These are the 5th 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 11 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 v5 and v4 (http://marc.info/?l=linux-raid&m=147629531615172): 1. Incorporate feedbacks; 2. Split reclaim patch into 3 smaller patches for (hopefully) easier review; 3. Rename different modes of a stripe to "caching" and "writing-out"; 4. Remove flag R5_WantCache; 5. Rename flag R5_InCache to R5_InJournal; 6. Remove flag STRIPE_R5C_WRITTEN and use R5_InJournal bit of dev[pd_idx].flags instead; 7. Remove dev_in_cache from stripe_head; 8. Add logic to handle alloc_page() failure in handle_stripe_dirtying(); Song Liu (11): 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 mode of r5cache md/r5cache: write-out mode and reclaim support md/r5cache: sysfs entry r5c_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 md/r5cache: handle alloc_page failure drivers/md/raid5-cache.c | 1822 +++++++++++++++++++++++++++++++++++++++++----- drivers/md/raid5.c | 322 +++++--- drivers/md/raid5.h | 154 +++- 3 files changed, 1987 insertions(+), 311 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
