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Edit File: damon.h

/* SPDX-License-Identifier: GPL-2.0 */ /* * DAMON api * * Author: SeongJae Park <sjpark@amazon.de> */ #ifndef _DAMON_H_ #define _DAMON_H_ #include <linux/mutex.h> #include <linux/time64.h> #include <linux/types.h> /* Minimal region size. Every damon_region is aligned by this. */ #define DAMON_MIN_REGION PAGE_SIZE /** * struct damon_addr_range - Represents an address region of [@start, @end). * @start: Start address of the region (inclusive). * @end: End address of the region (exclusive). */ struct damon_addr_range { unsigned long start; unsigned long end; }; /** * struct damon_region - Represents a monitoring target region. * @ar: The address range of the region. * @sampling_addr: Address of the sample for the next access check. * @nr_accesses: Access frequency of this region. * @list: List head for siblings. */ struct damon_region { struct damon_addr_range ar; unsigned long sampling_addr; unsigned int nr_accesses; struct list_head list; }; /** * struct damon_target - Represents a monitoring target. * @id: Unique identifier for this target. * @nr_regions: Number of monitoring target regions of this target. * @regions_list: Head of the monitoring target regions of this target. * @list: List head for siblings. * * Each monitoring context could have multiple targets. For example, a context * for virtual memory address spaces could have multiple target processes. The * @id of each target should be unique among the targets of the context. For * example, in the virtual address monitoring context, it could be a pidfd or * an address of an mm_struct. */ struct damon_target { unsigned long id; unsigned int nr_regions; struct list_head regions_list; struct list_head list; }; struct damon_ctx; /** * struct damon_primitive Monitoring primitives for given use cases. * * @init: Initialize primitive-internal data structures. * @update: Update primitive-internal data structures. * @prepare_access_checks: Prepare next access check of target regions. * @check_accesses: Check the accesses to target regions. * @reset_aggregated: Reset aggregated accesses monitoring results. * @target_valid: Determine if the target is valid. * @cleanup: Clean up the context. * * DAMON can be extended for various address spaces and usages. For this, * users should register the low level primitives for their target address * space and usecase via the &damon_ctx.primitive. Then, the monitoring thread * (&damon_ctx.kdamond) calls @init and @prepare_access_checks before starting * the monitoring, @update after each &damon_ctx.primitive_update_interval, and * @check_accesses, @target_valid and @prepare_access_checks after each * &damon_ctx.sample_interval. Finally, @reset_aggregated is called after each * &damon_ctx.aggr_interval. * * @init should initialize primitive-internal data structures. For example, * this could be used to construct proper monitoring target regions and link * those to @damon_ctx.adaptive_targets. * @update should update the primitive-internal data structures. For example, * this could be used to update monitoring target regions for current status. * @prepare_access_checks should manipulate the monitoring regions to be * prepared for the next access check. * @check_accesses should check the accesses to each region that made after the * last preparation and update the number of observed accesses of each region. * It should also return max number of observed accesses that made as a result * of its update. The value will be used for regions adjustment threshold. * @reset_aggregated should reset the access monitoring results that aggregated * by @check_accesses. * @target_valid should check whether the target is still valid for the * monitoring. * @cleanup is called from @kdamond just before its termination. */ struct damon_primitive { void (*init)(struct damon_ctx *context); void (*update)(struct damon_ctx *context); void (*prepare_access_checks)(struct damon_ctx *context); unsigned int (*check_accesses)(struct damon_ctx *context); void (*reset_aggregated)(struct damon_ctx *context); bool (*target_valid)(void *target); void (*cleanup)(struct damon_ctx *context); }; /* * struct damon_callback Monitoring events notification callbacks. * * @before_start: Called before starting the monitoring. * @after_sampling: Called after each sampling. * @after_aggregation: Called after each aggregation. * @before_terminate: Called before terminating the monitoring. * @private: User private data. * * The monitoring thread (&damon_ctx.kdamond) calls @before_start and * @before_terminate just before starting and finishing the monitoring, * respectively. Therefore, those are good places for installing and cleaning * @private. * * The monitoring thread calls @after_sampling and @after_aggregation for each * of the sampling intervals and aggregation intervals, respectively. * Therefore, users can safely access the monitoring results without additional * protection. For the reason, users are recommended to use these callback for * the accesses to the results. * * If any callback returns non-zero, monitoring stops. */ struct damon_callback { void *private; int (*before_start)(struct