Re: fsck memory leak

["U.Mutlu" <for-gmane@mutluit.com>]

Ruediger Meier wrote on 12/04/2015 10:40 PM:
> On Friday 04 December 2015, U.Mutlu wrote:
>> I think it's a double-edged sword: if user has less memory then
>> the integrated caching will IMO degrade the performance.
>
> It will use as much memory as available (not more). Ideally Linux would
> use always 100% memory. You've spent money for memory ... why you
> wouldn't want to use it?
>
> After ...
> $ echo 3 > /proc/sys/vm/drop_caches
>
> ... my memory looks like this:
> $ free -h
>               total    used    free       shared    buffers     cached
> Mem:          7.7G    1.8G    6.0G         230M       4.4M       487M
> -/+ buffers/cache:    1.3G    6.5G
> Swap:         1.7G     68M    1.6G
>
> Then after ...
> $ dd if=/dev/sda of=/dev/null count=8K bs=1M
>
> ... cache/buffer is filled
> $ free -h
>               total    used    free       shared    buffers     cached
> Mem:          7.7G    7.6G    168M <=(1)   230M       5.6G       665M
> -/+ buffers/cache:    1.3G    6.5G <=(2)
> Swap:         1.7G     68M    1.6G
>
> ... and this should not change until reboot.
>
> (1) shows that almost 100% memory is "in use"
> (2) shows that it's just buffer or cache

Try the test with fsck at boot with drop_caches=0, and you will get an
illogical result as shown in my initial posting.

I'm not a friend of such default integrated system caching, it reminds
me of Windows idiocy. This is nothing but a diskcache in ram, but then
the admin should have the the freedom to set the size of the cache via
a config file in etc, for example /etc/default/cache or in /etc/default/tmpfs.

> sorun yapma ;)

:-)

> Rudi