Re: [PATCH v4 29/35] mm: slub: Move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context

[Vlastimil Babka]

On 8/9/21 3:41 PM, Qian Cai wrote:

>>  static void flush_all(struct kmem_cache *s)
>>  {
>> -	on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1);
>> +	struct slub_flush_work *sfw;
>> +	unsigned int cpu;
>> +
>> +	mutex_lock(&flush_lock);
> 
> Vlastimil, taking the lock here could trigger a warning during memory offline/online due to the locking order:
> 
> slab_mutex -> flush_lock

Here's the full fixup, also incorporating Mike's fix. Thanks.

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