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From: Wei Yang <richard.weiyang@gmail.com>
To: richard@nod.at, anton.ivanov@cambridgegreys.com,
	johannes@sipsolutions.net
Cc: linux-um@lists.infradead.org, linux-mm@kvack.org,
	Wei Yang <richard.weiyang@gmail.com>,
	Jeff Dike <jdike@linux.intel.com>,
	Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>,
	Alasdair G Kergon <agk@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Rapoport <rppt@kernel.org>,
	David Hildenbrand <david@redhat.com>
Subject: [PATCH v2] um/mm: remove redundant assignment of max_low_pfn
Date: Sat, 15 Jun 2024 03:41:50 +0000	[thread overview]
Message-ID: <20240615034150.2958-1-richard.weiyang@gmail.com> (raw)

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.

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

---
v2: remove redundant assignment of max_low_pfn
---
 arch/um/kernel/mem.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index ca91accd64fc..a5b4fe2ad931 100644
--- a/arch/um/kernel/mem.c
+++ b/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;
 }
-- 
2.34.1



             reply	other threads:[~2024-06-15  3:42 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-15  3:41 Wei Yang [this message]
2024-06-15  8:17 ` [PATCH v2] um/mm: remove redundant assignment of max_low_pfn Mike Rapoport
2024-07-23  3:43 ` Wei Yang

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