linux-kernel - Re: [PATCH v3 10/21] slab: remove cpu (partial) slabs usage from allocation paths

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Message-ID: <g73gai6ztmaxrigoqwvstyeatdsb6wjunli6gbbhvy7fxqomzv@la3452pj5na4>
Date: Tue, 20 Jan 2026 16:36:15 +0800
From: Hao Li <hao.li@...ux.dev>
To: Vlastimil Babka <vbabka@...e.cz>
Cc: Harry Yoo <harry.yoo@...cle.com>, Petr Tesarik <ptesarik@...e.com>, 
	Christoph Lameter <cl@...two.org>, David Rientjes <rientjes@...gle.com>, 
	Roman Gushchin <roman.gushchin@...ux.dev>, Andrew Morton <akpm@...ux-foundation.org>, 
	Uladzislau Rezki <urezki@...il.com>, "Liam R. Howlett" <Liam.Howlett@...cle.com>, 
	Suren Baghdasaryan <surenb@...gle.com>, Sebastian Andrzej Siewior <bigeasy@...utronix.de>, 
	Alexei Starovoitov <ast@...nel.org>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, 
	linux-rt-devel@...ts.linux.dev, bpf@...r.kernel.org, kasan-dev@...glegroups.com
Subject: Re: [PATCH v3 10/21] slab: remove cpu (partial) slabs usage from
 allocation paths

On Fri, Jan 16, 2026 at 03:40:30PM +0100, Vlastimil Babka wrote:
> We now rely on sheaves as the percpu caching layer and can refill them
> directly from partial or newly allocated slabs. Start removing the cpu
> (partial) slabs code, first from allocation paths.
> 
> This means that any allocation not satisfied from percpu sheaves will
> end up in ___slab_alloc(), where we remove the usage of cpu (partial)
> slabs, so it will only perform get_partial() or new_slab(). In the
> latter case we reuse alloc_from_new_slab() (when we don't use
> the debug/tiny alloc_single_from_new_slab() variant).
> 
> In get_partial_node() we used to return a slab for freezing as the cpu
> slab and to refill the partial slab. Now we only want to return a single
> object and leave the slab on the list (unless it became full). We can't
> simply reuse alloc_single_from_partial() as that assumes freeing uses
> free_to_partial_list(). Instead we need to use __slab_update_freelist()
> to work properly against a racing __slab_free().
> 
> The rest of the changes is removing functions that no longer have any
> callers.
> 
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
> ---
>  mm/slub.c | 612 ++++++++------------------------------------------------------
>  1 file changed, 79 insertions(+), 533 deletions(-)
> 

Looks good to me.
Reviewed-by: Hao Li <hao.li@...ux.dev>

-- 
Thanks,
Hao