[PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE5090d

8 messages, 4 authors, 2012-09-27 · open the first message on its own page

[PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Shaohui Xie <hidden>
Date: 2012-08-24 11:20:38

PowerPC platform only supports ZONE_DMA zone for 64bit kernel, so all the
memory will be put into this zone. If the memory size is greater than
the device's DMA capability and device uses dma_alloc_coherent to allocate
memory, it will get an address which is over the device's DMA addressing,
the device will fail.

So we split the memory to two zones: zone ZONE_DMA32 & ZONE_NORMAL, since
we already allocate PCICSRBAR/PEXCSRBAR right below the 4G boundary (if the
lowest PCI address is above 4G), so we constrain the DMA zone ZONE_DMA32
to 2GB, also, we clear flag __GFP_DMA & __GFP_DMA32 and set __GFP_DMA32 only
if the device's dma_mask < total memory size. By doing this, devices which
cannot DMA all the memory will be limited to ZONE_DMA32, but devices which
can DMA all the memory will not be affected by this limitation.

Signed-off-by: Shaohui Xie <redacted>
Signed-off-by: Mingkai Hu <redacted>
Signed-off-by: Chen Yuanquan <redacted>
---
changes for v2:
1. use a config option for using two zones (ZONE_DMA32 & ZONE_NORMAL) in
freescale 64 bit kernel.

 arch/powerpc/Kconfig      |    3 +++
 arch/powerpc/kernel/dma.c |   15 +++++++++++++++
 arch/powerpc/mm/mem.c     |    4 ++++
 3 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 352f416..a96fbbb 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -629,6 +629,9 @@ config ZONE_DMA
 	bool
 	default y
 
+config ZONE_DMA32
+	def_bool (PPC64 && PPC_FSL_BOOK3E)
+
 config NEED_DMA_MAP_STATE
 	def_bool (PPC64 || NOT_COHERENT_CACHE)

diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index 355b9d8..cbf5ac1 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c

@@ -41,9 +41,24 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t size,
 #else
 	struct page *page;
 	int node = dev_to_node(dev);
+#ifdef CONFIG_ZONE_DMA32
+	phys_addr_t top_ram_pfn = memblock_end_of_DRAM();
 
+	/*
+	 * check for crappy device which has dma_mask < ZONE_DMA, and
+	 * we are not going to support it, just warn and fail.
+	 */
+	if (*dev->dma_mask < DMA_BIT_MASK(31)) {
+		dev_err(dev, "Unsupported dma_mask 0x%llx\n", *dev->dma_mask);
+		return NULL;
+	}
 	/* ignore region specifiers */
+	flag  &= ~(__GFP_HIGHMEM | __GFP_DMA | __GFP_DMA32);
+	if (*dev->dma_mask < top_ram_pfn - 1)
+		flag |= __GFP_DMA32;
+#else
 	flag  &= ~(__GFP_HIGHMEM);
+#endif
 
 	page = alloc_pages_node(node, flag, get_order(size));
 	if (page == NULL)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index baaafde..2a11e49 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c

@@ -280,6 +280,10 @@ void __init paging_init(void)
 #ifdef CONFIG_HIGHMEM
 	max_zone_pfns[ZONE_DMA] = lowmem_end_addr >> PAGE_SHIFT;
 	max_zone_pfns[ZONE_HIGHMEM] = top_of_ram >> PAGE_SHIFT;
+#elif defined CONFIG_ZONE_DMA32
+	max_zone_pfns[ZONE_DMA32] = min_t(phys_addr_t, top_of_ram,
+					1ull << 31) >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_NORMAL] = top_of_ram >> PAGE_SHIFT;
 #else
 	max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
 #endif

-- 
1.6.4

Re: [PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Kumar Gala <hidden>
Date: 2012-08-30 20:50:02

On Aug 24, 2012, at 5:50 AM, Shaohui Xie wrote:

PowerPC platform only supports ZONE_DMA zone for 64bit kernel, so all =

the

memory will be put into this zone. If the memory size is greater than
the device's DMA capability and device uses dma_alloc_coherent to =

allocate

memory, it will get an address which is over the device's DMA =

addressing,

the device will fail.
=20
So we split the memory to two zones: zone ZONE_DMA32 & ZONE_NORMAL, =

