linux-kernel - Re: [RFC PATCH v2 0/6] slub: Delay freezing of CPU partial slabs

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Message-ID: <4b687334-9667-2655-ab5b-a1aecedb5591@suse.cz>
Date:   Tue, 24 Oct 2023 10:20:10 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     Chengming Zhou <chengming.zhou@...ux.dev>, cl@...ux.com,
        penberg@...nel.org
Cc:     rientjes@...gle.com, iamjoonsoo.kim@....com,
        akpm@...ux-foundation.org, roman.gushchin@...ux.dev,
        42.hyeyoo@...il.com, willy@...radead.org, pcc@...gle.com,
        tytso@....edu, maz@...nel.org, ruansy.fnst@...itsu.com,
        vishal.moola@...il.com, lrh2000@....edu.cn, hughd@...gle.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Chengming Zhou <zhouchengming@...edance.com>
Subject: Re: [RFC PATCH v2 0/6] slub: Delay freezing of CPU partial slabs

On 10/24/23 04:20, Chengming Zhou wrote:
> On 2023/10/23 23:46, Vlastimil Babka wrote:
>> Or more precisely, instead of returning the acquired "object" we would
>> return the first slab removed from partial list. I think it would simplify
>> the code a bit, and further reduce list_lock holding times.
> 
> Ok, I will do this in the next version. But I find we have to return the object
> in the "IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)" case, in which
> we need to allocate a single object under the node list_lock.

Ah, right.

> Maybe we can use "struct partial_context" to return the object in this case?
> 
>  struct partial_context {
> -       struct slab **slab;
>         gfp_t flags;
>         unsigned int orig_size;
> +       void *object;
>  };
> 
> Then we can change all get_partial interfaces to return a slab. Do you agree
> with this way?

Yeah, good idea! Thanks!