From:   Stefan Roesch <shr@devkernel.io>
To:     linux-mm@kvack.org
Cc:     shr@devkernel.io, linux-doc@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: [RESEND RFC PATCH v1 00/20] mm: process/cgroup ksm support
Date:   Mon, 23 Jan 2023 09:37:28 -0800
Message-Id: <20230123173748.1734238-1-shr@devkernel.io>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

So far KSM can only be enabled by calling madvise for memory regions. Wha=
t is
required to enable KSM for more workloads is to enable / disable it at th=
e
process / cgroup level.

1. New options for prctl system command
This patch series adds two new options to the prctl system call. The firs=
t
one allows to enable KSM at the process level and the second one to query=
 the
setting.

The setting will be inherited by child processes.

With the above setting, KSM can be enabled for the seed process of a cgro=
up
and all processes in the cgroup will inherit the setting.

2. Changes to KSM processing
When KSM is enabled at the process level, the KSM code will iterate over =
all
the VMA's and enable KSM for the eligible VMA's.

When forking a process that has KSM enabled, the setting will be inherite=
d by
the new child process.

In addition when KSM is disabled for a process, KSM will be disabled for =
the
VMA's where KSM has been enabled.

3. Add tracepoints to KSM
Currently KSM has no tracepoints. This adds tracepoints to the key KSM fu=
nctions
to make it easier to debug KSM.

4. Add general_profit metric
The general_profit metric of KSM is specified in the documentation, but n=
ot
calculated. This adds the general profit metric to /sys/kernel/debug/mm/k=
sm.

5. Add more metrics to ksm_stat
This adds the process profit and ksm type metric to /proc/<pid>/ksm_stat.

6. Add more tests to ksm_tests
This adds an option to specify the merge type to the ksm_tests. This allo=
ws to
test madvise and prctl KSM. It also adds a new option to query if prctl K=
SM has
been enabled. It adds a fork test to verify that the KSM process setting =
is
inherited by client processes.


Stefan Roesch (20):
  mm: add new flag to enable ksm per process
  mm: add flag to __ksm_enter
  mm: add flag to __ksm_exit call
  mm: invoke madvise for all vmas in scan_get_next_rmap_item
  mm: support disabling of ksm for a process
  mm: add new prctl option to get and set ksm for a process
  mm: add tracepoints to ksm
  mm: split off pages_volatile function
  mm: expose general_profit metric
  docs: document general_profit sysfs knob
  mm: calculate ksm process profit metric
  mm: add ksm_merge_type() function
  mm: expose ksm process profit metric in ksm_stat
  mm: expose ksm merge type in ksm_stat
  docs: document new procfs ksm knobs
  tools: add new prctl flags to prctl in tools dir
  selftests/vm: add KSM prctl merge test
  selftests/vm: add KSM get merge type test
  selftests/vm: add KSM fork test
  selftests/vm: add two functions for debugging merge outcome

 Documentation/ABI/testing/sysfs-kernel-mm-ksm |   8 +
 Documentation/admin-guide/mm/ksm.rst          |   8 +-
 MAINTAINERS                                   |   1 +
 fs/proc/base.c                                |   5 +
 include/linux/ksm.h                           |  19 +-
 include/linux/sched/coredump.h                |   1 +
 include/trace/events/ksm.h                    | 257 ++++++++++++++++++
 include/uapi/linux/prctl.h                    |   2 +
 kernel/sys.c                                  |  29 ++
 mm/ksm.c                                      | 134 ++++++++-
 tools/include/uapi/linux/prctl.h              |   2 +
 tools/testing/selftests/vm/Makefile           |   3 +-
 tools/testing/selftests/vm/ksm_tests.c        | 254 ++++++++++++++---
 13 files changed, 665 insertions(+), 58 deletions(-)
 create mode 100644 include/trace/events/ksm.h


base-commit: c1649ec55708ae42091a2f1bca1ab49ecd722d55
--=20
2.30.2