diff options
Diffstat (limited to 'include/linux/damon.h')
| -rw-r--r-- | include/linux/damon.h | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/include/linux/damon.h b/include/linux/damon.h index e00ddf1ed39c..5881e4ac30be 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -2,7 +2,7 @@ /* * DAMON api * - * Author: SeongJae Park <sjpark@amazon.de> + * Author: SeongJae Park <sj@kernel.org> */ #ifndef _DAMON_H_ @@ -136,6 +136,9 @@ enum damos_action { * @weight_nr_accesses: Weight of the region's nr_accesses for prioritization. * @weight_age: Weight of the region's age for prioritization. * + * @get_score: Feedback function for self-tuning quota. + * @get_score_arg: Parameter for @get_score + * * To avoid consuming too much CPU time or IO resources for applying the * &struct damos->action to large memory, DAMON allows users to set time and/or * size quotas. The quotas can be set by writing non-zero values to &ms and @@ -153,6 +156,17 @@ enum damos_action { * You could customize the prioritization logic by setting &weight_sz, * &weight_nr_accesses, and &weight_age, because monitoring operations are * encouraged to respect those. + * + * If @get_score function pointer is set, DAMON calls it back with + * @get_score_arg and get the return value of it for every @reset_interval. + * Then, DAMON adjusts the effective quota using the return value as a feedback + * score to the current quota, using its internal feedback loop algorithm. + * + * The feedback loop algorithem assumes the quota input and the feedback score + * output are in a positive proportional relationship, and the goal of the + * tuning is getting the feedback screo value of 10,000. If @ms and/or @sz are + * set together, those work as a hard limit quota. If neither @ms nor @sz are + * set, the mechanism starts from the quota of one byte. */ struct damos_quota { unsigned long ms; @@ -163,6 +177,9 @@ struct damos_quota { unsigned int weight_nr_accesses; unsigned int weight_age; + unsigned long (*get_score)(void *arg); + void *get_score_arg; + /* private: */ /* For throughput estimation */ unsigned long total_charged_sz; @@ -179,6 +196,9 @@ struct damos_quota { /* For prioritization */ unsigned long histogram[DAMOS_MAX_SCORE + 1]; unsigned int min_score; + + /* For feedback loop */ + unsigned long esz_bp; }; /** |