We can simply set root memcg as the map's memcg to disable bpf memory
accounting. bpf_map_area_alloc is a little special as it gets the memcg
from current rather than from the map, so we need to disable GFP_ACCOUNT
specifically for it.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
---
include/linux/bpf.h | 8 ++++++++
kernel/bpf/memalloc.c | 3 ++-
kernel/bpf/syscall.c | 5 +++--
3 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index fe0bf48..4385418 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -28,6 +28,7 @@
#include <linux/btf.h>
#include <linux/rcupdate_trace.h>
#include <linux/static_call.h>
+#include <linux/memcontrol.h>
struct bpf_verifier_env;
struct bpf_verifier_log;
@@ -2933,4 +2934,11 @@ static inline bool type_is_alloc(u32 type)
return type & MEM_ALLOC;
}
+static inline gfp_t bpf_memcg_flags(gfp_t flags)
+{
+ if (memcg_bpf_enabled())
+ return flags | __GFP_ACCOUNT;
+ return flags;
+}
+
#endif /* _LINUX_BPF_H */
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index ebcc3dd..6da9051 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -395,7 +395,8 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu)
unit_size = size;
#ifdef CONFIG_MEMCG_KMEM
- objcg = get_obj_cgroup_from_current();
+ if (memcg_bpf_enabled())
+ objcg = get_obj_cgroup_from_current();
#endif
for_each_possible_cpu(cpu) {
c = per_cpu_ptr(pc, cpu);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 9d94a35..cda8d00 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -309,7 +309,7 @@ static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)
* __GFP_RETRY_MAYFAIL to avoid such situations.
*/
- const gfp_t gfp = __GFP_NOWARN | __GFP_ZERO | __GFP_ACCOUNT;
+ gfp_t gfp = bpf_memcg_flags(__GFP_NOWARN | __GFP_ZERO);
unsigned int flags = 0;
unsigned long align = 1;
void *area;
@@ -418,7 +418,8 @@ static void bpf_map_save_memcg(struct bpf_map *map)
* So we have to check map->objcg for being NULL each time it's
* being used.
*/
- map->objcg = get_obj_cgroup_from_current();
+ if (memcg_bpf_enabled())
+ map->objcg = get_obj_cgroup_from_current();
}
static void bpf_map_release_memcg(struct bpf_map *map)
--
1.8.3.1
