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

From: Vlastimil Babka <vbabka@suse.cz>
To: Chengming Zhou <chengming.zhou@linux.dev>,
	cl@linux.com, penberg@kernel.org
Cc: rientjes@google.com, iamjoonsoo.kim@lge.com,
	akpm@linux-foundation.org, roman.gushchin@linux.dev,
	42.hyeyoo@gmail.com, willy@infradead.org, pcc@google.com,
	tytso@mit.edu, maz@kernel.org, ruansy.fnst@fujitsu.com,
	vishal.moola@gmail.com, lrh2000@pku.edu.cn, hughd@google.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Chengming Zhou <zhouchengming@bytedance.com>
Subject: Re: [RFC PATCH v2 0/6] slub: Delay freezing of CPU partial slabs
Date: Tue, 24 Oct 2023 10:20:10 +0200	[thread overview]
Message-ID: <4b687334-9667-2655-ab5b-a1aecedb5591@suse.cz> (raw)
In-Reply-To: <72361910-240f-4aa2-a695-117e1b14a804@linux.dev>

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!