Re: [PATCH 1/1] rbtree: correct mask for extracting node's parent

2016-08-18 Thread zijun_hu
On 08/18/2016 05:01 PM, Peter Zijlstra wrote:
> On Thu, Aug 18, 2016 at 04:19:10PM +0800, zijun_hu wrote:
>> From: zijun_hu 
>>
>> for LP64 ABI, struct rb_node aligns at 8 bytes boundary due to
>> sizeof(long) == 8 normally, so 0x07 should be used to extract
>> node's parent rather than 0x03
> 
> Doesn't matter though, in practise. The remaining bits are always 0.
> 
okay, understand
it maybe more readable to replace hard coding numbers by macros




Re: [PATCH 1/1] rbtree: correct mask for extracting node's parent

2016-08-18 Thread zijun_hu
On 08/18/2016 05:01 PM, Peter Zijlstra wrote:
> On Thu, Aug 18, 2016 at 04:19:10PM +0800, zijun_hu wrote:
>> From: zijun_hu 
>>
>> for LP64 ABI, struct rb_node aligns at 8 bytes boundary due to
>> sizeof(long) == 8 normally, so 0x07 should be used to extract
>> node's parent rather than 0x03
> 
> Doesn't matter though, in practise. The remaining bits are always 0.
> 
okay, understand
it maybe more readable to replace hard coding numbers by macros




Re: [PATCH 1/1] rbtree: correct mask for extracting node's parent

2016-08-18 Thread Peter Zijlstra
On Thu, Aug 18, 2016 at 04:19:10PM +0800, zijun_hu wrote:
> From: zijun_hu 
> 
> for LP64 ABI, struct rb_node aligns at 8 bytes boundary due to
> sizeof(long) == 8 normally, so 0x07 should be used to extract
> node's parent rather than 0x03

Doesn't matter though, in practise. The remaining bits are always 0.




Re: [PATCH 1/1] rbtree: correct mask for extracting node's parent

2016-08-18 Thread Peter Zijlstra
On Thu, Aug 18, 2016 at 04:19:10PM +0800, zijun_hu wrote:
> From: zijun_hu 
> 
> for LP64 ABI, struct rb_node aligns at 8 bytes boundary due to
> sizeof(long) == 8 normally, so 0x07 should be used to extract
> node's parent rather than 0x03

Doesn't matter though, in practise. The remaining bits are always 0.