[to-be-updated] mm-page_alloc-only-update-lowmem_reserve_ratio-on-sysctl-write.patch removed from -mm tree

The quilt patch titled
     Subject: mm/page_alloc: only update lowmem_reserve_ratio on sysctl write
has been removed from the -mm tree.  Its filename was
     mm-page_alloc-only-update-lowmem_reserve_ratio-on-sysctl-write.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: Jianlin Shi <[email protected]>
Subject: mm/page_alloc: only update lowmem_reserve_ratio on sysctl write
Date: Sat, 1 Aug 2026 23:11:25 +0800

lowmem_reserve_ratio_sysctl_handler() ignores the return value of
proc_dointvec_minmax() and always calls setup_per_zone_lowmem_reserve(),
even for read operations.

Fix two issues:

1. Propagate errors from proc_dointvec_minmax() instead of always
   returning success.  For example, writing non-integer garbage to the
   sysctl now returns an error instead of silently succeeding with
   unchanged values.

2. Only call setup_per_zone_lowmem_reserve() when the sysctl is
   actually written.  Reading /proc/sys/vm/lowmem_reserve_ratio should
   not recompute derived lowmem_reserve[] and totalreserve_pages when
   the inputs did not change, matching min_free_kbytes and
   watermark_scale_factor handlers.

Drop the manual "< 1 -> 0" sanitization loop and set .extra1 = SYSCTL_ZERO
on the ctl_table entry so proc_dointvec_minmax() enforces the minimum on
write; negative values now return -EINVAL instead of being silently
coerced to 0 (suggested by Vlastimil Babka).

Link: https://lore.kernel.org/[email protected]
Link: https://lore.kernel.org/linux-mm/[email protected]/
Signed-off-by: Jianlin Shi <[email protected]>
Reviewed-by: Vlastimil Babka (SUSE) <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/page_alloc.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/mm/page_alloc.c~mm-page_alloc-only-update-lowmem_reserve_ratio-on-sysctl-write
+++ a/mm/page_alloc.c
@@ -6925,16 +6925,15 @@ static int sysctl_min_slab_ratio_sysctl_
 static int lowmem_reserve_ratio_sysctl_handler(const struct ctl_table *table,
 		int write, void *buffer, size_t *length, loff_t *ppos)
 {
-	int i;
+	int rc;
 
-	proc_dointvec_minmax(table, write, buffer, length, ppos);
+	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
+	if (rc)
+		return rc;
 
-	for (i = 0; i < MAX_NR_ZONES; i++) {
-		if (sysctl_lowmem_reserve_ratio[i] < 1)
-			sysctl_lowmem_reserve_ratio[i] = 0;
-	}
+	if (write)
+		setup_per_zone_lowmem_reserve();
 
-	setup_per_zone_lowmem_reserve();
 	return 0;
 }
 
@@ -7033,6 +7032,7 @@ static const struct ctl_table page_alloc
 		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
 		.mode		= 0644,
 		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
+		.extra1		= SYSCTL_ZERO,
 	},
 #ifdef CONFIG_NUMA
 	{
_

Patches currently in -mm which might be from [email protected] are

ipc-only-destroy-orphaned-shm-segments-on-sysctl-write.patch