linux-kernel - Re: [PATCH v4 2/9] slab: add sheaf support for batching kfree

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Message-ID: <07f321d5-4416-4be4-9696-00f0d83895f5@suse.cz>
Date: Thu, 15 May 2025 10:45:36 +0200
From: Vlastimil Babka <vbabka@...e.cz>
To: Suren Baghdasaryan <surenb@...gle.com>
Cc: "Liam R. Howlett" <Liam.Howlett@...cle.com>,
 Christoph Lameter <cl@...ux.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 2/9] slab: add sheaf support for batching kfree_rcu()
 operations

On 5/14/25 16:01, Vlastimil Babka wrote:
> On 5/6/25 23:34, Suren Baghdasaryan wrote:
>> On Fri, Apr 25, 2025 at 1:27 AM Vlastimil Babka <vbabka@...e.cz> wrote:
>>> @@ -2631,6 +2637,24 @@ static void sheaf_flush_unused(struct kmem_cache *s, struct slab_sheaf *sheaf)
>>>         sheaf->size = 0;
>>>  }
>>>
>>> +static void __rcu_free_sheaf_prepare(struct kmem_cache *s,
>>> +                                    struct slab_sheaf *sheaf);
>> 
>> I think you could safely move __rcu_free_sheaf_prepare() here and
>> avoid the above forward declaration.
> 
> Right, done.
> 
>>> @@ -5304,6 +5340,140 @@ bool free_to_pcs(struct kmem_cache *s, void *object)
>>>         return true;
>>>  }
>>>
>>> +static void __rcu_free_sheaf_prepare(struct kmem_cache *s,
>>> +                                    struct slab_sheaf *sheaf)
>> 
>> This function seems to be an almost exact copy of free_to_pcs_bulk()
>> from your previous patch. Maybe they can be consolidated?
> 
> True, I've extracted it to __kmem_cache_free_bulk_prepare().

... and that was a mistake as free_to_pcs_bulk() diverges in patch 9/9 in a
way that this makes it too infeasible