linux-kernel - Re: [PATCH v3 2/2] mm/slub: refactor deactivate

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Message-ID: <YibjQpm55PldiKji@carbon.dhcp.thefacebook.com>
Date:   Mon, 7 Mar 2022 21:01:54 -0800
From:   Roman Gushchin <roman.gushchin@...ux.dev>
To:     Hyeonggon Yoo <42.hyeyoo@...il.com>
Cc:     linux-mm@...ck.org, Christoph Lameter <cl@...ux.com>,
        Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Marco Elver <elver@...gle.com>,
        Matthew WilCox <willy@...radead.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] mm/slub: refactor deactivate_slab()

On Mon, Mar 07, 2022 at 07:40:56AM +0000, Hyeonggon Yoo wrote:
> Simplify deactivate_slab() by unlocking n->list_lock and retrying
> cmpxchg_double() when cmpxchg_double() fails, and perform
> add_{partial,full} only when it succeed.
> 
> Releasing and taking n->list_lock again here is not harmful as SLUB
> avoids deactivating slabs as much as possible.
> 
> [ vbabka@...e.cz: perform add_{partial,full} when cmpxchg_double()
>   succeed.
> 
>   count deactivating full slabs even if debugging flag is not set. ]
> 
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@...il.com>

Reviewed-by: Roman Gushchin <roman.gushchin@...ux.dev>

Thanks!