From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: Issues dropping vm fs caches with kernel 3.5.2 + bcache master Date: Mon, 20 Aug 2012 17:15:14 -0700 Message-ID: <20120821001514.GB21953@google.com> References: <20120820202921.GA21953@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Javier Marcet Cc: Linux BCache Mailing List List-Id: linux-bcache@vger.kernel.org On Mon, Aug 20, 2012 at 11:06:30PM +0200, Javier Marcet wrote: > >> 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 hung. > >> > >> 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 tried it - I can reproduce it, but it's gone in 3.6. Looks like a 3.5 bug, not a bcache bug. I'm gonna reset the master branch to my current dev branch soon as I've tested it a bit more, but I'd suggest the bcache-3.2 branch - that's the best tested code.