Re: [RFC] mm/mremap: Remove redundant checks inside vma_expandable()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 07/11/2017 08:50 AM, Michal Hocko wrote:
> On Tue 11-07-17 08:26:40, Vlastimil Babka wrote:
>> On 07/11/2017 08:03 AM, Michal Hocko wrote:
>>>
>>> Are you telling me that two if conditions cause more than a second
>>> difference? That sounds suspicious.
>>
>> It's removing also a call to get_unmapped_area(), AFAICS. That means a
>> vma search?
> 
> Ohh, right. I have somehow missed that. Is this removal intentional?

I think it is: "Checking for availability of virtual address range at
the end of the VMA for the incremental size is also reduntant at this
point."

> The
> changelog is silent about it.

It doesn't explain why it's redundant, indeed. Unfortunately, the commit
f106af4e90ea ("fix checks for expand-in-place mremap") which added this,
also doesn't explain why it's needed.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]
  Powered by Linux