On Thu, Mar 28, 2013 at 09:03:16PM +0400, Konstantin Khlebnikov wrote: > Naoya Horiguchi wrote: > >Currently we fail to include any data on hugepages into coredump, > >because VM_DONTDUMP is set on hugetlbfs's vma. This behavior was recently > >introduced by commit 314e51b98 "mm: kill vma flag VM_RESERVED and > >mm->reserved_vm counter". This looks to me a serious regression, > >so let's fix it. > > That was introduced in my patch? Really? > Here was VM_RESERVED and it had the same effect as VM_DONTDUMP. At least I thought so. vma_dump_size() does like this (the diff is the one in 314e51b98): static unsigned long vma_dump_size(struct vm_area_struct *vma, unsigned long mm_flags) { #define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) /* always dump the vdso and vsyscall sections */ if (always_dump_vma(vma)) goto whole; if (vma->vm_flags & VM_DONTDUMP) return 0; /* Hugetlb memory check */ if (vma->vm_flags & VM_HUGETLB) { if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) goto whole; if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) goto whole; } /* Do not dump I/O mapped devices or special mappings */ - if (vma->vm_flags & (VM_IO | VM_RESERVED)) + if (vma->vm_flags & VM_IO) return 0; We have hugetlb memory check after VM_DONTDUMP check, so the following changed the behavior. --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -110,7 +110,7 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) * way when do_mmap_pgoff unwinds (may be important on powerpc * and ia64). */ - vma->vm_flags |= VM_HUGETLB | VM_RESERVED; + vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND | VM_DONTDUMP; vma->vm_ops = &hugetlb_vm_ops; if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) I think we don't have to set VM_DONTDUMP on hugetlbfs's vma. Thanks, Naoya -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>