1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * DAMON api
4 *
5 * Author: SeongJae Park <sj@kernel.org>
6 */
7
8 #ifndef _DAMON_H_
9 #define _DAMON_H_
10
11 #include <linux/memcontrol.h>
12 #include <linux/mutex.h>
13 #include <linux/time64.h>
14 #include <linux/types.h>
15 #include <linux/random.h>
16
17 /* Minimal region size. Every damon_region is aligned by this. */
18 #define DAMON_MIN_REGION PAGE_SIZE
19 /* Max priority score for DAMON-based operation schemes */
20 #define DAMOS_MAX_SCORE (99)
21
22 /* Get a random number in [l, r) */
23 static inline unsigned long damon_rand(unsigned long l, unsigned long r)
24 {
25 return l + get_random_u32_below(r - l);
26 }
27
28 /**
29 * struct damon_addr_range - Represents an address region of [@start, @end).
30 * @start: Start address of the region (inclusive).
31 * @end: End address of the region (exclusive).
32 */
33 struct damon_addr_range {
34 unsigned long start;
35 unsigned long end;
36 };
37
38 /**
39 * struct damon_region - Represents a monitoring target region.
40 * @ar: The address range of the region.
41 * @sampling_addr: Address of the sample for the next access check.
42 * @nr_accesses: Access frequency of this region.
43 * @nr_accesses_bp: @nr_accesses in basis point (0.01%) that updated for
44 * each sampling interval.
45 * @list: List head for siblings.
46 * @age: Age of this region.
47 *
48 * @nr_accesses is reset to zero for every &damon_attrs->aggr_interval and be
49 * increased for every &damon_attrs->sample_interval if an access to the region
50 * during the last sampling interval is found. The update of this field should
51 * not be done with direct access but with the helper function,
52 * damon_update_region_access_rate().
53 *
54 * @nr_accesses_bp is another representation of @nr_accesses in basis point
55 * (1 in 10,000) that updated for every &damon_attrs->sample_interval in a
56 * manner similar to moving sum. By the algorithm, this value becomes
57 * @nr_accesses * 10000 for every &struct damon_attrs->aggr_interval. This can
58 * be used when the aggregation interval is too huge and therefore cannot wait
59 * for it before getting the access monitoring results.
60 *
61 * @age is initially zero, increased for each aggregation interval, and reset
62 * to zero again if the access frequency is significantly changed. If two
63 * regions are merged into a new region, both @nr_accesses and @age of the new
64 * region are set as region size-weighted average of those of the two regions.
65 */
66 struct damon_region {
67 struct damon_addr_range ar;
68 unsigned long sampling_addr;
69 unsigned int nr_accesses;
70 unsigned int nr_accesses_bp;
71 struct list_head list;
72
73 unsigned int age;
74 /* private: Internal value for age calculation. */
75 unsigned int last_nr_accesses;
76 };
77
78 /**
79 * struct damon_target - Represents a monitoring target.
80 * @pid: The PID of the virtual address space to monitor.
81 * @nr_regions: Number of monitoring target regions of this target.
82 * @regions_list: Head of the monitoring target regions of this target.
83 * @list: List head for siblings.
84 *
85 * Each monitoring context could have multiple targets. For example, a context
86 * for virtual memory address spaces could have multiple target processes. The
87 * @pid should be set for appropriate &struct damon_operations including the
88 * virtual address spaces monitoring operations.
89 */
90 struct damon_target {
91 struct pid *pid;
92 unsigned int nr_regions;
93 struct list_head regions_list;
94 struct list_head list;
95 };
96
97 /**
98 * enum damos_action - Represents an action of a Data Access Monitoring-based
99 * Operation Scheme.
100 *
101 * @DAMOS_WILLNEED: Call ``madvise()`` for the region with MADV_WILLNEED.
102 * @DAMOS_COLD: Call ``madvise()`` for the region with MADV_COLD.
103 * @DAMOS_PAGEOUT: Call ``madvise()`` for the region with MADV_PAGEOUT.
104 * @DAMOS_HUGEPAGE: Call ``madvise()`` for the region with MADV_HUGEPAGE.
105 * @DAMOS_NOHUGEPAGE: Call ``madvise()`` for the region with MADV_NOHUGEPAGE.
