linux-kernel - Re: [PATCH v4 9/9] mm, slub: skip percpu sheaves for remote object freeing

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Message-ID: <1ceedd5b-16c1-4844-815d-1623ab7e7ae8@suse.cz>
Date: Mon, 28 Apr 2025 09:08:56 +0200
From: Vlastimil Babka <vbabka@...e.cz>
To: "Christoph Lameter (Ampere)" <cl@...two.org>
Cc: Suren Baghdasaryan <surenb@...gle.com>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>,
 David Rientjes <rientjes@...gle.com>,
 Roman Gushchin <roman.gushchin@...ux.dev>, Harry Yoo <harry.yoo@...cle.com>,
 Uladzislau Rezki <urezki@...il.com>, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
 maple-tree@...ts.infradead.org
Subject: Re: [PATCH v4 9/9] mm, slub: skip percpu sheaves for remote object
 freeing

On 4/25/25 19:35, Christoph Lameter (Ampere) wrote:
> On Fri, 25 Apr 2025, Vlastimil Babka wrote:
> 
>> @@ -5924,8 +5948,15 @@ void slab_free(struct kmem_cache *s, struct slab *slab, void *object,
>>  	if (unlikely(!slab_free_hook(s, object, slab_want_init_on_free(s), false)))
>>  		return;
>>
>> -	if (!s->cpu_sheaves || !free_to_pcs(s, object))
>> -		do_slab_free(s, slab, object, object, 1, addr);
>> +	if (s->cpu_sheaves) {
>> +		if (likely(!IS_ENABLED(CONFIG_NUMA) ||
>> +			   slab_nid(slab) == numa_node_id())) {
> 
> Ah. ok this removes remote object freeing to the pcs.
> 
> numa_mem_id() is needed to support memory less numa nodes.

Ah right those... will fix, thanks.

>> +			free_to_pcs(s, object);
>> +			return;
>> +		}
>> +	}
>> +
>> +	do_slab_free(s, slab, object, object, 1, addr);
>>  }
>>
>>  #ifdef CONFIG_MEMCG
>>
>>