+ um-mm-remove-redundant-assignment-of-max_low_pfn.patch added to mm-unstable branch

+ um-mm-remove-redundant-assignment-of-max_low_pfn.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: um/mm: remove redundant assignment of max_low_pfn
has been added to the -mm mm-unstable branch.  Its filename is
     um-mm-remove-redundant-assignment-of-max_low_pfn.patch

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

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

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------------------------------------------------------
From: Wei Yang <richard.weiyang@gmail.com>
Subject: um/mm: remove redundant assignment of max_low_pfn
Date: Sat, 15 Jun 2024 03:41:50 +0000

Current calculation of max_low_pfn is introduced in commit af84eab20891
("[PATCH] uml: fix LVM crash").  It is intended to set max_low_pfn to the
same value as max_pfn.

But I am not sure why the max_pfn is set to totalram_pages, which
represents the number of usable pages in system instead of an absolute
page frame number.  (The change history stops there.)

While we have already calculate it in setup_physmem(), so not necessary to
do it again.

Also this would help changing totalram_pages accounting, since we plan to
move the accounting into __free_pages_core().  With this change,
totalram_pages may not represent the total usable pages at this point,
since some pages would be deferred initialized.

Link: https://lkml.kernel.org/r/20240615034150.2958-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/um/kernel/mem.c |    1 -
 1 file changed, 1 deletion(-)

--- a/arch/um/kernel/mem.c~um-mm-remove-redundant-assignment-of-max_low_pfn
+++ a/arch/um/kernel/mem.c
@@ -73,7 +73,6 @@ void __init mem_init(void)
 
 	/* this will put all low memory onto the freelists */
 	memblock_free_all();
-	max_low_pfn = totalram_pages();
 	max_pfn = max_low_pfn;
 	kmalloc_ok = 1;
 }
_

Patches currently in -mm which might be from richard.weiyang@gmail.com are

um-mm-remove-redundant-assignment-of-max_low_pfn.patch