* [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-04 8:02 ` zijun_hu
0 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-04 8:02 UTC (permalink / raw)
To: Andrew Morton, tj, hannes
Cc: mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
>From e40d1066f61394992e0167f259001ae9d2581dc1 Mon Sep 17 00:00:00 2001
From: zijun_hu <zijun_hu@htc.com>
Date: Thu, 4 Aug 2016 14:22:52 +0800
Subject: [PATCH] mm/vmalloc: fix align value calculation error
it causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags
it is fixed by using order_base_2 instead of fls_long() due to lack of
get_count_order() for long parameter
Signed-off-by: zijun_hu <zijun_hu@htc.com>
---
mm/vmalloc.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 91f44e7..8b17c51 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1357,11 +1357,19 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
{
struct vmap_area *va;
struct vm_struct *area;
+ int ioremap_size_order;
BUG_ON(in_interrupt());
- if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, fls_long(size),
- PAGE_SHIFT, IOREMAP_MAX_ORDER);
+ if (flags & VM_IOREMAP) {
+ if (unlikely(size < 2))
+ ioremap_size_order = size;
+ else if (unlikely((signed long)size < 0))
+ ioremap_size_order = sizeof(size) * 8;
+ else
+ ioremap_size_order = order_base_2(size);
+ align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
+ IOREMAP_MAX_ORDER);
+ }
size = PAGE_ALIGN(size);
if (unlikely(!size))
--
1.9.1
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-04 8:02 ` zijun_hu
0 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-04 8:02 UTC (permalink / raw)
To: Andrew Morton, tj, hannes
Cc: mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
2016-08-04 8:02 ` zijun_hu
@ 2016-08-04 8:36 ` zijun_hu
-1 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-04 8:36 UTC (permalink / raw)
To: Andrew Morton, tj, hannes
Cc: mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 08/04/2016 04:02 PM, zijun_hu wrote:
>>From e40d1066f61394992e0167f259001ae9d2581dc1 Mon Sep 17 00:00:00 2001
> From: zijun_hu <zijun_hu@htc.com>
> Date: Thu, 4 Aug 2016 14:22:52 +0800
> Subject: [PATCH] mm/vmalloc: fix align value calculation error
>
> it causes double align requirement for __get_vm_area_node() if parameter
> size is power of 2 and VM_IOREMAP is set in parameter flags
>
> it is fixed by using order_base_2 instead of fls_long() due to lack of
> get_count_order() for long parameter
>
> Signed-off-by: zijun_hu <zijun_hu@htc.com>
> ---
> mm/vmalloc.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 91f44e7..8b17c51 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1357,11 +1357,19 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
> {
> struct vmap_area *va;
> struct vm_struct *area;
> + int ioremap_size_order;
>
> BUG_ON(in_interrupt());
> - if (flags & VM_IOREMAP)
> - align = 1ul << clamp_t(int, fls_long(size),
> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
> + if (flags & VM_IOREMAP) {
> + if (unlikely(size < 2))
> + ioremap_size_order = size;
> + else if (unlikely((signed long)size < 0))
> + ioremap_size_order = sizeof(size) * 8;
> + else
> + ioremap_size_order = order_base_2(size);
> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
> + IOREMAP_MAX_ORDER);
> + }
>
> size = PAGE_ALIGN(size);
> if (unlikely(!size))
>
another fix approach is shown as follows
From: zijun_hu <zijun_hu@htc.com>
Date: Thu, 4 Aug 2016 14:22:52 +0800
Subject: [PATCH] mm/vmalloc: fix align value calculation error
it causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags
it is fixed by handling the specail case manually due to lack of
get_count_order() for long parameter
Signed-off-by: zijun_hu <zijun_hu@htc.com>
---
mm/vmalloc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 91f44e7..dbbca8a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
{
struct vmap_area *va;
struct vm_struct *area;
+ int ioremap_size_order;
BUG_ON(in_interrupt());
- if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, fls_long(size),
- PAGE_SHIFT, IOREMAP_MAX_ORDER);
+ if (flags & VM_IOREMAP) {
+ ioremap_size_order = fls_long(size);
+ if (is_power_of_2(size) && size != 1)
+ ioremap_size_order--;
+ align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
+ IOREMAP_MAX_ORDER);
+ }
size = PAGE_ALIGN(size);
if (unlikely(!size))
--
1.9.1
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-04 8:36 ` zijun_hu
0 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-04 8:36 UTC (permalink / raw)
To: Andrew Morton, tj, hannes
