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![Colin Ian King](/assets/img/avatar_default.png)
There are a few spelling mistakes in the code. Fix these. Link: https://lkml.kernel.org/r/20211028184157.614544-1-colin.i.king@gmail.com Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Reviewed-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1088 lines
26 KiB
C
1088 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Data Access Monitor
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*
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* Author: SeongJae Park <sjpark@amazon.de>
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*/
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#define pr_fmt(fmt) "damon: " fmt
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#include <linux/damon.h>
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#include <linux/delay.h>
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#include <linux/kthread.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/damon.h>
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#ifdef CONFIG_DAMON_KUNIT_TEST
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#undef DAMON_MIN_REGION
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#define DAMON_MIN_REGION 1
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#endif
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/* Get a random number in [l, r) */
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#define damon_rand(l, r) (l + prandom_u32_max(r - l))
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static DEFINE_MUTEX(damon_lock);
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static int nr_running_ctxs;
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/*
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* Construct a damon_region struct
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*
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* Returns the pointer to the new struct if success, or NULL otherwise
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*/
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struct damon_region *damon_new_region(unsigned long start, unsigned long end)
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{
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struct damon_region *region;
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region = kmalloc(sizeof(*region), GFP_KERNEL);
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if (!region)
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return NULL;
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region->ar.start = start;
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region->ar.end = end;
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region->nr_accesses = 0;
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INIT_LIST_HEAD(®ion->list);
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region->age = 0;
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region->last_nr_accesses = 0;
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return region;
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}
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/*
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* Add a region between two other regions
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*/
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inline void damon_insert_region(struct damon_region *r,
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struct damon_region *prev, struct damon_region *next,
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struct damon_target *t)
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{
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__list_add(&r->list, &prev->list, &next->list);
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t->nr_regions++;
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}
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void damon_add_region(struct damon_region *r, struct damon_target *t)
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{
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list_add_tail(&r->list, &t->regions_list);
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t->nr_regions++;
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}
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static void damon_del_region(struct damon_region *r, struct damon_target *t)
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{
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list_del(&r->list);
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t->nr_regions--;
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}
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static void damon_free_region(struct damon_region *r)
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{
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kfree(r);
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}
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void damon_destroy_region(struct damon_region *r, struct damon_target *t)
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{
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damon_del_region(r, t);
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damon_free_region(r);
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}
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struct damos *damon_new_scheme(
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unsigned long min_sz_region, unsigned long max_sz_region,
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unsigned int min_nr_accesses, unsigned int max_nr_accesses,
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unsigned int min_age_region, unsigned int max_age_region,
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enum damos_action action, struct damos_quota *quota,
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struct damos_watermarks *wmarks)
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{
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struct damos *scheme;
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scheme = kmalloc(sizeof(*scheme), GFP_KERNEL);
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if (!scheme)
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return NULL;
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scheme->min_sz_region = min_sz_region;
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scheme->max_sz_region = max_sz_region;
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scheme->min_nr_accesses = min_nr_accesses;
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scheme->max_nr_accesses = max_nr_accesses;
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scheme->min_age_region = min_age_region;
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scheme->max_age_region = max_age_region;
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scheme->action = action;
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scheme->stat_count = 0;
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scheme->stat_sz = 0;
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INIT_LIST_HEAD(&scheme->list);
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scheme->quota.ms = quota->ms;
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scheme->quota.sz = quota->sz;
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scheme->quota.reset_interval = quota->reset_interval;
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scheme->quota.weight_sz = quota->weight_sz;
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scheme->quota.weight_nr_accesses = quota->weight_nr_accesses;
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scheme->quota.weight_age = quota->weight_age;
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scheme->quota.total_charged_sz = 0;
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scheme->quota.total_charged_ns = 0;
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scheme->quota.esz = 0;
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scheme->quota.charged_sz = 0;
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scheme->quota.charged_from = 0;
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scheme->quota.charge_target_from = NULL;
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scheme->quota.charge_addr_from = 0;
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scheme->wmarks.metric = wmarks->metric;
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scheme->wmarks.interval = wmarks->interval;
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scheme->wmarks.high = wmarks->high;
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scheme->wmarks.mid = wmarks->mid;
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scheme->wmarks.low = wmarks->low;
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scheme->wmarks.activated = true;
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return scheme;
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}
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void damon_add_scheme(struct damon_ctx *ctx, struct damos *s)
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{
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list_add_tail(&s->list, &ctx->schemes);
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}
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static void damon_del_scheme(struct damos *s)
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{
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list_del(&s->list);
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}
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static void damon_free_scheme(struct damos *s)
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{
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kfree(s);
