[PATCH rfc 1/9] mm: memcg: introduce memcontrol-v1.c

[Roman Gushchin <roman.gushchin@linux.dev>]

This patch introduces the mm/memcontrol-v1.c source file which will be used for
all legacy (cgroup v1) memory cgroup code.

As of now, let's compile it if CONFIG_MEMCG is set, similar to mm/memcontrol.c.
Later on it can be switched to use a separate config option, so that the legacy
code won't be compiled if not required.

Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
---
 mm/Makefile        | 3 ++-
 mm/memcontrol-v1.c | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)
 create mode 100644 mm/memcontrol-v1.c

diff --git a/mm/Makefile b/mm/Makefile
index 25da205becdd..c717a3ee612e 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -26,6 +26,7 @@ KCOV_INSTRUMENT_page_alloc.o := n
 KCOV_INSTRUMENT_debug-pagealloc.o := n
 KCOV_INSTRUMENT_kmemleak.o := n
 KCOV_INSTRUMENT_memcontrol.o := n
+KCOV_INSTRUMENT_memcontrol-v1.o := n
 KCOV_INSTRUMENT_mmzone.o := n
 KCOV_INSTRUMENT_vmstat.o := n
 KCOV_INSTRUMENT_failslab.o := n
@@ -95,7 +96,7 @@ obj-$(CONFIG_NUMA) += memory-tiers.o
 obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
 obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
 obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
-obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
+obj-$(CONFIG_MEMCG) += memcontrol.o memcontrol-v1.o vmpressure.o
 ifdef CONFIG_SWAP
 obj-$(CONFIG_MEMCG) += swap_cgroup.o
 endif
diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
new file mode 100644
index 000000000000..4bc66fc244c0
--- /dev/null
+++ b/mm/memcontrol-v1.c
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
-- 
2.43.2