From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: Containers and /proc/sys/vm/drop_caches Date: Thu, 06 Jan 2011 14:15:40 -0800 Message-ID: <1294352140.30082.3.camel@nimitz> References: <20110105094022.GA5366@glandium.org> <4D243EC3.1050101@free.fr> <20110105140159.GC2718@hallyn.com> <20110106214315.GJ29064@count0.beaverton.ibm.com> <1294350605.26733.3.camel@nimitz> <20110106220841.GK29064@count0.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110106220841.GK29064-52DBMbEzqgQ/wnmkkaCWp/UQ3DHhIser@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Matt Helsley Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Mike Hommey , Balbir Singh List-Id: containers.vger.kernel.org On Thu, 2011-01-06 at 14:08 -0800, Matt Helsley wrote: > Is drop_caches well-defined? IOW would it be permissible to > not actually drop all or any of the cache entries or to do nothing and > still report success instead of, say, EPERM, to a container? It's really just a hint or a request. It's possible that an echo 3 > /proc/sys/vm/drop_caches returns '2' (for the two bytes written), indicating success and yet, not a single object was freed. There's currently no way to tell how much work it did, or to figure out why it did a certain amount of work. Frankly, in a container, it probably just shouldn't even show up in /proc. -- Dave