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}
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void damon_destroy_scheme(struct damos *s)
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{
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damon_del_scheme(s);
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damon_free_scheme(s);
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}
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/*
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* Construct a damon_target struct
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*
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* Returns the pointer to the new struct if success, or NULL otherwise
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*/
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struct damon_target *damon_new_target(unsigned long id)
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{
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struct damon_target *t;
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t = kmalloc(sizeof(*t), GFP_KERNEL);
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if (!t)
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return NULL;
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t->id = id;
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t->nr_regions = 0;
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INIT_LIST_HEAD(&t->regions_list);
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return t;
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}
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void damon_add_target(struct damon_ctx *ctx, struct damon_target *t)
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{
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list_add_tail(&t->list, &ctx->adaptive_targets);
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}
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bool damon_targets_empty(struct damon_ctx *ctx)
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{
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return list_empty(&ctx->adaptive_targets);
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}
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static void damon_del_target(struct damon_target *t)
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{
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list_del(&t->list);
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}
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void damon_free_target(struct damon_target *t)
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{
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struct damon_region *r, *next;
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damon_for_each_region_safe(r, next, t)
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damon_free_region(r);
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kfree(t);
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}
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void damon_destroy_target(struct damon_target *t)
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{
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damon_del_target(t);
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damon_free_target(t);
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}
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unsigned int damon_nr_regions(struct damon_target *t)
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{
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return t->nr_regions;
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}
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struct damon_ctx *damon_new_ctx(void)
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{
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struct damon_ctx *ctx;
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ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return NULL;
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ctx->sample_interval = 5 * 1000;
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ctx->aggr_interval = 100 * 1000;
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ctx->primitive_update_interval = 60 * 1000 * 1000;
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ktime_get_coarse_ts64(&ctx->last_aggregation);
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ctx->last_primitive_update = ctx->last_aggregation;
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mutex_init(&ctx->kdamond_lock);
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ctx->min_nr_regions = 10;
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ctx->max_nr_regions = 1000;
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INIT_LIST_HEAD(&ctx->adaptive_targets);
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INIT_LIST_HEAD(&ctx->schemes);
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return ctx;
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}
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static void damon_destroy_targets(struct damon_ctx *ctx)
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{
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struct damon_target *t, *next_t;
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if (ctx->primitive.cleanup) {
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ctx->primitive.cleanup(ctx);
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return;
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}
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damon_for_each_target_safe(t, next_t, ctx)
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damon_destroy_target(t);
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}
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void damon_destroy_ctx(struct damon_ctx *ctx)
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{
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struct damos *s, *next_s;
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damon_destroy_targets(ctx);
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damon_for_each_scheme_safe(s, next_s, ctx)
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damon_destroy_scheme(s);
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kfree(ctx);
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}
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/**
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* damon_set_targets() - Set monitoring targets.
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* @ctx: monitoring context
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* @ids: array of target ids
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* @nr_ids: number of entries in @ids
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*
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* This function should not be called while the kdamond is running.
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*
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* Return: 0 on success, negative error code otherwise.
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*/
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int damon_set_targets(struct damon_ctx *ctx,
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unsigned long *ids, ssize_t nr_ids)
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{
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ssize_t i;
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struct damon_target *t, *next;
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damon_destroy_targets(ctx);
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for (i = 0; i < nr_ids; i++) {
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t = damon_new_target(ids[i]);
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if (!t) {
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pr_err("Failed to alloc damon_target\n");
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/* The caller should do cleanup of the ids itself */
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damon_for_each_target_safe(t, next, ctx)
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damon_destroy_target(t);
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return -ENOMEM;
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}
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damon_add_target(ctx, t);
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}
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return 0;
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}
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/**
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* damon_set_attrs() - Set attributes for the monitoring.
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* @ctx: monitoring context
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* @sample_int: time interval between samplings
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* @aggr_int: time interval between aggregations
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* @primitive_upd_int: time interval between monitoring primitive updates
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* @min_nr_reg: minimal number of regions
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* @max_nr_reg: maximum number of regions
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*
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* This function should not be called while the kdamond is running.
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* Every time interval is in micro-seconds.
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*
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* Return: 0 on success, negative error code otherwise.
