Messages in this thread | | | Subject | Re: [RFC] mm/mremap: Remove redundant checks inside vma_expandable() | From | Vlastimil Babka <> | Date | Tue, 11 Jul 2017 08:26:40 +0200 |
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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?
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