106 * @DAMOS_LRU_PRIO: Prioritize the region on its LRU lists.
107 * @DAMOS_LRU_DEPRIO: Deprioritize the region on its LRU lists.
108 * @DAMOS_MIGRATE_HOT: Migrate the regions prioritizing warmer regions.
109 * @DAMOS_MIGRATE_COLD: Migrate the regions prioritizing colder regions.
110 * @DAMOS_STAT: Do nothing but count the stat.
111 * @NR_DAMOS_ACTIONS: Total number of DAMOS actions
112 *
113 * The support of each action is up to running &struct damon_operations.
114 * &enum DAMON_OPS_VADDR and &enum DAMON_OPS_FVADDR supports all actions except
115 * &enum DAMOS_LRU_PRIO and &enum DAMOS_LRU_DEPRIO. &enum DAMON_OPS_PADDR
116 * supports only &enum DAMOS_PAGEOUT, &enum DAMOS_LRU_PRIO, &enum
117 * DAMOS_LRU_DEPRIO, and &DAMOS_STAT.
118 */
119 enum damos_action {
120 DAMOS_WILLNEED,
121 DAMOS_COLD,
122 DAMOS_PAGEOUT,
123 DAMOS_HUGEPAGE,
124 DAMOS_NOHUGEPAGE,
125 DAMOS_LRU_PRIO,
126 DAMOS_LRU_DEPRIO,
127 DAMOS_MIGRATE_HOT,
128 DAMOS_MIGRATE_COLD,
129 DAMOS_STAT, /* Do nothing but only record the stat */
130 NR_DAMOS_ACTIONS,
131 };
132
133 /**
134 * enum damos_quota_goal_metric - Represents the metric to be used as the goal
135 *
136 * @DAMOS_QUOTA_USER_INPUT: User-input value.
137 * @DAMOS_QUOTA_SOME_MEM_PSI_US: System level some memory PSI in us.
138 * @NR_DAMOS_QUOTA_GOAL_METRICS: Number of DAMOS quota goal metrics.
139 *
140 * Metrics equal to larger than @NR_DAMOS_QUOTA_GOAL_METRICS are unsupported.
141 */
142 enum damos_quota_goal_metric {
143 DAMOS_QUOTA_USER_INPUT,
144 DAMOS_QUOTA_SOME_MEM_PSI_US,
145 NR_DAMOS_QUOTA_GOAL_METRICS,
146 };
147
148 /**
149 * struct damos_quota_goal - DAMOS scheme quota auto-tuning goal.
150 * @metric: Metric to be used for representing the goal.
151 * @target_value: Target value of @metric to achieve with the tuning.
152 * @current_value: Current value of @metric.
153 * @last_psi_total: Last measured total PSI
154 * @list: List head for siblings.
155 *
156 * Data structure for getting the current score of the quota tuning goal. The
157 * score is calculated by how close @current_value and @target_value are. Then
158 * the score is entered to DAMON's internal feedback loop mechanism to get the
159 * auto-tuned quota.
160 *
161 * If @metric is DAMOS_QUOTA_USER_INPUT, @current_value should be manually
162 * entered by the user, probably inside the kdamond callbacks. Otherwise,
163 * DAMON sets @current_value with self-measured value of @metric.
164 */
165 struct damos_quota_goal {
166 enum damos_quota_goal_metric metric;
167 unsigned long target_value;
168 unsigned long current_value;
169 /* metric-dependent fields */
170 union {
171 u64 last_psi_total;
172 };
173 struct list_head list;
174 };
175
176 /**
177 * struct damos_quota - Controls the aggressiveness of the given scheme.
178 * @reset_interval: Charge reset interval in milliseconds.
179 * @ms: Maximum milliseconds that the scheme can use.
180 * @sz: Maximum bytes of memory that the action can be applied.
181 * @goals: Head of quota tuning goals (&damos_quota_goal) list.
182 * @esz: Effective size quota in bytes.
183 *
184 * @weight_sz: Weight of the region's size for prioritization.
185 * @weight_nr_accesses: Weight of the region's nr_accesses for prioritization.
186 * @weight_age: Weight of the region's age for prioritization.