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*/
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int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int,
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unsigned long aggr_int, unsigned long primitive_upd_int,
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unsigned long min_nr_reg, unsigned long max_nr_reg)
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{
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if (min_nr_reg < 3) {
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pr_err("min_nr_regions (%lu) must be at least 3\n",
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min_nr_reg);
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return -EINVAL;
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}
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if (min_nr_reg > max_nr_reg) {
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pr_err("invalid nr_regions. min (%lu) > max (%lu)\n",
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min_nr_reg, max_nr_reg);
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return -EINVAL;
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}
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ctx->sample_interval = sample_int;
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ctx->aggr_interval = aggr_int;
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ctx->primitive_update_interval = primitive_upd_int;
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ctx->min_nr_regions = min_nr_reg;
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ctx->max_nr_regions = max_nr_reg;
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return 0;
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}
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/**
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* damon_set_schemes() - Set data access monitoring based operation schemes.
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* @ctx: monitoring context
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* @schemes: array of the schemes
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* @nr_schemes: number of entries in @schemes
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*
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* This function should not be called while the kdamond of the context is
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* running.
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*
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* Return: 0 if success, or negative error code otherwise.
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*/
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int damon_set_schemes(struct damon_ctx *ctx, struct damos **schemes,
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ssize_t nr_schemes)
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{
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struct damos *s, *next;
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ssize_t i;
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damon_for_each_scheme_safe(s, next, ctx)
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damon_destroy_scheme(s);
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for (i = 0; i < nr_schemes; i++)
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damon_add_scheme(ctx, schemes[i]);
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return 0;
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}
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/**
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* damon_nr_running_ctxs() - Return number of currently running contexts.
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*/
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int damon_nr_running_ctxs(void)
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{
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int nr_ctxs;
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mutex_lock(&damon_lock);
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nr_ctxs = nr_running_ctxs;
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mutex_unlock(&damon_lock);
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return nr_ctxs;
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}
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/* Returns the size upper limit for each monitoring region */
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static unsigned long damon_region_sz_limit(struct damon_ctx *ctx)
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{
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struct damon_target *t;
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struct damon_region *r;
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unsigned long sz = 0;
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damon_for_each_target(t, ctx) {
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damon_for_each_region(r, t)
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sz += r->ar.end - r->ar.start;
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}
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if (ctx->min_nr_regions)
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sz /= ctx->min_nr_regions;
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if (sz < DAMON_MIN_REGION)
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sz = DAMON_MIN_REGION;
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return sz;
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}
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static int kdamond_fn(void *data);
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/*
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* __damon_start() - Starts monitoring with given context.
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* @ctx: monitoring context
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*
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* This function should be called while damon_lock is hold.
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*
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* Return: 0 on success, negative error code otherwise.
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*/
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static int __damon_start(struct damon_ctx *ctx)
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{
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int err = -EBUSY;
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mutex_lock(&ctx->kdamond_lock);
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if (!ctx->kdamond) {
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err = 0;
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ctx->kdamond = kthread_run(kdamond_fn, ctx, "kdamond.%d",
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nr_running_ctxs);
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if (IS_ERR(ctx->kdamond)) {
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err = PTR_ERR(ctx->kdamond);
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ctx->kdamond = NULL;
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}
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}
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mutex_unlock(&ctx->kdamond_lock);
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return err;
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}
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/**
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* damon_start() - Starts the monitorings for a given group of contexts.
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* @ctxs: an array of the pointers for contexts to start monitoring
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* @nr_ctxs: size of @ctxs
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*
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* This function starts a group of monitoring threads for a group of monitoring
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* contexts. One thread per each context is created and run in parallel. The
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* caller should handle synchronization between the threads by itself. If a
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* group of threads that created by other 'damon_start()' call is currently
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* running, this function does nothing but returns -EBUSY.
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*
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* Return: 0 on success, negative error code otherwise.
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*/
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int damon_start(struct damon_ctx **ctxs, int nr_ctxs)
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{
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int i;
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int err = 0;
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mutex_lock(&damon_lock);
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if (nr_running_ctxs) {
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mutex_unlock(&damon_lock);
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return -EBUSY;
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}
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for (i = 0; i < nr_ctxs; i++) {
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err = __damon_start(ctxs[i]);
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if (err)
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break;
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nr_running_ctxs++;
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}
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mutex_unlock(&damon_lock);
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return err;
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}
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/*
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* __damon_stop() - Stops monitoring of given context.
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* @ctx: monitoring context
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*
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* Return: 0 on success, negative error code otherwise.
