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

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Message-ID: <CAJuCfpG6cCo1WUo3N116DOavmRE6=aeS_s2Hzceqdytgc955xw@mail.gmail.com>
Date: Thu, 15 May 2025 08:03:59 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: Vlastimil Babka <vbabka@...e.cz>
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 Thu, May 15, 2025 at 1:45 AM Vlastimil Babka <vbabka@...e.cz> wrote:
>
> 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

Ah, I see. Makes sense. Sorry for the misleading suggestion.