* Re: [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions()
2013-01-04 9:10 [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions() Lin Feng
@ 2013-01-04 14:56 ` Tejun Heo
2013-01-07 1:29 ` Lin Feng
2013-01-05 1:04 ` Wanpeng Li
2013-01-05 1:04 ` Wanpeng Li
2 siblings, 1 reply; 6+ messages in thread
From: Tejun Heo @ 2013-01-04 14:56 UTC (permalink / raw)
To: Lin Feng
Cc: akpm, mingo, yinghai, liwanp, benh, tangchen, linux-mm,
linux-kernel
On Fri, Jan 04, 2013 at 05:10:50PM +0800, Lin Feng wrote:
> The memmove span covers from (next+1) to the end of the array, and the index
> of next is (i+1), so the index of (next+1) is (i+2). So the size of remaining
> array elements is (type->cnt - (i + 2)).
>
> PS. It seems that memblock_merge_regions() could be made some improvement:
> we need't memmove the remaining array elements until we find a none-mergable
> element, but now we memmove everytime we find a neighboring compatible region.
> I'm not sure if the trial is worth though.
>
> Cc: Tejun Heo <tj@kernel.org>
> Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
> ---
> mm/memblock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 6259055..85ce056 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -314,7 +314,7 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
> }
>
> this->size += next->size;
> - memmove(next, next + 1, (type->cnt - (i + 1)) * sizeof(*next));
> + memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
Heh, that's confusing. Nice catch. Can you please also add a comment
explaning the index so that it's less confusing for the future readers?
Thanks.
--
tejun
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions()
2013-01-04 14:56 ` Tejun Heo
@ 2013-01-07 1:29 ` Lin Feng
0 siblings, 0 replies; 6+ messages in thread
From: Lin Feng @ 2013-01-07 1:29 UTC (permalink / raw)
To: Tejun Heo
Cc: akpm, mingo, yinghai, liwanp, benh, tangchen, linux-mm,
linux-kernel
On 01/04/2013 10:56 PM, Tejun Heo wrote:
> On Fri, Jan 04, 2013 at 05:10:50PM +0800, Lin Feng wrote:
>> The memmove span covers from (next+1) to the end of the array, and the index
>> of next is (i+1), so the index of (next+1) is (i+2). So the size of remaining
>> array elements is (type->cnt - (i + 2)).
>>
>> PS. It seems that memblock_merge_regions() could be made some improvement:
>> we need't memmove the remaining array elements until we find a none-mergable
>> element, but now we memmove everytime we find a neighboring compatible region.
>> I'm not sure if the trial is worth though.
>>
>> Cc: Tejun Heo <tj@kernel.org>
>> Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
>> ---
>> mm/memblock.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index 6259055..85ce056 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -314,7 +314,7 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
>> }
>>
>> this->size += next->size;
>> - memmove(next, next + 1, (type->cnt - (i + 1)) * sizeof(*next));
>> + memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
>
> Heh, that's confusing. Nice catch. Can you please also add a comment
> explaning the index so that it's less confusing for the future readers?
Hi Tejun,
Glad to. I will resend it soon.
thanks,
linfeng
>
> Thanks.
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions()
2013-01-04 9:10 [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions() Lin Feng
2013-01-04 14:56 ` Tejun Heo
@ 2013-01-05 1:04 ` Wanpeng Li
2013-01-07 1:31 ` Lin Feng
2013-01-05 1:04 ` Wanpeng Li
2 siblings, 1 reply; 6+ messages in thread
From: Wanpeng Li @ 2013-01-05 1:04 UTC (permalink / raw)
To: Lin Feng; +Cc: akpm, tj, mingo, yinghai, benh, tangchen, linux-mm, linux-kernel
On Fri, Jan 04, 2013 at 05:10:50PM +0800, Lin Feng wrote:
>The memmove span covers from (next+1) to the end of the array, and the index
>of next is (i+1), so the index of (next+1) is (i+2). So the size of remaining
>array elements is (type->cnt - (i + 2)).
>
Make sense.
