linux-kernel - Re: [PATCH v3 18/21] slab: update overview comments

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Message-ID: <aXHGfLV6FdlNPc14@hyeyoo>
Date: Thu, 22 Jan 2026 15:41:00 +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 v3 18/21] slab: update overview comments

On Fri, Jan 16, 2026 at 03:40:38PM +0100, Vlastimil Babka wrote:
> The changes related to sheaves made the description of locking and other
> details outdated. Update it to reflect current state.
> 
> Also add a new copyright line due to major changes.
> 
> Reviewed-by: Suren Baghdasaryan <surenb@...gle.com>
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
> ---
> @@ -112,47 +123,46 @@
> + *   node->barn->lock (spinlock)
>   *
> - *   lockless fastpaths
> + *   Lockless freeing
> + *
> + *   Objects may have to be freed to their slabs when they are from a remote
> + *   node (where we want to avoid filling local sheaves with remote objects)
> + *   or when there are too many full sheaves. On architectures supporting
> + *   cmpxchg_double this is done by a lockless update of slab's freelist and
> + *   counters, otherwise slab_lock is taken. This only needs to take the
> + *   list_lock if it's a first free to a full slab, or when there are too many
> + *   fully free slabs and some need to be discarded.

nit: "or when a slab becomes empty after the free"?
because we don't check nr_partial before acquiring list_lock.

With that addressed,
Reviewed-by: Harry Yoo <harry.yoo@...cle.com>

-- 
Cheers,
Harry / Hyeonggon