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.