since

we already allocate PCICSRBAR/PEXCSRBAR right below the 4G boundary =

(if the

lowest PCI address is above 4G), so we constrain the DMA zone =

ZONE_DMA32

to 2GB, also, we clear flag __GFP_DMA & __GFP_DMA32 and set =

__GFP_DMA32 only

if the device's dma_mask < total memory size. By doing this, devices =

which

cannot DMA all the memory will be limited to ZONE_DMA32, but devices =

which

can DMA all the memory will not be affected by this limitation.
=20
Signed-off-by: Shaohui Xie <redacted>
Signed-off-by: Mingkai Hu <redacted>
Signed-off-by: Chen Yuanquan <redacted>
---
changes for v2:
1. use a config option for using two zones (ZONE_DMA32 & ZONE_NORMAL) =

in

freescale 64 bit kernel.
=20
arch/powerpc/Kconfig      |    3 +++
arch/powerpc/kernel/dma.c |   15 +++++++++++++++
arch/powerpc/mm/mem.c     |    4 ++++
3 files changed, 22 insertions(+), 0 deletions(-)

Ben,

What's the feeling of doing this on ppc64 always?=20

- k

quoted hunk

=20

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 352f416..a96fbbb 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -629,6 +629,9 @@ config ZONE_DMA

	bool
	default y
=20
+config ZONE_DMA32
+	def_bool (PPC64 && PPC_FSL_BOOK3E)
+
config NEED_DMA_MAP_STATE
	def_bool (PPC64 || NOT_COHERENT_CACHE)
=20

diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index 355b9d8..cbf5ac1 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c

@@ -41,9 +41,24 @@ void *dma_direct_alloc_coherent(struct device *dev, =

size_t size,

#else
	struct page *page;
	int node =3D dev_to_node(dev);
+#ifdef CONFIG_ZONE_DMA32
+	phys_addr_t top_ram_pfn =3D memblock_end_of_DRAM();
=20
+	/*
+	 * check for crappy device which has dma_mask < ZONE_DMA, and
+	 * we are not going to support it, just warn and fail.
+	 */
+	if (*dev->dma_mask < DMA_BIT_MASK(31)) {
+		dev_err(dev, "Unsupported dma_mask 0x%llx\n", =

*dev->dma_mask);

quoted hunk

+		return NULL;
+	}
	/* ignore region specifiers */
+	flag  &=3D ~(__GFP_HIGHMEM | __GFP_DMA | __GFP_DMA32);
+	if (*dev->dma_mask < top_ram_pfn - 1)
+		flag |=3D __GFP_DMA32;
+#else
	flag  &=3D ~(__GFP_HIGHMEM);
+#endif
=20
	page =3D alloc_pages_node(node, flag, get_order(size));
	if (page =3D=3D NULL)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index baaafde..2a11e49 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c

@@ -280,6 +280,10 @@ void __init paging_init(void)

#ifdef CONFIG_HIGHMEM
	max_zone_pfns[ZONE_DMA] =3D lowmem_end_addr >> PAGE_SHIFT;
	max_zone_pfns[ZONE_HIGHMEM] =3D top_of_ram >> PAGE_SHIFT;
+#elif defined CONFIG_ZONE_DMA32
+	max_zone_pfns[ZONE_DMA32] =3D min_t(phys_addr_t, top_of_ram,
+					1ull << 31) >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_NORMAL] =3D top_of_ram >> PAGE_SHIFT;
#else
	max_zone_pfns[ZONE_DMA] =3D top_of_ram >> PAGE_SHIFT;
#endif
--=20
1.6.4
=20
=20
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Re: [PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2012-09-09 23:38:01

On Thu, 2012-08-30 at 15:49 -0500, Kumar Gala wrote:

On Aug 24, 2012, at 5:50 AM, Shaohui Xie wrote:

quoted

PowerPC platform only supports ZONE_DMA zone for 64bit kernel, so all the
memory will be put into this zone. If the memory size is greater than
the device's DMA capability and device uses dma_alloc_coherent to allocate
memory, it will get an address which is over the device's DMA addressing,
the device will fail.

So we split the memory to two zones: zone ZONE_DMA32 & ZONE_NORMAL, since
we already allocate PCICSRBAR/PEXCSRBAR right below the 4G boundary (if the
lowest PCI address is above 4G), so we constrain the DMA zone ZONE_DMA32
to 2GB, also, we clear flag __GFP_DMA & __GFP_DMA32 and set __GFP_DMA32 only
if the device's dma_mask < total memory size. By doing this, devices which
cannot DMA all the memory will be limited to ZONE_DMA32, but devices which
can DMA all the memory will not be affected by this limitation.

Signed-off-by: Shaohui Xie <redacted>
Signed-off-by: Mingkai Hu <redacted>
Signed-off-by: Chen Yuanquan <redacted>
---
changes for v2:
1. use a config option for using two zones (ZONE_DMA32 & ZONE_NORMAL) in
freescale 64 bit kernel.

