+ mm-page_alloc-remove-redundant-read_once.patch added to mm-new branch

+ mm-page_alloc-remove-redundant-read_once.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: page_alloc: remove redundant READ_ONCE
has been added to the -mm mm-new branch.  Its filename is
     mm-page_alloc-remove-redundant-read_once.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-remove-redundant-read_once.patch

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

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------------------------------------------------------
From: Songtang Liu <liusongtang@bytedance.com>
Subject: mm: page_alloc: remove redundant READ_ONCE
Date: Wed, 2 Apr 2025 03:41:16 -0400

In the current code, batch is a local variable, and it cannot be
concurrently modified.  It's unnecessary to use READ_ONCE here, so remove
it.

Link: https://lkml.kernel.org/r/CAA=HWd1kn01ym8YuVFuAqK2Ggq3itEGkqX8T6eCXs_C7tiv-Jw@mail.gmail.com
Fixes: 51a755c56dc0 ("mm: tune PCP high automatically")
Signed-off-by: Songtang Liu <liusongtang@bytedance.com>
Reviewed-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/page_alloc.c~mm-page_alloc-remove-redundant-read_once
+++ a/mm/page_alloc.c
@@ -2634,7 +2634,7 @@ static void free_frozen_page_commit(stru
 		free_high = (pcp->free_count >= batch &&
 			     (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) &&
 			     (!(pcp->flags & PCPF_FREE_HIGH_BATCH) ||
-			      pcp->count >= READ_ONCE(batch)));
+			      pcp->count >= batch));
 		pcp->flags |= PCPF_PREV_FREE_HIGH_ORDER;
 	} else if (pcp->flags & PCPF_PREV_FREE_HIGH_ORDER) {
 		pcp->flags &= ~PCPF_PREV_FREE_HIGH_ORDER;
_

Patches currently in -mm which might be from liusongtang@bytedance.com are

mm-page_alloc-remove-redundant-read_once.patch