Cc: mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 08/04/2016 04:02 PM, zijun_hu wrote:
>>From e40d1066f61394992e0167f259001ae9d2581dc1 Mon Sep 17 00:00:00 2001
> From: zijun_hu <zijun_hu@htc.com>
> Date: Thu, 4 Aug 2016 14:22:52 +0800
> Subject: [PATCH] mm/vmalloc: fix align value calculation error
>
> it causes double align requirement for __get_vm_area_node() if parameter
> size is power of 2 and VM_IOREMAP is set in parameter flags
>
> it is fixed by using order_base_2 instead of fls_long() due to lack of
> get_count_order() for long parameter
>
> Signed-off-by: zijun_hu <zijun_hu@htc.com>
> ---
> mm/vmalloc.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 91f44e7..8b17c51 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1357,11 +1357,19 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
> {
> struct vmap_area *va;
> struct vm_struct *area;
> + int ioremap_size_order;
>
> BUG_ON(in_interrupt());
> - if (flags & VM_IOREMAP)
> - align = 1ul << clamp_t(int, fls_long(size),
> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
> + if (flags & VM_IOREMAP) {
> + if (unlikely(size < 2))
> + ioremap_size_order = size;
> + else if (unlikely((signed long)size < 0))
> + ioremap_size_order = sizeof(size) * 8;
> + else
> + ioremap_size_order = order_base_2(size);
> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
> + IOREMAP_MAX_ORDER);
> + }
>
> size = PAGE_ALIGN(size);
> if (unlikely(!size))
>
another fix approach is shown as follows
From: zijun_hu <zijun_hu@htc.com>
Date: Thu, 4 Aug 2016 14:22:52 +0800
Subject: [PATCH] mm/vmalloc: fix align value calculation error
it causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags
it is fixed by handling the specail case manually due to lack of
get_count_order() for long parameter
Signed-off-by: zijun_hu <zijun_hu@htc.com>
---
mm/vmalloc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 91f44e7..dbbca8a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
{
struct vmap_area *va;
struct vm_struct *area;
+ int ioremap_size_order;
BUG_ON(in_interrupt());
- if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, fls_long(size),
- PAGE_SHIFT, IOREMAP_MAX_ORDER);
+ if (flags & VM_IOREMAP) {
+ ioremap_size_order = fls_long(size);
+ if (is_power_of_2(size) && size != 1)
+ ioremap_size_order--;
+ align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
+ IOREMAP_MAX_ORDER);
+ }
size = PAGE_ALIGN(size);
if (unlikely(!size))
--
1.9.1
--
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^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
2016-08-04 8:36 ` zijun_hu
@ 2016-08-04 21:24 ` Andrew Morton
-1 siblings, 0 replies; 14+ messages in thread
From: Andrew Morton @ 2016-08-04 21:24 UTC (permalink / raw)
To: zijun_hu
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
>
> it causes double align requirement for __get_vm_area_node() if parameter
> size is power of 2 and VM_IOREMAP is set in parameter flags
>
> it is fixed by handling the specail case manually due to lack of
> get_count_order() for long parameter
>
> ...
>
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
> {
> struct vmap_area *va;
> struct vm_struct *area;
> + int ioremap_size_order;
>
> BUG_ON(in_interrupt());
> - if (flags & VM_IOREMAP)
> - align = 1ul << clamp_t(int, fls_long(size),
> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
> + if (flags & VM_IOREMAP) {
> + ioremap_size_order = fls_long(size);
> + if (is_power_of_2(size) && size != 1)
> + ioremap_size_order--;
> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
> + IOREMAP_MAX_ORDER);
> + }
>
> size = PAGE_ALIGN(size);
> if (unlikely(!size))
I'm having trouble with this, and a more complete description would
have helped!
As far as I can tell, the current code will decide the following:
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x8000
And your patch will change it so that
size=0x10000: alignment=0x8000
size=0x0f000: alignment=0x8000
Correct?
If so, I'm struggling to see the sense in this. Shouldn't we be
changing things so that
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x10000
?
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-04 21:24 ` Andrew Morton
0 siblings, 0 replies; 14+ messages in thread
From: Andrew Morton @ 2016-08-04 21:24 UTC (permalink / raw)
To: zijun_hu
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
>
> it causes double align requirement for __get_vm_area_node() if parameter
> size is power of 2 and VM_IOREMAP is set in parameter flags
>
> it is fixed by handling the specail case manually due to lack of
> get_count_order() for long parameter
>
> ...