There must have been a misunderstanding. I think this should be a
runtime choice, possibly by the platform code. Any reason that can't be
done ?

Also how does Intel do it ? Do they have iommu and ZONE_DMA32 co-exist ?

Cheers,
Ben.

RE: [PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Xie Shaohui-B21989 <hidden>
Date: 2012-09-10 09:51:21

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RE: [PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Xie Shaohui-B21989 <hidden>
Date: 2012-09-20 10:15:01

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Re: [PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Kumar Gala <hidden>
Date: 2012-09-20 13:36:44

On Sep 20, 2012, at 5:14 AM, Xie Shaohui-B21989 wrote:

quoted

On Thu, 2012-08-30 at 15:49 -0500, Kumar Gala wrote:

quoted

On Aug 24, 2012, at 5:50 AM, Shaohui Xie wrote:
=20

quoted

PowerPC platform only supports ZONE_DMA zone for 64bit kernel, so
all the memory will be put into this zone. If the memory size is
greater than the device's DMA capability and device uses
dma_alloc_coherent to allocate memory, it will get an address
which is over the device's DMA addressing, the device will fail.
=20
So we split the memory to two zones: zone ZONE_DMA32 &
ZONE_NORMAL, since we already allocate PCICSRBAR/PEXCSRBAR right
below the 4G boundary (if the lowest PCI address is above 4G), so
we constrain the DMA zone ZONE_DMA32 to 2GB, also, we clear flag
__GFP_DMA &
__GFP_DMA32 and set __GFP_DMA32 only if the device's dma_mask <
total memory size. By doing this, devices which cannot DMA all the
memory will be limited to ZONE_DMA32, but devices which can DMA
all

the memory will not be affected by this limitation.

quoted

=20
Signed-off-by: Shaohui Xie <redacted>
Signed-off-by: Mingkai Hu <redacted>
Signed-off-by: Chen Yuanquan <redacted>
---
changes for v2:
1. use a config option for using two zones (ZONE_DMA32 &
ZONE_NORMAL) in freescale 64 bit kernel.
=20

=20
There must have been a misunderstanding. I think this should be a
runtime choice, possibly by the platform code. Any reason that can't =

be

quoted

done ?

quoted

=20

[S.H] Do you mean this:
=20
phys_addr_t platform_dma_size (maybe a default value should be used, =

then

quoted

platform code will change it)
=20
if (top_of_ram > platform_dma_size)
	max_zone_pfns[ZONE_DMA] =3D platform_dma_size >> PAGE_SHIFT; =

else

quoted

	max_zone_pfns[ZONE_DMA] =3D top_of_ram >> PAGE_SHIFT;
=20
max_zone_pfns[ZONE_NORMAL] =3D top_of_ram >> PAGE_SHIFT;
=20

quoted

Also how does Intel do it ?

[S.H] below are codes in Intel:
=20
403 void __init zone_sizes_init(void)
404 {
405         unsigned long max_zone_pfns[MAX_NR_ZONES];
406
407         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
408
409 #ifdef CONFIG_ZONE_DMA
410         max_zone_pfns[ZONE_DMA]         =3D MAX_DMA_PFN;
411 #endif
412 #ifdef CONFIG_ZONE_DMA32
413         max_zone_pfns[ZONE_DMA32]       =3D MAX_DMA32_PFN;
414 #endif
415         max_zone_pfns[ZONE_NORMAL]      =3D max_low_pfn;
416 #ifdef CONFIG_HIGHMEM
417         max_zone_pfns[ZONE_HIGHMEM]     =3D max_pfn;
418 #endif
419
=20
For x86_64, there is no CONFIG_HIGHMEM, so there will be three zones:
ZONE_DMA/ZONE_DMA32/ZONE_NORMAL.
=20

[S.H] Hello, Ben,
=20
I have some questions, though I'm still expecting your comments.
PPC does not have ZONE_DMA32 by default, if we want to use it, we need =

to add "config ZONE_DMA32" in Kconfig first.

If setting multiple zones without ZONE_DMA, kmalloc in =

"include/linux/slab_def.h" will fail if it uses flag GFP_DMA.

For the runtime choice in 64-bit kernel, what exactly multiple zones =

should be used?

"ZONE_DMA & ZONE_NORMAL" or "ZONE_DMA & ZONE_DMA32 & ZONE_NORMAL"?
Then what the size should be set for them respectively?
=20
Please comment, Thanks!

I think Ben is saying that Kconfig would enable ZONE_DMA32 for all =
PPC64, but make it runtime/per platform how we setup the zone's such =
that either ZONE_DMA32 is set to MAX_DMA32_PFN or it set to same value =
as ZONE_DMA.

