Am Mittwoch, 17. Juli 2013, 09:38:34 schrieb Seth Jennings: > On Wed, Jul 17, 2013 at 01:41:44PM +0200, Martin Steigerwald wrote: > > Is there any way to run zcache concurrently with zswap? I.e. use zcache only > > for read caches for filesystem and zswap for swap? > > No, at least not with zcache's frontswap features enabled. frontswap is a very > simple API that allows only one "backend" to register with it at a time. So > that means _either_ zswap or zcache. > > The only way they can be used in a meaningful way together is to use the > "nofrontswap" zcache option in the kernel boot parameters to prevent > zcache overriding zswap's frontswap registration. > > But the general answer is no, they shouldn't be used together. > > > > > > What is better suited for swap? zswap or zcache? > > zswap targets the specific case of caching swapped out pages in a compressed > cache and this is much simpler than zcache. zswap is also in mainline as of > 3.11-rc1. Thanks. Okay, then I will test zswap for now. I have a nice use case for it: Playing PlaneShift while a full KDE session is open with 8 GB of RAM. The PlaneShift client easily takes 2 GB RSS and to complicate matters I think there is even a mem leak either in Intel Mesa driver or in PS client. zswap may not help much with that I think. This brought down my laptop several times with a storm to swap which locked the machine - no mouse movements possible - for minutes while using the SSD like wild (LED constantly lid). Currently I see zswap did some work: merkaba:/sys/kernel/debug/zswap> grep . * duplicate_entry:0 pool_limit_hit:0 pool_pages:14565 reject_alloc_fail:0 reject_compress_poor:1905 reject_kmemcache_fail:0 reject_reclaim_fail:0 stored_pages:29092 written_back_pages:0 About a hour later: merkaba:/sys/kernel/debug/zswap> grep . * duplicate_entry:0 pool_limit_hit:0 pool_pages:18924 reject_alloc_fail:0 reject_compress_poor:1907 reject_kmemcache_fail:0 reject_reclaim_fail:0 stored_pages:37820 written_back_pages:0 > zcache, a driver in the staging tree, is much more complex offers some other > functionality like compressed page/file cache for certain filesystems using > cleancache and a remote-RAM system called RAMster. I´d be interested in the cleancache stuff, but I wonder whether it would make much of a difference with a desktop workload. Anyway, for a while I focus on testing zswap. -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href