From b1838f8952123842b00d6f8979e0f19a3b680e87 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Thu, 10 Oct 2013 14:36:00 +0900 Subject: [PATCH] f2fs: fix the starvation problem on cp_rwsem This patch removes the logic previously introduced to address the starvation on cp_rwsem. One potential there-in bug is that we should cover the wait.list with spin_lock, but the previous code broke this rule. And, actually current rwsem handles this starvation issue reasonably, so that we didn't need to do this before neither. Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 13 ------------- fs/f2fs/super.c | 1 - 2 files changed, 14 deletions(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index a955a59dfdbe..308967b71674 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -18,8 +18,6 @@ #include #include #include -#include -#include /* * For mount options @@ -360,7 +358,6 @@ struct f2fs_sb_info { struct inode *meta_inode; /* cache meta blocks */ struct mutex cp_mutex; /* checkpoint procedure lock */ struct rw_semaphore cp_rwsem; /* blocking FS operations */ - wait_queue_head_t cp_wait; /* checkpoint wait queue */ struct mutex node_write; /* locking node writes */ struct mutex writepages; /* mutex for writepages() */ int por_doing; /* recovery is doing or not */ @@ -516,13 +513,6 @@ static inline void clear_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f) static inline void f2fs_lock_op(struct f2fs_sb_info *sbi) { - /* - * If the checkpoint thread is waiting for cp_rwsem, add cuurent task - * into wait list to avoid the checkpoint thread starvation - */ - while (!list_empty(&sbi->cp_rwsem.wait_list)) - wait_event_interruptible(sbi->cp_wait, - list_empty(&sbi->cp_rwsem.wait_list)); down_read(&sbi->cp_rwsem); } @@ -539,9 +529,6 @@ static inline void f2fs_lock_all(struct f2fs_sb_info *sbi) static inline void f2fs_unlock_all(struct f2fs_sb_info *sbi) { up_write(&sbi->cp_rwsem); - - /* wake up all tasks blocked by checkpoint */ - wake_up_all(&sbi->cp_wait); } /* diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 539c009d4138..3b786c85b5cd 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -841,7 +841,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) spin_lock_init(&sbi->stat_lock); init_rwsem(&sbi->bio_sem); init_rwsem(&sbi->cp_rwsem); - init_waitqueue_head(&sbi->cp_wait); init_sb_info(sbi); /* get an inode for meta space */