187 *
188 * To avoid consuming too much CPU time or IO resources for applying the
189 * &struct damos->action to large memory, DAMON allows users to set time and/or
190 * size quotas. The quotas can be set by writing non-zero values to &ms and
191 * &sz, respectively. If the time quota is set, DAMON tries to use only up to
192 * &ms milliseconds within &reset_interval for applying the action. If the
193 * size quota is set, DAMON tries to apply the action only up to &sz bytes
194 * within &reset_interval.
195 *
196 * Internally, the time quota is transformed to a size quota using estimated
197 * throughput of the scheme's action. DAMON then compares it against &sz and
198 * uses smaller one as the effective quota.
199 *
200 * If @goals is not empt, DAMON calculates yet another size quota based on the
201 * goals using its internal feedback loop algorithm, for every @reset_interval.
202 * Then, if the new size quota is smaller than the effective quota, it uses the
203 * new size quota as the effective quota.
204 *
205 * The resulting effective size quota in bytes is set to @esz.
206 *
207 * For selecting regions within the quota, DAMON prioritizes current scheme's
208 * target memory regions using the &struct damon_operations->get_scheme_score.
209 * You could customize the prioritization logic by setting &weight_sz,
210 * &weight_nr_accesses, and &weight_age, because monitoring operations are
211 * encouraged to respect those.
212 */
213 struct damos_quota {
214 unsigned long reset_interval;
215 unsigned long ms;
216 unsigned long sz;
217 struct list_head goals;
218 unsigned long esz;
219
220 unsigned int weight_sz;
221 unsigned int weight_nr_accesses;
222 unsigned int weight_age;
223
224 /* private: */
225 /* For throughput estimation */
226 unsigned long total_charged_sz;
227 unsigned long total_charged_ns;
228
229 /* For charging the quota */
230 unsigned long charged_sz;
231 unsigned long charged_from;
232 struct damon_target *charge_target_from;
233 unsigned long charge_addr_from;
234
235 /* For prioritization */
236 unsigned long histogram[DAMOS_MAX_SCORE + 1];
237 unsigned int min_score;
238
239 /* For feedback loop */
240 unsigned long esz_bp;
241 };
242
243 /**
244 * enum damos_wmark_metric - Represents the watermark metric.
245 *
246 * @DAMOS_WMARK_NONE: Ignore the watermarks of the given scheme.
247 * @DAMOS_WMARK_FREE_MEM_RATE: Free memory rate of the system in [0,1000].
248 * @NR_DAMOS_WMARK_METRICS: Total number of DAMOS watermark metrics
249 */
250 enum damos_wmark_metric {
251 DAMOS_WMARK_NONE,
252 DAMOS_WMARK_FREE_MEM_RATE,
253 NR_DAMOS_WMARK_METRICS,
254 };
255
256 /**
257 * struct damos_watermarks - Controls when a given scheme should be activated.
258 * @metric: Metric for the watermarks.
259 * @interval: Watermarks check time interval in microseconds.
260 * @high: High watermark.
261 * @mid: Middle watermark.
262 * @low: Low watermark.
263 *
264 * If &metric is &DAMOS_WMARK_NONE, the scheme is always active. Being active
265 * means DAMON does monitoring and applying the action of the scheme to
266 * appropriate memory regions. Else, DAMON checks &metric of the system for at
267 * least every &interval microseconds and works as below.
268 *
269 * If &metric is higher than &high, the scheme is inactivated. If &metric is
270 * between &mid and &low, the scheme is activated. If &metric is lower than
271 * &low, the scheme is inactivated.
272 */
273 struct damos_watermarks {
274 enum damos_wmark_metric metric;
275 unsigned long interval;
276 unsigned long high;
277 unsigned long mid;
278 unsigned long low;
279
280 /* private: */
281 bool activated;
282 };
283
284 /**
285 * struct damos_stat - Statistics on a given scheme.
286 * @nr_tried: Total number of regions that the scheme is tried to be applied.
287 * @sz_tried: Total size of regions that the scheme is tried to be applied.
288 * @nr_applied: Total number of regions that the scheme is applied.
289 * @sz_applied: Total size of regions that the scheme is applied.
290 * @qt_exceeds: Total number of times the quota of the scheme has exceeded.
