Re: [PATCH bpf-next v7 1/2] mm/bpf: Add bpf_proactive_reclaim kfunc

[Andrew Morton]

On Fri,  4 Sep 2026 18:20:19 +0800 "Hui Zhu" <hui.zhu@xxxxxxxxx> wrote:

> @@ -159,6 +160,74 @@ __bpf_kfunc void bpf_mem_cgroup_flush_stats(struct mem_cgroup *memcg)
>  	mem_cgroup_flush_stats(memcg);
>  }
>  
> +/*
> + * Reclaim must not recurse: try_to_free_mem_cgroup_pages() overwrites
> + * current->reclaim_state, so a nested call would corrupt the outer
> + * reclaim state. Reclaim windows are marked with PF_MEMALLOC;
> + * reclaim_state is also checked because it is installed slightly
> + * before PF_MEMALLOC.
> + */
> +static bool bpf_in_reclaim_context(void)
> +{
> +	return (current->flags & PF_MEMALLOC) || current->reclaim_state;
> +}
> +

Would life improve if try_to_free_mem_cgroup_pages() didn't do that? 
If try_to_free_mem_cgroup_pages() (or some variant of it) were to
permit nesting?

	rs = new_thing(current, &sc.reclaim_state);
	...
	set_task_reclaim_state(current, rs);

?