Re: [PATCH 07/13] writeback: explicit low bound for vm.dirty_ratio

KOSAKI Motohiro
2010-08-10T03:12:06Z

> Subject: writeback: explicit low bound for vm.dirty_ratio
> From: Wu Fengguang <fengguang.wu@intel.com>
> Date: Thu Jul 15 10:28:57 CST 2010
>
> Force a user visible low bound of 5% for the vm.dirty_ratio interface.
>
> This is an interface change. When doing
>
> echo N > /proc/sys/vm/dirty_ratio
>
> where N < 5, the old behavior is pretend to accept the value, while
> the new behavior is to reject it explicitly with -EINVAL. This will
> possibly break user space if they checks the return value.

Umm.. I dislike this change. Is there any good reason to refuse explicit
admin's will? Why 1-4% is so bad? Internal clipping can be changed later
but explicit error behavior is hard to change later.

personally I prefer to
- accept all value, or
- clipping value in dirty_ratio_handler

Both don't have explicit ABI change.

Thanks.