linux-kernel - [PATCH V2] x86/mm: Fix zone ranges boot printout

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Date:	Tue, 9 Dec 2014 11:27:20 +0800
From:	Xishi Qiu <qiuxishi@...wei.com>
To:	Ingo Molnar <mingo@...nel.org>, <dave@...1.net>,
	Rik van Riel <riel@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>
CC:	<linux-tip-commits@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux MM <linux-mm@...ck.org>, Xishi Qiu <qiuxishi@...wei.com>
Subject: [PATCH V2] x86/mm: Fix zone ranges boot printout

Changelog:
V2:
	-fix building warnings of min(...).

This is the usual physical memory layout boot printout:
...
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x00001000-0x00ffffff]
[    0.000000]   DMA32    [mem 0x01000000-0xffffffff]
[    0.000000]   Normal   [mem 0x100000000-0xc3fffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x00001000-0x00099fff]
[    0.000000]   node   0: [mem 0x00100000-0xbf78ffff]
[    0.000000]   node   0: [mem 0x100000000-0x63fffffff]
[    0.000000]   node   1: [mem 0x640000000-0xc3fffffff]
...

This is the log when we set "mem=2G" on the boot cmdline:
...
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x00001000-0x00ffffff]
[    0.000000]   DMA32    [mem 0x01000000-0xffffffff]  // should be 0x7fffffff, right?
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x00001000-0x00099fff]
[    0.000000]   node   0: [mem 0x00100000-0x7fffffff]
...

This patch fixes the printout, the following log shows the right ranges:
...
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x00001000-0x00ffffff]
[    0.000000]   DMA32    [mem 0x01000000-0x7fffffff]
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x00001000-0x00099fff]
[    0.000000]   node   0: [mem 0x00100000-0x7fffffff]
...

Signed-off-by: Xishi Qiu <qiuxishi@...wei.com>
---
 arch/x86/mm/init.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 66dba36..963945d 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -674,10 +674,12 @@ void __init zone_sizes_init(void)
 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 
 #ifdef CONFIG_ZONE_DMA
-	max_zone_pfns[ZONE_DMA]		= MAX_DMA_PFN;
+	max_zone_pfns[ZONE_DMA]		= min_t(unsigned long,
+						max_low_pfn, MAX_DMA_PFN);
 #endif
 #ifdef CONFIG_ZONE_DMA32
-	max_zone_pfns[ZONE_DMA32]	= MAX_DMA32_PFN;
+	max_zone_pfns[ZONE_DMA32]	= min_t(unsigned long,
+						max_low_pfn, MAX_DMA32_PFN);
 #endif
 	max_zone_pfns[ZONE_NORMAL]	= max_low_pfn;
 #ifdef CONFIG_HIGHMEM
-- 
2.0.0


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