These are the 7th version of patches to enable write cache part of raid5-cache. The journal part was released with kernel 4.4. The caching part uses same disk format of raid456 journal, and provides acceleration to writes. Write operations are committed (bio_endio) once the data is secured in journal. Reconstruct and RMW are postponed to writing-out phase, which is usually not on the critical path. The changes are organized in 10 patches (details below). Patch for chunk_aligned_read in earlier RFC is not included yet (http://marc.info/?l=linux-raid&m=146432700719277). But we may still need some optimizations later, especially for SSD raid devices. Changes between v7 and v6 (http://marc.info/?l=linux-raid&m=147881079931937): 1. Incorprate feedbacks; 2. Modify representation of write-back state machine to use STRIPE_R5C_CACHING instead of STRIPE_R5C_WRITE_OUT. This reduces state trasitions in write-through mode; 3. For prexor, allocate extra orig_page instead of page; 4. Rename and refactor of some functions and variables; 5. Remove path 11 (handle alloc_page failure). I will propose a simpler retry patch later. Song Liu (10): md/r5cache: Check array size in r5l_init_log md/r5cache: move some code to raid5.h md/r5cache: State machine for raid5-cache write back mode md/r5cache: caching phase of r5cache md/r5cache: write-out phase and reclaim support md/r5cache: sysfs entry journal_mode md/r5cache: refactoring journal recovery code md/r5cache: r5cache recovery: part 1 md/r5cache: r5cache recovery: part 2 md/r5cache: handle SYNC and FUA drivers/md/raid5-cache.c | 1798 ++++++++++++++++++++++++++++++++++++++++------ drivers/md/raid5.c | 301 +++++--- drivers/md/raid5.h | 166 ++++- 3 files changed, 1935 insertions(+), 330 deletions(-) -- 2.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
