[PATCH 0/6] add generic round_up_pow2() macro

[PATCH 0/6] add generic round_up_pow2() macro

[Nick Wilson]

Randy.Dunlap wrote:
> >+#define ALIGN_DATA_SIZE(size)       ((size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1))                      
>                                                                                                        
> ISTM that we need a generic round_up() function or macro in kernel.h.                                  
>                                                                                                        
> a.out.h, reiserfs_fs.h, and ufs_fs.h all have their own round-up                                       
> macros.                                                                                                
 
I've found many more places in the kernel that use their own functions for
doing this. These patches are the beginning of an attempt to clean these
up.

The first patch adds a generic round_up_pow2() macro to kernel.h. The
remaining patches modify a few files to make use of the new macro.
Comments welcome.

Thanks,
        
Nick

[PATCH 1/6] include/linux/kernel.h: use generic round_up_pow2() macro

[Nick Wilson]

From: Nick Wilson <njw@osdl.org>

Add a generic macro to kernel.h to round up to the next multiple of n.

Signed-off-by: Nick Wilson <njw@osdl.org>
---


 kernel.h |    5 +++++
 1 files changed, 5 insertions(+)

Index: linux/include/linux/kernel.h
===================================================================
--- linux.orig/include/linux/kernel.h	2005-04-07 15:13:56.000000000 -0700
+++ linux/include/linux/kernel.h	2005-04-07 15:47:15.000000000 -0700
@@ -246,6 +246,11 @@ extern void dump_stack(void);
 #define max_t(type,x,y) \
 	({ type __x = (x); type __y = (y); __x > __y ? __x: __y; })
 
+/*
+ * Round x up to the next multiple of n.
+ * n must be a power of 2. 
+ */
+#define round_up_pow2(x,n) (((x) + (n) - 1) & ~((n) - 1))
 
 /**
  * container_of - cast a member of a structure out to the containing structure
_

[PATCH 2/6] include/linux/kernel.h: use generic round_up_pow2() macro

[Nick Wilson]

From: Nick Wilson <njw@osdl.org>

Use the generic round_up_pow2() instead of a custom rounding method.

Signed-off-by: Nick Wilson <njw@osdl.org>
---


 kernel.h |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

Index: linux/include/linux/kernel.h
===================================================================
--- linux.orig/include/linux/kernel.h	2005-04-07 15:44:05.000000000 -0700
+++ linux/include/linux/kernel.h	2005-04-07 15:44:53.000000000 -0700
@@ -28,7 +28,7 @@ extern const char linux_banner[];
 #define STACK_MAGIC	0xdeadbeef
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
-#define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))
+#define ALIGN		round_up_pow2
 
 #define	KERN_EMERG	"<0>"	/* system is unusable			*/
 #define	KERN_ALERT	"<1>"	/* action must be taken immediately	*/
_

[PATCH 3/6] include/linux/a.out.h: use generic round_up_pow2() macro

[Nick Wilson]

From: Nick Wilson <njw@osdl.org>

Use the generic round_up_pow2() instead of a custom rounding method.

Signed-off-by: Nick Wilson <njw@osdl.org>
---


 a.out.h |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

Index: linux/include/linux/a.out.h
===================================================================
--- linux.orig/include/linux/a.out.h	2005-04-07 15:37:22.000000000 -0700
+++ linux/include/linux/a.out.h	2005-04-07 15:45:34.000000000 -0700
@@ -138,7 +138,7 @@ enum machine_type {
 #endif
 #endif
 
-#define _N_SEGMENT_ROUND(x) (((x) + SEGMENT_SIZE - 1) & ~(SEGMENT_SIZE - 1))
+#define _N_SEGMENT_ROUND(x) round_up_pow2(x, SEGMENT_SIZE)
 
 #define _N_TXTENDADDR(x) (N_TXTADDR(x)+(x).a_text)
 
_

Re: [PATCH 0/6] add generic round_up_pow2() macro

[Andrew Morton]

Nick Wilson <njw@osdl.org> wrote:
>
> The first patch adds a generic round_up_pow2() macro to kernel.h. The
>  remaining patches modify a few files to make use of the new macro.

We already have ALIGN() and roundup_pow_of_two().

[PATCH 4/6] kernel/resource.c: use generic round_up_pow2() macro

[Nick Wilson]

From: Nick Wilson <njw@osdl.org>

Use the generic round_up_pow2() instead of a custom rounding method.

Signed-off-by: Nick Wilson <njw@osdl.org>
---


 resource.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

Index: linux/kernel/resource.c
===================================================================
--- linux.orig/kernel/resource.c	2005-04-07 15:13:56.000000000 -0700
+++ linux/kernel/resource.c	2005-04-07 15:45:57.000000000 -0700
@@ -263,7 +263,7 @@ static int find_resource(struct resource
 			new->start = min;
 		if (new->end > max)
 			new->end = max;
-		new->start = (new->start + align - 1) & ~(align - 1);
+		new->start = round_up_pow2(new->start, align);
 		if (alignf)
 			alignf(alignf_data, new, size, align);
 		if (new->start < new->end && new->end - new->start + 1 >= size) {
_

[PATCH 5/6] lib/bitmap.c: use generic round_up_pow2() macro

[Nick Wilson]

From: Nick Wilson <njw@osdl.org>

Use the generic round_up_pow2() instead of a custom rounding method.

