Re: [PATCH v5 2/6] fs/dcache: Make negative dentry tracking configurable

[Andrew Morton]

On Mon,  2 Jul 2018 13:51:59 +0800 Waiman Long <longman@xxxxxxxxxx> wrote:

> The negative dentry tracking is made a configurable option so that
> users who don't care about negative dentry tracking will have the
> option to disable it. The new config option DCACHE_TRACK_NEG_ENTRY
> is disabled by default.
> 
> If this option is enabled, a new kernel parameter "neg_dentry_pc=<%>"
> allows users to set the soft limit on how many negative dentries are
> allowed as a percentage of the total system memory. The default is 2%
> and this new parameter accept a range of 0-10% where 0% means there
> is no limit.
> 
> When the soft limit is reached, a warning message will be printed to
> the console to alert the system administrator.

It would be much more convenient if this was tunable at runtime via yet
another /proc knob.  Is there any particular reason why we can't do this?