@@ -55,13 +55,16 @@ struct damon_task {
*
* @sample_interval: The time between access samplings.
* @aggr_interval: The time between monitor results aggregations.
+ * @regions_update_interval: The time between monitor regions updates.
* @min_nr_regions: The number of initial monitoring regions.
* @max_nr_regions: The maximum number of 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. All time intervals are in
- * micro-seconds.
+ * 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
+ * @regions_update_interval. All time intervals are in micro-seconds.
*
* @kdamond: Kernel thread who does the monitoring.
* @kdamond_stop: Notifies whether kdamond should stop.
@@ -81,10 +84,12 @@ struct damon_task {
struct damon_ctx {
unsigned long sample_interval;
unsigned long aggr_interval;
+ unsigned long regions_update_interval;
unsigned long min_nr_regions;
unsigned long max_nr_regions;
struct timespec64 last_aggregation;
+ struct timespec64 last_regions_update;
struct task_struct *kdamond;
bool kdamond_stop;
@@ -94,8 +99,8 @@ struct damon_ctx {
};
int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids);
-int damon_set_attrs(struct damon_ctx *ctx,
- unsigned long sample_int, unsigned long aggr_int,
+int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int,
+ unsigned long aggr_int, unsigned long regions_update_int,
unsigned long min_nr_reg, unsigned long max_nr_reg);
int damon_start(struct damon_ctx *ctx);
int damon_stop(struct damon_ctx *ctx);
@@ -10,6 +10,7 @@
*
* - Functions and macros for DAMON data structures
* - Functions for the initial monitoring target regions construction
+ * - Functions for the dynamic monitoring target regions update
* - Functions for the access checking of the regions
* - Functions for DAMON core logics and features
* - Functions for the DAMON programming interface
@@ -418,6 +419,91 @@ static void kdamond_init_regions(struct damon_ctx *ctx)
damon_init_regions_of(ctx, t);
}
+/*
+ * Functions for the dynamic monitoring target regions update
+ */
+
+/*
+ * Check whether regions are intersecting
+ *
+ * Note that this function checks 'struct damon_region' and 'struct region'.
+ *
+ * Returns true if it is.
+ */
+static bool damon_intersect(struct damon_region *r, struct region *re)
+{
+ return !(r->vm_end <= re->start || re->end <= r->vm_start);
+}
+
+/*
+ * Update damon regions for the three big regions of the given task
+ *
+ * t the given task
+ * bregions the three big regions of the task
+ */
+static void damon_apply_three_regions(struct damon_ctx *ctx,
+ struct damon_task *t, struct region bregions[3])
+{
+ struct damon_region *r, *next;
+ unsigned int i = 0;
+
+ /* Remove regions which are not in the three big regions now */
+ damon_for_each_region_safe(r, next, t) {
+ for (i = 0; i < 3; i++) {
+ if (damon_intersect(r, &bregions[i]))
+ break;
+ }
+ if (i == 3)
+ damon_destroy_region(r);
+ }
+
+ /* Adjust intersecting regions to fit with the three big regions */
+ for (i = 0; i < 3; i++) {
+ struct damon_region *first = NULL, *last;
+ struct damon_region *newr;
+ struct region *br;
+
+ br = &bregions[i];
+ /* Get the first and last regions which intersects with br */
+ damon_for_each_region(r, t) {
+ if (damon_intersect(r, br)) {
+ if (!first)
+ first = r;
+ last = r;
+ }
+ if (r->vm_start >= br->end)
+ break;
+ }
+ if (!first) {
+ /* no damon_region intersects with this big region */
+ newr = damon_new_region(ctx,
+ ALIGN_DOWN(br->start, MIN_REGION),
+ ALIGN(br->end, MIN_REGION));
+ if (!newr)
+ continue;
+ damon_insert_region(newr, damon_prev_region(r), r);
+ } else {
+ first->vm_start = ALIGN_DOWN(br->start, MIN_REGION);
+ last->vm_end = ALIGN(br->end, MIN_REGION);
+ }
+ }
+}
+
+/*
+ * Update regions for current memory mappings
+ */
+static void kdamond_update_regions(struct damon_ctx *ctx)
+{
+ struct region three_regions[3];
+ struct damon_task *t;
+
+ damon_for_each_task(t, ctx) {
+ if (damon_three_regions_of(t, three_regions))
+ continue;
+ damon_apply_three_regions(ctx, t, three_regions);
+ }
+}
+
/*
* Functions for the access checking of the regions
*/
@@ -738,6 +824,17 @@ static void kdamond_split_regions(struct damon_ctx *ctx)
last_nr_regions = nr_regions;
}
+/*
+ * Check whether it is time to check and apply the dynamic mmap changes
+ *
+ * Returns true if it is.
+ */
+static bool kdamond_need_update_regions(struct damon_ctx *ctx)
+{
+ return damon_check_reset_time_interval(&ctx->last_regions_update,
+ ctx->regions_update_interval);
+}
+
/*
* Check whether current monitoring should be stopped
*
@@ -793,6 +890,9 @@ static int kdamond_fn(void *data)
kdamond_reset_aggregated(ctx);
kdamond_split_regions(ctx);
}
+
+ if (kdamond_need_update_regions(ctx))
+ kdamond_update_regions(ctx);
}
damon_for_each_task(t, ctx) {
damon_for_each_region_safe(r, next, t)
@@ -900,6 +1000,7 @@ int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids)
* damon_set_attrs() - Set attributes for the monitoring.
* @ctx: monitoring context
* @sample_int: time interval between samplings
+ * @regions_update_int: time interval between vma update checks
* @aggr_int: time interval between aggregations
* @min_nr_reg: minimal number of regions
* @max_nr_reg: maximum number of regions
@@ -909,8 +1010,8 @@ int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids)
*
* Return: 0 on success, negative error code otherwise.
*/
-int damon_set_attrs(struct damon_ctx *ctx,
- unsigned long sample_int, unsigned long aggr_int,
+int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int,
+ unsigned long aggr_int, unsigned long regions_update_int,
unsigned long min_nr_reg, unsigned long max_nr_reg)
{
if (min_nr_reg < 3) {
@@ -926,6 +1027,7 @@ int damon_set_attrs(struct damon_ctx *ctx,
ctx->sample_interval = sample_int;
ctx->aggr_interval = aggr_int;
+ ctx->regions_update_interval = regions_update_int;
ctx->min_nr_regions = min_nr_reg;
ctx->max_nr_regions = max_nr_reg;