linux-kernel - Re: [PATCH RFC v2 04/20] slab: add sheaves to most caches

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Message-ID: <aWnewyp0L0WRUPud@hyeyoo>
Date: Fri, 16 Jan 2026 15:46:27 +0900
From: Harry Yoo <harry.yoo@...cle.com>
To: Vlastimil Babka <vbabka@...e.cz>
Cc: Petr Tesarik <ptesarik@...e.com>, Christoph Lameter <cl@...two.org>,
        David Rientjes <rientjes@...gle.com>,
        Roman Gushchin <roman.gushchin@...ux.dev>, Hao Li <hao.li@...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 RFC v2 04/20] slab: add sheaves to most caches

On Mon, Jan 12, 2026 at 04:16:58PM +0100, Vlastimil Babka wrote:
> In the first step to replace cpu (partial) slabs with sheaves, enable
> sheaves for almost all caches. Treat args->sheaf_capacity as a minimum,
> and calculate sheaf capacity with a formula that roughly follows the
> formula for number of objects in cpu partial slabs in set_cpu_partial().
> 
> This should achieve roughly similar contention on the barn spin lock as
> there's currently for node list_lock without sheaves, to make
> benchmarking results comparable. It can be further tuned later.
> 
> Don't enable sheaves for bootstrap caches as that wouldn't work. In
> order to recognize them by SLAB_NO_OBJ_EXT, make sure the flag exists
> even for !CONFIG_SLAB_OBJ_EXT.
> 
> This limitation will be lifted for kmalloc caches after the necessary
> bootstrapping changes.
> 
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
> ---

Looks good to me,
Reviewed-by: Harry Yoo <harry.yoo@...cle.com>

-- 
Cheers,
Harry / Hyeonggon