>
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
> {
> struct vmap_area *va;
> struct vm_struct *area;
> + int ioremap_size_order;
>
> BUG_ON(in_interrupt());
> - if (flags & VM_IOREMAP)
> - align = 1ul << clamp_t(int, fls_long(size),
> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
> + if (flags & VM_IOREMAP) {
> + ioremap_size_order = fls_long(size);
> + if (is_power_of_2(size) && size != 1)
> + ioremap_size_order--;
> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
> + IOREMAP_MAX_ORDER);
> + }
>
> size = PAGE_ALIGN(size);
> if (unlikely(!size))
I'm having trouble with this, and a more complete description would
have helped!
As far as I can tell, the current code will decide the following:
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x8000
And your patch will change it so that
size=0x10000: alignment=0x8000
size=0x0f000: alignment=0x8000
Correct?
If so, I'm struggling to see the sense in this. Shouldn't we be
changing things so that
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x10000
?
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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see: http://www.linux-mm.org/ .
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
2016-08-04 21:24 ` Andrew Morton
@ 2016-08-05 2:27 ` zijun_hu
-1 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-05 2:27 UTC (permalink / raw)
To: Andrew Morton
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 08/05/2016 05:24 AM, Andrew Morton wrote:
>>
>> it causes double align requirement for __get_vm_area_node() if parameter
>> size is power of 2 and VM_IOREMAP is set in parameter flags
>>
>> it is fixed by handling the specail case manually due to lack of
>> get_count_order() for long parameter
>>
>> ...
>>
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>> {
>> struct vmap_area *va;
>> struct vm_struct *area;
>> + int ioremap_size_order;
>>
>> BUG_ON(in_interrupt());
>> - if (flags & VM_IOREMAP)
>> - align = 1ul << clamp_t(int, fls_long(size),
>> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
>> + if (flags & VM_IOREMAP) {
>> + ioremap_size_order = fls_long(size);
>> + if (is_power_of_2(size) && size != 1)
>> + ioremap_size_order--;
>> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
>> + IOREMAP_MAX_ORDER);
>> + }
>>
>> size = PAGE_ALIGN(size);
>> if (unlikely(!size))
>
> I'm having trouble with this, and a more complete description would
> have helped!
>
> As far as I can tell, the current code will decide the following:
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x8000
>
no, the current code doesn't achieve the above results as shown below
size=0x10000 -> fls_long(0x10000)=17 -> alignment=0x20000
size=0x0f000 -> fls_long(0x0f000)=16 -> alignment=0x10000
it is wrong for power of 2 value such as size=0x10000
> And your patch will change it so that
>
> size=0x10000: alignment=0x8000
> size=0x0f000: alignment=0x8000
>
> Correct?
>
no, my patch will results in the following calculations
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x10000
> If so, I'm struggling to see the sense in this. Shouldn't we be
> changing things so that
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x10000
>
> ?
okay, it is the aim of my patch as explained above
>
>
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-05 2:27 ` zijun_hu
0 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-05 2:27 UTC (permalink / raw)
To: Andrew Morton
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 08/05/2016 05:24 AM, Andrew Morton wrote:
>>
>> it causes double align requirement for __get_vm_area_node() if parameter
>> size is power of 2 and VM_IOREMAP is set in parameter flags
>>
>> it is fixed by handling the specail case manually due to lack of
>> get_count_order() for long parameter
>>
>> ...
>>
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>> {
>> struct vmap_area *va;
>> struct vm_struct *area;
>> + int ioremap_size_order;
>>
>> BUG_ON(in_interrupt());
>> - if (flags & VM_IOREMAP)
>> - align = 1ul << clamp_t(int, fls_long(size),
>> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
>> + if (flags & VM_IOREMAP) {
>> + ioremap_size_order = fls_long(size);
>> + if (is_power_of_2(size) && size != 1)
>> + ioremap_size_order--;
>> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
>> + IOREMAP_MAX_ORDER);
>> + }
>>
>> size = PAGE_ALIGN(size);
>> if (unlikely(!size))
>
> I'm having trouble with this, and a more complete description would
> have helped!
>
> As far as I can tell, the current code will decide the following:
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x8000
>
no, the current code doesn't achieve the above results as shown below
size=0x10000 -> fls_long(0x10000)=17 -> alignment=0x20000
size=0x0f000 -> fls_long(0x0f000)=16 -> alignment=0x10000
it is wrong for power of 2 value such as size=0x10000
> And your patch will change it so that
>
> size=0x10000: alignment=0x8000
> size=0x0f000: alignment=0x8000
>
> Correct?
