kernel/linux.git/include/linux/damon.h, branch linux-6.9.y

mm/damon/core: implement PSI metric DAMOS quota goal

2024-02-24T01:48:28+00:00

Extend DAMOS quota goal metric with system wide memory pressure stall time. Specifically, the system level 'some' PSI for memory is used. The target value can be set in microseconds. DAMOS measures the increased amount of the PSI metric in last quota_reset_interval and use the ratio of it versus the user-specified target PSI value as the score for the auto-tuning feedback loop. Link: https://lkml.kernel.org/r/20240219194431.159606-14-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: support multiple metrics for quota goal

2024-02-24T01:48:28+00:00

DAMOS quota auto-tuning asks users to assess the current tuned quota and provide the feedback in a manual and repeated way. It allows users generate the feedback from a source that the kernel cannot access, and writing a script or a function for doing the manual and repeated feeding is not a big deal. However, additional works are additional works, and it could be more efficient if DAMOS could do the fetch itself, especially in case of DAMON sysfs interface use case, since it can avoid the context switches between the user-space and the kernel-space, though the overhead would be only trivial in most cases. Also in many cases, feedbacks could be made from kernel-accessible sources, such as PSI, CPU usage, etc. Make the quota goal to support multiple types of metrics including such ones. Link: https://lkml.kernel.org/r/20240219194431.159606-13-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: let goal specified with only target and current values

2024-02-24T01:48:28+00:00

DAMOS quota auto-tuning feature let users to set the goal by providing a function for getting the current score of the tuned quota. It allows flexible goal setup, but only simple user-set quota is currently being used. As a result, the only user of the DAMOS quota auto-tuning is using a silly void pointer casting based score value passing function. Simplify the interface and the user code by letting user directly set the target and the current value. Link: https://lkml.kernel.org/r/20240219194431.159606-12-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: remove ->goal field of damos_quota

2024-02-24T01:48:28+00:00

DAMOS quota auto-tuning feature supports static signle goal and dynamic multiple goals via DAMON kernel API, specifically via ->goal and ->goals fields of damos_quota struct, respectively. All in-tree DAMOS kernel API users are using only the dynamic multiple goals now. Remove the unsued static single goal interface. Link: https://lkml.kernel.org/r/20240219194431.159606-11-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: add multiple goals per damos_quota and helpers for those

2024-02-24T01:48:27+00:00

The feedback-driven DAMOS quota auto-tuning feature allows only single goal to the DAMON kernel API users. The API users could implement multiple goals for the end-users on their level, and that's what DAMON sysfs interface is doing. More DAMON kernel API users such as DAMON_RECLAIM would need to do similar work. To reduce unnecessary future duplciated efforts, support multiple goals from DAMOS core layer. To make the support in minimum non-destructive change, keep the old single goal setup interface, and add multiple goals setup. The single goal will treated as one of the multiple goals, so old API users are not required to make any change. Link: https://lkml.kernel.org/r/20240219194431.159606-9-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: split out quota goal related fields to a struct

2024-02-24T01:48:27+00:00

'struct damos_quota' is not small now. Split out fields for quota goal to a separate struct for easier reading. Link: https://lkml.kernel.org/r/20240219194431.159606-8-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon: move comments and fields for damos-quota-prioritization to the end

2024-02-24T01:48:27+00:00

The comments and definition of 'struct damos_quota' lists a few fields for effective quota generation first, fields for regions prioritization under the quota, and then remaining fields for effective quota generation. Readers' should unnecesssarily switch their context in the middle. List all the fields for the effective quota first, and then fields for the prioritization for making it easier to read. Link: https://lkml.kernel.org/r/20240219194431.159606-7-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: set damos_quota->esz as public field and document

2024-02-24T01:48:25+00:00

Patch series "mm/damon: let DAMOS feeds and tame/auto-tune itself". The Aim-oriented Feedback-driven DAMOS Aggressiveness Auto-tuning patchset[1] which has merged since commit 9294a037c015 ("mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning") made the mechanism and the policy separated. That is, users can set a part of DAMOS control policies without a deep understanding of the mechanism but just their demands such as SLA. However, users are still required to do some additional work of manually collecting their target metric and feeding it to DAMOS. In the case of end-users who use DAMON sysfs interface, the context switches between user-space and kernel-space could also make it inefficient. The overhead is supposed to be only trivial in common cases, though. Meanwhile, in simple use cases, the target metric could be common system metrics that the kernel can efficiently self-retrieve, such as memory pressure stall time (PSI). Extend DAMOS quota auto-tuning to support multiple types of metrics including the DAMOS self-retrievable ones, and add support for memory pressure stall time metric. Different types of metrics can be supported in future. The auto-tuning capability is currently supported for only users of DAMOS kernel API and DAMON sysfs interface. Extend the support to DAMON_RECLAIM. Patches Sequence ================ First five patches are for helping debugging and fine-tuning existing quota control features. The first one (patch 1) exposes the effective quota that is made with given user inputs to DAMOS kernel API users and kernel-doc documents. Following four patches implement (patches 1, 2 and 3) and document (patches 4 and 5) a new DAMON sysfs file that exposes the value. Following six patches cleanup and simplify the existing DAMOS quota auto-tuning code by improving layout of comments and data structures (patches 6 and 7), supporting common use cases, namely multiple goals (patches 8, 9 and 10), and simplifying the interface (patch 11). Then six patches for the main purpose of this patchset follow. The first three changes extend the core logic for various target metrics (patch 12), implement memory pressure stall time-based target metric support (patch 13), and update DAMON sysfs interface to support the new target metric (patch 14). Then, documentation updates for the features on design (patch 15), ABI (patch 16), and usage (patch 17) follow. Last three patches add auto-tuning support on DAMON_RECLAIM. The patches implement DAMON_RECLAIM parameters for user-feedback driven quota auto-tuning (patch 18), memory pressure stall time-driven quota self-tuning (patch 19), and finally update the DAMON_RECLAIM usage document for the new parameters (patch 20). [1] https://lore.kernel.org/all/20231130023652.50284-1-sj@kernel.org/ This patch (of 20): DAMOS allow users to specify the quota as they want in multiple ways including time quota, size quota, and feedback-based auto-tuning. DAMOS makes one effective quota out of the inputs and use it at the end. Knowing the current effective quota helps understanding DAMOS' internal mechanism and fine-tuning quotas. DAMON kernel API users can get the information from ->esz field of damos_quota struct, but the field is marked as private purpose, and not kernel-doc documented. Make it public and document. Link: https://lkml.kernel.org/r/20240219194431.159606-1-sj@kernel.org Link: https://lkml.kernel.org/r/20240219194431.159606-2-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon: update email of SeongJae

2023-12-20T22:48:13+00:00

Patch series "mm/damon: misc updates for 6.8". Update comments, tests, and documents for DAMON. This patch (of 6): SeongJae is using his kernel.org account for DAMON development. Update the old email addresses on the comments of DAMON source files. Link: https://lkml.kernel.org/r/20231213190338.54146-1-sj@kernel.org Link: https://lkml.kernel.org/r/20231213190338.54146-2-sj@kernel.org Signed-off-by: SeongJae Park Cc: Jonathan Corbet Signed-off-by: Andrew Morton

sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes

2023-12-20T22:47:18+00:00