Re: [PATCH v2] writeback: avoid race when update bandwidth

Fengguang Wu
2012-06-12T11:52:35Z

On Tue, Jun 12, 2012 at 07:46:01PM +0800, Wanpeng Li wrote:
> From: Wanpeng Li <liwp@linux.vnet.ibm.com>
>
> "V1 -> V2"
> * remove dirty_lock
>
> Since bdi->wb.list_lock is used to protect the b_* lists,
> so the flushers who call wb_writeback to writeback pages will
> stuck when bandwidth update policy holds this lock. In order
> to avoid this race we can introduce a new bandwidth_lock who
> is responsible for protecting bandwidth update policy.
>
> Signed-off-by: Wanpeng Li <liwp.linux@gmail.com>

Applied with a new title "writeback: use a standalone lock for
updating write bandwidth". "race" is sensitive because it often
refers to some locking error.

Thank you!

Fengguang