>
no, my patch will results in the following calculations
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x10000
> If so, I'm struggling to see the sense in this. Shouldn't we be
> changing things so that
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x10000
>
> ?
okay, it is the aim of my patch as explained above
>
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
2016-08-04 21:24 ` Andrew Morton
@ 2016-08-05 15:48 ` zijun_hu
-1 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-05 15:48 UTC (permalink / raw)
To: Andrew Morton
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 2016/8/5 5:24, Andrew Morton wrote:
>>
>> it causes double align requirement for __get_vm_area_node() if parameter
>> size is power of 2 and VM_IOREMAP is set in parameter flags
>>
>> it is fixed by handling the specail case manually due to lack of
>> get_count_order() for long parameter
>>
>> ...
>>
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>> {
>> struct vmap_area *va;
>> struct vm_struct *area;
>> + int ioremap_size_order;
>>
>> BUG_ON(in_interrupt());
>> - if (flags & VM_IOREMAP)
>> - align = 1ul << clamp_t(int, fls_long(size),
>> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
>> + if (flags & VM_IOREMAP) {
>> + ioremap_size_order = fls_long(size);
>> + if (is_power_of_2(size) && size != 1)
>> + ioremap_size_order--;
>> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
>> + IOREMAP_MAX_ORDER);
>> + }
>>
>> size = PAGE_ALIGN(size);
>> if (unlikely(!size))
>
> I'm having trouble with this, and a more complete description would
> have helped!
>
> As far as I can tell, the current code will decide the following:
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x8000
>
no, the current code doesn't achieve the above results as shown below
size=0x10000 -> fls_long(0x10000)=17 -> alignment=0x20000
size=0x0f000 -> fls_long(0x0f000)=16 -> alignment=0x10000
it is wrong for power of 2 value such as size=0x10000
> And your patch will change it so that
>
> size=0x10000: alignment=0x8000
> size=0x0f000: alignment=0x8000
>
> Correct?
>
no, my patch will results in the following calculations
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x10000
> If so, I'm struggling to see the sense in this. Shouldn't we be
> changing things so that
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x10000
>
> ?
okay, it is the aim of my patch as explained above
i provide another solution as shown below
i appreciate it since it is more canonical
please help to review and apply it kindly
>From 1fa79b706735908b2c7aed635dcad7ed9c0a2a87 Mon Sep 17 00:00:00 2001
From: zijun_hu <zijun_hu@htc.com>
Date: Fri, 5 Aug 2016 22:10:07 +0800
Subject: [PATCH 1/1] mm/vmalloc: fix align value calculation error
it causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags
get_order_long() is implemented and used instead of fls_long() for
fixing the bug
Signed-off-by: zijun_hu <zijun_hu@htc.com>
---
include/linux/bitops.h | 17 +++++++++++++++++
mm/vmalloc.c | 2 +-
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 299e76b..c18448d 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -192,6 +192,23 @@ static inline unsigned fls_long(unsigned long l)
}
/**
+ * get_order_long - get order after rounding @l up to power of 2
+ * @l: parameter
+ *
+ * it is same as get_count_order() but long type parameter
+ * or 0 is returned if @l == 0UL
+ */
+static inline int get_order_long(unsigned long l)
+{
+ if (l == 0UL)
+ return 0;
+ else if (l & (l - 1UL))
+ return fls_long(l);
+ else
+ return fls_long(l) - 1;
+}
+
+/**
* __ffs64 - find first set bit in a 64 bit word
* @word: The 64 bit word
*
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 91f44e7..7d717f3 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
BUG_ON(in_interrupt());
if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, fls_long(size),
+ align = 1ul << clamp_t(int, get_order_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
size = PAGE_ALIGN(size);
--
1.9.1
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-05 15:48 ` zijun_hu
0 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-05 15:48 UTC (permalink / raw)
To: Andrew Morton
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 2016/8/5 5:24, Andrew Morton wrote:
>>
>> it causes double align requirement for __get_vm_area_node() if parameter
>> size is power of 2 and VM_IOREMAP is set in parameter flags
>>
>> it is fixed by handling the specail case manually due to lack of
>> get_count_order() for long parameter
>>
>> ...
