Changes in dm_pcache.h

a4a508df2aa34f8650afde54ea804321c618f45f - Merge tag 'v6.18' into next

Sat, 13 Dec 2025 09:18:20 +0000

Merge tag 'v6.18' into nextSync up with the mainline to bring in the latest APIs. List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

2ace52718376fdb56aca863da2eebe70d7e2ddb1 - Merge branch 'objtool/core'

Fri, 21 Nov 2025 10:21:20 +0000

Merge branch 'objtool/core'Bring in the UDB and objtool data annotations to avoid conflicts while further extending the bug exceptions.Signed-off-by: Peter Zijlstra List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

f39b6c468c52745dbca9a842d91c8373fda208ab - Merge tag 'v6.18-rc6' into for-linus

Tue, 18 Nov 2025 07:16:55 +0000

Merge tag 'v6.18-rc6' into for-linusSync up with the mainline to bring in definition ofINPUT_PROP_HAPTIC_TOUCHPAD. List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

cb9f145f638d7afa633632a9290d6ad06caeb8ee - Merge remote-tracking branch 'drm/drm-next' into msm-next-robclark

Sat, 01 Nov 2025 12:47:30 +0000

Merge remote-tracking branch 'drm/drm-next' into msm-next-robclarkBack-merge drm-next to get caught up.Signed-off-by: Rob Clark List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

ec2e0fb07d789976c601bec19ecced7a501c3705 - Merge tag 'asoc-fix-v6.18-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

Thu, 16 Oct 2025 18:14:24 +0000

Merge tag 'asoc-fix-v6.18-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linusASoC: Fixes for v6.18A moderately large collection of driver specific fixes, plus a few newquirks and device IDs. The NAU8821 changes are a little large but morein mechanical ways than in ways that are complex. List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

82ee50252dc891e3f3b32d923bb4f656d300b772 - Merge drm/drm-next into drm-xe-next

Tue, 14 Oct 2025 09:31:49 +0000

Merge drm/drm-next into drm-xe-nextBackmerging to bring in 6.18-rc1.Signed-off-by: Thomas Hellström List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

48a710760e10a4f36e11233a21860796ba204b1e - Merge drm/drm-fixes into drm-misc-fixes

Tue, 14 Oct 2025 08:59:58 +0000

Merge drm/drm-fixes into drm-misc-fixesUpdating drm-misc-fixes to the state of v6.18-rc1.Signed-off-by: Thomas Zimmermann List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

2acee98fcc61052d63fab4539fcb6ee677555645 - Merge drm/drm-next into drm-intel-next

Tue, 14 Oct 2025 07:37:11 +0000

Merge drm/drm-next into drm-intel-nextSync to v6.18-rc1.Signed-off-by: Jani Nikula List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

4f38da1f027ea2c9f01bb71daa7a299c191b6940 - spi: Merge up v6.18-rc1

Mon, 13 Oct 2025 12:32:13 +0000

spi: Merge up v6.18-rc1Ensure my CI has a sensible baseline. List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

9b966ae42235a88eaea714be09ff3d698535bdfe - Merge drm/drm-next into drm-misc-next

Mon, 13 Oct 2025 07:19:19 +0000

Merge drm/drm-next into drm-misc-nextUpdating drm-misc-next to the state of v6.18-rc1.Signed-off-by: Thomas Zimmermann List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

7dbec0bbc3b468310be172f1ce6ddc9411c84952 - Merge tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Sat, 04 Oct 2025 01:48:02 +0000

Merge tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dmPull device mapper updates from Mikulas Patocka: - a new dm-pcache target for read/write caching on persistent memory - fix typos in docs - misc small refactoring - mark dm-error with DM_TARGET_PASSES_INTEGRITY - dm-request-based: fix NULL pointer dereference and quiesce_depth out of sync - dm-linear: optimize REQ_PREFLUSH - dm-vdo: return error on corrupted metadata - dm-integrity: support asynchronous hash interface* tag 'for-6.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (27 commits) dm raid: use proper md_ro_state enumerators dm-integrity: prefer synchronous hash interface dm-integrity: enable asynchronous hash interface dm-integrity: rename internal_hash dm-integrity: add the "offset" argument dm-integrity: allocate the recalculate buffer with kmalloc dm-integrity: introduce integrity_kmap and integrity_kunmap dm-integrity: replace bvec_kmap_local with kmap_local_page dm-integrity: use internal variable for digestsize dm vdo: return error on corrupted metadata in start_restoring_volume functions dm vdo: Update code to use mem_is_zero dm: optimize REQ_PREFLUSH with data when using the linear target dm-pcache: use int type to store negative error codes dm: fix "writen"->"written" dm-pcache: cleanup: fix coding style report by checkpatch.pl dm-pcache: remove ctrl_lock for pcache_cache_segment dm: fix NULL pointer dereference in __dm_suspend() dm: fix queue start/stop imbalance under suspend/load/resume races dm-pcache: add persistent cache target in device-mapper dm error: mark as DM_TARGET_PASSES_INTEGRITY ... List of files: /linux/drivers/md/dm-pcache/dm_pcache.h

1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 - dm-pcache: add persistent cache target in device-mapper

Tue, 12 Aug 2025 08:24:52 +0000

dm-pcache: add persistent cache target in device-mapperThis patch introduces dm-pcache, a new DM target that places a DAX-capable persistent-memory device in front of any slower block device anduses it as a high-throughput, low-latency cache.Design highlights------------------ DAX data path – data is copied directly between DRAM and the pmem mapping, bypassing the block layer’s overhead.- Segmented, crash-consistent layout - all layout metadata are dual-replicated CRC-protected. - atomic kset flushes; key replay on mount guarantees cache integrity even after power loss.- Striped multi-tree index - Multi‑tree indexing for high parallelism. - overlap-resolution logic ensures non-intersecting cached extents.- Background services - write-back worker flushes dirty keys in order, preserving backing-device crash consistency. This is important for checkpoint in cloud storage. - garbage collector reclaims clean segments when utilisation exceeds a tunable threshold.- Data integrity – optional CRC32 on cached payload; metadata always protected.Comparison with existing block-level caches---------------------------------------------------------------------------------------------------------------------------------| Feature | pcache (this patch) | bcache | dm-writecache ||----------------------------------|---------------------------------|------------------------------|---------------------------|| pmem access method | DAX | bio (block I/O) | DAX || Write latency (4 K rand-write) | ~5 µs | ~20 µs | ~5 µs || Concurrency | multi subtree index | global index tree | single tree + wc_lock || IOPS (4K randwrite, 32 numjobs) | 2.1 M | 352 K | 283 K || Read-cache support | YES | YES | NO || Deployment | no re-format of backend | backend devices must be | no re-format of backend || | | reformatted | || Write-back ordering | log-structured; | no ordering guarantee | no ordering guarantee || | preserves app-IO-order | | || Data integrity checks | metadata + data CRC(optional) | metadata CRC only | none |---------------------------------------------------------------------------------------------------------------------------------Signed-off-by: Dongsheng Yang Signed-off-by: Mikulas Patocka List of files: /linux/drivers/md/dm-pcache/dm_pcache.h