291 */
292 struct damos_stat {
293 unsigned long nr_tried;
294 unsigned long sz_tried;
295 unsigned long nr_applied;
296 unsigned long sz_applied;
297 unsigned long qt_exceeds;
298 };
299
300 /**
301 * enum damos_filter_type - Type of memory for &struct damos_filter
302 * @DAMOS_FILTER_TYPE_ANON: Anonymous pages.
303 * @DAMOS_FILTER_TYPE_MEMCG: Specific memcg's pages.
304 * @DAMOS_FILTER_TYPE_YOUNG: Recently accessed pages.
305 * @DAMOS_FILTER_TYPE_ADDR: Address range.
306 * @DAMOS_FILTER_TYPE_TARGET: Data Access Monitoring target.
307 * @NR_DAMOS_FILTER_TYPES: Number of filter types.
308 *
309 * The anon pages type and memcg type filters are handled by underlying
310 * &struct damon_operations as a part of scheme action trying, and therefore
311 * accounted as 'tried'. In contrast, other types are handled by core layer
312 * before trying of the action and therefore not accounted as 'tried'.
313 *
314 * The support of the filters that handled by &struct damon_operations depend
315 * on the running &struct damon_operations.
316 * &enum DAMON_OPS_PADDR supports both anon pages type and memcg type filters,
317 * while &enum DAMON_OPS_VADDR and &enum DAMON_OPS_FVADDR don't support any of
318 * the two types.
319 */
320 enum damos_filter_type {
321 DAMOS_FILTER_TYPE_ANON,
322 DAMOS_FILTER_TYPE_MEMCG,
323 DAMOS_FILTER_TYPE_YOUNG,
324 DAMOS_FILTER_TYPE_ADDR,
325 DAMOS_FILTER_TYPE_TARGET,
326 NR_DAMOS_FILTER_TYPES,
327 };
328
329 /**
330 * struct damos_filter - DAMOS action target memory filter.
331 * @type: Type of the page.
332 * @matching: If the matching page should filtered out or in.
333 * @memcg_id: Memcg id of the question if @type is DAMOS_FILTER_MEMCG.
334 * @addr_range: Address range if @type is DAMOS_FILTER_TYPE_ADDR.
335 * @target_idx: Index of the &struct damon_target of
336 * &damon_ctx->adaptive_targets if @type is
337 * DAMOS_FILTER_TYPE_TARGET.
338 * @list: List head for siblings.
339 *
340 * Before applying the &damos->action to a memory region, DAMOS checks if each
341 * page of the region matches to this and avoid applying the action if so.
342 * Support of each filter type depends on the running &struct damon_operations
343 * and the type. Refer to &enum damos_filter_type for more detai.
344 */
345 struct damos_filter {
346 enum damos_filter_type type;
347 bool matching;
348 union {
349 unsigned short memcg_id;
350 struct damon_addr_range addr_range;
351 int target_idx;
352 };
353 struct list_head list;
354 };
355
356 /**
357 * struct damos_access_pattern - Target access pattern of the given scheme.
358 * @min_sz_region: Minimum size of target regions.
359 * @max_sz_region: Maximum size of target regions.
360 * @min_nr_accesses: Minimum ``->nr_accesses`` of target regions.
361 * @max_nr_accesses: Maximum ``->nr_accesses`` of target regions.
362 * @min_age_region: Minimum age of target regions.
363 * @max_age_region: Maximum age of target regions.
364 */
365 struct damos_access_pattern {
366 unsigned long min_sz_region;
367 unsigned long max_sz_region;
368 unsigned int min_nr_accesses;
369 unsigned int max_nr_accesses;
370 unsigned int min_age_region;
371 unsigned int max_age_region;
372 };
373
374 /**
375 * struct damos - Represents a Data Access Monitoring-based Operation Scheme.
376 * @pattern: Access pattern of target regions.
377 * @action: &damo_action to be applied to the target regions.
378 * @apply_interval_us: The time between applying the @action.
379 * @quota: Control the aggressiveness of this scheme.
380 * @wmarks: Watermarks for automated (in)activation of this scheme.
381 * @target_nid: Destination node if @action is "migrate_{hot,cold}".
382 * @filters: Additional set of &struct damos_filter for &action.
383 * @stat: Statistics of this scheme.
384 * @list: List head for siblings.