>>
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1357,11 +1357,16 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>> {
>> struct vmap_area *va;
>> struct vm_struct *area;
>> + int ioremap_size_order;
>>
>> BUG_ON(in_interrupt());
>> - if (flags & VM_IOREMAP)
>> - align = 1ul << clamp_t(int, fls_long(size),
>> - PAGE_SHIFT, IOREMAP_MAX_ORDER);
>> + if (flags & VM_IOREMAP) {
>> + ioremap_size_order = fls_long(size);
>> + if (is_power_of_2(size) && size != 1)
>> + ioremap_size_order--;
>> + align = 1ul << clamp_t(int, ioremap_size_order, PAGE_SHIFT,
>> + IOREMAP_MAX_ORDER);
>> + }
>>
>> size = PAGE_ALIGN(size);
>> if (unlikely(!size))
>
> I'm having trouble with this, and a more complete description would
> have helped!
>
> As far as I can tell, the current code will decide the following:
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x8000
>
no, the current code doesn't achieve the above results as shown below
size=0x10000 -> fls_long(0x10000)=17 -> alignment=0x20000
size=0x0f000 -> fls_long(0x0f000)=16 -> alignment=0x10000
it is wrong for power of 2 value such as size=0x10000
> And your patch will change it so that
>
> size=0x10000: alignment=0x8000
> size=0x0f000: alignment=0x8000
>
> Correct?
>
no, my patch will results in the following calculations
size=0x10000: alignment=0x10000
size=0x0f000: alignment=0x10000
> If so, I'm struggling to see the sense in this. Shouldn't we be
> changing things so that
>
> size=0x10000: alignment=0x10000
> size=0x0f000: alignment=0x10000
>
> ?
okay, it is the aim of my patch as explained above
i provide another solution as shown below
i appreciate it since it is more canonical
please help to review and apply it kindly
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
2016-08-05 15:48 ` zijun_hu
@ 2016-08-09 21:28 ` Andrew Morton
-1 siblings, 0 replies; 14+ messages in thread
From: Andrew Morton @ 2016-08-09 21:28 UTC (permalink / raw)
To: zijun_hu
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On Fri, 5 Aug 2016 23:48:21 +0800 zijun_hu <zijun_hu@zoho.com> wrote:
> From: zijun_hu <zijun_hu@htc.com>
> Date: Fri, 5 Aug 2016 22:10:07 +0800
> Subject: [PATCH 1/1] mm/vmalloc: fix align value calculation error
>
> it causes double align requirement for __get_vm_area_node() if parameter
> size is power of 2 and VM_IOREMAP is set in parameter flags
>
> get_order_long() is implemented and used instead of fls_long() for
> fixing the bug
Makes sense. I think.
> --- a/include/linux/bitops.h
> +++ b/include/linux/bitops.h
> @@ -192,6 +192,23 @@ static inline unsigned fls_long(unsigned long l)
> }
>
> /**
> + * get_order_long - get order after rounding @l up to power of 2
> + * @l: parameter
> + *
> + * it is same as get_count_order() but long type parameter
> + * or 0 is returned if @l == 0UL
> + */
> +static inline int get_order_long(unsigned long l)
> +{
> + if (l == 0UL)
> + return 0;
> + else if (l & (l - 1UL))
> + return fls_long(l);
> + else
> + return fls_long(l) - 1;
> +}
> +
> +/**
> * __ffs64 - find first set bit in a 64 bit word
> * @word: The 64 bit word
> *
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 91f44e7..7d717f3 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>
> BUG_ON(in_interrupt());
> if (flags & VM_IOREMAP)
> - align = 1ul << clamp_t(int, fls_long(size),
> + align = 1ul << clamp_t(int, get_order_long(size),
> PAGE_SHIFT, IOREMAP_MAX_ORDER);
>
> size = PAGE_ALIGN(size);
It would be better to call this get_count_order_long(), I think? To
match get_count_order()?
get_count_order() is a weird name and perhaps both of these should be
renamed to things which actually make sense. That's a separate issue.