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*/
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static int __damon_stop(struct damon_ctx *ctx)
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{
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struct task_struct *tsk;
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mutex_lock(&ctx->kdamond_lock);
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tsk = ctx->kdamond;
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if (tsk) {
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get_task_struct(tsk);
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mutex_unlock(&ctx->kdamond_lock);
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kthread_stop(tsk);
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put_task_struct(tsk);
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return 0;
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}
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mutex_unlock(&ctx->kdamond_lock);
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return -EPERM;
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}
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/**
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* damon_stop() - Stops the monitorings for a given group of contexts.
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* @ctxs: an array of the pointers for contexts to stop monitoring
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* @nr_ctxs: size of @ctxs
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*
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* Return: 0 on success, negative error code otherwise.
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*/
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int damon_stop(struct damon_ctx **ctxs, int nr_ctxs)
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{
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int i, err = 0;
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for (i = 0; i < nr_ctxs; i++) {
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/* nr_running_ctxs is decremented in kdamond_fn */
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err = __damon_stop(ctxs[i]);
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if (err)
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return err;
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}
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return err;
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}
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/*
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* damon_check_reset_time_interval() - Check if a time interval is elapsed.
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* @baseline: the time to check whether the interval has elapsed since
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* @interval: the time interval (microseconds)
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*
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* See whether the given time interval has passed since the given baseline
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* time. If so, it also updates the baseline to current time for next check.
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*
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* Return: true if the time interval has passed, or false otherwise.
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*/
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static bool damon_check_reset_time_interval(struct timespec64 *baseline,
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unsigned long interval)
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{
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struct timespec64 now;
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ktime_get_coarse_ts64(&now);
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if ((timespec64_to_ns(&now) - timespec64_to_ns(baseline)) <
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interval * 1000)
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return false;
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*baseline = now;
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return true;
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}
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/*
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* Check whether it is time to flush the aggregated information
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*/
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static bool kdamond_aggregate_interval_passed(struct damon_ctx *ctx)
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{
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return damon_check_reset_time_interval(&ctx->last_aggregation,
