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- /* SPDX-License-Identifier: GPL-2.0 */
- /*
- * DAMON api
- *
- * Author: SeongJae Park <[email protected]>
- */
- #ifndef _DAMON_H_
- #define _DAMON_H_
- #include <linux/mutex.h>
- #include <linux/time64.h>
- #include <linux/types.h>
- #include <linux/random.h>
- /* Minimal region size. Every damon_region is aligned by this. */
- #define DAMON_MIN_REGION PAGE_SIZE
- /* Max priority score for DAMON-based operation schemes */
- #define DAMOS_MAX_SCORE (99)
- /* Get a random number in [l, r) */
- static inline unsigned long damon_rand(unsigned long l, unsigned long r)
- {
- return l + prandom_u32_max(r - l);
- }
- /**
- * 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.
- * @age: Age of this region.
- *
- * @age is initially zero, increased for each aggregation interval, and reset
- * to zero again if the access frequency is significantly changed. If two
- * regions are merged into a new region, both @nr_accesses and @age of the new
- * region are set as region size-weighted average of those of the two regions.
- */
- struct damon_region {
- struct damon_addr_range ar;
- unsigned long sampling_addr;
- unsigned int nr_accesses;
- struct list_head list;
- unsigned int age;
- /* private: Internal value for age calculation. */
- unsigned int last_nr_accesses;
- };
- /**
- * struct damon_target - Represents a monitoring target.
- * @pid: The PID of the virtual address space to monitor.
- * @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
- * @pid should be set for appropriate &struct damon_operations including the
- * virtual address spaces monitoring operations.
- */
- struct damon_target {
- struct pid *pid;
- unsigned int nr_regions;
- struct list_head regions_list;
- struct list_head list;
- };
- /**
- * enum damos_action - Represents an action of a Data Access Monitoring-based
- * Operation Scheme.
- *
- * @DAMOS_WILLNEED: Call ``madvise()`` for the region with MADV_WILLNEED.
- * @DAMOS_COLD: Call ``madvise()`` for the region with MADV_COLD.
- * @DAMOS_PAGEOUT: Call ``madvise()`` for the region with MADV_PAGEOUT.
- * @DAMOS_HUGEPAGE: Call ``madvise()`` for the region with MADV_HUGEPAGE.
- * @DAMOS_NOHUGEPAGE: Call ``madvise()`` for the region with MADV_NOHUGEPAGE.
- * @DAMOS_LRU_PRIO: Prioritize the region on its LRU lists.
- * @DAMOS_LRU_DEPRIO: Deprioritize the region on its LRU lists.
- * @DAMOS_STAT: Do nothing but count the stat.
- * @NR_DAMOS_ACTIONS: Total number of DAMOS actions
- */
- enum damos_action {
- DAMOS_WILLNEED,
- DAMOS_COLD,
- DAMOS_PAGEOUT,
- DAMOS_HUGEPAGE,
- DAMOS_NOHUGEPAGE,
- DAMOS_LRU_PRIO,
- DAMOS_LRU_DEPRIO,
- DAMOS_STAT, /* Do nothing but only record the stat */
- NR_DAMOS_ACTIONS,
- };
- /**
- * struct damos_quota - Controls the aggressiveness of the given scheme.
- * @ms: Maximum milliseconds that the scheme can use.
- * @sz: Maximum bytes of memory that the action can be applied.
- * @reset_interval: Charge reset interval in milliseconds.
- *
- * @weight_sz: Weight of the region's size for prioritization.
- * @weight_nr_accesses: Weight of the region's nr_accesses for prioritization.
- * @weight_age: Weight of the region's age for prioritization.
- *
- * 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
- * &sz, respectively. If the time quota is set, DAMON tries to use only up to
- * &ms milliseconds within &reset_interval for applying the action. If the
- * size quota is set, DAMON tries to apply the action only up to &sz bytes
- * within &reset_interval.
- *
- * Internally, the time quota is transformed to a size quota using estimated
- * throughput of the scheme's action. DAMON then compares it against &sz and
- * uses smaller one as the effective quota.
- *
- * For selecting regions within the quota, DAMON prioritizes current scheme's
- * target memory regions using the &struct damon_operations->get_scheme_score.
- * You could customize the prioritization logic by setting &weight_sz,
- * &weight_nr_accesses, and &weight_age, because monitoring operations are
- * encouraged to respect those.