damon_ctx *context); int (*after_sampling)(struct damon_ctx *context); int (*after_aggregation)(struct damon_ctx *context); int (*before_terminate)(struct damon_ctx *context); }; /** * struct damon_ctx - Represents a context for each monitoring. This is the * main interface that allows users to set the attributes and get the results * of the monitoring. * * @sample_interval: The time between access samplings. * @aggr_interval: The time between monitor results aggregations. * @primitive_update_interval: The time between monitoring primitive updates. * * For each @sample_interval, DAMON checks whether each region is accessed or * not. It aggregates and keeps the access information (number of accesses to * each region) for @aggr_interval time. DAMON also checks whether the target * memory regions need update (e.g., by ``mmap()`` calls from the application, * in case of virtual memory monitoring) and applies the changes for each * @primitive_update_interval. All time intervals are in micro-seconds. * Please refer to &struct damon_primitive and &struct damon_callback for more * detail. * * @kdamond: Kernel thread who does the monitoring. * @kdamond_stop: Notifies whether kdamond should stop. * @kdamond_lock: Mutex for the synchronizations with @kdamond. * * For each monitoring context, one kernel thread for the monitoring is * created. The pointer to the thread is stored in @kdamond. * * Once started, the monitoring thread runs until explicitly required to be * terminated or every monitoring target is invalid. The validity of the * targets is checked via the &damon_primitive.target_valid of @primitive. The * termination can also be explicitly requested by writing non-zero to * @kdamond_stop. The thread sets @kdamond to NULL when it terminates. * Therefore, users can know whether the monitoring is ongoing or terminated by * reading @kdamond. Reads and writes to @kdamond and @kdamond_stop from * outside of the monitoring thread must be protected by @kdamond_lock. * * Note that the monitoring thread protects only @kdamond and @kdamond_stop via * @kdamond_lock. Accesses to other fields must be protected by themselves. * * @primitive: Set of monitoring primitives for given use cases. * @callback: Set of callbacks for monitoring events notifications. * * @min_nr_regions: The minimum number of adaptive monitoring regions. * @max_nr_regions: The maximum number of adaptive monitoring regions. * @adaptive_targets: Head of monitoring targets (&damon_target) list. */ struct damon_ctx { unsigned long sample_interval; unsigned long aggr_interval; unsigned long primitive_update_interval; /* private: internal use only */ struct timespec64 last_aggregation; struct timespec64 last_primitive_update; /* public: */ struct task_struct *kdamond; bool kdamond_stop; struct mutex kdamond_lock; struct damon_primitive primitive; struct damon_callback callback; unsigned long min_nr_regions; unsigned long max_nr_regions; struct list_head adaptive_targets; }; #define damon_next_region(r) \ (container_of(r->list.next, struct damon_region, list)) #define damon_prev_region(r) \ (container_of(r->list.prev, struct damon_region, list)) #define damon_for_each_region(r, t) \ list_for_each_entry(r, &t->regions_list, list) #define damon_for_each_region_safe(r, next, t) \ list_for_each_entry_safe(r, next, &t->regions_list, list) #define damon_for_each_target(t, ctx) \ list_for_each_entry(t, &(ctx)->adaptive_targets, list) #define damon_for_each_target_safe(t, next, ctx) \ list_for_each_entry_safe(t, next, &(ctx)->adaptive_targets, list) #ifdef CONFIG_DAMON struct damon_region *damon_new_region(unsigned long start, unsigned long end); inline void damon_insert_region(struct damon_region *r, struct damon_region *prev, struct damon_region *next, struct damon_target *t); void damon_add_region(struct damon_region *r, struct damon_target *t); void damon_destroy_region(struct damon_region *r, struct damon_target *t); struct damon_target *damon_new_target(unsigned long id); void damon_add_target(struct damon_ctx *ctx, struct damon_target *t); void damon_free_target(struct damon_target *t); void damon_destroy_target(struct damon_target *t); unsigned int damon_nr_regions(struct damon_target *t); struct damon_ctx *damon_new_ctx(void); void damon_destroy_ctx(struct damon_ctx *ctx); int damon_set_targets(struct damon_ctx *ctx, unsigned long *ids, ssize_t nr_ids); int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, unsigned long aggr_int, unsigned long primitive_upd_int, unsigned long min_nr_reg, unsigned long max_nr_reg); int damon_nr_running_ctxs(void); int damon_start(struct damon_ctx **ctxs, int nr_ctxs); int damon_stop(struct damon_ctx **ctxs, int nr_ctxs); #endif /* CONFIG_DAMON */ #ifdef CONFIG_DAMON_VADDR /* Monitoring primitives for virtual memory address spaces */ void damon_va_init(struct damon_ctx *ctx); void damon_va_update(struct damon_ctx *ctx); void damon_va_prepare_access_checks(struct damon_ctx *ctx); unsigned int damon_va_check_accesses(struct damon_ctx *ctx); bool damon_va_target_valid(void *t); void damon_va_cleanup(struct damon_ctx *ctx); void damon_va_set_primitives(struct damon_ctx *ctx); #endif /* CONFIG_DAMON_VADDR */ #endif /* _DAMON_H */