The quilt patch titled
Subject: Documentation/admin-guide/mm/pagemap.rst: drop "Using pagemap to do something useful"
has been removed from the -mm tree. Its filename was
documentation-admin-guide-mm-pagemaprst-drop-using-pagemap-to-do-something-useful.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: Documentation/admin-guide/mm/pagemap.rst: drop "Using pagemap to do something useful"
Date: Fri, 7 Jun 2024 14:23:57 +0200
That example was added in 2008. In 2015, we restricted access to the PFNs
in the pagemap to CAP_SYS_ADMIN, making that approach quite less usable.
It's 2024 now, and using that racy and low-lewel mechanism to calculate
the USS should not be considered a good example anymore. /proc/$pid/smaps
and /proc/$pid/smaps_rollup can do a much better job without any of that
low-level handling.
Let's just drop that example.
Link: https://lkml.kernel.org/r/20240607122357.115423-7-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lance Yang <ioworker0@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/mm/pagemap.rst | 21 ---------------------
1 file changed, 21 deletions(-)
--- a/Documentation/admin-guide/mm/pagemap.rst~documentation-admin-guide-mm-pagemaprst-drop-using-pagemap-to-do-something-useful
+++ a/Documentation/admin-guide/mm/pagemap.rst
@@ -173,27 +173,6 @@ LRU related page flags
The page-types tool in the tools/mm directory can be used to query the
above flags.
-Using pagemap to do something useful
-====================================
-
-The general procedure for using pagemap to find out about a process' memory
-usage goes like this:
-
- 1. Read ``/proc/pid/maps`` to determine which parts of the memory space are
- mapped to what.
- 2. Select the maps you are interested in -- all of them, or a particular
- library, or the stack or the heap, etc.
- 3. Open ``/proc/pid/pagemap`` and seek to the pages you would like to examine.
- 4. Read a u64 for each page from pagemap.
- 5. Open ``/proc/kpagecount`` and/or ``/proc/kpageflags``. For each PFN you
- just read, seek to that entry in the file, and read the data you want.
-
-For example, to find the "unique set size" (USS), which is the amount of
-memory that a process is using that is not shared with any other process,
-you can go through every map in the process, find the PFNs, look those up
-in kpagecount, and tally up the number of pages that are only referenced
-once.
-
Exceptions for Shared Memory
============================
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-pass-meminit_context-to-__free_pages_core.patch
mm-pass-meminit_context-to-__free_pages_core-fix.patch
mm-pass-meminit_context-to-__free_pages_core-fix-2.patch
mm-pass-meminit_context-to-__free_pages_core-fix-3.patch
mm-memory_hotplug-initialize-memmap-of-zone_device-with-pageoffline-instead-of-pagereserved.patch
mm-memory_hotplug-skip-adjust_managed_page_count-for-pageoffline-pages-when-offlining.patch
mm-read-page_type-using-read_once.patch
mm-migrate-make-migrate_misplaced_folio-return-0-on-success.patch
mm-migrate-move-numa-hinting-fault-folio-isolation-checks-under-ptl.patch
