[PATCH v5 0/2] mm: improve write performance with RWF_DONTCACHE

[Jeff Layton <jlayton@kernel.org>]

This patch series is intended to improve write performce with
RWF_DONTCACHE. The main difference in this version is an updated comment
over filemap_dontcache_kick_writeback(), using the verbiage suggested
by Jan.

I've also dropped the two patches that add the benchmarks that I was
using for testing. I don't think they're appropriate for inclusion here,
though we could consider cleaning them up and adding them to xfstests or
something if there is interest.

Christian, please consider these for v7.2.

Thanks,

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
Changes in v5:
- Flesh out comment over filemap_dontcache_kick_writeback()
- Drop testcases from posting
- Link to v4: https://lore.kernel.org/r/20260501-dontcache-v4-0-5d5e6dc71cb3@kernel.org

Changes in v4:
- Track DONTCACHE dirty pages per bdi_writeback
- New benchmark for competing buffered and dontcache writers
- New benchmark replicating Jens' original 32 concurrent writer test
- Link to v3: https://lore.kernel.org/r/20260426-dontcache-v3-0-79eb37da9547@kernel.org

Changes in v3:
- Track dirty DONTCACHE pages in the VM
- Have flusher write back a proportional number of pages after DONTCACHE write
- Link to v2: https://lore.kernel.org/r/20260408-dontcache-v2-0-948dec1e756b@kernel.org

Changes in v2:
- kick flusher thread instead of initiating writeback inline
- add mechanism to run 'perf lock' around the testcases
- Link to v1: https://lore.kernel.org/r/20260401-dontcache-v1-0-1f5746fab47a@kernel.org

---
Jeff Layton (2):
      mm: track DONTCACHE dirty pages per bdi_writeback
      mm: kick writeback flusher for IOCB_DONTCACHE with targeted dirty tracking

 fs/fs-writeback.c                | 65 ++++++++++++++++++++++++++++++++++++++++
 include/linux/backing-dev-defs.h |  3 ++
 include/linux/fs.h               |  6 ++--
 include/trace/events/writeback.h |  3 +-
 mm/filemap.c                     | 13 +++++++-
 mm/page-writeback.c              |  6 ++++
 6 files changed, 90 insertions(+), 6 deletions(-)
---
base-commit: 7e2326f4275c11652e1fdaae11de06159fef1d90
change-id: 20260401-dontcache-5811efd7eaf3

Best regards,
-- 
Jeff Layton <jlayton@kernel.org>