Re: [PATCH] take2: enable acpi_os_allocate() to allocate larger memory

[Kenji Kaneshige <kaneshige.kenji-+CUm20s59erQFUHtdCDX3A@public.gmane.org>]

Hi,

Thank you for the information.

Please note that the failure of reading /proc/acpi/dsdt is
just an example. I think there will be other cases that
acpi_os_allocate() needs to allocate memory larger than the
maximum allocation size of kmalloc(). For example, custom
DSDT cannot be loaded on my machine without this patch. So
I think we need this patch even if /proc/acpi/dsdt will be
removed in the future.

Thanks,
Kenji Kaneshige


Brown, Len wrote:
> My personal preference is to delete /proc/acpi/dsdt
> rather than complicate other code to support a feature
> that shouldn't exist.
> 
> We've got an updated user-space utility that can read dsdt,
> multiple ssdt, etc -- should be available in an acpica release soon;
> replacing the current pmtools acpidmp.
> 
> -Len
> 
> 
>>-----Original Message-----
>>From: Kenji Kaneshige [mailto:kaneshige.kenji-+CUm20s59erQFUHtdCDX3A@public.gmane.org] 
>>Sent: Tuesday, May 24, 2005 4:28 AM
>>To: Brown, Len; acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
>>Cc: Alan Cox
>>Subject: [PATCH] take2: enable acpi_os_allocate() to allocate 
>>larger memory
>>
>>Hi,
>>
>>Here is an updated patch to enable acpi_os_allocate() to allocate
>>larger memory. This patch is based on the feedback from Alan Cox
>>(Thank you!).
>>
>>Len, could you consider applying this patch?
>>
>>Thanks,
>>Kenji Kaneshige
>>
>>---
>>
>>I encountered the problem that I could not read /proc/acpi/dsdt on my
>>machine. It turned out that acpi_os_allocate() was failed to allocate
>>buffer. The DSDT on my machine was too large for acpi_os_allocate() to
>>allocate the buffer.
>>
>>Current acpi_os_allocate() interface is implemented by using kmalloc()
>>whose maximum allocation size is limited. So acpi_os_allocate() would
>>fail if larger size than maximum allocation size of kmalloc was
>>specified. I think this restriction should be removed.
>>
>>The following patch enables acpi_os_allocate() to allocate larger
>>memory.
>>
>>Signed-off-by: Kenji Kaneshige <kaneshige.kenji-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
>>
>>---
>>
>>linux-2.6.12-rc4-kanesige/drivers/acpi/osl.c |   12 ++++++++++--
>>1 files changed, 10 insertions(+), 2 deletions(-)
>>
>>diff -puN drivers/acpi/osl.c~fix_acpi_os_allocate drivers/acpi/osl.c
>>--- linux-2.6.12-rc4/drivers/acpi/osl.c~fix_acpi_os_allocate	
>>2005-05-24 16:32:51.000000000 +0900
>>+++ linux-2.6.12-rc4-kanesige/drivers/acpi/osl.c	
>>2005-05-24 16:34:25.000000000 +0900
>>@@ -37,6 +37,7 @@
>>#include <linux/delay.h>
>>#include <linux/workqueue.h>
>>#include <linux/nmi.h>
>>+#include <linux/vmalloc.h>
>>#include <acpi/acpi.h>
>>#include <asm/io.h>
>>#include <acpi/acpi_bus.h>
>>@@ -145,13 +146,20 @@ acpi_os_vprintf(const char *fmt, va_list
>>void *
>>acpi_os_allocate(acpi_size size)
>>{
>>-	return kmalloc(size, GFP_KERNEL);
>>+	void *ptr = kmalloc(size, 
>>GFP_KERNEL|__GFP_NORETRY|__GFP_NOWARN);
>>+	if (!ptr)
>>+		ptr = vmalloc(size);
>>+	return ptr;
>>}
>>
>>void
>>acpi_os_free(void *ptr)
>>{
>>-	kfree(ptr);
>>+	if (VMALLOC_START <= (unsigned long)ptr &&
>>+	    (unsigned long)ptr < VMALLOC_END)
>>+		vfree(ptr);
>>+	else
>>+		kfree(ptr);
>>}
>>EXPORT_SYMBOL(acpi_os_free);
>>
>>
>>_
>>
> 
> 



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