On Sat 07-10-17 06:58:04, Yafang Shao wrote:
> After disable periodic writeback by writing 0 to
> dirty_writeback_centisecs, the handler wb_workfn() will not be
> entered again until the dirty background limit reaches or
> sync syscall is executed or no enough free memory available or
> vmscan is triggered.
> So the periodic writeback can't be enabled by writing a non-zero
> value to dirty_writeback_centisecs
> As it can be disabled by sysctl, it should be able to enable by
> sysctl as well.
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> mm/page-writeback.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 0b9c5cb..e202f37 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -1972,7 +1972,13 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
> int dirty_writeback_centisecs_handler(struct ctl_table *table, int write,
> void __user *buffer, size_t *length, loff_t *ppos)
> {
> - proc_dointvec(table, write, buffer, length, ppos);
> + unsigned int old_interval = dirty_writeback_interval;
> + int ret;
> +
> + ret = proc_dointvec(table, write, buffer, length, ppos);
> + if (!ret && !old_interval && dirty_writeback_interval)
> + wakeup_flusher_threads(0, WB_REASON_PERIODIC);
> +
I agree it is good to schedule some writeback. However Jens has some
changes queued in linux-block tree in this area so your change won't apply.
So please base your changes on his tree.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
