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From: Hou Tao <houtao@huaweicloud.com>
To: bpf@vger.kernel.org
Cc: Martin KaFai Lau <martin.lau@linux.dev>,
	Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
	Hao Luo <haoluo@google.com>, Yonghong Song <yhs@fb.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Jiri Olsa <jolsa@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	rcu@vger.kernel.org, houtao1@huawei.com
Subject: [RFC PATCH bpf-next 5/6] bpf: Use BPF_MA_NO_REUSE in htab map
Date: Fri, 30 Dec 2022 12:11:50 +0800	[thread overview]
Message-ID: <20221230041151.1231169-6-houtao@huaweicloud.com> (raw)
In-Reply-To: <20221230041151.1231169-1-houtao@huaweicloud.com>

From: Hou Tao <houtao1@huawei.com>

Use BPF_MA_NO_REUSE in htab map to disable the immediate reuse of free
elements, so the lookup procedure will not return incorrect result.

After the change, the performance of "./map_perf_test 4 18 8192" will
drop from 520K to 330K events per sec on one CPU.

Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 kernel/bpf/hashtab.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 623111d4276d..e1636c5d0051 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -574,14 +574,14 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 				goto free_prealloc;
 		}
 	} else {
-		err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, 0,
+		err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, BPF_MA_NO_REUSE,
 					 htab_elem_ctor);
 		if (err)
 			goto free_map_locked;
 		if (percpu) {
 			err = bpf_mem_alloc_init(&htab->pcpu_ma,
 						 round_up(htab->map.value_size, 8),
-						 BPF_MA_PERCPU, NULL);
+						 BPF_MA_PERCPU | BPF_MA_NO_REUSE, NULL);
 			if (err)
 				goto free_map_locked;
 		}
-- 
2.29.2


  parent reply	other threads:[~2022-12-30  4:12 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-30  4:11 [RFC PATCH bpf-next 0/6] bpf: Handle reuse in bpf memory alloc Hou Tao
2022-12-30  4:11 ` [RFC PATCH bpf-next 1/6] bpf: Support ctor in bpf memory allocator Hou Tao
2022-12-30  4:11 ` [RFC PATCH bpf-next 2/6] bpf: Factor out a common helper free_llist() Hou Tao
2022-12-30  4:11 ` [RFC PATCH bpf-next 3/6] bpf: Pass bitwise flags to bpf_mem_alloc_init() Hou Tao
2022-12-30  4:11 ` [RFC PATCH bpf-next 4/6] bpf: Introduce BPF_MA_NO_REUSE for bpf memory allocator Hou Tao
2022-12-30  4:11 ` Hou Tao [this message]
2022-12-30  4:11 ` [RFC PATCH bpf-next 6/6] selftests/bpf: Add test case for element reuse in htab map Hou Tao
2023-01-01  1:26 ` [RFC PATCH bpf-next 0/6] bpf: Handle reuse in bpf memory alloc Alexei Starovoitov
2023-01-01 18:48   ` Yonghong Song
2023-01-03 13:47     ` Hou Tao
2023-01-04  6:10       ` Yonghong Song
2023-01-04  6:30         ` Hou Tao
2023-01-04  7:14           ` Yonghong Song
2023-01-04 18:26             ` Alexei Starovoitov
2023-02-10 16:32               ` Kumar Kartikeya Dwivedi
2023-02-10 21:06                 ` Alexei Starovoitov
2023-02-11  1:09                   ` Hou Tao
2023-02-11 16:33                     ` Alexei Starovoitov
2023-02-11 16:34                       ` Alexei Starovoitov
2023-02-15  1:54                         ` Martin KaFai Lau
2023-02-15  4:02                           ` Hou Tao
2023-02-15  7:22                             ` Martin KaFai Lau
2023-02-16  2:11                               ` Hou Tao
2023-02-16  7:47                                 ` Martin KaFai Lau
2023-02-16  8:18                                   ` Hou Tao
2023-02-16 13:55                         ` Hou Tao
2023-02-16 16:35                           ` Alexei Starovoitov
2023-02-17  1:19                             ` Hou Tao
2023-02-22 19:30                               ` Alexei Starovoitov
2023-02-15  2:35                       ` Hou Tao
2023-02-15  2:42                         ` Alexei Starovoitov
2023-02-15  3:00                           ` Hou Tao
2023-01-03 13:40   ` Hou Tao
2023-01-03 19:38     ` Alexei Starovoitov
2023-01-10  6:26       ` Martin KaFai Lau

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