Hi, > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx] > Sent: Friday, December 06, 2013 12:12 PM > To: Chao Yu > Cc: linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; 谭姝 > Subject: Re: [f2fs-dev] [PATCH 2/5 V2] f2fs: add unlikely() macro for compiler optimization > > Hi, > > Just in case, if you agreed the following comments, I'll fix those and > merge the patch by myself. > Thanks, Agreed, thanks. > > 2013-12-05 (목), 17:15 +0800, Chao Yu: > > As we know, some of our branch condition will rarely be true. So we could add > > 'unlikely' to let compiler optimize these code, by this way we could drop > > unneeded 'jump' assemble code to improve performance. > > > > change log: > > o add *unlikely* as many as possible across the whole source files at once > > suggested by Jaegeuk Kim. > > > > Suggested-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx> > > Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx> > > --- > > fs/f2fs/checkpoint.c | 10 +++++----- > > fs/f2fs/data.c | 4 ++-- > > fs/f2fs/dir.c | 4 ++-- > > fs/f2fs/f2fs.h | 8 ++++---- > > fs/f2fs/node.c | 16 ++++++++-------- > > fs/f2fs/segment.h | 2 +- > > 6 files changed, 22 insertions(+), 22 deletions(-) > > > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > > index 38f4a224..6580808 100644 > > --- a/fs/f2fs/checkpoint.c > > +++ b/fs/f2fs/checkpoint.c > > @@ -82,8 +82,8 @@ static int f2fs_write_meta_page(struct page *page, > > struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb); > > > > /* Should not write any meta pages, if any IO error was occurred */ > > - if (wbc->for_reclaim || sbi->por_doing || > > - is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)) { > > + if (unlikely(wbc->for_reclaim || sbi->por_doing || > > + is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG))) { > > if (unlikely(sbi->por_doing || is_set_ckpt_flags(F2FS_CKPT(sbi), > CP_ERROR_FLAG))) > goto redirty_out; > if (wbc->for_reclaim) > goto redirty_out; > > redirty_out: > > dec_page_count(sbi, F2FS_DIRTY_META); > > wbc->pages_skipped++; > > set_page_dirty(page); > > @@ -137,7 +137,7 @@ long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type, > > nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, > > PAGECACHE_TAG_DIRTY, > > min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1); > > - if (nr_pages == 0) > > + if (unlikely(nr_pages == 0)) > > break; > > > > for (i = 0; i < nr_pages; i++) { > > @@ -150,7 +150,7 @@ long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type, > > unlock_page(page); > > break; > > } > > - if (nwritten++ >= nr_to_write) > > + if (unlikely(nwritten++ >= nr_to_write)) > > nwritten++; > > if (unlikely(nwritten >= nr_to_write)) > > > > break; > > } > > pagevec_release(&pvec); > > @@ -200,7 +200,7 @@ int acquire_orphan_inode(struct f2fs_sb_info *sbi) > > max_orphans = (sbi->blocks_per_seg - 2 - NR_CURSEG_TYPE) > > * F2FS_ORPHANS_PER_BLOCK; > > mutex_lock(&sbi->orphan_inode_mutex); > > - if (sbi->n_orphans >= max_orphans) > > + if (unlikely(sbi->n_orphans >= max_orphans)) > > err = -ENOSPC; > > else > > sbi->n_orphans++; > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index 4e2fc09..2ce5a9e 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -251,7 +251,7 @@ int reserve_new_block(struct dnode_of_data *dn) > > > > if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC)) > > return -EPERM; > > - if (!inc_valid_block_count(sbi, dn->inode, 1)) > > + if (unlikely(!inc_valid_block_count(sbi, dn->inode, 1))) > > return -ENOSPC; > > > > trace_f2fs_reserve_new_block(dn->inode, dn->nid, dn->ofs_in_node); > > @@ -711,7 +711,7 @@ static int f2fs_write_data_page(struct page *page, > > > > zero_user_segment(page, offset, PAGE_CACHE_SIZE); > > write: > > - if (sbi->por_doing) { > > + if (unlikely(sbi->por_doing)) { > > err = AOP_WRITEPAGE_ACTIVATE; > > goto redirty_out; > > } > > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c > > index 594fc1b..0cc26ba 100644 > > --- a/fs/f2fs/dir.c > > +++ b/fs/f2fs/dir.c > > @@ -190,7 +190,7 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir, > > unsigned int max_depth; > > unsigned int level; > > > > - if (namelen > F2FS_NAME_LEN) > > + if (unlikely(namelen > F2FS_NAME_LEN)) > > return NULL; > > > > if (npages == 0) > > @@ -461,7 +461,7 @@ int __f2fs_add_link(struct inode *dir, const struct qstr *name, struct inode *in > > } > > > > start: > > - if (current_depth == MAX_DIR_HASH_DEPTH) > > + if (unlikely(current_depth == MAX_DIR_HASH_DEPTH)) > > return -ENOSPC; > > > > /* Increase the depth, if required */ > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > > index 10eca02..dca18b3 100644 > > --- a/fs/f2fs/f2fs.h > > +++ b/fs/f2fs/f2fs.h > > @@ -574,7 +574,7 @@ static inline void f2fs_unlock_all(struct f2fs_sb_info *sbi) > > static inline int check_nid_range(struct f2fs_sb_info *sbi, nid_t nid) > > { > > WARN_ON((nid >= NM_I(sbi)->max_nid)); > > - if (nid >= NM_I(sbi)->max_nid) > > + if (unlikely(nid >= NM_I(sbi)->max_nid)) > > return -EINVAL; > > return 0; > > } > > @@ -600,7 +600,7 @@ static inline bool inc_valid_block_count(struct f2fs_sb_info *sbi, > > spin_lock(&sbi->stat_lock); > > valid_block_count = > > sbi->total_valid_block_count + (block_t)count; > > - if (valid_block_count > sbi->user_block_count) { > > + if (unlikely(valid_block_count > sbi->user_block_count)) { > > spin_unlock(&sbi->stat_lock); > > return false; > > } > > @@ -719,13 +719,13 @@ static inline bool inc_valid_node_count(struct f2fs_sb_info *sbi, > > spin_lock(&sbi->stat_lock); > > > > valid_block_count = sbi->total_valid_block_count + 1; > > - if (valid_block_count > sbi->user_block_count) { > > + if (unlikely(valid_block_count > sbi->user_block_count)) { > > spin_unlock(&sbi->stat_lock); > > return false; > > } > > > > valid_node_count = sbi->total_valid_node_count + 1; > > - if (valid_node_count > sbi->total_node_count) { > > + if (unlikely(valid_node_count > sbi->total_node_count)) { > > spin_unlock(&sbi->stat_lock); > > return false; > > } > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > > index 5e2588f..48cbf76 100644 > > --- a/fs/f2fs/node.c > > +++ b/fs/f2fs/node.c > > @@ -94,7 +94,7 @@ static void ra_nat_pages(struct f2fs_sb_info *sbi, int nid) > > int i; > > > > for (i = 0; i < FREE_NID_PAGES; i++, nid += NAT_ENTRY_PER_BLOCK) { > > - if (nid >= nm_i->max_nid) > > + if (unlikely(nid >= nm_i->max_nid)) > > nid = 0; > > index = current_nat_addr(sbi, nid); > > > > @@ -1160,7 +1160,7 @@ int wait_on_node_pages_writeback(struct f2fs_sb_info *sbi, nid_t ino) > > struct page *page = pvec.pages[i]; > > > > /* until radix tree lookup accepts end_index */ > > - if (page->index > end) > > + if (unlikely(page->index > end)) > > continue; > > > > if (ino && ino_of_node(page) == ino) { > > @@ -1190,7 +1190,7 @@ static int f2fs_write_node_page(struct page *page, > > block_t new_addr; > > struct node_info ni; > > > > - if (sbi->por_doing) > > + if (unlikely(sbi->por_doing)) > > goto redirty_out; > > > > wait_on_page_writeback(page); > > @@ -1326,7 +1326,7 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build) > > return -1; > > > > /* 0 nid should not be used */ > > - if (nid == 0) > > + if (unlikely(nid == 0)) > > return 0; > > > > if (build) { > > @@ -1379,7 +1379,7 @@ static void scan_nat_page(struct f2fs_nm_info *nm_i, > > > > for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) { > > > > - if (start_nid >= nm_i->max_nid) > > + if (unlikely(start_nid >= nm_i->max_nid)) > > break; > > > > blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr); > > @@ -1413,7 +1413,7 @@ static void build_free_nids(struct f2fs_sb_info *sbi) > > f2fs_put_page(page, 1); > > > > nid += (NAT_ENTRY_PER_BLOCK - (nid % NAT_ENTRY_PER_BLOCK)); > > - if (nid >= nm_i->max_nid) > > + if (unlikely(nid >= nm_i->max_nid)) > > nid = 0; > > > > if (i++ == FREE_NID_PAGES) > > @@ -1447,7 +1447,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid) > > struct free_nid *i = NULL; > > struct list_head *this; > > retry: > > - if (sbi->total_valid_node_count + 1 >= nm_i->max_nid) > > + if (unlikely(sbi->total_valid_node_count + 1 >= nm_i->max_nid)) > > return false; > > > > spin_lock(&nm_i->free_nid_list_lock); > > @@ -1557,7 +1557,7 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page) > > new_ni = old_ni; > > new_ni.ino = ino; > > > > - if (!inc_valid_node_count(sbi, NULL)) > > + if (unlikely(!inc_valid_node_count(sbi, NULL))) > > WARN_ON(1); > > set_node_addr(sbi, &new_ni, NEW_ADDR); > > inc_valid_inode_count(sbi); > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > > index 26812fc..ea56376 100644 > > --- a/fs/f2fs/segment.h > > +++ b/fs/f2fs/segment.h > > @@ -457,7 +457,7 @@ static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, int freed) > > int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES); > > int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS); > > > > - if (sbi->por_doing) > > + if (unlikely(sbi->por_doing)) > > return false; > > > > return ((free_sections(sbi) + freed) <= (node_secs + 2 * dent_secs + > > -- > Jaegeuk Kim > Samsung -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
