On Thu 21-09-17 21:59:52, Yafang Shao wrote: > we can find the logic in domain_dirty_limits() that > when dirty bg_thresh is bigger than dirty thresh, > bg_thresh will be set as thresh * 1 / 2. > if (bg_thresh >= thresh) > bg_thresh = thresh / 2; > > But actually we can set vm background dirtiness bigger than > vm dirtiness successfully. This behavior may mislead us. > We'd better do this validity check at the beginning. > > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> Looks good. You can add: Reviewed-by: Jan Kara <jack@xxxxxxx> Just one nit below: > + > + /* needn't do validity check if the value is not different. */ > + if (ret == 0 && write && dirty_background_ratio != old_ratio) { Whitespace before the comment is broken. Generally I don't think the comment brings much so I'd just delete it. 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>