_env *env, struct cl_io *io, struct cl_object *clob; int ret = 0; __u64 kms; + struct ll_sb_info *sbi; + struct ll_ra_info *ra; + ENTRY; + ENTRY; + clob = io->ci_obj; inode = vvp_object_inode(clob); + sbi = ll_i2sbi(inode); + ra = &sbi->ll_ra_info; + + /** + * In case we have a limited max_cached_mb, readahead + * should be stopped if it have run out of all LRU slots. + */ + if (atomic_read(&ra->ra_cur_pages) >= sbi->ll_cache->ccc_lru_max) { + ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT); + RETURN(0); + } memset(ria, 0, sizeof(*ria)); ret = ll_readahead_file_kms(env, io, &kms); @@ -711,6 +758,9 @@ static int ll_readahead(const struct lu_env *env, struct cl_io *io, if (ras->ras_window_pages > 0) end_idx = ras->ras_window_start_idx + ras->ras_window_pages - 1; + if (skip_index) + end_idx = start_idx + ras->ras_window_pages - 1; + /* Enlarge the RA window to encompass the full read */ if (vio->vui_ra_valid && end_idx < vio->vui_ra_start_idx + vio->vui_ra_pages - 1) @@ -761,8 +811,21 @@ static int ll_readahead(const struct lu_env *env, struct cl_io *io, vio->vui_ra_start_idx + vio->vui_ra_pages - 1; pages_min = vio->vui_ra_start_idx + vio->vui_ra_pages - ria->ria_start_idx; + /** + * For performance reason, exceeding @ra_max_pages + * are allowed, but this should be limited with RPC + * size in case a large block size read issued. Trim + * to RPC boundary. + */ + pages_min = min(pages_min, ras->ras_rpc_pages - + (ria->ria_start_idx % ras->ras_rpc_pages)); } + /* don't over reserved for mmap range read */ + if (skip_index) + pages_min = 0; + if (pages_min > pages) + pages = pages_min; ria->ria_reserved = ll_ra_count_get(ll_i2sbi(inode), ria, pages, pages_min); if (ria->ria_reserved < pages) @@ -773,8 +836,8 @@ static int ll_readahead(const struct lu_env *env, struct cl_io *io, 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, ras, ria, &ra_end_idx); - + ret = ll_read_ahead_pages(env, io, queue, ras, ria, &ra_end_idx, + skip_index); if (ria->ria_reserved != 0) ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved); @@ -870,6 +933,10 @@ void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras) ras_reset(ras, 0); ras->ras_last_read_end_bytes = 0; ras->ras_requests = 0; + ras->ras_range_min_start_idx = 0; + ras->ras_range_max_end_idx = 0; + ras->ras_range_requests = 0; + ras->ras_last_range_pages = 0; } /* @@ -1018,6 +1085,73 @@ static inline bool is_loose_seq_read(struct ll_readahead_state *ras, loff_t pos) 8UL << PAGE_SHIFT, 8UL << PAGE_SHIFT); } +static inline bool is_loose_mmap_read(struct ll_sb_info *sbi, + struct ll_readahead_state *ras, + unsigned long pos) +{ + unsigned long range_pages = sbi->ll_ra_info.ra_range_pages; + + return pos_in_window(pos, ras->ras_last_read_end_bytes, + range_pages << PAGE_SHIFT, + range_pages << PAGE_SHIFT); +} + +/** + * We have observed slow mmap read performances for some + * applications. The problem is if access pattern is neither + * sequential nor stride, but could be still adjacent in a + * small range and then seek a random position. + * + * So the pattern could be something like this: + * + * [1M data] [hole] [0.5M data] [hole] [0.7M data] [1M data] + * + * + * Every time an application reads mmap data, it may not only + * read a single 4KB page, but aslo a cluster of nearby pages in + * a range(e.g. 1MB) of the first page after a cache miss. + * + * The readahead engine is modified to track the range size of + * a cluster of mmap reads, so that after a seek and/or cache miss, + * the range size is used to efficiently prefetch multiple pages + * in a single RPC rather than many small RPCs. + */ +static void ras_detect_cluster_range(struct ll_readahead_state *ras, + struct ll_sb_info *sbi, + unsigned long pos, unsigned long count) +{ + pgoff_t last_pages, pages; + pgoff_t end_idx = (pos + count - 1) >> PAGE_SHIFT; + + last_pages = ras->ras_range_max_end_idx - + ras->ras_range_min_start_idx + 1; + /* First time come here */ + if (!ras->ras_range_max_end_idx) + goto out; + + /* Random or Stride read */ + if (!is_loose_mmap_read(sbi, ras, pos)) + goto out; + + ras->ras_range_requests++; + if (ras->ras_range_max_end_idx < end_idx) + ras->ras_range_max_end_idx = end_idx; + + if (ras->ras_range_min_start_idx > (pos >> PAGE_SHIFT)) + ras->ras_range_min_start_idx = pos >> PAGE_SHIFT; + + /* Out of range, consider it as random or stride */ + pages = ras->ras_range_max_end_idx - + ras->ras_range_min_start_idx + 1; + if (pages <= sbi->ll_ra_info.ra_range_pages) + return; +out: + ras->ras_last_range_pages = last_pages; + ras->ras_range_requests = 0; + ras->ras_range_min_start_idx = pos >> PAGE_SHIFT; + ras->ras_range_max_end_idx = end_idx; +} + static void ras_detect_read_pattern(struct ll_readahead_state *ras, struct ll_sb_info *sbi, loff_t pos, size_t count, bool mmap) @@ -1066,8 +1200,12 @@ static void ras_detect_read_pattern(struct ll_readahead_state *ras, ras->ras_consecutive_bytes += count; if (mmap) { pgoff_t idx = ras->ras_consecutive_bytes >> PAGE_SHIFT; + unsigned long ra_range_pages = + max_t(unsigned long, RA_MIN_MMAP_RANGE_PAGES, + sbi->ll_ra_info.ra_range_pages); - if ((idx >= 4 && (idx & 3UL) == 0) || stride_detect) + if ((idx >= ra_range_pages && + idx % ra_range_pages == 0) || stride_detect) ras->ras_need_increase_window = true; } else if ((ras->ras_consecutive_requests > 1 || stride_detect)) { ras->ras_need_increase_window = true; @@ -1154,7 +1292,7 @@ static bool index_in_stride_window(struct ll_readahead_state *ras, */ static void ras_update(struct ll_sb_info *sbi, struct inode *inode, struct ll_readahead_state *ras, pgoff_t index, - enum ras_update_flags flags) + enum ras_update_flags flags, struct cl_io *io) { struct ll_ra_info *ra = &sbi->ll_ra_info; bool hit = flags & LL_RAS_HIT; @@ -1176,10 +1314,48 @@ static void ras_update(struct ll_sb_info *sbi, struct inode *inode, if (ras->ras_no_miss_check) GOTO(out_unlock, 0); - if (flags & LL_RAS_MMAP) + if (io && io->ci_rand_read) + GOTO(out_unlock, 0); + + if (io && io->ci_seq_read) { + if (!hit) { + /* to avoid many small read RPC here */ + ras->ras_window_pages = sbi->ll_ra_info.ra_range_pages; + ll_ra_stats_inc_sbi(sbi, RA_STAT_MMAP_RANGE_READ); + } + goto skip; + } + + if (flags & LL_RAS_MMAP) { + unsigned long ra_pages; + + ras_detect_cluster_range(ras, sbi, index << PAGE_SHIFT, + PAGE_SIZE); ras_detect_read_pattern(ras, sbi, (loff_t)index << PAGE_SHIFT, PAGE_SIZE, true); + /* we did not detect anything but we could prefetch */ + if (!ras->ras_need_increase_window && + ras->ras_window_pages <= sbi->ll_ra_info.ra_range_pages && + ras->ras_range_requests >= 2) { + if (!hit) { + ra_pages = max_t(unsigned long, + RA_MIN_MMAP_RANGE_PAGES, + ras->ras_last_range_pages); + if (index < ra_pages / 2) + index = 0; + else + index -= ra_pages / 2; + ras->ras_window_pages = ra_pages; + ll_ra_stats_inc_sbi(sbi, + RA_STAT_MMAP_RANGE_READ); + } else { + ras->ras_window_pages = 0; + } + goto skip; + } + } + if (!hit && ras->ras_window_pages && index < ras->ras_next_readahead_idx && pos_in_window(index, ras->ras_window_start_idx, 0, @@ -1218,6 +1394,8 @@ static void ras_update(struct ll_sb_info *sbi, struct inode *inode, GOTO(out_unlock, 0); } } + +skip: ras_set_start(ras, index); if (stride_io_mode(ras)) { @@ -1439,8 +1617,8 @@ int ll_io_read_page(const struct lu_env *env, struct cl_io *io, { struct inode *inode = vvp_object_inode(page->cp_obj); struct ll_sb_info *sbi = ll_i2sbi(inode); - struct ll_file_data *fd = file->private_data; - struct ll_readahead_state *ras = &fd->fd_ras; + struct ll_file_data *fd = NULL; + struct ll_readahead_state *ras = NULL; struct