From: SeongJae Park <sjpark@xxxxxxxxx> The monitoring target address range can be dynamically changed. For example, virtual memory could be dynamically mapped and unmapped. Physical memory could be hot-plugged. As the changes could be quite frequent in some cases, DAMON checks the dynamic memory mapping changes and applies it to the abstracted target area only for each of a user-specified time interval, ``regions update interval``. Signed-off-by: SeongJae Park <sjpark@xxxxxxxxx> Reviewed-by: Leonard Foerster <foersleo@xxxxxxxxx> --- include/linux/damon.h | 20 +++++++++++++++----- mm/damon.c | 23 +++++++++++++++++++++-- 2 files changed, 36 insertions(+), 7 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index 97ddc74e207f..3c0b92a679e8 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -61,13 +61,16 @@ 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 minimum number of 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. @@ -88,6 +91,7 @@ struct damon_task { * @tasks_list: Head of monitoring target tasks (&damon_task) list. * * @init_target_regions: Constructs initial monitoring target regions. + * @update_target_regions: Updates monitoring target regions. * @prepare_access_checks: Prepares next access check of target regions. * @check_accesses: Checks the access of target regions. * @sample_cb: Called for each sampling interval. @@ -96,11 +100,14 @@ struct damon_task { * DAMON can be extended for various address spaces by users. For this, users * can register the target address space dependent low level functions for * their usecases via the callback pointers of the context. The monitoring - * thread calls @init_target_regions before starting the monitoring, and + * thread calls @init_target_regions before starting the monitoring, + * @update_target_regions for each @regions_update_interval, and * @prepare_access_checks and @check_accesses for each @sample_interval. * * @init_target_regions should construct proper monitoring target regions and * link those to the DAMON context struct. + * @update_target_regions should update the monitoring target regions for + * current status. * @prepare_access_checks should manipulate the monitoring regions to be * prepare for the next access check. * @check_accesses should check the accesses to each region that made after the @@ -115,10 +122,12 @@ 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; @@ -128,6 +137,7 @@ struct damon_ctx { /* callbacks */ void (*init_target_regions)(struct damon_ctx *context); + void (*update_target_regions)(struct damon_ctx *context); void (*prepare_access_checks)(struct damon_ctx *context); unsigned int (*check_accesses)(struct damon_ctx *context); void (*sample_cb)(struct damon_ctx *context); @@ -135,8 +145,8 @@ 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); diff --git a/mm/damon.c b/mm/damon.c index d9d0b69d00f5..b8a021af50c6 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -385,6 +385,17 @@ static void kdamond_split_regions(struct damon_ctx *ctx) last_nr_regions = nr_regions; } +/* + * Check whether it is time to check and apply the target monitoring regions + * + * 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 * @@ -455,6 +466,12 @@ static int kdamond_fn(void *data) kdamond_reset_aggregated(ctx); kdamond_split_regions(ctx); } + + if (kdamond_need_update_regions(ctx)) { + if (ctx->update_target_regions) + ctx->update_target_regions(ctx); + sz_limit = damon_region_sz_limit(ctx); + } } damon_for_each_task(t, ctx) { damon_for_each_region_safe(r, next, t) @@ -562,6 +579,7 @@ 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 target regions update * @aggr_int: time interval between aggregations * @min_nr_reg: minimal number of regions * @max_nr_reg: maximum number of regions @@ -571,8 +589,8 @@ 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) { @@ -588,6 +606,7 @@ 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; -- 2.17.1