x86/mm: Fix zone ranges boot printout

PATCH Superseded Xishi Qiu 2 participants 3 messages Dec 9, 2014 – Dec 10, 2014

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Memory management x86 x86 MM

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Xishi Qiu

author

2014-12-09 03:27 UTC #0 lore raw

PATCH v2 1/1 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 <[email protected]>

---
 arch/x86/mm/init.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

arch/x86/mm/init.c +4 -2

index 66dba36..963945d 100644
@@ -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

Signature · 1 line

2.0.0

Andrew Morton

maintainer

2014-12-09 22:50 UTC #1 lore raw

Quoted 9 lines · On Tue, 9 Dec 2014 11:27:20 +0800 Xishi Qiu <[email protected]> wrote:

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

arch/x86/mm/init.c void __init zone_sizes_init(void) · line 678

Quoted 6 lines

arch/x86/mm/init.c +2 -1

@@ -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);

MAX_DMA_PFN has type int.

arch/x86/mm/init.c void __init zone_sizes_init(void) · line 682

Quoted 5 lines

arch/x86/mm/init.c +2 -1

 #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);

MAX_DMA32_PFN has type UL (I think?) so there's no need for min_t here.

arch/x86/mm/init.c void __init zone_sizes_init(void) · line 685

Quoted 3 lines

arch/x86/mm/init.c +0 -0

 #endif
 	max_zone_pfns[ZONE_NORMAL]	= max_low_pfn;
 #ifdef CONFIG_HIGHMEM

Let's try to get the types correct, rather than hacking around fixing up fallout from earlier incorrect type choices?

What is the type of a pfn? Unsigned long, generally, when we bother thinking about it.

So how about we make MAX_DMA_PFN have type UL? I assume that fixes the warning?

If we do this, we should also be able to undo the min_t hackery in arch/x86/kernel/e820.c:memblock_find_dma_reserve().

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Xishi Qiu

author

2014-12-10 01:40 UTC #2 lore raw

Quoted 36 lines · Andrew Morton

Quoted 9 lines · On Tue, 9 Dec 2014 11:27:20 +0800 Xishi Qiu <[email protected]> wrote:
Changelog:
V2:
-fix building warnings of min(...).
...
arch/x86/mm/init.c void __init zone_sizes_init(void) · line 678
Quoted 6 lines
arch/x86/mm/init.c +2 -1
@@ -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);
MAX_DMA_PFN has type int.
arch/x86/mm/init.c void __init zone_sizes_init(void) · line 682
Quoted 5 lines
arch/x86/mm/init.c +2 -1
 #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);
MAX_DMA32_PFN has type UL (I think?) so there's no need for min_t here.
arch/x86/mm/init.c void __init zone_sizes_init(void) · line 685
Quoted 3 lines
arch/x86/mm/init.c +0 -0
 #endif
 	max_zone_pfns[ZONE_NORMAL]	= max_low_pfn;
 #ifdef CONFIG_HIGHMEM
Let's try to get the types correct, rather than hacking around fixing up fallout from earlier incorrect type choices?

Quoted 9 lines

What is the type of a pfn? Unsigned long, generally, when we bother thinking about it.
So how about we make MAX_DMA_PFN have type UL? I assume that fixes the warning?
If we do this, we should also be able to undo the min_t hackery in arch/x86/kernel/e820.c:memblock_find_dma_reserve().

Hi Andrew,

Thanks for your suggestion, I'll resend V3.

Thanks,
Xishi Qiu

Quoted 3 lines

.