The patch titled
Subject: mm: introduce page memcg flags
has been removed from the -mm tree. Its filename was
mm-introduce-page-memcg-flags.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Roman Gushchin <guro@xxxxxx>
Subject: mm: introduce page memcg flags
The lowest bit in page->memcg_data is used to distinguish between struct
memory_cgroup pointer and a pointer to a objcgs array. All checks and
modifications of this bit are open-coded.
Let's formalize it using page memcg flags, defined in enum
page_memcg_data_flags.
Additional flags might be added later.
Link: https://lkml.kernel.org/r/20201027001657.3398190-4-guro@xxxxxx
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)
--- a/include/linux/memcontrol.h~mm-introduce-page-memcg-flags
+++ a/include/linux/memcontrol.h
@@ -337,6 +337,15 @@ struct mem_cgroup {
extern struct mem_cgroup *root_mem_cgroup;
+enum page_memcg_data_flags {
+ /* page->memcg_data is a pointer to an objcgs vector */
+ MEMCG_DATA_OBJCGS = (1UL << 0),
+ /* the next bit after the last actual flag */
+ __NR_MEMCG_DATA_FLAGS = (1UL << 1),
+};
+
+#define MEMCG_DATA_FLAGS_MASK (__NR_MEMCG_DATA_FLAGS - 1)
+
/*
* page_memcg - get the memory cgroup associated with a page
* @page: a pointer to the page struct
@@ -398,13 +407,7 @@ static inline struct mem_cgroup *page_me
*/
unsigned long memcg_data = READ_ONCE(page->memcg_data);
- /*
- * The lowest bit set means that memcg isn't a valid
- * memcg pointer, but a obj_cgroups pointer.
- * In this case the page is shared and doesn't belong
- * to any specific memory cgroup.
- */
- if (memcg_data & 0x1UL)
+ if (memcg_data & MEMCG_DATA_OBJCGS)
return NULL;
return (struct mem_cgroup *)memcg_data;
@@ -423,7 +426,11 @@ static inline struct mem_cgroup *page_me
*/
static inline struct obj_cgroup **page_objcgs(struct page *page)
{
- return (struct obj_cgroup **)(READ_ONCE(page->memcg_data) & ~0x1UL);
+ unsigned long memcg_data = READ_ONCE(page->memcg_data);
+
+ VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS), page);
+
+ return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}
/*
@@ -438,10 +445,10 @@ static inline struct obj_cgroup **page_o
{
unsigned long memcg_data = READ_ONCE(page->memcg_data);
- if (memcg_data && (memcg_data & 0x1UL))
- return (struct obj_cgroup **)(memcg_data & ~0x1UL);
+ if (!memcg_data || !(memcg_data & MEMCG_DATA_OBJCGS))
+ return NULL;
- return NULL;
+ return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}
/*
@@ -454,7 +461,8 @@ static inline struct obj_cgroup **page_o
static inline bool set_page_objcgs(struct page *page,
struct obj_cgroup **objcgs)
{
- return !cmpxchg(&page->memcg_data, 0, (unsigned long)objcgs | 0x1UL);
+ return !cmpxchg(&page->memcg_data, 0, (unsigned long)objcgs |
+ MEMCG_DATA_OBJCGS);
}
#else
static inline struct obj_cgroup **page_objcgs(struct page *page)
_
Patches currently in -mm which might be from guro@xxxxxx are
mm-memcg-slab-fix-obj_cgroup_charge-return-value-handling.patch
mm-memcg-fix-obsolete-code-comments.patch
mm-memcg-deprecate-the-non-hierarchical-mode.patch
docs-cgroup-v1-reflect-the-deprecation-of-the-non-hierarchical-mode.patch
cgroup-remove-obsoleted-broken_hierarchy-and-warned_broken_hierarchy.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings-fix.patch
mm-slub-call-account_slab_page-after-slab-page-initialization.patch
mm-memcg-slab-pre-allocate-obj_cgroups-for-slab-caches-with-slab_account.patch
mm-memcg-slab-pre-allocate-obj_cgroups-for-slab-caches-with-slab_account-v2.patch
