Re: [PATCH v6 05/14] mm/damon: Implement callbacks

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Mon, 24 Feb 2020 13:30:38 +0100
SeongJae Park <sjpark@amazon.com> wrote:

> From: SeongJae Park <sjpark@amazon.de>
> 
> This commit implements callbacks for DAMON.  Using this, DAMON users can
> install their callbacks for each step of the access monitoring so that
> they can do something interesting with the monitored access pattrns

patterns

> online.  For example, callbacks can report the monitored patterns to
> users or do some access pattern based memory management such as
> proactive reclamations or access pattern based THP promotions/demotions
> decision makings.
> 
> Signed-off-by: SeongJae Park <sjpark@amazon.de>
> ---
>  mm/damon.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/mm/damon.c b/mm/damon.c
> index 6a17408e83c2..554720778e8a 100644
> --- a/mm/damon.c
> +++ b/mm/damon.c
> @@ -83,6 +83,10 @@ struct damon_ctx {
>  	struct rnd_state rndseed;
>  
>  	struct list_head tasks_list;	/* 'damon_task' objects */
> +
> +	/* callbacks */
> +	void (*sample_cb)(struct damon_ctx *context);
> +	void (*aggregate_cb)(struct damon_ctx *context);
>  };
>  
>  /* Get a random number in [l, r) */
> @@ -814,9 +818,13 @@ static int kdamond_fn(void *data)
>  			}
>  			mmput(mm);
>  		}
> +		if (ctx->sample_cb)
> +			ctx->sample_cb(ctx);
>  
>  		if (kdamond_aggregate_interval_passed(ctx)) {
>  			kdamond_merge_regions(ctx, max_nr_accesses / 10);
> +			if (ctx->aggregate_cb)
> +				ctx->aggregate_cb(ctx);
>  			kdamond_flush_aggregated(ctx);
>  			kdamond_split_regions(ctx);
>  		}