- */
- struct damos_quota {
- unsigned long ms;
- unsigned long sz;
- unsigned long reset_interval;
- unsigned int weight_sz;
- unsigned int weight_nr_accesses;
- unsigned int weight_age;
- /* private: */
- /* For throughput estimation */
- unsigned long total_charged_sz;
- unsigned long total_charged_ns;
- unsigned long esz; /* Effective size quota in bytes */
- /* For charging the quota */
- unsigned long charged_sz;
- unsigned long charged_from;
- struct damon_target *charge_target_from;
- unsigned long charge_addr_from;
- /* For prioritization */
- unsigned long histogram[DAMOS_MAX_SCORE + 1];
- unsigned int min_score;
- };
- /**
- * enum damos_wmark_metric - Represents the watermark metric.
- *
- * @DAMOS_WMARK_NONE: Ignore the watermarks of the given scheme.
- * @DAMOS_WMARK_FREE_MEM_RATE: Free memory rate of the system in [0,1000].
- * @NR_DAMOS_WMARK_METRICS: Total number of DAMOS watermark metrics
- */
- enum damos_wmark_metric {
- DAMOS_WMARK_NONE,
- DAMOS_WMARK_FREE_MEM_RATE,
- NR_DAMOS_WMARK_METRICS,
- };
- /**
- * struct damos_watermarks - Controls when a given scheme should be activated.
- * @metric: Metric for the watermarks.
- * @interval: Watermarks check time interval in microseconds.
- * @high: High watermark.
- * @mid: Middle watermark.
- * @low: Low watermark.
- *
- * If &metric is &DAMOS_WMARK_NONE, the scheme is always active. Being active
- * means DAMON does monitoring and applying the action of the scheme to
- * appropriate memory regions. Else, DAMON checks &metric of the system for at
- * least every &interval microseconds and works as below.
- *
- * If &metric is higher than &high, the scheme is inactivated. If &metric is
- * between &mid and &low, the scheme is activated. If &metric is lower than
- * &low, the scheme is inactivated.
- */
- struct damos_watermarks {
- enum damos_wmark_metric metric;
- unsigned long interval;
- unsigned long high;
- unsigned long mid;
- unsigned long low;
- /* private: */
- bool activated;
- };
- /**
- * struct damos_stat - Statistics on a given scheme.
- * @nr_tried: Total number of regions that the scheme is tried to be applied.
- * @sz_tried: Total size of regions that the scheme is tried to be applied.
- * @nr_applied: Total number of regions that the scheme is applied.
- * @sz_applied: Total size of regions that the scheme is applied.
- * @qt_exceeds: Total number of times the quota of the scheme has exceeded.
- */
- struct damos_stat {
- unsigned long nr_tried;
- unsigned long sz_tried;
- unsigned long nr_applied;
- unsigned long sz_applied;
- unsigned long qt_exceeds;
- };
- /**
- * struct damos_access_pattern - Target access pattern of the given scheme.
- * @min_sz_region: Minimum size of target regions.
- * @max_sz_region: Maximum size of target regions.
- * @min_nr_accesses: Minimum ``->nr_accesses`` of target regions.
- * @max_nr_accesses: Maximum ``->nr_accesses`` of target regions.
- * @min_age_region: Minimum age of target regions.
- * @max_age_region: Maximum age of target regions.
- */
- struct damos_access_pattern {
- unsigned long min_sz_region;
- unsigned long max_sz_region;
- unsigned int min_nr_accesses;
- unsigned int max_nr_accesses;
- unsigned int min_age_region;
- unsigned int max_age_region;
- };
- /**
- * struct damos - Represents a Data Access Monitoring-based Operation Scheme.
- * @pattern: Access pattern of target regions.
- * @action: &damo_action to be applied to the target regions.
- * @quota: Control the aggressiveness of this scheme.
- * @wmarks: Watermarks for automated (in)activation of this scheme.
- * @stat: Statistics of this scheme.
- * @list: List head for siblings.
- *
- * For each aggregation interval, DAMON finds regions which fit in the
- * &pattern and applies &action to those. To avoid consuming too much
- * CPU time or IO resources for the &action, "a is used.
- *
- * To do the work only when needed, schemes can be activated for specific
- * system situations using &wmarks. If all schemes that registered to the
- * monitoring context are inactive, DAMON stops monitoring either, and just
- * repeatedly checks the watermarks.
- *
- * If all schemes that registered to a &struct damon_ctx are inactive, DAMON
- * stops monitoring and just repeatedly checks the watermarks.