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ctx->aggr_interval);
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}
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/*
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* Reset the aggregated monitoring results ('nr_accesses' of each region).
|
|
*/
|
|
static void kdamond_reset_aggregated(struct damon_ctx *c)
|
|
{
|
|
struct damon_target *t;
|
|
|
|
damon_for_each_target(t, c) {
|
|
struct damon_region *r;
|
|
|
|
damon_for_each_region(r, t) {
|
|
trace_damon_aggregated(t, r, damon_nr_regions(t));
|
|
r->last_nr_accesses = r->nr_accesses;
|
|
r->nr_accesses = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void damon_split_region_at(struct damon_ctx *ctx,
|
|
struct damon_target *t, struct damon_region *r,
|
|
unsigned long sz_r);
|
|
|
|
static bool __damos_valid_target(struct damon_region *r, struct damos *s)
|
|
{
|
|
unsigned long sz;
|
|
|
|
sz = r->ar.end - r->ar.start;
|
|
return s->min_sz_region <= sz && sz <= s->max_sz_region &&
|
|
s->min_nr_accesses <= r->nr_accesses &&
|
|
r->nr_accesses <= s->max_nr_accesses &&
|
|
s->min_age_region <= r->age && r->age <= s->max_age_region;
|
|
}
|
|
|
|
static bool damos_valid_target(struct damon_ctx *c, struct damon_target *t,
|
|
struct damon_region *r, struct damos *s)
|
|
{
|
|
bool ret = __damos_valid_target(r, s);
|
|
|
|
if (!ret || !s->quota.esz || !c->primitive.get_scheme_score)
|
|
return ret;
|
|
|
|
return c->primitive.get_scheme_score(c, t, r, s) >= s->quota.min_score;
|
|
}
|
|
|
|
static void damon_do_apply_schemes(struct damon_ctx *c,
|
|
struct damon_target *t,
|
|
struct damon_region *r)
|
|
{
|
|
struct damos *s;
|
|
|
|
damon_for_each_scheme(s, c) {
|
|
struct damos_quota *quota = &s->quota;
|
|
unsigned long sz = r->ar.end - r->ar.start;
|
|
struct timespec64 begin, end;
|
|
|
|
if (!s->wmarks.activated)
|
|
continue;
|
|
|
|
/* Check the quota */
|
|
if (quota->esz && quota->charged_sz >= quota->esz)
|
|
continue;
|
|
|
|
/* Skip previously charged regions */
|
|
if (quota->charge_target_from) {
|
|
if (t != quota->charge_target_from)
|
|
continue;
|
|
if (r == damon_last_region(t)) {
|
|
quota->charge_target_from = NULL;
|
|
quota->charge_addr_from = 0;
|
|
continue;
|
|
}
|
|
if (quota->charge_addr_from &&
|
|
r->ar.end <= quota->charge_addr_from)
|
|
continue;
|
|
|
|
if (quota->charge_addr_from && r->ar.start <
|
|
quota->charge_addr_from) {
|
|
sz = ALIGN_DOWN(quota->charge_addr_from -
|
|
r->ar.start, DAMON_MIN_REGION);
|
|
if (!sz) {
|
|
if (r->ar.end - r->ar.start <=
|
|
DAMON_MIN_REGION)
|
|
continue;
|
|
sz = DAMON_MIN_REGION;
|
|
}
|
|
damon_split_region_at(c, t, r, sz);
|
|
r = damon_next_region(r);
|
|
sz = r->ar.end - r->ar.start;
|
|
}
|
|
quota->charge_target_from = NULL;
|
|
quota->charge_addr_from = 0;
|
|
}
|
|
|
|
if (!damos_valid_target(c, t, r, s))
|
|
continue;
|
|
|
|
/* Apply the scheme */
|
|
if (c->primitive.apply_scheme) {
|
|
if (quota->esz &&
|
|
quota->charged_sz + sz > quota->esz) {
|
|
sz = ALIGN_DOWN(quota->esz - quota->charged_sz,
|
|
DAMON_MIN_REGION);
|
|
if (!sz)
|
|
goto update_stat;
|
|
damon_split_region_at(c, t, r, sz);
|
|
}
|
|
ktime_get_coarse_ts64(&begin);
|
|
c->primitive.apply_scheme(c, t, r, s);
|
|
ktime_get_coarse_ts64(&end);
|
|
quota->total_charged_ns += timespec64_to_ns(&end) -
|
|
timespec64_to_ns(&begin);
|
|
quota->charged_sz += sz;
|
|
if (quota->esz && quota->charged_sz >= quota->esz) {
|
|
quota->charge_target_from = t;
|
|
quota->charge_addr_from = r->ar.end + 1;
|
|
}
|
|
}
|
|
if (s->action != DAMOS_STAT)
|
|
r->age = 0;
|
|
|
|
update_stat:
|
|
s->stat_count++;
|
|
s->stat_sz += sz;
|
|
}
|
|
}
|
|
|
|
/* Shouldn't be called if quota->ms and quota->sz are zero */
|
|
static void damos_set_effective_quota(struct damos_quota *quota)
|
|
{
|
|
unsigned long throughput;
|
|
unsigned long esz;
|
|
|
|
if (!quota->ms) {
|
|
quota->esz = quota->sz;
|
|
return;
|
|
}
|
|
|
|
if (quota->total_charged_ns)
|
|
throughput = quota->total_charged_sz * 1000000 /
|
|
quota->total_charged_ns;
|
|
else
|
|
throughput = PAGE_SIZE * 1024;
|
|
esz = throughput * quota->ms;
|
|
|
|
if (quota->sz && quota->sz < esz)
|
|
esz = quota->sz;
|
|
quota->esz = esz;
|
|
}
|
|
|
|
static void kdamond_apply_schemes(struct damon_ctx *c)
|
|
{
|
|
struct damon_target *t;
|
|
struct damon_region *r, *next_r;
|
|
struct damos *s;
|
|
|
|
damon_for_each_scheme(s, c) {
|
|
struct damos_quota *quota = &s->quota;
|
|
unsigned long cumulated_sz;
|
|
unsigned int score, max_score = 0;
|
|
|
|
if (!s->wmarks.activated)
|
|
continue;
|
|
|
|
if (!quota->ms && !quota->sz)
|
|
continue;
|
|
|
|
/* New charge window starts */
|
|
if (time_after_eq(jiffies, quota->charged_from +
|
|
msecs_to_jiffies(
|
|
quota->reset_interval))) {
|
|
quota->total_charged_sz += quota->charged_sz;
|
|
quota->charged_from = jiffies;
|
|
quota->charged_sz = 0;
|
|
damos_set_effective_quota(quota);
|
|
}
|
|
|
