1 2** ZCACHE PLAN FOR PROMOTION FROM STAGING ** 3 4Last updated: Feb 13, 2013 5 6PLAN STEPS 7 81. merge zcache and ramster to eliminate horrible code duplication 92. converge on a predictable, writeback-capable allocator 103. use debugfs instead of sysfs (per akpm feedback in 2011) 114. zcache side of cleancache/mm WasActive patch 125. zcache side of frontswap exclusive gets 136. zcache must be able to writeback to physical swap disk 14 (per Andrea Arcangeli feedback in 2011) 157. implement adequate policy for writeback 168. frontswap/cleancache work to allow zcache to be loaded 17 as a module 189. get core mm developer to review 1910. incorporate feedback from review 2011. get review/acks from 1-2 additional mm developers 2112. incorporate any feedback from additional mm reviews 2213. propose location/file-naming in mm tree 2314. repeat 9-13 as necessary until akpm is happy and merges 24 25STATUS/OWNERSHIP 26 271. DONE as part of "new" zcache; in staging/zcache for 3.9 282. DONE as part of "new" zcache (cf zbud.[ch]); in staging/zcache for 3.9 29 (this was the core of the zcache1 vs zcache2 flail) 303. DONE as part of "new" zcache; in staging/zcache for 3.9 314. DONE (w/caveats) as part of "new" zcache; per cleancache performance 32 feedback see https://lkml.org/lkml/2011/8/17/351, in 33 staging/zcache for 3.9; dependent on proposed mm patch, see 34 https://lkml.org/lkml/2012/1/25/300 355. DONE as part of "new" zcache; performance tuning only, 36 in staging/zcache for 3.9; dependent on frontswap patch 37 merged in 3.7 (33c2a174) 386. DONE (w/caveats), prototyped as part of "new" zcache, had 39 bad memory leak; reimplemented to use sjennings clever tricks 40 and proposed mm patches with new version in staging/zcache 41 for 3.9, see https://lkml.org/lkml/2013/2/6/437; 427. PROTOTYPED as part of "new" zcache; in staging/zcache for 3.9; 43 needs more review (plan to discuss at LSF/MM 2013) 449. IN PROGRESS; owned by Konrad Wilk; Mel Gorman provided 45 great feedback in August 2012 (unfortunately of "old" 46 zcache) 4711. NOT DONE; owned by Konrad Wilk and Bob Liu 4812. TBD (depends on quantity of feedback) 4913. PROPOSED; one suggestion proposed by Dan; needs more ideas/feedback 5014. TBD (depends on feedback) 51 52WHO NEEDS TO AGREE 53 54Not sure. Seth Jennings is now pursuing a separate but semi-parallel 55track. Akpm clearly has to approve for any mm merge to happen. Minchan 56Kim has interest but may be happy if/when zram is merged into mm. Konrad 57Wilk may be maintainer if akpm decides compression is maintainable 58separately from the rest of mm. (More LSF/MM 2013 discussion.) 59 60ZCACHE FUTURE NEW FUNCTIONALITY 61 62A. Support zsmalloc as an alternative high-density allocator 63 (See https://lkml.org/lkml/2013/1/23/511) 64B. Possibly support three zbuds per pageframe when space allows 65