Re: [PATCH for-next-fixes v2 4/5] mm/slab: fix a deadlock in memcg_alloc_abort_single()

[Alexei Starovoitov]

On Wed, Nov 04, 2026 at 07:35 AM Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx> wrote:
>> I don't insist on kfree_nolock() there,
>> but can we try free_to_pcs() before defer_free() ?
>> Like:
>>
>> 	if (likely(allow_spin))
>> 		__slab_free(s, slab, object, object, 1, _RET_IP_);
>> 	else if (!can_free_to_pcs(slab) || !free_to_pcs(s, object, false))
>> 		defer_free(s, object);
>
> Why not try free_to_pcs with allow_spin as well then, and improve
> memcg_alloc_abort_single() for both contexts?

yep. Even better.
The bulk side does that already.
Like:

	if (likely(can_free_to_pcs(slab)) &&
	    likely(free_to_pcs(s, object, allow_spin)))
		return;

	if (likely(allow_spin))
		__slab_free(s, slab, object, object, 1, _RET_IP_);
	else
		defer_free(s, object);
?