This patch series introduces asynchronous writeback to the zram module.
By moving to an asynchronous model, we can perform writeback operations
more efficiently.

The series is structured as follows:

The first patch is a preparatory refactoring that moves all
writeback-related code into its own files (zram_wb.[ch]) without any
functional changes.

The second patch introduces the core infrastructure for asynchronicity,
including a dedicated kthread, a request queue, and helper functions to
manage writeback requests.

The final patch enables asynchronous writeback by switching from
submit_bio_wait() to the non-blocking submit_bio(). This patch also
includes performance benchmarks demonstrating a 27% improvement in
idle writeback speed on an Android platform.

Changes in v2:
- Rebase and spilt to a series of patchset
- Add test results
- Link to v1: https://lore.kernel.org/all/20250618132622.3730219-1-richardycc@google.com/

Richard Chang (3):
  zram: refactor writeback helpers
  zram: add async writeback infrastructure
  zram: enable asynchronous writeback

 drivers/block/zram/Makefile   |   1 +
 drivers/block/zram/zram_drv.c | 157 +++++++--------------
 drivers/block/zram/zram_drv.h |  30 ++++
 drivers/block/zram/zram_wb.c  | 248 ++++++++++++++++++++++++++++++++++
 drivers/block/zram/zram_wb.h  |  42 ++++++
 5 files changed, 371 insertions(+), 107 deletions(-)
 create mode 100644 drivers/block/zram/zram_wb.c
 create mode 100644 drivers/block/zram/zram_wb.h

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2.50.1.565.gc32cd1483b-goog