From e298c8a818a3e517582e60c412f4a41b3a1647c5 Mon Sep 17 00:00:00 2001 From: Yuezhang Mo Date: Mon, 7 Nov 2022 17:22:13 +0900 Subject: exfat: hint the empty entry which at the end of cluster chain After traversing all directory entries, hint the empty directory entry no matter whether or not there are enough empty directory entries. After this commit, hint the empty directory entries like this: 1. Hint the deleted directory entries if enough; 2. Hint the deleted and unused directory entries which at the end of the cluster chain no matter whether enough or not(Add by this commit); 3. If no any empty directory entries, hint the empty directory entries in the new cluster(Add by this commit). This avoids repeated traversal of directory entries, reduces CPU usage, and improves the performance of creating files and directories(especially on low-performance CPUs). Test create 5000 files in a class 4 SD card on imx6q-sabrelite with: for ((i=0;i<5;i++)); do sync time (for ((j=1;j<=1000;j++)); do touch file$((i*1000+j)); done) done The more files, the more performance improvements. Before After Improvement 1~1000 25.360s 22.168s 14.40% 1001~2000 38.242s 28.72ss 33.15% 2001~3000 49.134s 35.037s 40.23% 3001~4000 62.042s 41.624s 49.05% 4001~5000 73.629s 46.772s 57.42% Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon --- fs/exfat/dir.c | 26 ++++++++++++++++++++++---- fs/exfat/namei.c | 33 +++++++++++++++++++++------------ 2 files changed, 43 insertions(+), 16 deletions(-) (limited to 'fs/exfat') diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c index c0e60ff9ec7d..30d0ac43b66c 100644 --- a/fs/exfat/dir.c +++ b/fs/exfat/dir.c @@ -905,17 +905,24 @@ static inline void exfat_reset_empty_hint(struct exfat_hint_femp *hint_femp) static inline void exfat_set_empty_hint(struct exfat_inode_info *ei, struct exfat_hint_femp *candi_empty, struct exfat_chain *clu, - int dentry, int num_entries) + int dentry, int num_entries, int entry_type) { if (ei->hint_femp.eidx == EXFAT_HINT_NONE || ei->hint_femp.eidx > dentry) { + int total_entries = EXFAT_B_TO_DEN(i_size_read(&ei->vfs_inode)); + if (candi_empty->count == 0) { candi_empty->cur = *clu; candi_empty->eidx = dentry; } - candi_empty->count++; - if (candi_empty->count == num_entries) + if (entry_type == TYPE_UNUSED) + candi_empty->count += total_entries - dentry; + else + candi_empty->count++; + + if (candi_empty->count == num_entries || + candi_empty->count + candi_empty->eidx == total_entries) ei->hint_femp = *candi_empty; } } @@ -989,7 +996,8 @@ rewind: step = DIRENT_STEP_FILE; exfat_set_empty_hint(ei, &candi_empty, &clu, - dentry, num_entries); + dentry, num_entries, + entry_type); brelse(bh); if (entry_type == TYPE_UNUSED) @@ -1100,6 +1108,16 @@ not_found: goto rewind; } + /* + * set the EXFAT_EOF_CLUSTER flag to avoid search + * from the beginning again when allocated a new cluster + */ + if (ei->hint_femp.eidx == EXFAT_HINT_NONE) { + ei->hint_femp.cur.dir = EXFAT_EOF_CLUSTER; + ei->hint_femp.eidx = p_dir->size * dentries_per_clu; + ei->hint_femp.count = 0; + } + /* initialized hint_stat */ hint_stat->clu = p_dir->dir; hint_stat->eidx = 0; diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c index b617bebc3d0f..99e00a36c029 100644 --- a/fs/exfat/namei.c +++ b/fs/exfat/namei.c @@ -224,11 +224,18 @@ static int exfat_search_empty_slot(struct super_block *sb, if (hint_femp->eidx != EXFAT_HINT_NONE) { dentry = hint_femp->eidx; - if (num_entries <= hint_femp->count) { - hint_femp->eidx = EXFAT_HINT_NONE; - return dentry; - } + /* + * If hint_femp->count is enough, it is needed to check if + * there are actual empty entries. + * Otherwise, and if "dentry + hint_famp->count" is also equal + * to "p_dir->size * dentries_per_clu", it means ENOSPC. + */ + if (dentry + hint_femp->count == p_dir->size * dentries_per_clu && + num_entries > hint_femp->count) + return -ENOSPC; + + hint_femp->eidx = EXFAT_HINT_NONE; exfat_chain_dup(&clu, &hint_femp->cur); } else { exfat_chain_dup(&clu, p_dir); @@ -293,6 +300,12 @@ static int exfat_search_empty_slot(struct super_block *sb, } } + hint_femp->eidx = p_dir->size * dentries_per_clu - num_empty; + hint_femp->count = num_empty; + if (num_empty == 0) + exfat_chain_set(&hint_femp->cur, EXFAT_EOF_CLUSTER, 0, + clu.flags); + return -ENOSPC; } @@ -369,15 +382,11 @@ static int exfat_find_empty_entry(struct inode *inode, if (exfat_ent_set(sb, last_clu, clu.dir)) return -EIO; - if (hint_femp.eidx == EXFAT_HINT_NONE) { - /* the special case that new dentry - * should be allocated from the start of new cluster - */ - hint_femp.eidx = EXFAT_B_TO_DEN_IDX(p_dir->size, sbi); - hint_femp.count = sbi->dentries_per_clu; - + if (hint_femp.cur.dir == EXFAT_EOF_CLUSTER) exfat_chain_set(&hint_femp.cur, clu.dir, 0, clu.flags); - } + + hint_femp.count += sbi->dentries_per_clu; + hint_femp.cur.size++; p_dir->size++; size = EXFAT_CLU_TO_B(p_dir->size, sbi); -- cgit v1.2.3-58-ga151