However that's just a guess.

- k=

Re: [PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Kumar Gala <hidden>
Date: 2012-09-24 12:31:56

On Sep 20, 2012, at 8:36 AM, Kumar Gala wrote:

=20
On Sep 20, 2012, at 5:14 AM, Xie Shaohui-B21989 wrote:
=20

quoted

On Thu, 2012-08-30 at 15:49 -0500, Kumar Gala wrote:

quoted

On Aug 24, 2012, at 5:50 AM, Shaohui Xie wrote:
=20

quoted

PowerPC platform only supports ZONE_DMA zone for 64bit kernel, so
all the memory will be put into this zone. If the memory size is
greater than the device's DMA capability and device uses
dma_alloc_coherent to allocate memory, it will get an address
which is over the device's DMA addressing, the device will fail.
=20
So we split the memory to two zones: zone ZONE_DMA32 &
ZONE_NORMAL, since we already allocate PCICSRBAR/PEXCSRBAR right
below the 4G boundary (if the lowest PCI address is above 4G), so
we constrain the DMA zone ZONE_DMA32 to 2GB, also, we clear flag
__GFP_DMA &
__GFP_DMA32 and set __GFP_DMA32 only if the device's dma_mask <
total memory size. By doing this, devices which cannot DMA all =

the

quoted

memory will be limited to ZONE_DMA32, but devices which can DMA
all

the memory will not be affected by this limitation.

quoted

=20
Signed-off-by: Shaohui Xie <redacted>
Signed-off-by: Mingkai Hu <redacted>
Signed-off-by: Chen Yuanquan <redacted>
---
changes for v2:
1. use a config option for using two zones (ZONE_DMA32 &
ZONE_NORMAL) in freescale 64 bit kernel.
=20

=20
There must have been a misunderstanding. I think this should be a
runtime choice, possibly by the platform code. Any reason that =

can't be

quoted

done ?

quoted

=20

[S.H] Do you mean this:
=20
phys_addr_t platform_dma_size (maybe a default value should be used, =

then

quoted

platform code will change it)
=20
if (top_of_ram > platform_dma_size)
	max_zone_pfns[ZONE_DMA] =3D platform_dma_size >> PAGE_SHIFT; =

else

quoted

	max_zone_pfns[ZONE_DMA] =3D top_of_ram >> PAGE_SHIFT;
=20
max_zone_pfns[ZONE_NORMAL] =3D top_of_ram >> PAGE_SHIFT;
=20

quoted

Also how does Intel do it ?

[S.H] below are codes in Intel:
=20
403 void __init zone_sizes_init(void)
404 {
405         unsigned long max_zone_pfns[MAX_NR_ZONES];
406
407         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
408
409 #ifdef CONFIG_ZONE_DMA
410         max_zone_pfns[ZONE_DMA]         =3D MAX_DMA_PFN;
411 #endif
412 #ifdef CONFIG_ZONE_DMA32
413         max_zone_pfns[ZONE_DMA32]       =3D MAX_DMA32_PFN;
414 #endif
415         max_zone_pfns[ZONE_NORMAL]      =3D max_low_pfn;
416 #ifdef CONFIG_HIGHMEM
417         max_zone_pfns[ZONE_HIGHMEM]     =3D max_pfn;
418 #endif
419
=20
For x86_64, there is no CONFIG_HIGHMEM, so there will be three =

zones:

quoted

ZONE_DMA/ZONE_DMA32/ZONE_NORMAL.
=20

[S.H] Hello, Ben,
=20
I have some questions, though I'm still expecting your comments.
PPC does not have ZONE_DMA32 by default, if we want to use it, we =

need to add "config ZONE_DMA32" in Kconfig first.

quoted

If setting multiple zones without ZONE_DMA, kmalloc in =

"include/linux/slab_def.h" will fail if it uses flag GFP_DMA.

quoted

For the runtime choice in 64-bit kernel, what exactly multiple zones =

should be used?

quoted

"ZONE_DMA & ZONE_NORMAL" or "ZONE_DMA & ZONE_DMA32 & ZONE_NORMAL"?
Then what the size should be set for them respectively?
=20
Please comment, Thanks!

=20
I think Ben is saying that Kconfig would enable ZONE_DMA32 for all =

PPC64, but make it runtime/per platform how we setup the zone's such =
that either ZONE_DMA32 is set to MAX_DMA32_PFN or it set to same value =
as ZONE_DMA.

=20
However that's just a guess.

