lkml.org 
[lkml]   [2008]   [Aug]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] coredump_filter: add hugepage core dumping
From
Date
On Thu, 2008-08-28 at 14:24 +0900, KOSAKI Motohiro wrote:
> Now, hugepage's vma has VM_RESERVED flag because it cannot be swapped.
>
> and VM_RESERVED vma isn't core dumped because its flag often be used for
> kernel internal vma (e.g. vmalloc, sound related).
>
> So, hugepage is never dumped and it indicate hugepages's program can't be debugged easily.
>
> In these days, demand on making use of hugepage is increasing.
> IMO, native support for coredump of hugepage is useful.
>
>
> I think VM_RESERVED default dumping bahavior is good,
> then I'd like to add coredump_filter mask.
>
> This patch doesn't change dafault behavior.

I have tested this using both the provided C program and with a program
that used libhugetlbfs to back its text and data segments with huge
pages. This seems to work as expected. From a hugetlbfs perspective,
this seems like a reasonable patch to me.

> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> CC: Kawai, Hidehiro <hidehiro.kawai.ez@hitachi.com>
> CC: Hugh Dickins <hugh@veritas.com>
> CC: William Irwin <wli@holomorphy.com>
> CC: Adam Litke <agl@us.ibm.com>

Tested-by: Adam Litke <agl@us.ibm.com>
Acked-by: Adam Litke <agl@us.ibm.com>

> ---
> Documentation/filesystems/proc.txt | 3 ++-
> fs/binfmt_elf.c | 7 ++++++-
> include/linux/sched.h | 3 ++-
> 3 files changed, 10 insertions(+), 3 deletions(-)
>
> Index: b/Documentation/filesystems/proc.txt
> ===================================================================
> --- a/Documentation/filesystems/proc.txt
> +++ b/Documentation/filesystems/proc.txt
> @@ -2389,11 +2389,12 @@ will be dumped when the <pid> process is
> of memory types. If a bit of the bitmask is set, memory segments of the
> corresponding memory type are dumped, otherwise they are not dumped.
>
> -The following 4 memory types are supported:
> +The following 5 memory types are supported:
> - (bit 0) anonymous private memory
> - (bit 1) anonymous shared memory
> - (bit 2) file-backed private memory
> - (bit 3) file-backed shared memory
> + - (bit 5) hugetlb memory
>
> Note that MMIO pages such as frame buffer are never dumped and vDSO pages
> are always dumped regardless of the bitmask status.
> Index: b/include/linux/sched.h
> ===================================================================
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -402,8 +402,9 @@ extern int get_dumpable(struct mm_struct
> #define MMF_DUMP_MAPPED_PRIVATE 4
> #define MMF_DUMP_MAPPED_SHARED 5
> #define MMF_DUMP_ELF_HEADERS 6
> +#define MMF_DUMP_HUGETLB 7
> #define MMF_DUMP_FILTER_SHIFT MMF_DUMPABLE_BITS
> -#define MMF_DUMP_FILTER_BITS 5
> +#define MMF_DUMP_FILTER_BITS (MMF_DUMP_HUGETLB - MMF_DUMP_ANON_PRIVATE + 1)
> #define MMF_DUMP_FILTER_MASK \
> (((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
> #define MMF_DUMP_FILTER_DEFAULT \
> Index: b/fs/binfmt_elf.c
> ===================================================================
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -1160,11 +1160,16 @@ static unsigned long vma_dump_size(struc
> if (vma->vm_flags & VM_ALWAYSDUMP)
> goto whole;
>
> +#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
> +
> + if ((vma->vm_flags & VM_HUGETLB) && FILTER(HUGETLB))
> + goto whole;
> +
> /* Do not dump I/O mapped devices or special mappings */
> if (vma->vm_flags & (VM_IO | VM_RESERVED))
> return 0;
>
> -#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
>
> /* By default, dump shared memory if mapped from an anonymous file. */
> if (vma->vm_flags & VM_SHARED) {
>
>
--
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center



\
 
 \ /
  Last update: 2008-08-28 16:53    [W:0.142 / U:7.528 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site