linux-kernel - Re: [PATCH RFC v3 3/8] slab: add sheaf support for batching kfree

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Message-ID: <9073aa19-0f12-4dd7-8d10-2f159f3fd362@suse.cz>
Date: Tue, 22 Apr 2025 17:18:32 +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 RFC v3 3/8] slab: add sheaf support for batching
 kfree_rcu() operations

On 4/10/25 22:24, Suren Baghdasaryan wrote:
> On Mon, Mar 17, 2025 at 7:33 AM Vlastimil Babka <vbabka@...e.cz> wrote:
>> +do_free:
>> +
>> +       rcu_sheaf = pcs->rcu_free;
>> +
>> +       rcu_sheaf->objects[rcu_sheaf->size++] = obj;
>> +
>> +       if (likely(rcu_sheaf->size < s->sheaf_capacity)) {
>> +               localtry_unlock(&s->cpu_sheaves->lock);
>> +               stat(s, FREE_RCU_SHEAF);
>> +               return true;
>> +       }
>> +
>> +       pcs->rcu_free = NULL;
>> +       localtry_unlock(&s->cpu_sheaves->lock);
>> +
>> +       call_rcu(&rcu_sheaf->rcu_head, rcu_free_sheaf);
>> +
>> +       stat(s, FREE_RCU_SHEAF);
>> +       return true;
> 
> nit: I think the above code could be simplified to:
> 
> do_free:
>         rcu_sheaf = pcs->rcu_free;
>         rcu_sheaf->objects[rcu_sheaf->size++] = obj;
>         if (likely(rcu_sheaf->size < s->sheaf_capacity))
>                 rcu_sheaf = NULL;
>         else
>                 pcs->rcu_free = NULL;
> 
>         localtry_unlock(&s->cpu_sheaves->lock);
>         stat(s, FREE_RCU_SHEAF);
>         if (rcu_sheaf)
>                 call_rcu(&rcu_sheaf->rcu_head, rcu_free_sheaf);
> 
>         return true;

Right, done. Thanks.