Re: [PATCH 17/43] workqueue: update cwq alignement

[Oleg Nesterov]

On 02/26, Tejun Heo wrote:
>
> +static struct cpu_workqueue_struct *alloc_cwqs(void)
> +{
> +	const size_t size = sizeof(struct cpu_workqueue_struct);
> +	const size_t align = 1 << WORK_STRUCT_FLAG_BITS;
> +	struct cpu_workqueue_struct *cwqs;
> +#ifndef CONFIG_SMP
> +	void *ptr;
> +
> +	/*
> +	 * On UP, percpu allocator doesn't honor alignment parameter
> +	 * and simply uses arch-dependent default.  Allocate enough
> +	 * room to align cwq and put an extra pointer at the end
> +	 * pointing back to the originally allocated pointer which
> +	 * will be used for free.
> +	 */
> +	ptr = __alloc_percpu(size + align + sizeof(void *), 1);
> +	cwqs = PTR_ALIGN(ptr, align);
> +	*(void **)per_cpu_ptr(cwqs + 1, 0) = ptr;
> +#else

Nice trick, but perhaps it would be more simple/clear to just add
"void *my_memory" into cpu_workqueue_struct, under !CONFIG_SMP ?

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/