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>PS. It seems that memblock_merge_regions() could be made some improvement:
>we need't memmove the remaining array elements until we find a none-mergable
>element, but now we memmove everytime we find a neighboring compatible region.
>I'm not sure if the trial is worth though.
>
>Cc: Tejun Heo <tj@kernel.org>
>Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
>---
> mm/memblock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/mm/memblock.c b/mm/memblock.c
>index 6259055..85ce056 100644
>--- a/mm/memblock.c
>+++ b/mm/memblock.c
>@@ -314,7 +314,7 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
> }
>
> this->size += next->size;
>- memmove(next, next + 1, (type->cnt - (i + 1)) * sizeof(*next));
>+ memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
> type->cnt--;
> }
> }
>--
>1.7.11.7
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions()
2013-01-05 1:04 ` Wanpeng Li
@ 2013-01-07 1:31 ` Lin Feng
0 siblings, 0 replies; 6+ messages in thread
From: Lin Feng @ 2013-01-07 1:31 UTC (permalink / raw)
To: Wanpeng Li
Cc: akpm, tj, mingo, yinghai, benh, tangchen, linux-mm, linux-kernel
On 01/05/2013 09:04 AM, Wanpeng Li wrote:
> On Fri, Jan 04, 2013 at 05:10:50PM +0800, Lin Feng wrote:
>> The memmove span covers from (next+1) to the end of the array, and the index
>> of next is (i+1), so the index of (next+1) is (i+2). So the size of remaining
>> array elements is (type->cnt - (i + 2)).
>>
>
> Make sense.
Hi Wanpeng,
Thanks for your review. I will add it in next version.
thanks,
linfeng
>
> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>
>> PS. It seems that memblock_merge_regions() could be made some improvement:
>> we need't memmove the remaining array elements until we find a none-mergable
>> element, but now we memmove everytime we find a neighboring compatible region.
>> I'm not sure if the trial is worth though.
>>
>> Cc: Tejun Heo <tj@kernel.org>
>> Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
>> ---
>> mm/memblock.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index 6259055..85ce056 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -314,7 +314,7 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
>> }
>>
>> this->size += next->size;
>> - memmove(next, next + 1, (type->cnt - (i + 1)) * sizeof(*next));
>> + memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
>> type->cnt--;
>> }
>> }
>> --
>> 1.7.11.7
>
>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions()
2013-01-04 9:10 [RFC PATCH] mm: memblock: fix wrong memmove size in memblock_merge_regions() Lin Feng
2013-01-04 14:56 ` Tejun Heo
2013-01-05 1:04 ` Wanpeng Li
@ 2013-01-05 1:04 ` Wanpeng Li
2 siblings, 0 replies; 6+ messages in thread
From: Wanpeng Li @ 2013-01-05 1:04 UTC (permalink / raw)
To: Lin Feng; +Cc: akpm, tj, mingo, yinghai, benh, tangchen, linux-mm, linux-kernel
On Fri, Jan 04, 2013 at 05:10:50PM +0800, Lin Feng wrote:
>The memmove span covers from (next+1) to the end of the array, and the index
>of next is (i+1), so the index of (next+1) is (i+2). So the size of remaining
>array elements is (type->cnt - (i + 2)).
>
Make sense.
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>PS. It seems that memblock_merge_regions() could be made some improvement:
>we need't memmove the remaining array elements until we find a none-mergable
>element, but now we memmove everytime we find a neighboring compatible region.
>I'm not sure if the trial is worth though.
>
>Cc: Tejun Heo <tj@kernel.org>
>Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
>---
> mm/memblock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/mm/memblock.c b/mm/memblock.c
>index 6259055..85ce056 100644
>--- a/mm/memblock.c
>+++ b/mm/memblock.c
>@@ -314,7 +314,7 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
> }
>
> this->size += next->size;
>- memmove(next, next + 1, (type->cnt - (i + 1)) * sizeof(*next));
>+ memmove(next, next + 1, (type->cnt - (i + 2)) * sizeof(*next));
> type->cnt--;
> }
> }
>--
>1.7.11.7
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^ permalink raw reply [flat|nested] 6+ messages in thread