--- a/include/linux/bitops.h~mm-vmalloc-fix-align-value-calculation-error-fix
+++ a/include/linux/bitops.h
@@ -75,6 +75,23 @@ static inline int get_count_order(unsign
return order;
}
+/**
+ * get_count_order_long - get order after rounding @l up to power of 2
+ * @l: parameter
+ *
+ * The same as get_count_order() but accepts a long type parameter
+ * or 0 is returned if @l == 0UL
+ */
+static inline int get_count_order_long(unsigned long l)
+{
+ if (l == 0UL)
+ return 0;
+ else if (l & (l - 1UL))
+ return fls_long(l);
+ else
+ return fls_long(l) - 1;
+}
+
static __always_inline unsigned long hweight_long(unsigned long w)
{
return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
@@ -192,23 +209,6 @@ static inline unsigned fls_long(unsigned
}
/**
- * get_order_long - get order after rounding @l up to power of 2
- * @l: parameter
- *
- * it is same as get_count_order() but long type parameter
- * or 0 is returned if @l == 0UL
- */
-static inline int get_order_long(unsigned long l)
-{
- if (l == 0UL)
- return 0;
- else if (l & (l - 1UL))
- return fls_long(l);
- else
- return fls_long(l) - 1;
-}
-
-/**
* __ffs64 - find first set bit in a 64 bit word
* @word: The 64 bit word
*
--- a/mm/vmalloc.c~mm-vmalloc-fix-align-value-calculation-error-fix
+++ a/mm/vmalloc.c
@@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_n
BUG_ON(in_interrupt());
if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, get_order_long(size),
+ align = 1ul << clamp_t(int, get_count_order_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
size = PAGE_ALIGN(size);
_
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-09 21:28 ` Andrew Morton
0 siblings, 0 replies; 14+ messages in thread
From: Andrew Morton @ 2016-08-09 21:28 UTC (permalink / raw)
To: zijun_hu
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On Fri, 5 Aug 2016 23:48:21 +0800 zijun_hu <zijun_hu@zoho.com> wrote:
> From: zijun_hu <zijun_hu@htc.com>
> Date: Fri, 5 Aug 2016 22:10:07 +0800
> Subject: [PATCH 1/1] mm/vmalloc: fix align value calculation error
>
> it causes double align requirement for __get_vm_area_node() if parameter
> size is power of 2 and VM_IOREMAP is set in parameter flags
>
> get_order_long() is implemented and used instead of fls_long() for
> fixing the bug
Makes sense. I think.
> --- a/include/linux/bitops.h
> +++ b/include/linux/bitops.h
> @@ -192,6 +192,23 @@ static inline unsigned fls_long(unsigned long l)
> }
>
> /**
> + * get_order_long - get order after rounding @l up to power of 2
> + * @l: parameter
> + *
> + * it is same as get_count_order() but long type parameter
> + * or 0 is returned if @l == 0UL
> + */
> +static inline int get_order_long(unsigned long l)
> +{
> + if (l == 0UL)
> + return 0;
> + else if (l & (l - 1UL))
> + return fls_long(l);
> + else
> + return fls_long(l) - 1;
> +}
> +
> +/**
> * __ffs64 - find first set bit in a 64 bit word
> * @word: The 64 bit word
> *
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 91f44e7..7d717f3 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>
> BUG_ON(in_interrupt());
> if (flags & VM_IOREMAP)
> - align = 1ul << clamp_t(int, fls_long(size),
> + align = 1ul << clamp_t(int, get_order_long(size),
> PAGE_SHIFT, IOREMAP_MAX_ORDER);
>
> size = PAGE_ALIGN(size);
It would be better to call this get_count_order_long(), I think? To
match get_count_order()?
get_count_order() is a weird name and perhaps both of these should be
renamed to things which actually make sense. That's a separate issue.
--- a/include/linux/bitops.h~mm-vmalloc-fix-align-value-calculation-error-fix
+++ a/include/linux/bitops.h
@@ -75,6 +75,23 @@ static inline int get_count_order(unsign
return order;
}
+/**
+ * get_count_order_long - get order after rounding @l up to power of 2
+ * @l: parameter
+ *
+ * The same as get_count_order() but accepts a long type parameter
+ * or 0 is returned if @l == 0UL
+ */
+static inline int get_count_order_long(unsigned long l)
+{
+ if (l == 0UL)
+ return 0;
+ else if (l & (l - 1UL))
+ return fls_long(l);
+ else
+ return fls_long(l) - 1;
+}
+
static __always_inline unsigned long hweight_long(unsigned long w)
{
return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
@@ -192,23 +209,6 @@ static inline unsigned fls_long(unsigned
}
/**
- * get_order_long - get order after rounding @l up to power of 2
- * @l: parameter
- *
- * it is same as get_count_order() but long type parameter
- * or 0 is returned if @l == 0UL
- */
-static inline int get_order_long(unsigned long l)
-{
- if (l == 0UL)
- return 0;
- else if (l & (l - 1UL))
- return fls_long(l);
- else
- return fls_long(l) - 1;
-}
-
-/**
* __ffs64 - find first set bit in a 64 bit word
* @word: The 64 bit word
*
--- a/mm/vmalloc.c~mm-vmalloc-fix-align-value-calculation-error-fix
+++ a/mm/vmalloc.c
@@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_n
BUG_ON(in_interrupt());
if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, get_order_long(size),
+ align = 1ul << clamp_t(int, get_count_order_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
size = PAGE_ALIGN(size);
_
--
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
2016-08-09 21:28 ` Andrew Morton
@ 2016-08-10 5:32 ` zijun_hu
-1 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-10 5:32 UTC (permalink / raw)
To: Andrew Morton
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 08/10/2016 05:28 AM, Andrew Morton wrote:
> On Fri, 5 Aug 2016 23:48:21 +0800 zijun_hu <zijun_hu@zoho.com> wrote:
>
>> From: zijun_hu <zijun_hu@htc.com>
>> Date: Fri, 5 Aug 2016 22:10:07 +0800
>> Subject: [PATCH 1/1] mm/vmalloc: fix align value calculation error
>>
>> it causes double align requirement for __get_vm_area_node() if parameter
>> size is power of 2 and VM_IOREMAP is set in parameter flags
>>
>> get_order_long() is implemented and used instead of fls_long() for
>> fixing the bug
>
> Makes sense. I think.
