Re: [RFC PATCH 02/19] mm/damon/core: embed damon_probe objects in damon_ctx

[Gutierrez Asier <gutierrez.asier@huawei-partners.com>]

On 4/26/2026 11:52 PM, SeongJae Park wrote:
> Let damon_probe objects be able to be installed on a given damon_ctx, by
> adding a linked list header for storing the objects.  Add initialization
> and cleanup of the new field with helper functions, too.
> 
> Signed-off-by: SeongJae Park <sj@kernel.org>
> ---
>  include/linux/damon.h |  9 +++++++++
>  mm/damon/core.c       | 38 ++++++++++++++++++++++++++++++++++++++
>  2 files changed, 47 insertions(+)
> 
> diff --git a/include/linux/damon.h b/include/linux/damon.h
> index da2f026eac725..65d7ee0a70ac0 100644
> --- a/include/linux/damon.h
> +++ b/include/linux/damon.h
> @@ -859,6 +859,7 @@ struct damon_ctx {
>  
>  /* public: */
>  	struct damon_operations ops;
> +	struct list_head probes;
>  	unsigned long addr_unit;
>  	unsigned long min_region_sz;
>  	bool pause;
> @@ -892,6 +893,11 @@ static inline unsigned long damon_sz_region(struct damon_region *r)
>  	return r->ar.end - r->ar.start;
>  }
>  
> +#define damon_for_each_probe(p, ctx) \
> +	list_for_each_entry(p, &ctx->probes, list)
> +
> +#define damon_for_each_probe_safe(p, next, ctx) \
> +	list_for_each_entry_safe(p, next, &ctx->probes, list)
>  
>  #define damon_for_each_region(r, t) \
>  	list_for_each_entry(r, &t->regions_list, list)
> @@ -934,6 +940,9 @@ static inline unsigned long damon_sz_region(struct damon_region *r)
>  
>  #ifdef CONFIG_DAMON
>  
> +struct damon_probe *damon_new_probe(void);
> +void damon_add_probe(struct damon_ctx *ctx, struct damon_probe *probe);
> +
>  struct damon_region *damon_new_region(unsigned long start, unsigned long end);
>  
>  int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index f556786597c83..861ab977d1edf 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -109,6 +109,38 @@ int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id)
>  	return err;
>  }
>  
> +struct damon_probe *damon_new_probe(void)
> +{
> +	struct damon_probe *p;
> +
> +	p = kmalloc_obj(*p);
> +	if (!p)
> +		return NULL;
> +	INIT_LIST_HEAD(&p->list);
> +	return p;
> +}
> +
> +void damon_add_probe(struct damon_ctx *ctx, struct damon_probe *probe)
> +{
> +	list_add_tail(&probe->list, &ctx->probes);
> +}
> +
> +static void damon_del_probe(struct damon_probe *p)
> +{
> +	list_del(&p->list);
> +}
> +
> +static void damon_free_probe(struct damon_probe *p)
> +{
> +	kfree(p);
> +}
> +
> +static void damon_destroy_probe(struct damon_probe *p)
> +{
> +	damon_del_probe(p);
> +	damon_free_probe(p);

Why don't we inline list_del and kfree here instead of calling
damon_del/free_probe?

> +}
> +
>  #ifdef CONFIG_DAMON_DEBUG_SANITY
>  static void damon_verify_new_region(unsigned long start, unsigned long end)
>  {
> @@ -633,6 +665,8 @@ struct damon_ctx *damon_new_ctx(void)
>  	ctx->attrs.min_nr_regions = 10;
>  	ctx->attrs.max_nr_regions = 1000;
>  
> +	INIT_LIST_HEAD(&ctx->probes);
> +
>  	ctx->addr_unit = 1;
>  	ctx->min_region_sz = DAMON_MIN_REGION_SZ;
>  
> @@ -653,12 +687,16 @@ static void damon_destroy_targets(struct damon_ctx *ctx)
>  void damon_destroy_ctx(struct damon_ctx *ctx)
>  {
>  	struct damos *s, *next_s;
> +	struct damon_probe *p, *next_p;
>  
>  	damon_destroy_targets(ctx);
>  
>  	damon_for_each_scheme_safe(s, next_s, ctx)
>  		damon_destroy_scheme(s);
>  
> +	damon_for_each_probe_safe(p, next_p, ctx)
> +		damon_destroy_probe(p);
> +
>  	kfree(ctx);
>  }
>  

-- 
Asier Gutierrez
Huawei