linux/mm/damon
SeongJae Park 6e74d2bf5a mm/damon/core: add a new callback for watermarks checks
Patch series "mm/damon: Support online tuning".

Effects of DAMON and DAMON-based Operation Schemes highly depends on the
configurations.  Wrong configurations could even result in unexpected
efficiency degradations.  For finding a best configuration, repeating
incremental configuration changes and results measurements, in other
words, online tuning, could be helpful.

Nevertheless, DAMON kernel API supports only restrictive online tuning. 
Worse yet, the sysfs-based DAMON user interface doesn't support online
tuning at all.  DAMON_RECLAIM also doesn't support online tuning.

This patchset makes the DAMON kernel API, DAMON sysfs interface, and
DAMON_RECLAIM supports online tuning.

Sequence of patches
-------------------

First two patches enhance DAMON online tuning for kernel API users. 
Specifically, patch 1 let kernel API users to be able to do DAMON online
tuning without a restriction, and patch 2 makes error handling easier.

Following seven patches (patches 3-9) refactor code for better readability
and easier reuse of code fragments that will be useful for online tuning
support.

Patch 10 introduces DAMON callback based user request handling structure
for DAMON sysfs interface, and patch 11 enables DAMON online tuning via
DAMON sysfs interface.  Documentation patch (patch 12) for usage of it
follows.

Patch 13 enables online tuning of DAMON_RECLAIM and finally patch 14
documents the DAMON_RECLAIM online tuning usage.


This patch (of 14):

For updating input parameters for running DAMON contexts, DAMON kernel API
users can use the contexts' callbacks, as it is the safe place for context
internal data accesses.  When the context has DAMON-based operation
schemes and all schemes are deactivated due to their watermarks, however,
DAMON does nothing but only watermarks checks.  As a result, no callbacks
will be called back, and therefore the kernel API users cannot update the
input parameters including monitoring attributes, DAMON-based operation
schemes, and watermarks.

To let users easily update such DAMON input parameters in such a case,
this commit adds a new callback, 'after_wmarks_check()'.  It will be
called after each watermarks check.  Users can do the online input
parameters update in the callback even under the schemes deactivated case.

Link: https://lkml.kernel.org/r/20220429160606.127307-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13 07:20:08 -07:00
..
core-test.h mm/damon/core-test: add a kunit test case for ops registration 2022-04-29 14:37:00 -07:00
core.c mm/damon/core: add a new callback for watermarks checks 2022-05-13 07:20:08 -07:00
dbgfs-test.h mm/damon/dbgfs-test: fix is_target_id() change 2022-03-22 15:57:12 -07:00
dbgfs.c mm/damon/core: allow non-exclusive DAMON start/stop 2022-03-22 15:57:13 -07:00
Kconfig mm/damon: implement a minimal stub for sysfs-based DAMON interface 2022-03-22 15:57:13 -07:00
Makefile mm/damon: implement a minimal stub for sysfs-based DAMON interface 2022-03-22 15:57:13 -07:00
ops-common.c mm/damon: rename damon_primitives to damon_operations 2022-03-22 15:57:12 -07:00
ops-common.h mm/damon: rename damon_primitives to damon_operations 2022-03-22 15:57:12 -07:00
paddr.c Folio changes for 5.18 2022-03-22 17:03:12 -07:00
reclaim.c mm/damon/reclaim: fix the timer always stays active 2022-04-29 14:37:00 -07:00
sysfs.c mm/damon/sysfs: support fixed virtual address ranges monitoring 2022-05-13 07:20:06 -07:00
vaddr-test.h damon: vaddr-test: tweak code to make the logic clearer 2022-04-29 14:37:00 -07:00
vaddr.c mm/damon/vaddr: register a damon_operations for fixed virtual address ranges monitoring 2022-05-13 07:20:06 -07:00