Re: [PATCH 4/4] reiserfs: on-demand bitmap loading

[Hans Reiser <reiser@namesys.com>]

Jeff Mahoney wrote:

> Hans Reiser wrote:
>
> >Are you saying that you allow bitmaps to be unloaded?  If yes, how about
> >making that a separate option, and not the default?
>
>
> They're released, yes. Whether or not they're unloaded is up to the rest
> of the system, vm pressure, etc to determine. This isn't any different
> than the patch I posted before, which you ultimately approved in
> September.
>
> If the bitmaps are to be pinned at all, I'd prefer to make *that* the
> option. ReiserFS's behavior with respect to bitmaps is inconsistent with
> every other Linux file system. I'd prefer to make the dynamic bitmaps
> the default, and if you really must, add an option to continue to pin
> them.
>
> The fact remains that the bitmap blocks are infrequently accessed in
> comparison with other bits of metadata that we don't pin. They're not
> accessed at all in a read-only environment, and barely accessed in a
> light-write workload. If the bitmaps are truly in demand for heavy
> writing, the caches should keep those blocks in memory, the same as they
> do on other file systems. If another file system, application, or kernel
> subsystem needs that memory more, it should be available for it to claim.

Ok.

>
> -Jeff
>
> --
> Jeff Mahoney
> SUSE Labs