Messages in this thread | | | Date | Sat, 18 Apr 2015 09:16:53 -0700 | From | Mike Kravetz <> | Subject | Re: [RFC PATCH 4/4] mm: madvise allow remove operation for hugetlbfs |
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On 04/17/2015 10:11 AM, Mike Kravetz wrote: > On 04/17/2015 12:10 AM, Hillf Danton wrote: >>> >>> Now that we have hole punching support for hugetlbfs, we can >>> also support the MADV_REMOVE interface to it. >>> >>> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> >>> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> >>> --- >>> mm/madvise.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/mm/madvise.c b/mm/madvise.c >>> index d551475..c4a1027 100644 >>> --- a/mm/madvise.c >>> +++ b/mm/madvise.c >>> @@ -299,7 +299,7 @@ static long madvise_remove(struct vm_area_struct >>> *vma, >>> >>> *prev = NULL; /* tell sys_madvise we drop mmap_sem */ >>> >>> - if (vma->vm_flags & (VM_LOCKED | VM_HUGETLB)) >>> + if (vma->vm_flags & VM_LOCKED) >>> return -EINVAL; >>> >>> f = vma->vm_file; >>> -- >>> 2.1.0 >> >> After the above change offset is computed, >> >> offset = (loff_t)(start - vma->vm_start) >> + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); >> >> and I wonder if it is correct for huge page mapping. > > I think it will be correct. > > The above will be a (base) page size aligned offset into the file. > This offset will be huge page aligned in the fallocate hole punch > code. > > /* > * For hole punch round up the beginning offset of the hole and > * round down the end. > */ > hole_start = (offset + hpage_size - 1) & ~huge_page_mask(h); > hole_end = (offset + len - (hpage_size - 1)) * ~huge_page_mask(h); > > Was the alignment your concern, or something else?
Well, that alignment code in fallocate hole punch obviously wrong. :( Sorry about that. I'll send out an updated RFC with working hole punch.
-- Mike Kravetz
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