enable acpi_os_allocate() to allocate larger memory

PATCH In review Kenji Kaneshige 2 participants 3 messages May 23, 2005 – May 24, 2005 2 messages not in the archive ACPI

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Kenji Kaneshige

author

2005-05-23 11:28 UTC #0 lore raw

PATCH 1/1 enable acpi_os_allocate() to allocate larger memory

Hi,

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 <[email protected]>

---

 linux-2.6.12-rc4-kanesige/drivers/acpi/osl.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

drivers/acpi/osl.c renamed from drivers/acpi/osl.c~fix_acpi_os_allocate +10 -2

diff -puN drivers/acpi/osl.c~fix_acpi_os_allocate drivers/acpi/osl.c
@@ -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);
+	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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A message that is not in the archive (sent off-list or not yet received): [email protected]

Alan Cox

2005-05-23 13:42 UTC #2 lore raw

drivers/acpi/osl.c acpi_os_vprintf(const char *fmt, va_list · line 150

Quoted 3 lines · Kenji Kaneshige

drivers/acpi/osl.c renamed from drivers/acpi/osl.c~fix_acpi_os_allocate +2 -1
-	return kmalloc(size, GFP_KERNEL);
+	void *ptr = kmalloc(size, GFP_KERNEL);
+	if (!ptr)

This looks reasonable. Do you think it would be better to use GFP_KERNEL|__GFP_NORETRY|__GFP_NOWARN ?

Tbe __GFP_NORETRY tells the vm it is ok to fail the kmalloc rather than wait
and try for a long long time. The _NOWARN says "we know this can fail in normal
use so don't log failure". (See include/linux/gfp.h for more documentation)

Alan

A message that is not in the archive (sent off-list or not yet received): 1116855778.5744.47.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/[email protected]

Kenji Kaneshige

author

2005-05-24 02:27 UTC #4 lore raw

Quoted 10 lines · Alan Cox

drivers/acpi/osl.c acpi_os_vprintf(const char *fmt, va_list · line 150
Quoted 3 lines · Kenji Kaneshige
drivers/acpi/osl.c renamed from drivers/acpi/osl.c~fix_acpi_os_allocate +2 -1
-	return kmalloc(size, GFP_KERNEL);
+	void *ptr = kmalloc(size, GFP_KERNEL);
+	if (!ptr)
This looks reasonable. Do you think it would be better to use GFP_KERNEL|__GFP_NORETRY|__GFP_NOWARN ?

Yes, this makes sense.
I'll update the patch and post it again.

Thanks,
Kenji Kaneshige