Re: [RFC PATCH 0/4] mm/vmscan: honour node reclaim limits per type

[Michal Hocko]

On Mon 24-08-26 11:24:46, Ridong Chen wrote:
> 
> 
> On 8/21/2026 7:20 PM, Michal Hocko wrote:
> > On Fri 21-08-26 19:10:45, Ridong Chen wrote:
> > > > > Did you mean that min_slab_pages and min_unmapped_pages should influence
> > > > > proactive per-node reclaim?
> > > > 
> 
> I apologize for being incoherent in my last email, it was after a full day
> of work. What I wanted to say is that min_slab_pages and min_unmapped_pages
> should *not* influence proactive per-node reclaim.
> 
> > > > Nope, exactly opposite
> > > > 
> > > 
> > > I would really appreciate it if you could clarify this further. Sorry, I'm
> > > not sure I fully understand what you meant.
> > 
> > pro-active (userspace triggered) node reclaim should completely ignore
> > all those historical node_reclaim tunables.
> 
> Yeah, this matches my understanding. Apologies again for the confusing reply.
> 
> Since Johannes has acked patch 3, perhaps we can simply remove the
> conditional check in __node_reclaim and keep the shrink loop as follows:
> 
> ```
> @@ -7906,16 +7906,16 @@ static unsigned long __node_reclaim(struct
> pglist_data *pgdat,
>  	noreclaim_flag = memalloc_noreclaim_save();
>  	set_task_reclaim_state(p, &sc->reclaim_state);
> 
> -	if (node_pagecache_reclaimable(pgdat) > pgdat->min_unmapped_pages ||
> -	    node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B) > pgdat->min_slab_pages) {
> -		/*
> -		 * Free memory by calling shrink node with increasing
> -		 * priorities until we have enough memory freed.
> -		 */
> -		do {
> -			shrink_node(pgdat, sc);
> -		} while (sc->nr_reclaimed < nr_pages && --sc->priority >= 0);
> -	}
> +	/*
> +	 * Free memory by calling shrink node with increasing
> +	 * priorities until we have enough memory freed.
> +	 *
> +	 * What to reclaim is gated per type by sc->skip_slab_reclaim and
> +	 * sc->skip_file_reclaim.
> +	 */
> +	do {
> +		shrink_node(pgdat, sc);
> +	} while (sc->nr_reclaimed < nr_pages && --sc->priority >= 0);
> 
>  	set_task_reclaim_state(p, NULL);
>  	memalloc_noreclaim_restore(noreclaim_flag);

Could you post a stand alone patch with the full description please?
-- 
Michal Hocko
SUSE Labs