385 *
386 * For each @apply_interval_us, DAMON finds regions which fit in the
387 * &pattern and applies &action to those. To avoid consuming too much
388 * CPU time or IO resources for the &action, "a is used.
389 *
390 * If @apply_interval_us is zero, &damon_attrs->aggr_interval is used instead.
391 *
392 * To do the work only when needed, schemes can be activated for specific
393 * system situations using &wmarks. If all schemes that registered to the
394 * monitoring context are inactive, DAMON stops monitoring either, and just
395 * repeatedly checks the watermarks.
396 *
397 * @target_nid is used to set the migration target node for migrate_hot or
398 * migrate_cold actions, which means it's only meaningful when @action is either
399 * "migrate_hot" or "migrate_cold".
400 *
401 * Before applying the &action to a memory region, &struct damon_operations
402 * implementation could check pages of the region and skip &action to respect
403 * &filters
404 *
405 * After applying the &action to each region, &stat_count and &stat_sz is
406 * updated to reflect the number of regions and total size of regions that the
407 * &action is applied.
408 */
409 struct damos {
410 struct damos_access_pattern pattern;
411 enum damos_action action;
412 unsigned long apply_interval_us;
413 /* private: internal use only */
414 /*
415 * number of sample intervals that should be passed before applying
416 * @action
417 */
418 unsigned long next_apply_sis;
419 /* public: */
420 struct damos_quota quota;
421 struct damos_watermarks wmarks;
422 union {
423 int target_nid;
424 };
425 struct list_head filters;
426 struct damos_stat stat;
427 struct list_head list;
428 };
429
430 /**
431 * enum damon_ops_id - Identifier for each monitoring operations implementation
432 *
433 * @DAMON_OPS_VADDR: Monitoring operations for virtual address spaces
434 * @DAMON_OPS_FVADDR: Monitoring operations for only fixed ranges of virtual
435 * address spaces
436 * @DAMON_OPS_PADDR: Monitoring operations for the physical address space
437 * @NR_DAMON_OPS: Number of monitoring operations implementations
438 */
439 enum damon_ops_id {
440 DAMON_OPS_VADDR,
441 DAMON_OPS_FVADDR,
442 DAMON_OPS_PADDR,
443 NR_DAMON_OPS,
444 };
445
446 struct damon_ctx;
447
448 /**
449 * struct damon_operations - Monitoring operations for given use cases.
450 *
451 * @id: Identifier of this operations set.
452 * @init: Initialize operations-related data structures.
453 * @update: Update operations-related data structures.
454 * @prepare_access_checks: Prepare next access check of target regions.
455 * @check_accesses: Check the accesses to target regions.
456 * @reset_aggregated: Reset aggregated accesses monitoring results.
457 * @get_scheme_score: Get the score of a region for a scheme.
458 * @apply_scheme: Apply a DAMON-based operation scheme.
459 * @target_valid: Determine if the target is valid.
460 * @cleanup: Clean up the context.
461 *
462 * DAMON can be extended for various address spaces and usages. For this,
463 * users should register the low level operations for their target address
464 * space and usecase via the &damon_ctx.ops. Then, the monitoring thread
465 * (&damon_ctx.kdamond) calls @init and @prepare_access_checks before starting
466 * the monitoring, @update after each &damon_attrs.ops_update_interval, and
467 * @check_accesses, @target_valid and @prepare_access_checks after each
468 * &damon_attrs.sample_interval. Finally, @reset_aggregated is called after
469 * each &damon_attrs.aggr_interval.
470 *
471 * Each &struct damon_operations instance having valid @id can be registered
472 * via damon_register_ops() and selected by damon_select_ops() later.
473 * @init should initialize operations-related data structures. For example,
474 * this could be used to construct proper monitoring target regions and link
475 * those to @damon_ctx.adaptive_targets.
476 * @update should update the operations-related data structures. For example,
477 * this could be used to update monitoring target regions for current status.
478 * @prepare_access_checks should manipulate the monitoring regions to be
479 * prepared for the next access check.
480 * @check_accesses should check the accesses to each region that made after the
481 * last preparation and update the number of observed accesses of each region.
482 * It should also return max number of observed accesses that made as a result
483 * of its update. The value will be used for regions adjustment threshold.
