On Mon, Aug 20, 2012 at 09:03:08AM +0200, Javier Marcet wrote:

Hi,

I've recently set up a software RAID5 + bcache.

I'm using kernel 3.5.2 merged with bcache master branch. I'm quite
happy with the performance but
there is an important issue. I can't drop caches. Writing any number
to /proc/sys/vm/drop_caches
makes the system hungs.

Furthermore, so far I've been unable to curb bcache's memory
consumption using the available
sysctl knobs.

Is this problem known?

No I didn't know about that - thanks, I'll look into it.

Just out of curiousity, what are you doing? drop_caches isn't something
you want to use in normal operation...