Hi Mikulas,
This is V3 for dm-pcache, please take a look.
Code:
https://github.com/DataTravelGuide/linux tags/pcache_v3
Changelogs
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, then `defer_req()` handles two situations:
1. Cache-full – the most common case.
Here the request waits until the GC thread invalidates cache blocks and triggers a retry.
2. Memory-allocation failure – this means the system is already under severe memory pressure.
In this case the top priority is to keep I/O recoverable and to allow users to manually stop
the pcache device if they wish. Therefore, the request is rescheduled for a retry 5 seconds later.
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 | 307 ++++++
drivers/md/dm-pcache/backing_dev.h | 91 ++
drivers/md/dm-pcache/cache.c | 432 +++++++++
drivers/md/dm-pcache/cache.h | 615 ++++++++++++
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 | 881 ++++++++++++++++++
drivers/md/dm-pcache/cache_req.c | 855 +++++++++++++++++
drivers/md/dm-pcache/cache_segment.c | 293 ++++++
drivers/md/dm-pcache/cache_writeback.c | 281 ++++++
drivers/md/dm-pcache/dm_pcache.c | 506 ++++++++++
drivers/md/dm-pcache/dm_pcache.h | 68 ++
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, 5352 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