>
>> --- a/include/linux/bitops.h
>> +++ b/include/linux/bitops.h
>> @@ -192,6 +192,23 @@ static inline unsigned fls_long(unsigned long l)
>> }
>>
>> /**
>> + * get_order_long - get order after rounding @l up to power of 2
>> + * @l: parameter
>> + *
>> + * it is same as get_count_order() but long type parameter
>> + * or 0 is returned if @l == 0UL
>> + */
>> +static inline int get_order_long(unsigned long l)
>> +{
>> + if (l == 0UL)
>> + return 0;
>> + else if (l & (l - 1UL))
>> + return fls_long(l);
>> + else
>> + return fls_long(l) - 1;
>> +}
>> +
>> +/**
>> * __ffs64 - find first set bit in a 64 bit word
>> * @word: The 64 bit word
>> *
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index 91f44e7..7d717f3 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>>
>> BUG_ON(in_interrupt());
>> if (flags & VM_IOREMAP)
>> - align = 1ul << clamp_t(int, fls_long(size),
>> + align = 1ul << clamp_t(int, get_order_long(size),
>> PAGE_SHIFT, IOREMAP_MAX_ORDER);
>>
>> size = PAGE_ALIGN(size);
>
> It would be better to call this get_count_order_long(), I think? To
> match get_count_order()?
>
yes, i agree with you to correct function name
i provide another patch called v2 based on your suggestion as shown below
it have following correction against original patch v1
1) use name get_count_order_long() instead of get_order_long()
2) return -1 if @l == 0 to consist with get_order_long()
3) cast type to int before returning from get_count_order_long()
4) move up function parameter checking for __get_vm_area_node()
5) more commit message is offered to make issue and approach clear
any comments about new patch is welcome
this new patch called patch v2 is shown below
>From 868d3c100f41e16136eed50e47bbfb03d4a16d25 Mon Sep 17 00:00:00 2001
From: zijun_hu <zijun_hu@htc.com>
Date: Wed, 10 Aug 2016 12:13:41 +0800
Subject: [PATCH v2 1/1] mm/vmalloc: fix align value calculation error
it causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags, for example
size=0x10000 -> fls_long(0x10000)=17 -> align=0x20000
get_count_order_long() is implemented and used instead of fls_long() for
fixing the bug, for example
size=0x10000 -> get_count_order_long(0x10000)=16 -> align=0x10000
Signed-off-by: zijun_hu <zijun_hu@htc.com>
---
include/linux/bitops.h | 16 ++++++++++++++++
mm/vmalloc.c | 8 ++++----
2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 299e76b..93a07d1 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -192,6 +192,22 @@ static inline unsigned fls_long(unsigned long l)
}
/**
+ * get_count_order_long - get order after rounding @l up to power of 2
+ * @l: parameter
+ *
+ * it is same as get_count_order() but with long type parameter
+ */
+static inline int get_count_order_long(unsigned long l)
+{
+ if (l == 0UL)
+ return -1;
+ else if (l & (l - 1UL))
+ return (int)fls_long(l);
+ else
+ return (int)fls_long(l) - 1;
+}
+
+/**
* __ffs64 - find first set bit in a 64 bit word
* @word: The 64 bit word
*
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 91f44e7..80660a0 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1359,14 +1359,14 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
struct vm_struct *area;
BUG_ON(in_interrupt());
- if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, fls_long(size),
- PAGE_SHIFT, IOREMAP_MAX_ORDER);
-
size = PAGE_ALIGN(size);
if (unlikely(!size))
return NULL;
+ if (flags & VM_IOREMAP)
+ align = 1ul << clamp_t(int, get_count_order_long(size),
+ PAGE_SHIFT, IOREMAP_MAX_ORDER);
+
area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
if (unlikely(!area))
return NULL;
--
1.9.1
> get_count_order() is a weird name and perhaps both of these should be
> renamed to things which actually make sense. That's a separate issue.
