Hi Mikulas,
This is V4 for dm-pcache, please help to review.
Code:
https://github.com/DataTravelGuide/linux tags/pcache_v4
Changelogs
V4 from V3:
- go back to use mempool for allocation of cache_key and
backing_dev_req.
- introduce backing_bvec_cache and backing_dev->bvec_pool to
allocate bvecs for backing_dev_req. Currently, the obj_size of
bvec_cache is max size of bvecs. The bvecs are allocated only for
write‑back backing_dev_req requests, and only a limited number of
writeback requests
are allocated at the same time, so the resulting memory overhead
should
not be too severe.
If in the futer we found that this implementation results in
unacceptable memory waste,
we can optimize it by switching to a multi‑level slab design.
- remove ret-value checking for bio_init_clone() as there should
not be REQ_INTEGRITY in bio bi_opf, so bio_init_clone() never
fail.
- remove ret-value checking for backing_dev_req_alloc() and
cache_key_alloc().
V3 from V2:
- rebased against linux-dm dm-6.17
- add missing include file bitfiled.h (Mikulas)
- move kmem_cache from per-device to per-module (Mikulas)
- fix a memleak in error path found by failslab testing
- retry pcache_request in defer_req() when memory allocation
fail.
V2 from V1:
- introduce req_alloc() and req_init() in backing_dev.c, then we
can do req_alloc() before holding spinlock and do req_init()
in subtree_walk().
- introduce pre_alloc_key and pre_alloc_req in walk_ctx, that
means we can pre-allocate cache_key or backing_dev_request
before subtree walking.
- use mempool_alloc() with NOIO for the allocation of cache_key
and backing_dev_req.
- some coding style changes from comments of Jonathan.
V1 from RFC-V2:
- use crc32c to replace crc32
- only retry pcache_req when cache full, add pcache_req into defer_list,
and wait cache invalidation happen.
- new format for pcache table, it is more easily extended with
new parameters later.
- remove __packed.
- use spin_lock_irq in req_complete_fn to replace
spin_lock_irqsave.
- fix bug in backing_dev_bio_end with spin_lock_irqsave.
- queue_work() inside spinlock.
- introduce inline_bvecs in backing_dev_req.
- use kmalloc_array for bvecs allocation.
- calculate ->off with dm_target_offset() before use it.
Dongsheng Yang (11):
dm-pcache: add pcache_internal.h
dm-pcache: add backing device management
dm-pcache: add cache device
dm-pcache: add segment layer
dm-pcache: add cache_segment
dm-pcache: add cache_writeback
dm-pcache: add cache_gc
dm-pcache: add cache_key
dm-pcache: add cache_req
dm-pcache: add cache core
dm-pcache: initial dm-pcache target
.../admin-guide/device-mapper/dm-pcache.rst | 201 ++++
MAINTAINERS | 8 +
drivers/md/Kconfig | 2 +
drivers/md/Makefile | 1 +
drivers/md/dm-pcache/Kconfig | 17 +
drivers/md/dm-pcache/Makefile | 3 +
drivers/md/dm-pcache/backing_dev.c | 359 +++++++
drivers/md/dm-pcache/backing_dev.h | 98 ++
drivers/md/dm-pcache/cache.c | 448 +++++++++
drivers/md/dm-pcache/cache.h | 621 ++++++++++++
drivers/md/dm-pcache/cache_dev.c | 299 ++++++
drivers/md/dm-pcache/cache_dev.h | 70 ++
drivers/md/dm-pcache/cache_gc.c | 170 ++++
drivers/md/dm-pcache/cache_key.c | 883 ++++++++++++++++++
drivers/md/dm-pcache/cache_req.c | 834 +++++++++++++++++
drivers/md/dm-pcache/cache_segment.c | 293 ++++++
drivers/md/dm-pcache/cache_writeback.c | 259 +++++
drivers/md/dm-pcache/dm_pcache.c | 488 ++++++++++
drivers/md/dm-pcache/dm_pcache.h | 65 ++
drivers/md/dm-pcache/pcache_internal.h | 117 +++
drivers/md/dm-pcache/segment.c | 61 ++
drivers/md/dm-pcache/segment.h | 74 ++
22 files changed, 5371 insertions(+)
create mode 100644 Documentation/admin-guide/device-mapper/dm-pcache.rst
create mode 100644 drivers/md/dm-pcache/Kconfig
create mode 100644 drivers/md/dm-pcache/Makefile
create mode 100644 drivers/md/dm-pcache/backing_dev.c
create mode 100644 drivers/md/dm-pcache/backing_dev.h
create mode 100644 drivers/md/dm-pcache/cache.c
create mode 100644 drivers/md/dm-pcache/cache.h
create mode 100644 drivers/md/dm-pcache/cache_dev.c
create mode 100644 drivers/md/dm-pcache/cache_dev.h
create mode 100644 drivers/md/dm-pcache/cache_gc.c
create mode 100644 drivers/md/dm-pcache/cache_key.c
create mode 100644 drivers/md/dm-pcache/cache_req.c
create mode 100644 drivers/md/dm-pcache/cache_segment.c
create mode 100644 drivers/md/dm-pcache/cache_writeback.c
create mode 100644 drivers/md/dm-pcache/dm_pcache.c
create mode 100644 drivers/md/dm-pcache/dm_pcache.h
create mode 100644 drivers/md/dm-pcache/pcache_internal.h
create mode 100644 drivers/md/dm-pcache/segment.c
create mode 100644 drivers/md/dm-pcache/segment.h
--
2.43.0