cl_2queue *queue = &io->ci_queue; struct cl_sync_io *anchor = NULL; struct vvp_page *vpg; @@ -1450,10 +1628,15 @@ int ll_io_read_page(const struct lu_env *env, struct cl_io *io, pgoff_t io_end_index; ENTRY; + if (file) { + fd = file->private_data; + ras = &fd->fd_ras; + } + vpg = cl2vvp_page(cl_object_page_slice(page->cp_obj, page)); uptodate = vpg->vpg_defer_uptodate; - if (ll_readahead_enabled(sbi) && !vpg->vpg_ra_updated) { + if (ll_readahead_enabled(sbi) && !vpg->vpg_ra_updated && ras) { struct vvp_io *vio = vvp_env_io(env); enum ras_update_flags flags = 0; @@ -1461,7 +1644,7 @@ int ll_io_read_page(const struct lu_env *env, struct cl_io *io, flags |= LL_RAS_HIT; if (!vio->vui_ra_valid) flags |= LL_RAS_MMAP; - ras_update(sbi, inode, ras, vvp_index(vpg), flags); + ras_update(sbi, inode, ras, vvp_index(vpg), flags, io); } cl_2queue_init(queue); @@ -1474,15 +1657,19 @@ int ll_io_read_page(const struct lu_env *env, struct cl_io *io, cl_sync_io_init(anchor, 1); page->cp_sync_io = anchor; - cl_2queue_add(queue, page); + cl_2queue_add(queue, page, true); } io_start_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos); io_end_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos + io->u.ci_rw.crw_count - 1); - if (ll_readahead_enabled(sbi)) { + if (ll_readahead_enabled(sbi) && ras && !io->ci_rand_read) { + pgoff_t skip_index = 0; + + if (ras->ras_next_readahead_idx < vvp_index(vpg)) + skip_index = vvp_index(vpg); rc2 = ll_readahead(env, io, &queue->c2_qin, ras, - uptodate, file); + uptodate, file, skip_index); CDEBUG(D_READA, DFID " %d pages read ahead at %lu\n", PFID(ll_inode2fid(inode)), rc2, vvp_index(vpg)); } else if (vvp_index(vpg) == io_start_index && @@ -1548,6 +1735,15 @@ static int kickoff_async_readahead(struct file *file, unsigned long pages) pgoff_t start_idx = ras_align(ras, ras->ras_next_readahead_idx); pgoff_t end_idx = start_idx + pages - 1; + /** + * In case we have a limited max_cached_mb, readahead + * should be stopped if it have run out of all LRU slots. + */ + if (atomic_read(&ra->ra_cur_pages) >= sbi->ll_cache->ccc_lru_max) { + ll_ra_stats_inc(inode, RA_STAT_MAX_IN_FLIGHT); + return 0; + } + throttle = min(ra->ra_async_pages_per_file_threshold, ra->ra_max_pages_per_file); /* @@ -1577,6 +1773,8 @@ static int kickoff_async_readahead(struct file *file, unsigned long pages) ras->ras_next_readahead_idx = end_idx + 1; ras->ras_async_last_readpage_idx = start_idx; spin_unlock(&ras->ras_lock); + memcpy(lrw->lrw_jobid, ll_i2info(inode)->lli_jobid, + sizeof(lrw->lrw_jobid)); ll_readahead_work_add(inode, lrw); } else { return -ENOMEM; @@ -1596,10 +1794,11 @@ static bool ll_use_fast_io(struct file *file, unsigned long fast_read_pages = max(RA_REMAIN_WINDOW_MIN, ras->ras_rpc_pages); loff_t skip_pages; + loff_t stride_bytes = ras->ras_stride_bytes; - if (stride_io_mode(ras)) { + if (stride_io_mode(ras) && stride_bytes) { skip_pages = (ras->ras_stride_length + - ras->ras_stride_bytes - 1) / ras->ras_stride_bytes; + ras->ras_stride_bytes - 1) / stride_bytes; skip_pages *= fast_read_pages; } else { skip_pages = fast_read_pages; @@ -1659,7 +1858,7 @@ int ll_readpage(struct file *file, struct page *vmpage) /* For fast read, it updates read ahead state only * if the page is hit in cache because non cache page * case will be handled by slow read later. */ - ras_update(sbi, inode, ras, vvp_index(vpg), flags); + ras_update(sbi, inode, ras, vvp_index(vpg), flags, io); /* avoid duplicate ras_update() call */ vpg->vpg_ra_updated = 1; @@ -1697,9 +1896,9 @@ int ll_readpage(struct file *file, struct page *vmpage) */ if (file->f_flags & O_DIRECT && lcc && lcc->lcc_type == LCC_RW && - !io->ci_ignore_lockless) { + !io->ci_dio_lock) { unlock_page(vmpage); - io->ci_ignore_lockless = 1; + io->ci_dio_lock = 1; io->ci_need_restart = 1; RETURN(-ENOLCK); }