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Message-ID: <20101019135512.GA31193@darkstar>
Date: Tue, 19 Oct 2010 21:55:12 +0800
From: Dave Young <hidave.darkstar@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
kvm@...r.kernel.org
Subject: Re: [PATCH 1/2] Add vzalloc shortcut
On Mon, Oct 18, 2010 at 04:46:47PM -0700, Andrew Morton wrote:
> On Sat, 16 Oct 2010 12:33:31 +0800
> Dave Young <hidave.darkstar@...il.com> wrote:
>
> > Add vzalloc for convinience of vmalloc-then-memset-zero case
> >
> > Use __GFP_ZERO in vzalloc to zero fill the allocated memory.
> >
> > Signed-off-by: Dave Young <hidave.darkstar@...il.com>
> > ---
> > include/linux/vmalloc.h | 1 +
> > mm/vmalloc.c | 13 +++++++++++++
> > 2 files changed, 14 insertions(+)
> >
> > --- linux-2.6.orig/include/linux/vmalloc.h 2010-08-22 15:31:38.000000000 +0800
> > +++ linux-2.6/include/linux/vmalloc.h 2010-10-16 10:50:54.739996121 +0800
> > @@ -53,6 +53,7 @@ static inline void vmalloc_init(void)
> > #endif
> >
> > extern void *vmalloc(unsigned long size);
> > +extern void *vzalloc(unsigned long size);
> > extern void *vmalloc_user(unsigned long size);
> > extern void *vmalloc_node(unsigned long size, int node);
> > extern void *vmalloc_exec(unsigned long size);
> > --- linux-2.6.orig/mm/vmalloc.c 2010-08-22 15:31:39.000000000 +0800
> > +++ linux-2.6/mm/vmalloc.c 2010-10-16 10:51:57.126665918 +0800
> > @@ -1604,6 +1604,19 @@ void *vmalloc(unsigned long size)
> > EXPORT_SYMBOL(vmalloc);
> >
> > /**
> > + * vzalloc - allocate virtually contiguous memory with zero filled
>
> s/filled/fill/
>
> > + * @size: allocation size
> > + * Allocate enough pages to cover @size from the page level
> > + * allocator and map them into contiguous kernel virtual space.
> > + */
> > +void *vzalloc(unsigned long size)
> > +{
> > + return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
> > + PAGE_KERNEL, -1, __builtin_return_address(0));
> > +}
> > +EXPORT_SYMBOL(vzalloc);
>
> We'd need to add the same interface to nommu, please.
>
> Also, a slightly better implementation would be
>
> static inline void *__vmalloc_node_flags(unsigned long size, gfp_t flags)
> {
> return __vmalloc_node(size, 1, flags, PAGE_KERNEL, -1,
> __builtin_return_address(0));
> }
>
> void *vzalloc(unsigned long size)
> {
> return __vmalloc_node_flags(size,
> GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
> }
>
> void *vmalloc(unsigned long size)
> {
> return __vmalloc_node_flags(size, GFP_KERNEL | __GFP_HIGHMEM);
> }
>
> just to avoid code duplication (and possible later errors derived from it).
>
> Perhaps it should be always_inline, so the __builtin_return_address()
> can't get broken.
>
> Or just leave it the way you had it :)
>
>
Hi, here is the updated version:
---
Add vzalloc and vzalloc_node for convinience of vmalloc-then-memset-zero case
Use __GFP_ZERO in vzalloc to zero fill the allocated memory.