- *
- * After applying the &action to each region, &stat_count and &stat_sz is
- * updated to reflect the number of regions and total size of regions that the
- * &action is applied.
- */
- struct damos {
- struct damos_access_pattern pattern;
- enum damos_action action;
- struct damos_quota quota;
- struct damos_watermarks wmarks;
- struct damos_stat stat;
- struct list_head list;
- };
- /**
- * enum damon_ops_id - Identifier for each monitoring operations implementation
- *
- * @DAMON_OPS_VADDR: Monitoring operations for virtual address spaces
- * @DAMON_OPS_FVADDR: Monitoring operations for only fixed ranges of virtual
- * address spaces
- * @DAMON_OPS_PADDR: Monitoring operations for the physical address space
- * @NR_DAMON_OPS: Number of monitoring operations implementations
- */
- enum damon_ops_id {
- DAMON_OPS_VADDR,
- DAMON_OPS_FVADDR,
- DAMON_OPS_PADDR,
- NR_DAMON_OPS,
- };
- struct damon_ctx;
- /**
- * struct damon_operations - Monitoring operations for given use cases.
- *
- * @id: Identifier of this operations set.
- * @init: Initialize operations-related data structures.
- * @update: Update operations-related 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.
- * @get_scheme_score: Get the score of a region for a scheme.
- * @apply_scheme: Apply a DAMON-based operation scheme.
- * @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 operations for their target address
- * space and usecase via the &damon_ctx.ops. Then, the monitoring thread
- * (&damon_ctx.kdamond) calls @init and @prepare_access_checks before starting
- * the monitoring, @update after each &damon_ctx.ops_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.
- *
- * Each &struct damon_operations instance having valid @id can be registered
- * via damon_register_ops() and selected by damon_select_ops() later.
- * @init should initialize operations-related 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 operations-related 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.
- * @get_scheme_score should return the priority score of a region for a scheme
- * as an integer in [0, &DAMOS_MAX_SCORE].
- * @apply_scheme is called from @kdamond when a region for user provided
- * DAMON-based operation scheme is found. It should apply the scheme's action
- * to the region and return bytes of the region that the action is successfully
- * applied.
- * @target_valid should check whether the target is still valid for the
- * monitoring.
- * @cleanup is called from @kdamond just before its termination.
- */
- struct damon_operations {
- enum damon_ops_id id;
- 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);
- int (*get_scheme_score)(struct damon_ctx *context,
- struct damon_target *t, struct damon_region *r,
- struct damos *scheme);
- unsigned long (*apply_scheme)(struct damon_ctx *context,
- struct damon_target *t, struct damon_region *r,
- struct damos *scheme);
- bool (*target_valid)(struct damon_target *t);
- void (*cleanup)(struct damon_ctx *context);
- };
- /**
- * struct damon_callback - Monitoring events notification callbacks.
- *
- * @before_start: Called before starting the monitoring.
- * @after_wmarks_check: Called after each schemes' watermarks check.
- * @after_sampling: Called after each sampling.
- * @after_aggregation: Called after each aggregation.
- * @before_damos_apply: Called before applying DAMOS action.
- * @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_wmarks_check after each DAMON-based
- * operation schemes' watermarks check. If users need to make changes to the
- * attributes of the monitoring context while it's deactivated due to the
- * watermarks, this is the good place to do.
- *
- * 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_wmarks_check)(struct damon_ctx *context);
- int (*after_sampling)(struct damon_ctx *context);
- int (*after_aggregation)(struct damon_ctx *context);
- int (*before_damos_apply)(struct damon_ctx *context,
- struct damon_target *target,
- struct damon_region *region,
- struct damos *scheme);
- void (*before_terminate)(struct damon_ctx *context);
- };
- /**
- * struct damon_attrs - Monitoring attributes for accuracy/overhead control.
- *
- * @sample_interval: The time between access samplings.
- * @aggr_interval: The time between monitor results aggregations.
- * @ops_update_interval: The time between monitoring operations updates.
- * @min_nr_regions: The minimum number of adaptive monitoring
- * regions.
- * @max_nr_regions: The maximum number of adaptive monitoring
- * regions.
- *
- * 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
- * @ops_update_interval. All time intervals are in micro-seconds.
- * Please refer to &struct damon_operations and &struct damon_callback for more
- * detail.
- */
- struct damon_attrs {
- unsigned long sample_interval;
- unsigned long aggr_interval;
- unsigned long ops_update_interval;
- unsigned long min_nr_regions;
- unsigned long max_nr_regions;
- };
- /**
- * 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.
