Messages in this thread | | | From | Pasha Tatashin <> | Subject | Re: [RESEND PATCH v10 6/6] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() | Date | Fri, 17 Aug 2018 01:35:22 +0000 |
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On 7/6/18 5:01 AM, Jia He wrote: > Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns > where possible") optimized the loop in memmap_init_zone(). But there is > still some room for improvement. E.g. in early_pfn_valid(), if pfn and > pfn+1 are in the same memblock region, we can record the last returned > memblock region index and check whether pfn++ is still in the same > region. > > Currently it only improve the performance on arm/arm64 and will have no > impact on other arches. > > For the performance improvement, after this set, I can see the time > overhead of memmap_init() is reduced from 27956us to 13537us in my > armv8a server(QDF2400 with 96G memory, pagesize 64k).
This series would be a lot simpler if patches 4, 5, and 6 were dropped. The extra complexity does not make sense to save 0.0001s/T during not.
Patches 1-3, look OK, but without patches 4-5 __init_memblock should be made local static as I suggested earlier.
So, I think Jia should re-spin this series with only 3 patches. Or, Andrew could remove the from linux-next before merge.
Thank you, Pavel
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