Signed-off-by: Nick Wilson <njw@osdl.org>
---


 bitmap.c |    3 +--
 1 files changed, 1 insertion(+), 2 deletions(-)

Index: linux/lib/bitmap.c
===================================================================
--- linux.orig/lib/bitmap.c	2005-04-07 15:13:56.000000000 -0700
+++ linux/lib/bitmap.c	2005-04-07 15:46:15.000000000 -0700
@@ -289,7 +289,6 @@ EXPORT_SYMBOL(__bitmap_weight);
 
 #define CHUNKSZ				32
 #define nbits_to_hold_value(val)	fls(val)
-#define roundup_power2(val,modulus)	(((val) + (modulus) - 1) & ~((modulus) - 1))
 #define unhex(c)			(isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))
 #define BASEDEC 10		/* fancier cpuset lists input in decimal */
 
@@ -316,7 +315,7 @@ int bitmap_scnprintf(char *buf, unsigned
 	if (chunksz == 0)
 		chunksz = CHUNKSZ;
 
-	i = roundup_power2(nmaskbits, CHUNKSZ) - CHUNKSZ;
+	i = round_up_pow2(nmaskbits, CHUNKSZ) - CHUNKSZ;
 	for (; i >= 0; i -= CHUNKSZ) {
 		chunkmask = ((1ULL << chunksz) - 1);
 		word = i / BITS_PER_LONG;
_

[PATCH 6/6] mm/bootmem.c: use generic round_up_pow2() macro

[Nick Wilson]

From: Nick Wilson <njw@osdl.org>

Use the generic round_up_pow2() instead of a custom rounding method.

Signed-off-by: Nick Wilson <njw@osdl.org>
---


 bootmem.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

Index: linux/mm/bootmem.c
===================================================================
--- linux.orig/mm/bootmem.c	2005-04-07 15:13:56.000000000 -0700
+++ linux/mm/bootmem.c	2005-04-07 15:46:41.000000000 -0700
@@ -57,7 +57,7 @@ static unsigned long __init init_bootmem
 	pgdat->pgdat_next = pgdat_list;
 	pgdat_list = pgdat;
 
-	mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
+	mapsize = round_up_pow2(mapsize, sizeof(long));
 	bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
 	bdata->node_boot_start = (start << PAGE_SHIFT);
 	bdata->node_low_pfn = end;
@@ -178,7 +178,7 @@ __alloc_bootmem_core(struct bootmem_data
 	} else
 		preferred = 0;
 
-	preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
+	preferred = round_up_pow2(preferred, align) >> PAGE_SHIFT;
 	preferred += offset;
 	areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
 	incr = align >> PAGE_SHIFT ? : 1;
@@ -219,7 +219,7 @@ found:
 	 */
 	if (align < PAGE_SIZE &&
 	    bdata->last_offset && bdata->last_pos+1 == start) {
-		offset = (bdata->last_offset+align-1) & ~(align-1);
+		offset = round_up_pow2(bdata->last_offset, align);
 		BUG_ON(offset > PAGE_SIZE);
 		remaining_size = PAGE_SIZE-offset;
 		if (size < remaining_size) {
_

Re: [PATCH 0/6] add generic round_up_pow2() macro

[P]

Andrew Morton wrote:
> Nick Wilson <njw@osdl.org> wrote:
> 
>>The first patch adds a generic round_up_pow2() macro to kernel.h. The
>> remaining patches modify a few files to make use of the new macro.
> 
> 
> We already have ALIGN() and roundup_pow_of_two().

cool. It doesn't handle x={0,1} though.
Maybe we should have:

static inline unsigned long __attribute_const__ 
__roundup_pow_of_two(unsigned long x)
{
         return (1UL << fls(x - 1));
}

static inline unsigned long __attribute_const__ 
roundup_pow_of_two(unsigned long x)
{
         return (unlikely(x<2)?2:__roundup_pow_of_two(x));
}

-- 
Pádraig Brady - http://www.pixelbeat.org
--

Re: [PATCH 0/6] add generic round_up_pow2() macro

[P]

P@draigBrady.com wrote:
> Andrew Morton wrote:
> 
>> Nick Wilson <njw@osdl.org> wrote:
>>
>>> The first patch adds a generic round_up_pow2() macro to kernel.h. The
>>> remaining patches modify a few files to make use of the new macro.
>>
>>
>>
>> We already have ALIGN() and roundup_pow_of_two().
> 
> 
> cool. It doesn't handle x={0,1} though.

Well I should clarify.
2^0==1 is a special case that you probably
don't want as a result from the macro?

