On 04/08/2013 08:36 PM, Minchan Kim wrote: > On Tue, Apr 09, 2013 at 10:27:19AM +0900, Minchan Kim wrote: >> Hi Dan, >> >> On Mon, Apr 08, 2013 at 09:32:38AM -0700, Dan Magenheimer wrote: >>>> From: Minchan Kim [mailto:minchan@xxxxxxxxxx] >>>> Sent: Monday, April 08, 2013 12:01 AM >>>> Subject: [PATCH] mm: remove compressed copy from zram in-memory >>> >>> (patch removed) >>> >>>> Fragment ratio is almost same but memory consumption and compile time >>>> is better. I am working to add defragment function of zsmalloc. >>> >>> Hi Minchan -- >>> >>> I would be very interested in your design thoughts on >>> how you plan to add defragmentation for zsmalloc. In >> >> What I can say now about is only just a word "Compaction". >> As you know, zsmalloc has a transparent handle so we can do whatever >> under user. Of course, there is a tradeoff between performance >> and memory efficiency. I'm biased to latter for embedded usecase. >> >> And I might post it because as you know well, zsmalloc > > Incomplete sentense, > > I might not post it until promoting zsmalloc because as you know well, > zsmalloc/zram's all new stuffs are blocked into staging tree. > Even if we could add it into staging, as you know well, staging is where > every mm guys ignore so we end up needing another round to promote it. sigh. Yes. The lack of compaction/defragmentation support in zsmalloc has not been raised as an obstacle to mainline acceptance so I think we should wait to add new features to a yet-to-be accepted codebase. Also, I think this feature is more important to zram than it is to zswap/zcache as they can do writeback to free zpages. In other words, the fragmentation is a transient issue for zswap/zcache since writeback to the swap device is possible. Thanks, Seth -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>