kernel/linux.git/include/linux/damon.h, branch v6.12.80

mm/damon/core: remove per-scheme region priority histogram buffer

2024-09-09T23:39:00+00:00

Nobody is reading from or writing to the per-scheme region priorities histogram buffer. It is only wasting memory. Remove it. Link: https://lkml.kernel.org/r/20240826042323.87025-4-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: introduce per-context region priorities histogram buffer

2024-09-09T23:38:59+00:00

Patch series "replace per-quota region priorities histogram buffer with per-context one". Each DAMOS quota (struct damos_quota) maintains a histogram for total regions size per its prioritization score. DAMOS calcultes minimum prioritization score of regions that are ok to apply the DAMOS action to while respecting the quota. The histogram is constructed only for the calculation of the minimum score in damos_adjust_quota() for each quota which called by kdamond_fn(). Hence, there is no real reason to have per-quota histogram. Only per-kdamond histogram is needed, since parallel kdamonds could have races otherwise. The current implementation is only wasting the memory, and can easily cause unintended stack usage[1]. So, introducing a per-kdamond histogram and replacing the per-quota one with it would be the right solution for the issue. However, supporting multiple DAMON contexts per kdamond is still an ongoing work[2] without a clear estimated time of arrival. Meanwhile, per-context histogram could be an effective and straightforward solution having no blocker. Let's fix the problem first in the way. This patch (of 4): Introduce per-context buffer for region priority scores-total size histogram. Same to the per-quota one (->histogram of struct damos_quota), the new buffer is hidden from DAMON API users by being defined as a private field of DAMON context structure. It is dynamically allocated and de-allocated at the beginning and ending of the execution of the kdamond by kdamond_fn() itself. [1] commit 0742cadf5e4c ("mm/damon/lru_sort: adjust local variable to dynamic allocation") [2] https://lore.kernel.org/20240531122320.909060-1-yorha.op@gmail.com Link: https://lkml.kernel.org/r/20240826042323.87025-1-sj@kernel.org Link: https://lkml.kernel.org/r/20240826042323.87025-2-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: implement DAMON context commit function

2024-07-04T02:30:13+00:00

Implement functions for supporting online DAMON context level parameters update. The function receives two DAMON context structs. One is the struct that currently being used by a kdamond and therefore to be updated. The other one contains the parameters to be applied to the first one. The function applies the new parameters to the destination struct while keeping/updating the internal status and operation results. The function should be called from DAMON context-update-safe place, like DAMON callbacks. Link: https://lkml.kernel.org/r/20240618181809.82078-3-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/core: implement DAMOS quota goals online commit function

2024-07-04T02:30:13+00:00

Patch series "mm/damon: introduce DAMON parameters online commit function". DAMON context struct (damon_ctx) contains user requests (parameters), internal status, and operation results. For flexible usages, DAMON API users are encouraged to manually manipulate the struct. That works well for simple use cases. However, it has turned out that it is not that simple at least for online parameters udpate. It is easy to forget properly maintaining internal status and operation results. Also, such manual manipulation for online tuning is implemented multiple times on DAMON API users including DAMON sysfs interface, DAMON_RECLAIM and DAMON_LRU_SORT. As a result, we have multiple sources of bugs for same problem. Actually we found and fixed a few bugs from online parameter updating of DAMON API users. Implement a function for online DAMON parameters update in core layer, and replace DAMON API users' manual manipulation code for the use case. The core layer function could still have bugs, but this change reduces the source of bugs for the problem to one place. This patch (of 12): Implement functions for supporting online DAMOS quota goals parameters update. The function receives two DAMOS quota structs. One is the struct that currently being used by a kdamond and therefore to be updated. The other one contains the parameters to be applied to the first one. The function applies the new parameters to the destination struct while keeping/updating the internal status. The function should be called from parameters-update safe place, like DAMON callbacks. Link: https://lkml.kernel.org/r/20240618181809.82078-1-sj@kernel.org Link: https://lkml.kernel.org/r/20240618181809.82078-2-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton

