linux-kernel - [PATCH 1/2] mm/mempolicy: Simplify weighted interleave bulk alloc calculations

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Message-ID: <20250626200936.3974420-2-joshua.hahnjy@gmail.com>
Date: Thu, 26 Jun 2025 13:09:33 -0700
From: Joshua Hahn <joshua.hahnjy@...il.com>
To: Gregory Price <gourry@...rry.net>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	Alistair Popple <apopple@...dia.com>,
	Byungchul Park <byungchul@...com>,
	David Hildenbrand <david@...hat.com>,
	Matthew Brost <matthew.brost@...el.com>,
	Rakie Kim <rakie.kim@...com>,
	Ying Huang <ying.huang@...ux.alibaba.com>,
	Zi Yan <ziy@...dia.com>,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	kernel-team@...a.com
Subject: [PATCH 1/2] mm/mempolicy: Simplify weighted interleave bulk alloc calculations

Simplify the math used to figure out how many pages should be allocated
per node. Instead of making conditional additions and deletions, we can just
make them unconditional by using min(). No functional changes intended.

Signed-off-by: Joshua Hahn <joshua.hahnjy@...il.com>

---
 mm/mempolicy.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 3b1dfd08338b..78ad74a0e249 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2645,18 +2645,15 @@ static unsigned long alloc_pages_bulk_weighted_interleave(gfp_t gfp,
 	for (i = 0; i < nnodes; i++) {
 		node = next_node_in(prev_node, nodes);
 		weight = weights[node];
-		node_pages = weight * rounds;
-		/* If a delta exists, add this node's portion of the delta */
-		if (delta > weight) {
-			node_pages += weight;
-			delta -= weight;
-		} else if (delta) {
-			/* when delta is depleted, resume from that node */
-			node_pages += delta;
+		/* when delta is depleted, resume from that node */
+		if (delta && delta < weight) {
 			resume_node = node;
 			resume_weight = weight - delta;
-			delta = 0;
 		}
+		/* Add the node's portion of the delta, if there is one */
+		node_pages = weight * rounds + min(delta, weight);
+		delta -= min(delta, weight);
+
 		/* node_pages can be 0 if an allocation fails and rounds == 0 */
 		if (!node_pages)
 			break;
-- 
2.47.1