Re: [PATCH v3] mm/memory: drop PROCESS_PAGES_NON_PREEMPT_BATCH

[Peter Zijlstra <peterz@infradead.org>]

On Mon, Nov 09, 2026 at 07:15:51PM +0000, Shivank Garg wrote:
>  static void clear_contig_highpages(struct page *page, unsigned long addr,
> +		unsigned int nr_pages)
>  {
> +	unsigned int i;
> +
> +	might_sleep();
> +
>  	/*
>  	 * When clearing we want to operate on the largest extent possible to
>  	 * allow for architecture specific extent based optimizations.
>  	 *
> +	 * clear_user_highpages() (and primitives clear_user_pages(),
> +	 * clear_pages()) do not call cond_resched(). That is fine on
> +	 * preemptible kernels, where the scheduler can preempt the clearing
> +	 * at any point, so clear the whole range at once. Otherwise, clear
> +	 * one page at a time and reschedule in between.
>  	 */
> +	if (IS_ENABLED(CONFIG_PREEMPTION)) {
> +		clear_user_highpages(page, addr, nr_pages);
> +		return;
> +	}
>  
> +	for (i = 0; i < nr_pages; i++) {

FWIW one could do:

	for (int i = 0; i < nr_pages; i++) {

and forgo the earlier variable declaration.

>  		cond_resched();
> +		clear_user_highpage(page + i, addr + i * PAGE_SIZE);
>  	}
>  }