On Tue, Feb 22, 2011 at 04:27:29PM -0700, Jonathan Corbet wrote: > On Wed, 23 Feb 2011 00:01:47 +0100 > Andrea Righi <arighi@xxxxxxxxxxx> wrote: > > > > My immediate observation is that you're not really tracking the "owner" > > > here - you're tracking an opaque 16-bit token known only to the block > > > controller in a field which - if changed by anybody other than the block > > > controller - will lead to mayhem in the block controller. I think it > > > might be clearer - and safer - to say "blkcg" or some such instead of > > > "owner" here. > > > > Basically the idea here was to be as generic as possible and make this > > feature potentially available also to other subsystems, so that cgroup > > subsystems may represent whatever they want with the 16-bit token. > > However, no more than a single subsystem may be able to use this feature > > at the same time. > > That makes me nervous; it can't really be used that way unless we want to > say that certain controllers are fundamentally incompatible and can't be > allowed to play together. For whatever my $0.02 are worth (given the > state of the US dollar, that's not a whole lot), I'd suggest keeping the > current mechanism, but make it clear that it belongs to your controller. > If and when another controller comes along with a need for similar > functionality, somebody can worry about making it more general. OK, I understand. I'll use "blkio" instead of "owner". Also because I wouldn't like to introduce additional logic and overhead to check if two controllers are using this feature at the same time. Better to hard-code this information in the name of the functions. Probably the most generic solution is the one that you suggested: replace the mem_cgroup with a pointer to css_set. I'll also try to investigate this way. Thanks, -Andrea -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>