tools/mm: add script to display page state for a given PID and VADDR

Introduces a new drgn script, `show_page_info.py`, which allows users
to analyze the state of a page given a process ID (PID) and a virtual
address (VADDR).  This can help kernel developers or debuggers easily
inspect page-related information in a live kernel or vmcore.

The script extracts information such as the page flags, mapping, and
other metadata relevant to diagnosing memory issues.

Output example:
sudo ./show_page_info.py 1 0x7fc988181000
PID: 1 Comm: systemd mm: 0xffff8d22c4089700
RAW: 0017ffffc000416c fffff939062ff708 fffff939062ffe08 ffff8d23062a12a8
RAW: 0000000000000000 ffff8d2323438f60 0000002500000007 ffff8d23203ff500
Page Address:    0xfffff93905664e00
Page Flags:      PG_referenced|PG_uptodate|PG_lru|PG_head|PG_active|
                 PG_private|PG_reported|PG_has_hwpoisoned
Page Size:       4096
Page PFN:        0x159938
Page Physical:   0x159938000
Page Virtual:    0xffff8d2319938000
Page Refcount:   37
Page Mapcount:   7
Page Index:      0x0
Page Memcg Data: 0xffff8d23203ff500
Memcg Name:      init.scope
Memcg Path:      /sys/fs/cgroup/memory/init.scope
Page Mapping:    0xffff8d23062a12a8
Page Anon/File:  File
Page VMA:        0xffff8d22e06e0e40
VMA Start:       0x7fc988181000
VMA End:         0x7fc988185000
This page is part of a compound page.
This page is the head page of a compound page.
Head Page:       0xfffff93905664e00
Compound Order:  2
Number of Pages: 4

Link: https://lkml.kernel.org/r/20250530055855.687067-1-ye.liu@linux.dev
Signed-off-by: Ye Liu <liuye@kylinos.cn>
Tested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Omar Sandoval <osandov@osandov.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions