Re: [lc-devel] a problem? - /proc/sys/vm/comp_cache/size

[Rodrigo S. de C. <rc...@im...>]

On Fri, Jul 05, 2002 at 01:13:03PM +0200, Michal Plachta wrote:
> i found, that /proc/sys/vm/comp_cache/size is chainging itself as it
> wants...

Since all options for compressed cache are on, you have enabled the
"resize compressed cache on demand" option. Therefore, you cannot
resize compressed cache via the sysctl entry (it is written in the
configuration help). Compressed cache resizes by itself, using up to
size defined by "compsize=" kernel parameter. Recall that "compsize="
accepts input like the "mem=" parameter (compsize=32M, for example).

I will change permissions for /proc/sys/vm/comp_cache/size when resize
on demand option is enabled, so you won't be able to echo any value to
it.

> when i try to "echo 4096 > /proc/sys/vm/comp_cache/size" it changes
> for a few seconds (probably to the first next compress/decompress)
> and then it gains the last value.  (i'm trying to lower from ~11000
> to 4096)

That's right. Even if you set the variable to a new variable, the
resize on demand code uses the current size to grow or shrink the
cache.

> All options for cache compression in kernel: ON

Regards,
-- 
Rodrigo S. de Castro <rc...@im...>