- *
- * @attrs: Monitoring attributes for accuracy/overhead control.
- * @kdamond: Kernel thread who does the monitoring.
- * @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_operations.target_valid of @ops. The
- * termination can also be explicitly requested by calling damon_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 from outside of the monitoring thread must
- * be protected by @kdamond_lock.
- *
- * Note that the monitoring thread protects only @kdamond via @kdamond_lock.
- * Accesses to other fields must be protected by themselves.
- *
- * @ops: Set of monitoring operations for given use cases.
- * @callback: Set of callbacks for monitoring events notifications.
- *
- * @adaptive_targets: Head of monitoring targets (&damon_target) list.
- * @schemes: Head of schemes (&damos) list.
- */
- struct damon_ctx {
- struct damon_attrs attrs;
- /* private: internal use only */
- struct timespec64 last_aggregation;
- struct timespec64 last_ops_update;
- /* public: */
- struct task_struct *kdamond;
- struct mutex kdamond_lock;
- struct damon_operations ops;
- struct damon_callback callback;
- struct list_head adaptive_targets;
- struct list_head schemes;
- };
- static inline struct damon_region *damon_next_region(struct damon_region *r)
- {
- return container_of(r->list.next, struct damon_region, list);
- }
- static inline struct damon_region *damon_prev_region(struct damon_region *r)
- {
- return container_of(r->list.prev, struct damon_region, list);
- }
- static inline struct damon_region *damon_last_region(struct damon_target *t)
- {
- return list_last_entry(&t->regions_list, struct damon_region, list);
- }
- static inline struct damon_region *damon_first_region(struct damon_target *t)
- {
- return list_first_entry(&t->regions_list, struct damon_region, list);
- }
- static inline unsigned long damon_sz_region(struct damon_region *r)
- {
- return r->ar.end - r->ar.start;
- }
- #define damon_for_each_region(r, t) \
- list_for_each_entry(r, &t->regions_list, list)
- #define damon_for_each_region_from(r, t) \
- list_for_each_entry_from(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)
- #define damon_for_each_scheme(s, ctx) \
- list_for_each_entry(s, &(ctx)->schemes, list)
- #define damon_for_each_scheme_safe(s, next, ctx) \
- list_for_each_entry_safe(s, next, &(ctx)->schemes, list)
- #ifdef CONFIG_DAMON
- struct damon_region *damon_new_region(unsigned long start, unsigned long end);
- /*
- * Add a region between two other regions
- */
- static inline void damon_insert_region(struct damon_region *r,
- struct damon_region *prev, struct damon_region *next,
- struct damon_target *t)
- {
- __list_add(&r->list, &prev->list, &next->list);
- t->nr_regions++;
- }
- void damon_add_region(struct damon_region *r, struct damon_target *t);
- void damon_destroy_region(struct damon_region *r, struct damon_target *t);
- int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
- unsigned int nr_ranges);
- struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
- enum damos_action action, struct damos_quota *quota,
- struct damos_watermarks *wmarks);
- void damon_add_scheme(struct damon_ctx *ctx, struct damos *s);
- void damon_destroy_scheme(struct damos *s);
- struct damon_target *damon_new_target(void);
- void damon_add_target(struct damon_ctx *ctx, struct damon_target *t);
- bool damon_targets_empty(struct damon_ctx *ctx);
- 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_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs);
- void damon_set_schemes(struct damon_ctx *ctx,
- struct damos **schemes, ssize_t nr_schemes);
- int damon_nr_running_ctxs(void);
- bool damon_is_registered_ops(enum damon_ops_id id);
- int damon_register_ops(struct damon_operations *ops);
- int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id);
- static inline bool damon_target_has_pid(const struct damon_ctx *ctx)
- {
- return ctx->ops.id == DAMON_OPS_VADDR || ctx->ops.id == DAMON_OPS_FVADDR;
- }
- static inline unsigned int damon_max_nr_accesses(const struct damon_attrs *attrs)
- {
- /* {aggr,sample}_interval are unsigned long, hence could overflow */
- return min(attrs->aggr_interval / attrs->sample_interval,
- (unsigned long)UINT_MAX);
- }
- int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive);
- int damon_stop(struct damon_ctx **ctxs, int nr_ctxs);
- int damon_set_region_biggest_system_ram_default(struct damon_target *t,
- unsigned long *start, unsigned long *end);
- #endif /* CONFIG_DAMON */
- #endif /* _DAMON_H */
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