On Wed, Feb 06, 2013 at 10:27:41AM -0800, Dan Magenheimer wrote: > It was observed by Andrea Arcangeli in 2011 that zcache can get "full" > and there must be some way for compressed swap pages to be (uncompressed > and then) sent through to the backing swap disk. A prototype of this > functionality, called "unuse", was added in 2012 as part of a major update > to zcache (aka "zcache2"), but was left unfinished due to the unfortunate > temporary fork of zcache. > > This earlier version of the code had an unresolved memory leak > and was anyway dependent on not-yet-upstream frontswap and mm changes. > The code was meanwhile adapted by Seth Jennings for similar > functionality in zswap (which he calls "flush"). Seth also made some > clever simplifications which are herein ported back to zcache. As a > result of those simplifications, the frontswap changes are no longer > necessary, but a slightly different (and simpler) set of mm changes are > still required [1]. The memory leak is also fixed. > > Due to feedback from akpm in a zswap thread, this functionality in zcache > has now been renamed from "unuse" to "writeback". > > Although this zcache writeback code now works, there are open questions > as how best to handle the policy that drives it. As a result, this > patch also ties writeback to a new config option. And, since the > code still depends on not-yet-upstreamed mm patches, to avoid build > problems, the config option added by this patch temporarily depends > on "BROKEN"; this config dependency can be removed in trees that > contain the necessary mm patches. I'll wait for those options to be in Linus's tree before accepting a patch like this, sorry. greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