-- 
Pádraig Brady - http://www.pixelbeat.org
--

[PATCH] Use ALIGN to remove duplicate code

[Nick Wilson]

On Thu, Apr 07, 2005 at 05:50:42PM -0700, Andrew Morton wrote:
> Nick Wilson <njw@osdl.org> wrote:
> > The first patch adds a generic round_up_pow2() macro to kernel.h. The
> >  remaining patches modify a few files to make use of the new macro.
> 
> We already have ALIGN() and roundup_pow_of_two().

Andrew,

This patch makes use of ALIGN() to remove duplicate round-up code.

Signed-off-by: Nick Wilson <njw@osdl.org>
---


 include/linux/a.out.h |    2 +-
 kernel/resource.c     |    2 +-
 lib/bitmap.c          |    3 +--
 mm/bootmem.c          |    6 +++---
 4 files changed, 6 insertions(+), 7 deletions(-)

Index: linux/include/linux/a.out.h
===================================================================
--- linux.orig/include/linux/a.out.h	2005-04-08 10:59:14.000000000 -0700
+++ linux/include/linux/a.out.h	2005-04-08 11:00:40.000000000 -0700
@@ -138,7 +138,7 @@ enum machine_type {
 #endif
 #endif
 
-#define _N_SEGMENT_ROUND(x) (((x) + SEGMENT_SIZE - 1) & ~(SEGMENT_SIZE - 1))
+#define _N_SEGMENT_ROUND(x) ALIGN(x, SEGMENT_SIZE)
 
 #define _N_TXTENDADDR(x) (N_TXTADDR(x)+(x).a_text)
 
Index: linux/kernel/resource.c
===================================================================
--- linux.orig/kernel/resource.c	2005-04-08 10:59:36.000000000 -0700
+++ linux/kernel/resource.c	2005-04-08 11:00:50.000000000 -0700
@@ -263,7 +263,7 @@ static int find_resource(struct resource
 			new->start = min;
 		if (new->end > max)
 			new->end = max;
-		new->start = (new->start + align - 1) & ~(align - 1);
+		new->start = ALIGN(new->start, align);
 		if (alignf)
 			alignf(alignf_data, new, size, align);
 		if (new->start < new->end && new->end - new->start + 1 >= size) {
Index: linux/lib/bitmap.c
===================================================================
--- linux.orig/lib/bitmap.c	2005-04-08 10:59:40.000000000 -0700
+++ linux/lib/bitmap.c	2005-04-08 11:00:59.000000000 -0700
@@ -289,7 +289,6 @@ EXPORT_SYMBOL(__bitmap_weight);
 
 #define CHUNKSZ				32
 #define nbits_to_hold_value(val)	fls(val)
-#define roundup_power2(val,modulus)	(((val) + (modulus) - 1) & ~((modulus) - 1))
 #define unhex(c)			(isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))
 #define BASEDEC 10		/* fancier cpuset lists input in decimal */
 
@@ -316,7 +315,7 @@ int bitmap_scnprintf(char *buf, unsigned
 	if (chunksz == 0)
 		chunksz = CHUNKSZ;
 
-	i = roundup_power2(nmaskbits, CHUNKSZ) - CHUNKSZ;
+	i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
 	for (; i >= 0; i -= CHUNKSZ) {
 		chunkmask = ((1ULL << chunksz) - 1);
 		word = i / BITS_PER_LONG;
Index: linux/mm/bootmem.c
===================================================================
--- linux.orig/mm/bootmem.c	2005-04-08 10:59:43.000000000 -0700
+++ linux/mm/bootmem.c	2005-04-08 11:05:45.000000000 -0700
@@ -57,7 +57,7 @@ static unsigned long __init init_bootmem
 	pgdat->pgdat_next = pgdat_list;
 	pgdat_list = pgdat;
 
-	mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
+	mapsize = ALIGN(mapsize, sizeof(long));
 	bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
 	bdata->node_boot_start = (start << PAGE_SHIFT);
 	bdata->node_low_pfn = end;
@@ -178,7 +178,7 @@ __alloc_bootmem_core(struct bootmem_data
 	} else
 		preferred = 0;
 
-	preferred = ((preferred + align - 1) & ~(align - 1)) >> PAGE_SHIFT;
+	preferred = ALIGN(preferred, align) >> PAGE_SHIFT;
 	preferred += offset;
 	areasize = (size+PAGE_SIZE-1)/PAGE_SIZE;
 	incr = align >> PAGE_SHIFT ? : 1;
@@ -219,7 +219,7 @@ found:
 	 */
 	if (align < PAGE_SIZE &&
 	    bdata->last_offset && bdata->last_pos+1 == start) {
-		offset = (bdata->last_offset+align-1) & ~(align-1);
+		offset = ALIGN(bdata->last_offset, align);
 		BUG_ON(offset > PAGE_SIZE);
 		remaining_size = PAGE_SIZE-offset;
 		if (size < remaining_size) {
_