changes from first submit:
nommu part (Minchan kim and Andrew Morton)
comment fixes / __vmalloc_node_flags helper for clean code (Andrew Morton)
add vzalloc_node for completeness
Signed-off-by: Dave Young <hidave.darkstar@...il.com>
---
include/linux/vmalloc.h | 2 +
mm/nommu.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++-
mm/vmalloc.c | 46 +++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 94 insertions(+), 3 deletions(-)
--- linux-2.6.orig/include/linux/vmalloc.h 2010-10-19 20:44:20.383333459 +0800
+++ linux-2.6/include/linux/vmalloc.h 2010-10-19 20:45:07.366666782 +0800
@@ -53,8 +53,10 @@ static inline void vmalloc_init(void)
#endif
extern void *vmalloc(unsigned long size);
+extern void *vzalloc(unsigned long size);
extern void *vmalloc_user(unsigned long size);
extern void *vmalloc_node(unsigned long size, int node);
+extern void *vzalloc_node(unsigned long size, int node);
extern void *vmalloc_exec(unsigned long size);
extern void *vmalloc_32(unsigned long size);
extern void *vmalloc_32_user(unsigned long size);
--- linux-2.6.orig/mm/vmalloc.c 2010-10-19 20:44:20.383333459 +0800
+++ linux-2.6/mm/vmalloc.c 2010-10-19 20:53:01.296666793 +0800
@@ -1587,6 +1587,13 @@ void *__vmalloc(unsigned long size, gfp_
}
EXPORT_SYMBOL(__vmalloc);
+static inline void *__vmalloc_node_flags(unsigned long size,
+ int node, gfp_t flags)
+{
+ return __vmalloc_node(size, 1, flags, PAGE_KERNEL,
+ node, __builtin_return_address(0));
+}
+
/**
* vmalloc - allocate virtually contiguous memory
* @size: allocation size
@@ -1598,12 +1605,28 @@ EXPORT_SYMBOL(__vmalloc);
*/
void *vmalloc(unsigned long size)
{
- return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
- -1, __builtin_return_address(0));
+ return __vmalloc_node_flags(size, -1, GFP_KERNEL | __GFP_HIGHMEM);
}
EXPORT_SYMBOL(vmalloc);
/**
+ * vzalloc - allocate virtually contiguous memory with zero fill
+ * @size: allocation size
+ * Allocate enough pages to cover @size from the page level
+ * allocator and map them into contiguous kernel virtual space.
+ * The memory allocated is set to zero.
+ *
+ * For tight control over page level allocator and protection flags
+ * use __vmalloc() instead.
+ */
+void *vzalloc(unsigned long size)
+{
+ return __vmalloc_node_flags(size, -1,
+ GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
+}
+EXPORT_SYMBOL(vzalloc);
+
+/**
* vmalloc_user - allocate zeroed virtually contiguous memory for userspace
* @size: allocation size
*
@@ -1644,6 +1667,25 @@ void *vmalloc_node(unsigned long size, i
}
EXPORT_SYMBOL(vmalloc_node);
+/**
+ * vzalloc_node - allocate memory on a specific node with zero fill
+ * @size: allocation size
+ * @node: numa node
+ *
+ * Allocate enough pages to cover @size from the page level
+ * allocator and map them into contiguous kernel virtual space.
+ * The memory allocated is set to zero.
+ *
+ * For tight control over page level allocator and protection flags
+ * use __vmalloc_node() instead.
+ */
+void *vzalloc_node(unsigned long size, int node)
+{
+ return __vmalloc_node_flags(size, node,
+ GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
+}
+EXPORT_SYMBOL(vzalloc_node);
+
#ifndef PAGE_KERNEL_EXEC
# define PAGE_KERNEL_EXEC PAGE_KERNEL
#endif
--- linux-2.6.orig/mm/nommu.c 2010-10-19 20:44:20.383333459 +0800
+++ linux-2.6/mm/nommu.c 2010-10-19 20:45:07.370000115 +0800
@@ -293,11 +293,58 @@ void *vmalloc(unsigned long size)
}
EXPORT_SYMBOL(vmalloc);
+/*
+ * vzalloc - allocate virtually continguos memory with zero fill
+ *
+ * @size: allocation size
+ *
+ * Allocate enough pages to cover @size from the page level
+ * allocator and map them into continguos kernel virtual space.
+ * The memory allocated is set to zero.
+ *
+ * For tight control over page level allocator and protection flags
+ * use __vmalloc() instead.
+ */
+void *vzalloc(unsigned long size)
+{
+ return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
+ PAGE_KERNEL);
+}
+EXPORT_SYMBOL(vzalloc);
+
+/**
+ * vmalloc_node - allocate memory on a specific node
+ * @size: allocation size
+ * @node: numa node
+ *
+ * Allocate enough pages to cover @size from the page level
+ * allocator and map them into contiguous kernel virtual space.
+ *
+ * For tight control over page level allocator and protection flags
+ * use __vmalloc() instead.
+ */
void *vmalloc_node(unsigned long size, int node)
{
return vmalloc(size);
}
-EXPORT_SYMBOL(vmalloc_node);
+
+/**
+ * vzalloc_node - allocate memory on a specific node with zero fill
+ * @size: allocation size
+ * @node: numa node
+ *
+ * Allocate enough pages to cover @size from the page level
+ * allocator and map them into contiguous kernel virtual space.
+ * The memory allocated is set to zero.
+ *
+ * For tight control over page level allocator and protection flags
+ * use __vmalloc() instead.
+ */
+void *vzalloc_node(unsigned long size, int node)
+{
+ return vzalloc(size);
+}
+EXPORT_SYMBOL(vzalloc_node);
#ifndef PAGE_KERNEL_EXEC
# define PAGE_KERNEL_EXEC PAGE_KERNEL
--
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