[v4,10/36] slab: objext: introduce objext_flags as extension to page_memcg_data_flags

Commit Message

Suren Baghdasaryan Feb. 21, 2024, 7:40 p.m. UTC

Introduce objext_flags to store additional objext flags unrelated to memcg.

Signed-off-by: Suren Baghdasaryan <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
---
 include/linux/memcontrol.h | 29 ++++++++++++++++++++++-------
 mm/slab.h                  |  4 +---
 2 files changed, 23 insertions(+), 10 deletions(-)

Comments

Pasha Tatashin Feb. 22, 2024, 12:12 a.m. UTC | #1

On Wed, Feb 21, 2024 at 2:41 PM Suren Baghdasaryan <[e-mail]> wrote:
>
> Introduce objext_flags to store additional objext flags unrelated to memcg.
>
> Signed-off-by: Suren Baghdasaryan <[e-mail]>
> Reviewed-by: Kees Cook <[e-mail]>

Reviewed-by: Pasha Tatashin <[e-mail]>

Vlastimil Babka Feb. 26, 2024, 4:53 p.m. UTC | #2

On 2/21/24 20:40, Suren Baghdasaryan wrote:
> Introduce objext_flags to store additional objext flags unrelated to memcg.
> 
> Signed-off-by: Suren Baghdasaryan <[e-mail]>
> Reviewed-by: Kees Cook <[e-mail]>

Reviewed-by: Vlastimil Babka <[e-mail]>

Patch

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index eb1dc181e412..f3584e98b640 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -356,7 +356,22 @@  enum page_memcg_data_flags {
 	__NR_MEMCG_DATA_FLAGS  = (1UL << 2),
 };
 
-#define MEMCG_DATA_FLAGS_MASK (__NR_MEMCG_DATA_FLAGS - 1)
+#define __FIRST_OBJEXT_FLAG	__NR_MEMCG_DATA_FLAGS
+
+#else /* CONFIG_MEMCG */
+
+#define __FIRST_OBJEXT_FLAG	(1UL << 0)
+
+#endif /* CONFIG_MEMCG */
+
+enum objext_flags {
+	/* the next bit after the last actual flag */
+	__NR_OBJEXTS_FLAGS  = __FIRST_OBJEXT_FLAG,
+};
+
+#define OBJEXTS_FLAGS_MASK (__NR_OBJEXTS_FLAGS - 1)
+
+#ifdef CONFIG_MEMCG
 
 static inline bool folio_memcg_kmem(struct folio *folio);
 
@@ -390,7 +405,7 @@  static inline struct mem_cgroup *__folio_memcg(struct folio *folio)
 	VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_OBJEXTS, folio);
 	VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_KMEM, folio);
 
-	return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+	return (struct mem_cgroup *)(memcg_data & ~OBJEXTS_FLAGS_MASK);
 }
 
 /*
@@ -411,7 +426,7 @@  static inline struct obj_cgroup *__folio_objcg(struct folio *folio)
 	VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_OBJEXTS, folio);
 	VM_BUG_ON_FOLIO(!(memcg_data & MEMCG_DATA_KMEM), folio);
 
-	return (struct obj_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+	return (struct obj_cgroup *)(memcg_data & ~OBJEXTS_FLAGS_MASK);
 }
 
 /*
@@ -468,11 +483,11 @@  static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio)
 	if (memcg_data & MEMCG_DATA_KMEM) {
 		struct obj_cgroup *objcg;
 
-		objcg = (void *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+		objcg = (void *)(memcg_data & ~OBJEXTS_FLAGS_MASK);
 		return obj_cgroup_memcg(objcg);
 	}
 
-	return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+	return (struct mem_cgroup *)(memcg_data & ~OBJEXTS_FLAGS_MASK);
 }
 
 /*
@@ -511,11 +526,11 @@  static inline struct mem_cgroup *folio_memcg_check(struct folio *folio)
 	if (memcg_data & MEMCG_DATA_KMEM) {
 		struct obj_cgroup *objcg;
 
-		objcg = (void *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+		objcg = (void *)(memcg_data & ~OBJEXTS_FLAGS_MASK);
 		return obj_cgroup_memcg(objcg);
 	}
 
-	return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+	return (struct mem_cgroup *)(memcg_data & ~OBJEXTS_FLAGS_MASK);
 }
 
 static inline struct mem_cgroup *page_memcg_check(struct page *page)
diff --git a/mm/slab.h b/mm/slab.h
index 7f19b0a2acd8..13b6ba2abd74 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -560,10 +560,8 @@  static inline struct slabobj_ext *slab_obj_exts(struct slab *slab)
 							slab_page(slab));
 	VM_BUG_ON_PAGE(obj_exts & MEMCG_DATA_KMEM, slab_page(slab));
 
-	return (struct slabobj_ext *)(obj_exts & ~MEMCG_DATA_FLAGS_MASK);
-#else
-	return (struct slabobj_ext *)obj_exts;
 #endif
+	return (struct slabobj_ext *)(obj_exts & ~OBJEXTS_FLAGS_MASK);
 }
 
 int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,