From b7ad7512b84b26f1c0ec823647a387627c138d32 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Fri, 19 Feb 2016 18:08:46 +0800 Subject: f2fs: split journal cache from curseg cache In curseg cache, f2fs caches two different parts: - datas of current summay block, i.e. summary entries, footer info. - journal info, i.e. sparse nat/sit entries or io stat info. With this approach, 1) it may cause higher lock contention when we access or update both of the parts of cache since we use the same mutex lock curseg_mutex to protect the cache. 2) current summary block with last journal info will be writebacked into device as a normal summary block when flushing, however, we treat journal info as valid one only in current summary, so most normal summary blocks contain junk journal data, it wastes remaining space of summary block. So, in order to fix above issues, we split curseg cache into two parts: a) current summary block, protected by original mutex lock curseg_mutex b) journal cache, protected by newly introduced r/w semaphore journal_rwsem When loading curseg cache during ->mount, we store summary info and journal info into different caches; When doing checkpoint, we combine datas of two cache into current summary block for persisting. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/segment.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/f2fs/segment.h') diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 2f1a422..975c33d 100644 --- a/fs/f2fs/segment.h +++ b/fs/f2fs/segment.h @@ -258,6 +258,8 @@ struct victim_selection { struct curseg_info { struct mutex curseg_mutex; /* lock for consistency */ struct f2fs_summary_block *sum_blk; /* cached summary block */ + struct rw_semaphore journal_rwsem; /* protect journal area */ + struct f2fs_journal *journal; /* cached journal info */ unsigned char alloc_type; /* current allocation type */ unsigned int segno; /* current segment number */ unsigned short next_blkoff; /* next block offset to write */ -- cgit v1.1