Commit ee53cbfb authored by Yafang Shao's avatar Yafang Shao Committed by Alexei Starovoitov
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bpf: allow to disable bpf map memory accounting 



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: default avatarYafang Shao <laoar.shao@gmail.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarRoman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-4-laoar.shao@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ddef81b5

include/linux/bpf.h

+8 −0
Original line number Diff line number Diff line
@@ -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 */

kernel/bpf/memalloc.c

+2 −1
Original line number Diff line number Diff line
@@ -395,6 +395,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) 
		unit_size = size;



#ifdef CONFIG_MEMCG_KMEM

		if (memcg_bpf_enabled())

			objcg = get_obj_cgroup_from_current();

#endif

		for_each_possible_cpu(cpu) {

kernel/bpf/syscall.c

+3 −2
Original line number Diff line number Diff line
@@ -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;
@@ -418,6 +418,7 @@ 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.

	 */

	if (memcg_bpf_enabled())

		map->objcg = get_obj_cgroup_from_current();

}