linux-kernel - Re: [PATCH RFC 08/19] slab: handle kmalloc sheaves bootstrap

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Message-ID: <982967fc-5636-46dc-83a1-ed3f4d98c8ae@suse.cz>
Date: Wed, 29 Oct 2025 21:06:09 +0100
From: Vlastimil Babka <vbabka@...e.cz>
To: Harry Yoo <harry.yoo@...cle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
 Christoph Lameter <cl@...two.org>, David Rientjes <rientjes@...gle.com>,
 Roman Gushchin <roman.gushchin@...ux.dev>,
 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 08/19] slab: handle kmalloc sheaves bootstrap

On 10/27/25 07:12, Harry Yoo wrote:
>> @@ -8549,6 +8559,74 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
>>  	return s;
>>  }
>>  
>> +/*
>> + * Finish the sheaves initialization done normally by init_percpu_sheaves() and
>> + * init_kmem_cache_nodes(). For normal kmalloc caches we have to bootstrap it
>> + * since sheaves and barns are allocated by kmalloc.
>> + */
>> +static void __init bootstrap_cache_sheaves(struct kmem_cache *s)
>> +{
>> +	struct kmem_cache_args empty_args = {};
>> +	unsigned int capacity;
>> +	bool failed = false;
>> +	int node, cpu;
>> +
>> +	capacity = calculate_sheaf_capacity(s, &empty_args);
>> +
>> +	/* capacity can be 0 due to debugging or SLUB_TINY */
>> +	if (!capacity)
>> +		return;
> 
> I think pcs->main should still be !NULL in this case?

It will remain to be set to bootstrap_sheaf, and with s->sheaf_capacity
things will continue to work.