On Wed, 6 Apr 2022 21:15:20 -0600 Yu Zhao <yuzhao@xxxxxxxxxx> wrote:
>
> ...
>
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -6083,6 +6083,29 @@ static void mem_cgroup_move_task(void)
> }
> #endif
>
> +#ifdef CONFIG_LRU_GEN
> +static void mem_cgroup_attach(struct cgroup_taskset *tset)
> +{
> + struct cgroup_subsys_state *css;
> + struct task_struct *task = NULL;
> +
> + cgroup_taskset_for_each_leader(task, css, tset)
> + break;
Does this actually do anything?
> + if (!task)
> + return;
> +
> + task_lock(task);
> + if (task->mm && task->mm->owner == task)
> + lru_gen_migrate_mm(task->mm);
> + task_unlock(task);
> +}
>
> ...
>
> +static void update_batch_size(struct lru_gen_mm_walk *walk, struct folio *folio,
> + int old_gen, int new_gen)
> +{
> + int type = folio_is_file_lru(folio);
> + int zone = folio_zonenum(folio);
> + int delta = folio_nr_pages(folio);
> +
> + VM_BUG_ON(old_gen >= MAX_NR_GENS);
> + VM_BUG_ON(new_gen >= MAX_NR_GENS);
General rule: don't add new BUG_ONs, because they crash the kenrel.
It's better to use WARN_ON or WARN_ON_ONCE then try to figure out a way
to keep the kernel limping along. At least so the poor user can gather logs.
> + walk->batched++;
> +
> + walk->nr_pages[old_gen][type][zone] -= delta;
> + walk->nr_pages[new_gen][type][zone] += delta;
> +}
> +
