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

[Ridong Chen <ridong.chen@linux.dev>]

On 8/24/2026 4:42 PM, Michal Hocko wrote:
> 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?

I have just done so. I would appreciate any comments you might have on it.

Link: 
https://lore.kernel.org/linux-mm/20260826124409.35569-1-ridong.chen@linux.dev/T/#u

-- 
Best regards
Ridong