These are the 4th 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 reclaim path, which is (hopefully) not on the critical path. The changes are organized in 8 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 from PATCH v3 (http://marc.info/?l=linux-raid&m=147573807306070): 1. Make reclaim robust 2. Fix a bug in recovery Changes between v3 and v2 (http://marc.info/?l=linux-raid&m=147493266208102): 1. Incorporate feedback from Shaohua 2. Reorganize the patches, for hopefully easier review 3. Make sure no change to write through mode (journal only) 4. Change reclaim design to avoid deadlock due to log space Thanks, Song Song Liu (8): 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: write part of r5cache md/r5cache: reclaim support md/r5cache: sysfs entry r5c_state md/r5cache: r5c recovery md/r5cache: handle SYNC and FUA drivers/md/raid5-cache.c | 1593 ++++++++++++++++++++++++++++++++++++++++------ drivers/md/raid5.c | 254 +++++--- drivers/md/raid5.h | 150 ++++- 3 files changed, 1703 insertions(+), 294 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
