Messages in this thread | | | Date | Thu, 29 Aug 2019 04:54:57 -0700 | From | Matthew Wilcox <> | Subject | Re: [PATCH] mm/hugetlb: avoid looping to the same hugepage if !pages and !vmas |
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On Thu, Aug 29, 2019 at 07:37:22PM +0800, zhigang lu wrote: > This change greatly decrease the time of mmaping a file in hugetlbfs. > With MAP_POPULATE flag, it takes about 50 milliseconds to mmap a > existing 128GB file in hugetlbfs. With this change, it takes less > then 1 millisecond.
You're going to need to find a new way of sending patches; this patch is mangled by your mail system.
> @@ -4391,6 +4391,17 @@ long follow_hugetlb_page(struct mm_struct *mm, > struct vm_area_struct *vma, > break; > } > } > + > + if (!pages && !vmas && !pfn_offset && > + (vaddr + huge_page_size(h) < vma->vm_end) && > + (remainder >= pages_per_huge_page(h))) { > + vaddr += huge_page_size(h); > + remainder -= pages_per_huge_page(h); > + i += pages_per_huge_page(h); > + spin_unlock(ptl); > + continue; > + }
The concept seems good to me. The description above could do with some better explanation though.
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