|
if (!c->primitive.get_scheme_score)
|
|
continue;
|
|
|
|
/* Fill up the score histogram */
|
|
memset(quota->histogram, 0, sizeof(quota->histogram));
|
|
damon_for_each_target(t, c) {
|
|
damon_for_each_region(r, t) {
|
|
if (!__damos_valid_target(r, s))
|
|
continue;
|
|
score = c->primitive.get_scheme_score(
|
|
c, t, r, s);
|
|
quota->histogram[score] +=
|
|
r->ar.end - r->ar.start;
|
|
if (score > max_score)
|
|
max_score = score;
|
|
}
|
|
}
|
|
|
|
/* Set the min score limit */
|
|
for (cumulated_sz = 0, score = max_score; ; score--) {
|
|
cumulated_sz += quota->histogram[score];
|
|
if (cumulated_sz >= quota->esz || !score)
|
|
break;
|
|
}
|
|
quota->min_score = score;
|
|
}
|
|
|
|
damon_for_each_target(t, c) {
|
|
damon_for_each_region_safe(r, next_r, t)
|
|
damon_do_apply_schemes(c, t, r);
|
|
}
|
|
}
|
|
|
|
#define sz_damon_region(r) (r->ar.end - r->ar.start)
|
|
|
|
/*
|
|
* Merge two adjacent regions into one region
|
|
*/
|
|
static void damon_merge_two_regions(struct damon_target *t,
|
|
struct damon_region *l, struct damon_region *r)
|
|
{
|
|
unsigned long sz_l = sz_damon_region(l), sz_r = sz_damon_region(r);
|
|
|
|
l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) /
|
|
(sz_l + sz_r);
|
|
l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r);
|
|
l->ar.end = r->ar.end;
|
|
damon_destroy_region(r, t);
|
|
}
|
|
|
|
#define diff_of(a, b) (a > b ? a - b : b - a)
|
|
|
|
/*
|
|
* Merge adjacent regions having similar access frequencies
|
|
*
|
|
* t target affected by this merge operation
|
|
* thres '->nr_accesses' diff threshold for the merge
|
|
* sz_limit size upper limit of each region
|
|
*/
|
|
static void damon_merge_regions_of(struct damon_target *t, unsigned int thres,
|
|
unsigned long sz_limit)
|
|
{
|
|
struct damon_region *r, *prev = NULL, *next;
|
|
|
|
damon_for_each_region_safe(r, next, t) {
|
|
if (diff_of(r->nr_accesses, r->last_nr_accesses) > thres)
|
|
r->age = 0;
|
|
else
|
|
r->age++;
|
|
|
|
if (prev && prev->ar.end == r->ar.start &&
|
|
diff_of(prev->nr_accesses, r->nr_accesses) <= thres &&
|
|
sz_damon_region(prev) + sz_damon_region(r) <= sz_limit)
|
|
damon_merge_two_regions(t, prev, r);
|
|
else
|
|
prev = r;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Merge adjacent regions having similar access frequencies
|
|
*
|
|
* threshold '->nr_accesses' diff threshold for the merge
|
|
* sz_limit size upper limit of each region
|
|
*
|
|
* This function merges monitoring target regions which are adjacent and their
|
|
* access frequencies are similar. This is for minimizing the monitoring
|
|
* overhead under the dynamically changeable access pattern. If a merge was
|
|
* unnecessarily made, later 'kdamond_split_regions()' will revert it.
|
|
*/
|
|
static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold,
|
|
unsigned long sz_limit)
|
|
{
|
|
struct damon_target *t;
|
|
|
|
damon_for_each_target(t, c)
|
|
damon_merge_regions_of(t, threshold, sz_limit);
|
|
}
|
|
|
|
/*
|
|
* Split a region in two
|
|
*
|
|
* r the region to be split
|
|
* sz_r size of the first sub-region that will be made
|
|
*/
|
|
static void damon_split_region_at(struct damon_ctx *ctx,
|
|
struct damon_target *t, struct damon_region *r,
|
|
unsigned long sz_r)
|
|
{
|
|
struct damon_region *new;
|
|
|
|
new = damon_new_region(r->ar.start + sz_r, r->ar.end);
|
|
if (!new)
|
|
return;
|
|
|
|
r->ar.end = new->ar.start;
|
|
|
|
new->age = r->age;
|
|
new->last_nr_accesses = r->last_nr_accesses;
|
|
|
|
damon_insert_region(new, r, damon_next_region(r), t);
|
|
}
|
|
|
|
/* Split every region in the given target into 'nr_subs' regions */
|
|
static void damon_split_regions_of(struct damon_ctx *ctx,
|
|
struct damon_target *t, int nr_subs)
|
|
{
|
|
struct damon_region *r, *next;
|
|
unsigned long sz_region, sz_sub = 0;
|
|
int i;
|
|
|
|
damon_for_each_region_safe(r, next, t) {
|
|
sz_region = r->ar.end - r->ar.start;
|
|
|
|
for (i = 0; i < nr_subs - 1 &&
|
|
sz_region > 2 * DAMON_MIN_REGION; i++) {
|
|
/*
|
|
* Randomly select size of left sub-region to be at
|
|
* least 10 percent and at most 90% of original region
|
|
*/
|
|
sz_sub = ALIGN_DOWN(damon_rand(1, 10) *
|
|
sz_region / 10, DAMON_MIN_REGION);
|
|
/* Do not allow blank region */
|
|
if (sz_sub == 0 || sz_sub >= sz_region)
|
|
continue;
|
|
|
|
damon_split_region_at(ctx, t, r, sz_sub);
|
|
sz_region = sz_sub;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Split every target region into randomly-sized small regions
|
|
*
|
|
* This function splits every target region into random-sized small regions if
|
|
* current total number of the regions is equal or smaller than half of the
|
|
* user-specified maximum number of regions. This is for maximizing the
|
|
* monitoring accuracy under the dynamically changeable access patterns. If a
|
|
* split was unnecessarily made, later 'kdamond_merge_regions()' will revert
|
|
* it.
