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

Gutierrez Asier
2026-04-27T13:18:17Z

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