[LU-14820] WBC: trigger flush on background when exceed the dirty inode threshold

• Type: Technical task
• Resolution: Unresolved
• Priority: Minor
• Assignee: Qian Yingjin
• Reporter: Qian Yingjin

Description

Linux kernel only provides the periodic flush algorithm where the dirty inodes will stay in cache until dirty period is expired. This may result in many accumulated dirty inodes caching in memory before flushing. During this period, it does not make full use of the network and server capacity and resource.

 

Thus, it would better to design an aggressive dirty inodes flush algorithm on background when accumulated dirty inodes exceeds a threshold.

Moreover, the current writeback mechanism in kernel is single-threaded for each filesystem backend. It would better to parallelize the flushing of the dirty inodes on background.