|
|
*/
|
|
static void kdamond_split_regions(struct damon_ctx *ctx)
|
|
{
|
|
struct damon_target *t;
|
|
unsigned int nr_regions = 0;
|
|
static unsigned int last_nr_regions;
|
|
int nr_subregions = 2;
|
|
|
|
damon_for_each_target(t, ctx)
|
|
nr_regions += damon_nr_regions(t);
|
|
|
|
if (nr_regions > ctx->max_nr_regions / 2)
|
|
return;
|
|
|
|
/* Maybe the middle of the region has different access frequency */
|
|
if (last_nr_regions == nr_regions &&
|
|
nr_regions < ctx->max_nr_regions / 3)
|
|
nr_subregions = 3;
|
|
|
|
damon_for_each_target(t, ctx)
|
|
damon_split_regions_of(ctx, t, nr_subregions);
|
|
|
|
last_nr_regions = nr_regions;
|
|
}
|
|
|
|
/*
|
|
* Check whether it is time to check and apply the target monitoring regions
|
|
*
|
|
* Returns true if it is.
|
|
*/
|
|
static bool kdamond_need_update_primitive(struct damon_ctx *ctx)
|
|
{
|
|
return damon_check_reset_time_interval(&ctx->last_primitive_update,
|
|
ctx->primitive_update_interval);
|
|
}
|
|
|
|
/*
|
|
* Check whether current monitoring should be stopped
|
|
*
|
|
* The monitoring is stopped when either the user requested to stop, or all
|
|
* monitoring targets are invalid.
|
|
*
|
|
* Returns true if need to stop current monitoring.
|
|
*/
|
|
static bool kdamond_need_stop(struct damon_ctx *ctx)
|
|
{
|
|
struct damon_target *t;
|
|
|
|
if (kthread_should_stop())
|
|
return true;
|
|
|
|
if (!ctx->primitive.target_valid)
|
|
return false;
|
|
|
|
damon_for_each_target(t, ctx) {
|
|
if (ctx->primitive.target_valid(t))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric)
|
|
{
|
|
struct sysinfo i;
|
|
|
|
switch (metric) {
|
|
case DAMOS_WMARK_FREE_MEM_RATE:
|
|
si_meminfo(&i);
|
|
return i.freeram * 1000 / i.totalram;
|
|
default:
|
|
break;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* Returns zero if the scheme is active. Else, returns time to wait for next
|
|
* watermark check in micro-seconds.
|
|
*/
|
|
static unsigned long damos_wmark_wait_us(struct damos *scheme)
|
|
{
|
|
unsigned long metric;
|
|
|
|
if (scheme->wmarks.metric == DAMOS_WMARK_NONE)
|
|
return 0;
|
|
|
|
metric = damos_wmark_metric_value(scheme->wmarks.metric);
|
|
/* higher than high watermark or lower than low watermark */
|
|
if (metric > scheme->wmarks.high || scheme->wmarks.low > metric) {
|
|
if (scheme->wmarks.activated)
|
|
pr_debug("deactivate a scheme (%d) for %s wmark\n",
|
|
scheme->action,
|
|
metric > scheme->wmarks.high ?