mm/damon/paddr: introduce DAMOS_MIGRATE_HOT action for promotion

2024-07-04T02:30:13+00:00

This patch introduces DAMOS_MIGRATE_HOT action, which is similar to DAMOS_MIGRATE_COLD, but proritizes hot pages. It migrates pages inside the given region to the 'target_nid' NUMA node in the sysfs. Here is one of the example usage of this 'migrate_hot' action. $ cd /sys/kernel/mm/damon/admin/kdamonds/ $ cat contexts//schemes//action migrate_hot $ echo 0 > contexts//schemes//target_nid $ echo commit > state $ numactl -p 2 ./hot_cold 500M 600M & $ numastat -c -p hot_cold Per-node process memory usage (in MBs) PID Node 0 Node 1 Node 2 Total -------------- ------ ------ ------ ----- 701 (hot_cold) 501 0 601 1101 Link: https://lkml.kernel.org/r/20240614030010.751-7-honggyu.kim@sk.com Signed-off-by: Hyeongtak Ji Signed-off-by: Honggyu Kim Signed-off-by: SeongJae Park Cc: Gregory Price Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Masami Hiramatsu (Google) Cc: Mathieu Desnoyers Cc: Rakie Kim Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton

mm/damon/paddr: introduce DAMOS_MIGRATE_COLD action for demotion

2024-07-04T02:30:13+00:00

This patch introduces DAMOS_MIGRATE_COLD action, which is similar to DAMOS_PAGEOUT, but migrate folios to the given 'target_nid' in the sysfs instead of swapping them out. The 'target_nid' sysfs knob informs the migration target node ID. Here is one of the example usage of this 'migrate_cold' action. $ cd /sys/kernel/mm/damon/admin/kdamonds/ $ cat contexts//schemes//action migrate_cold $ echo 2 > contexts//schemes//target_nid $ echo commit > state $ numactl -p 0 ./hot_cold 500M 600M & $ numastat -c -p hot_cold Per-node process memory usage (in MBs) PID Node 0 Node 1 Node 2 Total -------------- ------ ------ ------ ----- 701 (hot_cold) 501 0 601 1101 Since there are some common routines with pageout, many functions have similar logics between pageout and migrate cold. damon_pa_migrate_folio_list() is a minimized version of shrink_folio_list(). Link: https://lkml.kernel.org/r/20240614030010.751-6-honggyu.kim@sk.com Signed-off-by: Honggyu Kim Signed-off-by: Hyeongtak Ji Signed-off-by: SeongJae Park Cc: Gregory Price Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Masami Hiramatsu (Google) Cc: Mathieu Desnoyers Cc: Rakie Kim Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton

mm/damon/sysfs-schemes: add target_nid on sysfs-schemes

2024-07-04T02:30:12+00:00

This patch adds target_nid under /sys/kernel/mm/damon/admin/kdamonds//contexts//schemes// The 'target_nid' can be used as the destination node for DAMOS actions such as DAMOS_MIGRATE_{HOT,COLD} in the follow up patches. [sj@kernel.org: document target_nid file] Link: https://lkml.kernel.org/r/20240618213630.84846-3-sj@kernel.org Link: https://lkml.kernel.org/r/20240614030010.751-4-honggyu.kim@sk.com Signed-off-by: Hyeongtak Ji Signed-off-by: Honggyu Kim Signed-off-by: SeongJae Park Cc: Gregory Price Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Masami Hiramatsu (Google) Cc: Mathieu Desnoyers Cc: Rakie Kim Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton

mm/damon: add DAMOS filter type YOUNG

2024-05-06T00:53:55+00:00

Define yet another DAMOS filter type, YOUNG. Like anon and memcg, the type of filter will be applied to each page in the memory region, and see if the page is accessed since the last check. Based on the 'matching' parameter, the page is filtered out or in. Note that this commit is adding only the type definition. The implementation should be made by DAMON operations sets. A commit for the implementation on 'paddr' DAMON operations set will follow. Link: https://lkml.kernel.org/r/20240426195247.100306-4-sj@kernel.org Signed-off-by: SeongJae Park Tested-by: Honggyu Kim Cc: Jonathan Corbet Signed-off-by: Andrew Morton

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