[PATCH v2 00/10] Support free page filtering looking up mem_map array

[HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>]

This patch set implements filtering free pages looking up mem_map
array instead of free lists. This is compatible for cyclic mode
because looking up mem_map can be divided into cycles. On the other
hand, dividing free pages contaiend in free lists is difficult since
they are not sorted in physical-address order.

* Changes

v1 => v2:
  - If debuginfo is not available enough, switch logic to freelist
    one. On v1, free page filtering was disabled in this case.
  - Add hard-coded values in wider kernel versions.
  - If some free pages possibly fail to be filtered, try to correct
    cyclic buffer size appropreately.
  - Correct the comment explaining the cyclic buffer overrun, which
    was broken on v1.

RFC => v1:
  - Logic is automatically selected at runtime according to the
    current mode. In cyclic mode, mem_map array logic is used. In
    non-cyclic mode, free list logic is used.
  - The RFC version is:
    http://lists.infradead.org/pipermail/kexec/2012-June/006441.html

* TODO

Add the following values in VMCOREINFO on the upstream kernel. These
are used in the mem_map logic.

  - OFFSET(page._mapcount)
  - OFFSET(page.private)
  - SIZE(pageflags)
  - NUMBER(PG_buddy)
  - NUMBER(PG_slab)
  - NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE)

* Test

I tested this patch set on the following kernel versions.

- 3.4
- 3.1
- 2.6.38
- 2.6.32
- 2.6.18

On the test, I manually specified VMCOREINFO while extending it with
the following values according to the kernel versions.

- 3.1, 3.4
NUMBER(PG_slab)=7
SIZE(pageflags)=4
OFFSET(page._mapcount)=24
OFFSET(page.private)=48
NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE)=-128

- 2.6.38
SIZE(pageflags)=4
OFFSET(page._mapcount)=12
OFFSET(page.private)=16
NUMBER(PG_slab)=7
NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE)=-2

- 2.6.32
NUMBER(PG_slab)=7
NUMBER(PG_buddy)=19
OFFSET(page._mapcount)=12
OFFSET(page.private)=16
SIZE(pageflags)=4

- 2.6.18
NUMBER(PG_slab)=7
NUMBER(PG_buddy)=19
OFFSET(page._mapcount)=12
OFFSET(page.private)=16

---

HATAYAMA Daisuke (10):
      Warn cyclic buffer overrun and correct it if possible
      Add page_is_buddy for old kernels
      Add page_is_buddy for PG_buddy
      Add page_is_buddy for recent kernels
      Exclude free pages by looking up mem_map array
      Add hardcoded page flag values
      Add debuginfo-related processing for VMCOREINFO/VMLINUX
      Add new parameters to various tables
      Add debuginfo interface for enum type size
      Move page flags setup for old kernels after debuginfo initialization


 dwarf_info.c   |   18 ++++
 dwarf_info.h   |    1 
 makedumpfile.c |  226 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 makedumpfile.h |   35 ++++++++-
 4 files changed, 269 insertions(+), 11 deletions(-)

-- 

Thanks.
HATAYAMA, Daisuke

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