Messages in this thread | | | Subject | Re: [RFC] mm/mremap: Remove redundant checks inside vma_expandable() | From | Anshuman Khandual <> | Date | Tue, 11 Jul 2017 16:36:40 +0530 |
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On 07/11/2017 12:20 PM, Michal Hocko wrote: > On Tue 11-07-17 08:26:40, Vlastimil Babka wrote: >> On 07/11/2017 08:03 AM, Michal Hocko wrote: >>> On Tue 11-07-17 09:58:42, Anshuman Khandual wrote: >>>>> here. This is hardly something that would save many cycles in a >>>>> relatively cold path. >>>> Though I have not done any detailed instruction level measurement, >>>> there is a reduction in real and system amount of time to execute >>>> the test with and without the patch. >>>> >>>> Without the patch >>>> >>>> real 0m2.100s >>>> user 0m0.162s >>>> sys 0m1.937s >>>> >>>> With this patch >>>> >>>> real 0m0.928s >>>> user 0m0.161s >>>> sys 0m0.756s >>> 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? The > changelog is silent about it.
Yeah it was.
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