484 * @reset_aggregated should reset the access monitoring results that aggregated
485 * by @check_accesses.
486 * @get_scheme_score should return the priority score of a region for a scheme
487 * as an integer in [0, &DAMOS_MAX_SCORE].
488 * @apply_scheme is called from @kdamond when a region for user provided
489 * DAMON-based operation scheme is found. It should apply the scheme's action
490 * to the region and return bytes of the region that the action is successfully
491 * applied.
492 * @target_valid should check whether the target is still valid for the
493 * monitoring.
494 * @cleanup is called from @kdamond just before its termination.
495 */
496 struct damon_operations {
497 enum damon_ops_id id;
498 void (*init)(struct damon_ctx *context);
499 void (*update)(struct damon_ctx *context);
500 void (*prepare_access_checks)(struct damon_ctx *context);
501 unsigned int (*check_accesses)(struct damon_ctx *context);
502 void (*reset_aggregated)(struct damon_ctx *context);
503 int (*get_scheme_score)(struct damon_ctx *context,
504 struct damon_target *t, struct damon_region *r,
505 struct damos *scheme);
506 unsigned long (*apply_scheme)(struct damon_ctx *context,
507 struct damon_target *t, struct damon_region *r,
508 struct damos *scheme);
509 bool (*target_valid)(struct damon_target *t);
510 void (*cleanup)(struct damon_ctx *context);
511 };
512
513 /**
514 * struct damon_callback - Monitoring events notification callbacks.
515 *
516 * @before_start: Called before starting the monitoring.
517 * @after_wmarks_check: Called after each schemes' watermarks check.
518 * @after_sampling: Called after each sampling.
519 * @after_aggregation: Called after each aggregation.
520 * @before_damos_apply: Called before applying DAMOS action.
521 * @before_terminate: Called before terminating the monitoring.
522 * @private: User private data.
523 *
524 * The monitoring thread (&damon_ctx.kdamond) calls @before_start and
525 * @before_terminate just before starting and finishing the monitoring,
526 * respectively. Therefore, those are good places for installing and cleaning
527 * @private.
528 *
529 * The monitoring thread calls @after_wmarks_check after each DAMON-based
530 * operation schemes' watermarks check. If users need to make changes to the
531 * attributes of the monitoring context while it's deactivated due to the
532 * watermarks, this is the good place to do.
533 *
534 * The monitoring thread calls @after_sampling and @after_aggregation for each
535 * of the sampling intervals and aggregation intervals, respectively.
536 * Therefore, users can safely access the monitoring results without additional
537 * protection. For the reason, users are recommended to use these callback for
538 * the accesses to the results.
539 *
540 * If any callback returns non-zero, monitoring stops.
541 */
542 struct damon_callback {
543 void *private;
544
545 int (*before_start)(struct damon_ctx *context);
546 int (*after_wmarks_check)(struct damon_ctx *context);
547 int (*after_sampling)(struct damon_ctx *context);
548 int (*after_aggregation)(struct damon_ctx *context);
549 int (*before_damos_apply)(struct damon_ctx *context,
550 struct damon_target *target,
551 struct damon_region *region,
552 struct damos *scheme);
553 void (*before_terminate)(struct damon_ctx *context);
554 };
555
556 /**
557 * struct damon_attrs - Monitoring attributes for accuracy/overhead control.
558 *
559 * @sample_interval: The time between access samplings.
560 * @aggr_interval: The time between monitor results aggregations.
561 * @ops_update_interval: The time between monitoring operations updates.
562 * @min_nr_regions: The minimum number of adaptive monitoring
563 * regions.
564 * @max_nr_regions: The maximum number of adaptive monitoring
565 * regions.
566 *
567 * For each @sample_interval, DAMON checks whether each region is accessed or
568 * not during the last @sample_interval. If such access is found, DAMON
569 * aggregates the information by increasing &damon_region->nr_accesses for
570 * @aggr_interval time. For each @aggr_interval, the count is reset. DAMON
571 * also checks whether the target memory regions need update (e.g., by
572 * ``mmap()`` calls from the application, in case of virtual memory monitoring)
573 * and applies the changes for each @ops_update_interval. All time intervals
574 * are in micro-seconds. Please refer to &struct damon_operations and &struct
575 * damon_callback for more detail.
