Merge tag 'cgroup-dmem-drm-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into drm-next

DMEM cgroup pull request

This introduces a new cgroup controller to limit the device memory.
Notable users would be DRM, dma-buf heaps, or v4l2.

This pull request is based on the series developped by Maarten
Lankhorst, Friedrich Vock, and I:
https://lore.kernel.org/all/20241204134410.1161769-1-dev@lankhorst.se/

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <mripard@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250110-cryptic-warm-mandrill-b71f5d@houat

3 files changed, 71 insertions, 1 deletions

diff --git a/include/linux/cgroup_dmem.h b/include/linux/cgroup_dmem.h
new file mode 100644
index 000000000000..dd4869f1d736
--- /dev/null
+++ b/include/linux/cgroup_dmem.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023-2024 Intel Corporation
+ */
+
+#ifndef _CGROUP_DMEM_H
+#define _CGROUP_DMEM_H
+
+#include <linux/types.h>
+#include <linux/llist.h>
+
+struct dmem_cgroup_pool_state;
+
+/* Opaque definition of a cgroup region, used internally */
+struct dmem_cgroup_region;
+
+#if IS_ENABLED(CONFIG_CGROUP_DMEM)
+struct dmem_cgroup_region *dmem_cgroup_register_region(u64 size, const char *name_fmt, ...) __printf(2,3);
+void dmem_cgroup_unregister_region(struct dmem_cgroup_region *region);
+int dmem_cgroup_try_charge(struct dmem_cgroup_region *region, u64 size,
+			   struct dmem_cgroup_pool_state **ret_pool,
+			   struct dmem_cgroup_pool_state **ret_limit_pool);
+void dmem_cgroup_uncharge(struct dmem_cgroup_pool_state *pool, u64 size);
+bool dmem_cgroup_state_evict_valuable(struct dmem_cgroup_pool_state *limit_pool,
+				      struct dmem_cgroup_pool_state *test_pool,
+				      bool ignore_low, bool *ret_hit_low);
+
+void dmem_cgroup_pool_state_put(struct dmem_cgroup_pool_state *pool);
+#else
+static inline __printf(2,3) struct dmem_cgroup_region *
+dmem_cgroup_register_region(u64 size, const char *name_fmt, ...)
+{
+	return NULL;
+}
+
+static inline void dmem_cgroup_unregister_region(struct dmem_cgroup_region *region)
+{ }
+
+static inline int dmem_cgroup_try_charge(struct dmem_cgroup_region *region, u64 size,
+					 struct dmem_cgroup_pool_state **ret_pool,
+					 struct dmem_cgroup_pool_state **ret_limit_pool)
+{
+	*ret_pool = NULL;
+
+	if (ret_limit_pool)
+		*ret_limit_pool = NULL;
+
+	return 0;
+}
+
+static inline void dmem_cgroup_uncharge(struct dmem_cgroup_pool_state *pool, u64 size)
+{ }
+
+static inline
+bool dmem_cgroup_state_evict_valuable(struct dmem_cgroup_pool_state *limit_pool,
+				      struct dmem_cgroup_pool_state *test_pool,
+				      bool ignore_low, bool *ret_hit_low)
+{
+	return true;
+}
+
+static inline void dmem_cgroup_pool_state_put(struct dmem_cgroup_pool_state *pool)
+{ }
+
+#endif
+#endif	/* _CGROUP_DMEM_H */
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index 445235487230..3fd0bcbf3080 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -65,6 +65,10 @@ SUBSYS(rdma)
 SUBSYS(misc)
 #endif
 
+#if IS_ENABLED(CONFIG_CGROUP_DMEM)
+SUBSYS(dmem)
+#endif
+
 /*
  * The following subsystems are not supported on the default hierarchy.
  */
diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
index 79dbd8bc35a7..46406f3fe34d 100644
--- a/include/linux/page_counter.h
+++ b/include/linux/page_counter.h
@@ -96,7 +96,7 @@ static inline void page_counter_reset_watermark(struct page_counter *counter)
 	counter->watermark = usage;
 }
 
-#ifdef CONFIG_MEMCG
+#if IS_ENABLED(CONFIG_MEMCG) || IS_ENABLED(CONFIG_CGROUP_DMEM)
 void page_counter_calculate_protection(struct page_counter *root,
 				       struct page_counter *counter,
 				       bool recursive_protection);