Re: [PATCH] xfs: use kmem_cache_free() for kmem_cache objects

Vlastimil Babka
2021-09-30T21:11:03Z

On 9/30/21 8:48 PM, Rustam Kovhaev wrote:
> On Thu, Sep 30, 2021 at 10:13:40AM +0200, Vlastimil Babka wrote:
>>
>> I think it's fair if something like XFS (not meant for tiny systems AFAIK?)
>> excludes SLOB (meant for tiny systems). Clearly nobody tried to use these
>> two together last 5 years anyway.
>
> +1 for adding Kconfig option, it seems like some things are not meant to
> be together.

But if we patch SLOB, we won't need it.

>> Maybe we could also just add the 4 bytes to all SLOB objects, declare
>> kfree() is always fine and be done with it. Yes, it will make SLOB footprint
>> somewhat less tiny, but even whan we added kmalloc power of two alignment
>> guarantees, the impact on SLOB was negligible.
>
> I'll send a patch to add a 4-byte header for kmem_cache_alloc()
> allocations.

Thanks. Please report in the changelog slab usage from /proc/meminfo
before and after patch (at least a snapshot after a full boot).

>>> Thoughts?
>>>
>>> Cheers,
>>>
>>> Dave.
>>>
>>