576 */
577 struct damon_attrs {
578 unsigned long sample_interval;
579 unsigned long aggr_interval;
580 unsigned long ops_update_interval;
581 unsigned long min_nr_regions;
582 unsigned long max_nr_regions;
583 };
584
585 /**
586 * struct damon_ctx - Represents a context for each monitoring. This is the
587 * main interface that allows users to set the attributes and get the results
588 * of the monitoring.
589 *
590 * @attrs: Monitoring attributes for accuracy/overhead control.
591 * @kdamond: Kernel thread who does the monitoring.
592 * @kdamond_lock: Mutex for the synchronizations with @kdamond.
593 *
594 * For each monitoring context, one kernel thread for the monitoring is
595 * created. The pointer to the thread is stored in @kdamond.
596 *
597 * Once started, the monitoring thread runs until explicitly required to be
598 * terminated or every monitoring target is invalid. The validity of the
599 * targets is checked via the &damon_operations.target_valid of @ops. The
600 * termination can also be explicitly requested by calling damon_stop().
601 * The thread sets @kdamond to NULL when it terminates. Therefore, users can
602 * know whether the monitoring is ongoing or terminated by reading @kdamond.
603 * Reads and writes to @kdamond from outside of the monitoring thread must
604 * be protected by @kdamond_lock.
605 *
606 * Note that the monitoring thread protects only @kdamond via @kdamond_lock.
607 * Accesses to other fields must be protected by themselves.
608 *
609 * @ops: Set of monitoring operations for given use cases.
610 * @callback: Set of callbacks for monitoring events notifications.
611 *
612 * @adaptive_targets: Head of monitoring targets (&damon_target) list.
613 * @schemes: Head of schemes (&damos) list.
614 */
615 struct damon_ctx {
616 struct damon_attrs attrs;
617
618 /* private: internal use only */
619 /* number of sample intervals that passed since this context started */
620 unsigned long passed_sample_intervals;
621 /*
622 * number of sample intervals that should be passed before next
623 * aggregation
624 */
625 unsigned long next_aggregation_sis;
626 /*
627 * number of sample intervals that should be passed before next ops
628 * update
629 */
630 unsigned long next_ops_update_sis;
631 /* for waiting until the execution of the kdamond_fn is started */
632 struct completion kdamond_started;
633
634 /* public: */
635 struct task_struct *kdamond;
636 struct mutex kdamond_lock;
637
638 struct damon_operations ops;
639 struct damon_callback callback;
640
641 struct list_head adaptive_targets;
642 struct list_head schemes;
643 };
644
645 static inline struct damon_region *damon_next_region(struct damon_region *r)
646 {
647 return container_of(r->list.next, struct damon_region, list);
648 }
649
650 static inline struct damon_region *damon_prev_region(struct damon_region *r)
651 {
652 return container_of(r->list.prev, struct damon_region, list);
653 }
654
655 static inline struct damon_region *damon_last_region(struct damon_target *t)
656 {
657 return list_last_entry(&t->regions_list, struct damon_region, list);
658 }
659
660 static inline struct damon_region *damon_first_region(struct damon_target *t)
661 {
662 return list_first_entry(&t->regions_list, struct damon_region, list);
663 }
664
665 static inline unsigned long damon_sz_region(struct damon_region *r)
666 {
667 return r->ar.end - r->ar.start;
668 }
669
670
671 #define damon_for_each_region(r, t) \
672 list_for_each_entry(r, &t->regions_list, list)
673
674 #define damon_for_each_region_from(r, t) \
675 list_for_each_entry_from(r, &t->regions_list, list)
676
677 #define damon_for_each_region_safe(r, next, t) \
678 list_for_each_entry_safe(r, next, &t->regions_list, list)
679
680 #define damon_for_each_target(t, ctx) \
681 list_for_each_entry(t, &(ctx)->adaptive_targets, list)
682
683 #define damon_for_each_target_safe(t, next, ctx) \
684 list_for_each_entry_safe(t, next, &(ctx)->adaptive_targets, list)
685
686 #define damon_for_each_scheme(s, ctx) \