>
okay, perhaps, another patch is applied to correct this weird name issue
in the future due to it is a separate issue now
we use get_count_order_long() to consist with get_order_long() now
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] mm/vmalloc: fix align value calculation error
@ 2016-08-10 5:32 ` zijun_hu
0 siblings, 0 replies; 14+ messages in thread
From: zijun_hu @ 2016-08-10 5:32 UTC (permalink / raw)
To: Andrew Morton
Cc: tj, hannes, mhocko, minchan, zijun_hu, rientjes, linux-kernel, linux-mm
On 08/10/2016 05:28 AM, Andrew Morton wrote:
> On Fri, 5 Aug 2016 23:48:21 +0800 zijun_hu <zijun_hu@zoho.com> wrote:
>
>> From: zijun_hu <zijun_hu@htc.com>
>> Date: Fri, 5 Aug 2016 22:10:07 +0800
>> Subject: [PATCH 1/1] mm/vmalloc: fix align value calculation error
>>
>> it causes double align requirement for __get_vm_area_node() if parameter
>> size is power of 2 and VM_IOREMAP is set in parameter flags
>>
>> get_order_long() is implemented and used instead of fls_long() for
>> fixing the bug
>
> Makes sense. I think.
>
>> --- a/include/linux/bitops.h
>> +++ b/include/linux/bitops.h
>> @@ -192,6 +192,23 @@ static inline unsigned fls_long(unsigned long l)
>> }
>>
>> /**
>> + * get_order_long - get order after rounding @l up to power of 2
>> + * @l: parameter
>> + *
>> + * it is same as get_count_order() but long type parameter
>> + * or 0 is returned if @l == 0UL
>> + */
>> +static inline int get_order_long(unsigned long l)
>> +{
>> + if (l == 0UL)
>> + return 0;
>> + else if (l & (l - 1UL))
>> + return fls_long(l);
>> + else
>> + return fls_long(l) - 1;
>> +}
>> +
>> +/**
>> * __ffs64 - find first set bit in a 64 bit word
>> * @word: The 64 bit word
>> *
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index 91f44e7..7d717f3 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
>>
>> BUG_ON(in_interrupt());
>> if (flags & VM_IOREMAP)
>> - align = 1ul << clamp_t(int, fls_long(size),
>> + align = 1ul << clamp_t(int, get_order_long(size),
>> PAGE_SHIFT, IOREMAP_MAX_ORDER);
>>
>> size = PAGE_ALIGN(size);
>
> It would be better to call this get_count_order_long(), I think? To
> match get_count_order()?
>
yes, i agree with you to correct function name
i provide another patch called v2 based on your suggestion as shown below
it have following correction against original patch v1
1) use name get_count_order_long() instead of get_order_long()
2) return -1 if @l == 0 to consist with get_order_long()
3) cast type to int before returning from get_count_order_long()
4) move up function parameter checking for __get_vm_area_node()
5) more commit message is offered to make issue and approach clear
any comments about new patch is welcome
this new patch called patch v2 is shown below
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2016-08-10 21:18 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-04 8:02 [PATCH] mm/vmalloc: fix align value calculation error zijun_hu
2016-08-04 8:02 ` zijun_hu
2016-08-04 8:36 ` zijun_hu
2016-08-04 8:36 ` zijun_hu
2016-08-04 21:24 ` Andrew Morton
2016-08-04 21:24 ` Andrew Morton
2016-08-05 2:27 ` zijun_hu
2016-08-05 2:27 ` zijun_hu
2016-08-05 15:48 ` zijun_hu
2016-08-05 15:48 ` zijun_hu
2016-08-09 21:28 ` Andrew Morton
2016-08-09 21:28 ` Andrew Morton
2016-08-10 5:32 ` zijun_hu
2016-08-10 5:32 ` zijun_hu
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