Ben,

Can you help clarify your thoughts here.

thanks

- k=

Re: [PATCH][v2] powerpc/mm: using two zones for freescale 64 bit kernel

From: Kumar Gala <hidden>
Date: 2012-09-27 12:37:21

On Sep 24, 2012, at 7:31 AM, Kumar Gala wrote:

=20
On Sep 20, 2012, at 8:36 AM, Kumar Gala wrote:
=20

quoted

=20
On Sep 20, 2012, at 5:14 AM, Xie Shaohui-B21989 wrote:
=20

quoted

On Thu, 2012-08-30 at 15:49 -0500, Kumar Gala wrote:

quoted

On Aug 24, 2012, at 5:50 AM, Shaohui Xie wrote:
=20

quoted

PowerPC platform only supports ZONE_DMA zone for 64bit kernel, =

so

quoted

all the memory will be put into this zone. If the memory size is
greater than the device's DMA capability and device uses
dma_alloc_coherent to allocate memory, it will get an address
which is over the device's DMA addressing, the device will fail.
=20
So we split the memory to two zones: zone ZONE_DMA32 &
ZONE_NORMAL, since we already allocate PCICSRBAR/PEXCSRBAR right
below the 4G boundary (if the lowest PCI address is above 4G), =

so

quoted

we constrain the DMA zone ZONE_DMA32 to 2GB, also, we clear flag
__GFP_DMA &
__GFP_DMA32 and set __GFP_DMA32 only if the device's dma_mask <
total memory size. By doing this, devices which cannot DMA all =

the

quoted

memory will be limited to ZONE_DMA32, but devices which can DMA
all

the memory will not be affected by this limitation.

quoted

=20
Signed-off-by: Shaohui Xie <redacted>
Signed-off-by: Mingkai Hu <redacted>
Signed-off-by: Chen Yuanquan <redacted>
---
changes for v2:
1. use a config option for using two zones (ZONE_DMA32 &
ZONE_NORMAL) in freescale 64 bit kernel.
=20

=20
There must have been a misunderstanding. I think this should be a
runtime choice, possibly by the platform code. Any reason that =

can't be

quoted

done ?

quoted

=20

[S.H] Do you mean this:
=20
phys_addr_t platform_dma_size (maybe a default value should be =

used, then

quoted

platform code will change it)
=20
if (top_of_ram > platform_dma_size)
	max_zone_pfns[ZONE_DMA] =3D platform_dma_size >> PAGE_SHIFT; =

else

quoted

	max_zone_pfns[ZONE_DMA] =3D top_of_ram >> PAGE_SHIFT;
=20
max_zone_pfns[ZONE_NORMAL] =3D top_of_ram >> PAGE_SHIFT;
=20

quoted

Also how does Intel do it ?

[S.H] below are codes in Intel:
=20
403 void __init zone_sizes_init(void)
404 {
405         unsigned long max_zone_pfns[MAX_NR_ZONES];
406
407         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
408
409 #ifdef CONFIG_ZONE_DMA
410         max_zone_pfns[ZONE_DMA]         =3D MAX_DMA_PFN;
411 #endif
412 #ifdef CONFIG_ZONE_DMA32
413         max_zone_pfns[ZONE_DMA32]       =3D MAX_DMA32_PFN;
414 #endif
415         max_zone_pfns[ZONE_NORMAL]      =3D max_low_pfn;
416 #ifdef CONFIG_HIGHMEM
417         max_zone_pfns[ZONE_HIGHMEM]     =3D max_pfn;
418 #endif
419
=20
For x86_64, there is no CONFIG_HIGHMEM, so there will be three =

zones:

quoted

ZONE_DMA/ZONE_DMA32/ZONE_NORMAL.
=20

[S.H] Hello, Ben,
=20
I have some questions, though I'm still expecting your comments.
PPC does not have ZONE_DMA32 by default, if we want to use it, we =

need to add "config ZONE_DMA32" in Kconfig first.

quoted

If setting multiple zones without ZONE_DMA, kmalloc in =

"include/linux/slab_def.h" will fail if it uses flag GFP_DMA.

quoted

For the runtime choice in 64-bit kernel, what exactly multiple zones =

should be used?

quoted

"ZONE_DMA & ZONE_NORMAL" or "ZONE_DMA & ZONE_DMA32 & ZONE_NORMAL"?
Then what the size should be set for them respectively?
=20
Please comment, Thanks!

=20
I think Ben is saying that Kconfig would enable ZONE_DMA32 for all =

PPC64, but make it runtime/per platform how we setup the zone's such =
that either ZONE_DMA32 is set to MAX_DMA32_PFN or it set to same value =
as ZONE_DMA.

quoted

=20
However that's just a guess.

=20
Ben,
=20
Can you help clarify your thoughts here.
=20
thanks

Ben?

- k=

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