687 list_for_each_entry(s, &(ctx)->schemes, list)
688
689 #define damon_for_each_scheme_safe(s, next, ctx) \
690 list_for_each_entry_safe(s, next, &(ctx)->schemes, list)
691
692 #define damos_for_each_quota_goal(goal, quota) \
693 list_for_each_entry(goal, "a->goals, list)
694
695 #define damos_for_each_quota_goal_safe(goal, next, quota) \
696 list_for_each_entry_safe(goal, next, &(quota)->goals, list)
697
698 #define damos_for_each_filter(f, scheme) \
699 list_for_each_entry(f, &(scheme)->filters, list)
700
701 #define damos_for_each_filter_safe(f, next, scheme) \
702 list_for_each_entry_safe(f, next, &(scheme)->filters, list)
703
704 #ifdef CONFIG_DAMON
705
706 struct damon_region *damon_new_region(unsigned long start, unsigned long end);
707
708 /*
709 * Add a region between two other regions
710 */
711 static inline void damon_insert_region(struct damon_region *r,
712 struct damon_region *prev, struct damon_region *next,
713 struct damon_target *t)
714 {
715 __list_add(&r->list, &prev->list, &next->list);
716 t->nr_regions++;
717 }
718
719 void damon_add_region(struct damon_region *r, struct damon_target *t);
720 void damon_destroy_region(struct damon_region *r, struct damon_target *t);
721 int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
722 unsigned int nr_ranges);
723 void damon_update_region_access_rate(struct damon_region *r, bool accessed,
724 struct damon_attrs *attrs);
725
726 struct damos_filter *damos_new_filter(enum damos_filter_type type,
727 bool matching);
728 void damos_add_filter(struct damos *s, struct damos_filter *f);
729 void damos_destroy_filter(struct damos_filter *f);
730
731 struct damos_quota_goal *damos_new_quota_goal(
732 enum damos_quota_goal_metric metric,
733 unsigned long target_value);
734 void damos_add_quota_goal(struct damos_quota *q, struct damos_quota_goal *g);
735 void damos_destroy_quota_goal(struct damos_quota_goal *goal);
736
737 struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
738 enum damos_action action,
739 unsigned long apply_interval_us,
740 struct damos_quota *quota,
741 struct damos_watermarks *wmarks,
742 int target_nid);
743 void damon_add_scheme(struct damon_ctx *ctx, struct damos *s);
744 void damon_destroy_scheme(struct damos *s);
745 int damos_commit_quota_goals(struct damos_quota *dst, struct damos_quota *src);
746
747 struct damon_target *damon_new_target(void);
748 void damon_add_target(struct damon_ctx *ctx, struct damon_target *t);
749 bool damon_targets_empty(struct damon_ctx *ctx);
750 void damon_free_target(struct damon_target *t);
751 void damon_destroy_target(struct damon_target *t);
752 unsigned int damon_nr_regions(struct damon_target *t);
753
754 struct damon_ctx *damon_new_ctx(void);
755 void damon_destroy_ctx(struct damon_ctx *ctx);
756 int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs);
757 void damon_set_schemes(struct damon_ctx *ctx,
758 struct damos **schemes, ssize_t nr_schemes);
759 int damon_commit_ctx(struct damon_ctx *old_ctx, struct damon_ctx *new_ctx);
760 int damon_nr_running_ctxs(void);
761 bool damon_is_registered_ops(enum damon_ops_id id);
762 int damon_register_ops(struct damon_operations *ops);
763 int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id);
764
765 static inline bool damon_target_has_pid(const struct damon_ctx *ctx)
766 {
767 return ctx->ops.id == DAMON_OPS_VADDR || ctx->ops.id == DAMON_OPS_FVADDR;
768 }
769
770 static inline unsigned int damon_max_nr_accesses(const struct damon_attrs *attrs)
771 {
772 /* {aggr,sample}_interval are unsigned long, hence could overflow */
773 return min(attrs->aggr_interval / attrs->sample_interval,
774 (unsigned long)UINT_MAX);
775 }
776
777
778 int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive);
779 int damon_stop(struct damon_ctx **ctxs, int nr_ctxs);
780
781 int damon_set_region_biggest_system_ram_default(struct damon_target *t,
782 unsigned long *start, unsigned long *end);
783
784 #endif /* CONFIG_DAMON */
785
786 #endif /* _DAMON_H */
787
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.