Re: [PATCH v4 4/4] slub: apply new pw_queue_on() interface

[Sebastian Andrzej Siewior]

On 2026-05-18 22:27:50 [-0300], Leonardo Bras wrote:
> @@ -4733,121 +4735,121 @@ void *alloc_from_pcs(struct kmem_cache *s, gfp_t gfp, int node)
>  
>  	/*
>  	 * We assume the percpu sheaves contain only local objects although it's
>  	 * not completely guaranteed, so we verify later.
>  	 */
>  	if (unlikely(node_requested && node != numa_mem_id())) {
>  		stat(s, ALLOC_NODE_MISMATCH);
>  		return NULL;
>  	}
>  
> -	if (!local_trylock(&s->cpu_sheaves->lock))
> +	if (!pw_trylock_local(&s->cpu_sheaves->lock))
>  		return NULL;

alloc_from_pcs() can be called from kmalloc_nolock()/ NMI context.
I don't remember why exactly local_trylock_t was introduced here instead
of a per-CPU spinlock_t. But there should be nothing wrong with a
trylock on it from NMI as you do here.

One thing worth noting, on !PREEMPT_RT, spin_trylock() always succeeds
on UP. kmalloc_nolock() checks for it, not sure about other callers.

Sebastian