+ mm-memcg-simplify-objcg-charge-size-and-stock-remainder-math.patch added to mm-new branch

+ mm-memcg-simplify-objcg-charge-size-and-stock-remainder-math.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: memcg: simplify objcg charge size and stock remainder math
has been added to the -mm mm-new branch.  Its filename is
     mm-memcg-simplify-objcg-charge-size-and-stock-remainder-math.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcg-simplify-objcg-charge-size-and-stock-remainder-math.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

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------------------------------------------------------
From: Johannes Weiner <jweiner@meta.com>
Subject: mm: memcg: simplify objcg charge size and stock remainder math
Date: Mon, 2 Mar 2026 14:50:15 -0500

Use PAGE_ALIGN() and a more natural cache remainder calculation.

Link: https://lkml.kernel.org/r/20260302195305.620713-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hao Li <hao.li@linux.dev>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memcontrol.c |   16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

--- a/mm/memcontrol.c~mm-memcg-simplify-objcg-charge-size-and-stock-remainder-math
+++ a/mm/memcontrol.c
@@ -3417,7 +3417,7 @@ out:
 static int obj_cgroup_charge_account(struct obj_cgroup *objcg, gfp_t gfp, size_t size,
 				     struct pglist_data *pgdat, enum node_stat_item idx)
 {
-	unsigned int nr_pages, nr_bytes;
+	size_t charge_size, remainder;
 	int ret;
 
 	if (likely(consume_obj_stock(objcg, size, pgdat, idx)))
@@ -3446,16 +3446,12 @@ static int obj_cgroup_charge_account(str
 	 * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
 	 * race.
 	 */
-	nr_pages = size >> PAGE_SHIFT;
-	nr_bytes = size & (PAGE_SIZE - 1);
+	charge_size = PAGE_ALIGN(size);
+	remainder = charge_size - size;
 
-	if (nr_bytes)
-		nr_pages += 1;
-
-	ret = obj_cgroup_charge_pages(objcg, gfp, nr_pages);
-	if (!ret && (nr_bytes || pgdat))
-		refill_obj_stock(objcg, nr_bytes ? PAGE_SIZE - nr_bytes : 0,
-					 false, size, pgdat, idx);
+	ret = obj_cgroup_charge_pages(objcg, gfp, charge_size >> PAGE_SHIFT);
+	if (!ret && (remainder || pgdat))
+		refill_obj_stock(objcg, remainder, false, size, pgdat, idx);
 
 	return ret;
 }
_

Patches currently in -mm which might be from jweiner@meta.com are

mm-memcg-factor-out-trylock_stock-and-unlock_stock.patch
mm-memcg-simplify-objcg-charge-size-and-stock-remainder-math.patch