// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 *  Swap reorganised 29.12.95, Stephen Tweedie.
 *  kswapd added: 7.1.96  sct
 *  Removed kswapd_ctl limits, and swap out as many pages as needed
 *  to bring the system back to freepages.high: 2.4.97, Rik van Riel.
 *  Zone aware kswapd started 02/00, Kanoj Sarcar (kanoj@sgi.com).
 *  Multiqueue VM started 5.8.00, Rik van Riel.
 */

/* Extracted unchanged from Linux v6.12, mm/vmscan.c:6659-6692.
 * Full function definition; surrounding kernel context is required.
 * Source: https://github.com/torvalds/linux/blob/v6.12/mm/vmscan.c#L6659
 * License text: GPL-2.0.txt (in this directory).
 */
static bool pgdat_balanced(pg_data_t *pgdat, int order, int highest_zoneidx)
{
	int i;
	unsigned long mark = -1;
	struct zone *zone;

	/*
	 * Check watermarks bottom-up as lower zones are more likely to
	 * meet watermarks.
	 */
	for (i = 0; i <= highest_zoneidx; i++) {
		zone = pgdat->node_zones + i;

		if (!managed_zone(zone))
			continue;

		if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING)
			mark = promo_wmark_pages(zone);
		else
			mark = high_wmark_pages(zone);
		if (zone_watermark_ok_safe(zone, order, mark, highest_zoneidx))
			return true;
	}

	/*
	 * If a node has no managed zone within highest_zoneidx, it does not
	 * need balancing by definition. This can happen if a zone-restricted
	 * allocation tries to wake a remote kswapd.
	 */
	if (mark == -1)
		return true;

	return false;
}