From 60433a9d038db006ca2f49e3c5f050dc46aaad3a Mon Sep 17 00:00:00 2001
From: Dmitry Rokosov <ddrokosov@salutedevices.com>
Date: Thu, 23 Nov 2023 10:19:43 +0300
Subject: [PATCH] samples: introduce new samples subdir for cgroup
Patch series "samples: introduce cgroup events listeners", v3.
To begin with, this patch series relocates the cgroup example code to the
samples/cgroup directory, which is the appropriate location for such code
snippets.
Furthermore, a new memcg events listener is introduced. This listener is
a simple yet effective tool for monitoring memory events and managing
counter changes during runtime.
Additionally, as per Andrew Morton's suggestion, a helpful reminder
comment is included in the memcontrol implementation. This comment serves
to ensure that the samples code is updated whenever new events are added.
This patch (of 3):
Move the cgroup_event_listener for cgroup v1 to the samples directory.
This suggestion was proposed by Andrew Morton during the discussion [1].
Link: https://lore.kernel.org/all/20231106140934.3f5d4960141562fe8da53906@linux-foundation.org/ [1]
Link: https://lkml.kernel.org/r/20231123071945.25811-1-ddrokosov@salutedevices.com
Link: https://lkml.kernel.org/r/20231123071945.25811-2-ddrokosov@salutedevices.com
Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
MAINTAINERS | 1 +
samples/Kconfig | 6 ++++++
samples/Makefile | 1 +
samples/cgroup/Makefile | 5 +++++
{tools => samples}/cgroup/cgroup_event_listener.c | 0
tools/cgroup/Makefile | 11 -----------
6 files changed, 13 insertions(+), 11 deletions(-)
create mode 100644 samples/cgroup/Makefile
rename {tools => samples}/cgroup/cgroup_event_listener.c (100%)
delete mode 100644 tools/cgroup/Makefile
diff --git a/MAINTAINERS b/MAINTAINERS
index 5c9d3d8546714..6f5d6962d26d1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5339,6 +5339,7 @@ L: linux-mm@kvack.org
S: Maintained
F: mm/memcontrol.c
F: mm/swap_cgroup.c
+F: samples/cgroup/*
F: tools/testing/selftests/cgroup/memcg_protection.m
F: tools/testing/selftests/cgroup/test_hugetlb_memcg.c
F: tools/testing/selftests/cgroup/test_kmem.c
diff --git a/samples/Kconfig b/samples/Kconfig
index b0ddf5f367388..b288d9991d27a 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -285,6 +285,12 @@ config SAMPLE_KMEMLEAK
Build a sample program which have explicitly leaks memory to test
kmemleak
+config SAMPLE_CGROUP
+ bool "Build cgroup sample code"
+ depends on CGROUPS && CC_CAN_LINK && HEADERS_INSTALL
+ help
+ Build samples that demonstrate the usage of the cgroup API.
+
source "samples/rust/Kconfig"
endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index 0a551c2b33f43..b85fa64390c51 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -3,6 +3,7 @@
subdir-$(CONFIG_SAMPLE_AUXDISPLAY) += auxdisplay
subdir-$(CONFIG_SAMPLE_ANDROID_BINDERFS) += binderfs
+subdir-$(CONFIG_SAMPLE_CGROUP) += cgroup
obj-$(CONFIG_SAMPLE_CONFIGFS) += configfs/
obj-$(CONFIG_SAMPLE_CONNECTOR) += connector/
obj-$(CONFIG_SAMPLE_FANOTIFY_ERROR) += fanotify/
diff --git a/samples/cgroup/Makefile b/samples/cgroup/Makefile
new file mode 100644
index 0000000000000..deef4530f5e77
--- /dev/null
+++ b/samples/cgroup/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+userprogs-always-y += cgroup_event_listener
+
+userccflags += -I usr/include
diff --git a/tools/cgroup/cgroup_event_listener.c b/samples/cgroup/cgroup_event_listener.c
similarity index 100%
rename from tools/cgroup/cgroup_event_listener.c
rename to samples/cgroup/cgroup_event_listener.c
diff --git a/tools/cgroup/Makefile b/tools/cgroup/Makefile
deleted file mode 100644
index ffca068e4a761..0000000000000
--- a/tools/cgroup/Makefile
+++ /dev/null
@@ -1,11 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-# Makefile for cgroup tools
-
-CFLAGS = -Wall -Wextra
-
-all: cgroup_event_listener
-%: %.c
- $(CC) $(CFLAGS) -o $@ $^
-
-clean:
- $(RM) cgroup_event_listener
--
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