On Thu, 20 Feb 2025 11:35:07 -0800 SeongJae Park <sj@xxxxxxxxxx> wrote:
> Decide whether to allow or reject by default on core and opertions layer
> handled filters evaluation stages, based on the last-installed filter's
> behavior. It is the opposite of the last installed filter's behavior.
> If there is any operations layer handled filters, core layer handled
> filters stage keeps allowing as the default behavior, since the last
> filter of core layer handled filters in the case is not really the last
> filter of the entire filtering stage.
The last sentence describing behavior is not really implemented with this
commit. See below.
>
> Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
> ---
> mm/damon/core.c | 31 +++++++++++++++++++++++++++++--
> 1 file changed, 29 insertions(+), 2 deletions(-)
>
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 78126a5145fd..9744ab9ca5c5 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -864,6 +864,29 @@ static int damos_commit_ops_filters(struct damos *dst, struct damos *src)
> return 0;
> }
>
> +/**
> + * damos_filters_default_reject() - decide whether to reject memory that didn't
> + * match with any given filter.
> + * @filters: Given DAMOS filters of a group.
> + */
> +static bool damos_filters_default_reject(struct list_head *filters)
> +{
> + struct damos_filter *last_filter;
> +
> + if (list_empty(filters))
> + return false;
> + last_filter = list_last_entry(filters, struct damos_filter, list);
> + return last_filter->allow;
> +}
> +
> +static void damos_set_filters_default_reject(struct damos *s)
> +{
> + s->core_filters_default_reject =
> + damos_filters_default_reject(&s->filters);
> + s->ops_filters_default_reject =
> + damos_filters_default_reject(&s->ops_filters);
> +}
->core_filters_default_reject should be 'false' if s->ops_filters is not empty,
since the last one of ->ops_filters is not the real last filter. But this code
is not handling the case.
I will fix this in the next revision.
Thanks,
SJ
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