|
|
"high" : "low");
|
|
scheme->wmarks.activated = false;
|
|
return scheme->wmarks.interval;
|
|
}
|
|
|
|
/* inactive and higher than middle watermark */
|
|
if ((scheme->wmarks.high >= metric && metric >= scheme->wmarks.mid) &&
|
|
!scheme->wmarks.activated)
|
|
return scheme->wmarks.interval;
|
|
|
|
if (!scheme->wmarks.activated)
|
|
pr_debug("activate a scheme (%d)\n", scheme->action);
|
|
scheme->wmarks.activated = true;
|
|
return 0;
|
|
}
|
|
|
|
static void kdamond_usleep(unsigned long usecs)
|
|
{
|
|
if (usecs > 100 * 1000)
|
|
schedule_timeout_interruptible(usecs_to_jiffies(usecs));
|
|
else
|
|
usleep_range(usecs, usecs + 1);
|
|
}
|
|
|
|
/* Returns negative error code if it's not activated but should return */
|
|
static int kdamond_wait_activation(struct damon_ctx *ctx)
|
|
{
|
|
struct damos *s;
|
|
unsigned long wait_time;
|
|
unsigned long min_wait_time = 0;
|
|
|
|
while (!kdamond_need_stop(ctx)) {
|
|
damon_for_each_scheme(s, ctx) {
|
|
wait_time = damos_wmark_wait_us(s);
|
|
if (!min_wait_time || wait_time < min_wait_time)
|
|
min_wait_time = wait_time;
|
|
}
|
|
if (!min_wait_time)
|
|
return 0;
|
|
|
|
kdamond_usleep(min_wait_time);
|
|
}
|
|
return -EBUSY;
|
|
}
|
|
|
|
/*
|
|
* The monitoring daemon that runs as a kernel thread
|
|
*/
|
|
static int kdamond_fn(void *data)
|
|
{
|
|
struct damon_ctx *ctx = (struct damon_ctx *)data;
|
|
struct damon_target *t;
|
|
struct damon_region *r, *next;
|
|
unsigned int max_nr_accesses = 0;
|
|
unsigned long sz_limit = 0;
|
|
bool done = false;
|
|
|
|
pr_debug("kdamond (%d) starts\n", current->pid);
|
|
|
|
if (ctx->primitive.init)
|
|
ctx->primitive.init(ctx);
|
|
if (ctx->callback.before_start && ctx->callback.before_start(ctx))
|
|
done = true;
|
|
|
|
sz_limit = damon_region_sz_limit(ctx);
|
|
|
|
while (!kdamond_need_stop(ctx) && !done) {
|
|
if (kdamond_wait_activation(ctx))
|
|
continue;
|
|
|
|
if (ctx->primitive.prepare_access_checks)
|
|
ctx->primitive.prepare_access_checks(ctx);
|
|
if (ctx->callback.after_sampling &&
|
|
ctx->callback.after_sampling(ctx))
|
|
done = true;
|
|
|
|
usleep_range(ctx->sample_interval, ctx->sample_interval + 1);
|
|
|
|
if (ctx->primitive.check_accesses)
|
|
max_nr_accesses = ctx->primitive.check_accesses(ctx);
|
|
|
|
if (kdamond_aggregate_interval_passed(ctx)) {
|
|
kdamond_merge_regions(ctx,
|
|
max_nr_accesses / 10,
|
|
sz_limit);
|
|
if (ctx->callback.after_aggregation &&
|
|
ctx->callback.after_aggregation(ctx))
|
|
done = true;
|
|
kdamond_apply_schemes(ctx);
|
|
kdamond_reset_aggregated(ctx);
|
|
kdamond_split_regions(ctx);
|
|
if (ctx->primitive.reset_aggregated)
|
|
ctx->primitive.reset_aggregated(ctx);
|
|
}
|
|
|
|
if (kdamond_need_update_primitive(ctx)) {
|
|
if (ctx->primitive.update)
|
|
ctx->primitive.update(ctx);
|
|
sz_limit = damon_region_sz_limit(ctx);
|
|
}
|
|
}
|
|
damon_for_each_target(t, ctx) {
|
|
damon_for_each_region_safe(r, next, t)
|
|
damon_destroy_region(r, t);
|
|
}
|
|
|
|
if (ctx->callback.before_terminate)
|
|
ctx->callback.before_terminate(ctx);
|
|
if (ctx->primitive.cleanup)
|
|
ctx->primitive.cleanup(ctx);
|
|
|
|
pr_debug("kdamond (%d) finishes\n", current->pid);
|
|
mutex_lock(&ctx->kdamond_lock);
|
|
ctx->kdamond = NULL;
|
|
mutex_unlock(&ctx->kdamond_lock);
|
|
|
|
mutex_lock(&damon_lock);
|
|
nr_running_ctxs--;
|
|
mutex_unlock(&damon_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#include "core-test.h"
|