From: Hou Tao <houtao@huaweicloud.com>
To: bpf@vger.kernel.org
Cc: Martin KaFai Lau <kafai@fb.com>,
Andrii Nakryiko <andrii@kernel.org>,
Song Liu <songliubraving@fb.com>, 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>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Jiri Olsa <jolsa@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
Delyan Kratunov <delyank@fb.com>,
rcu@vger.kernel.org, houtao1@huawei.com
Subject: [PATCH bpf-next 0/3] Remove unnecessary RCU grace period chaining
Date: Tue, 11 Oct 2022 15:11:25 +0800 [thread overview]
Message-ID: <20221011071128.3470622-1-houtao@huaweicloud.com> (raw)
From: Hou Tao <houtao1@huawei.com>
Hi,
Now bpf uses RCU grace period chaining to wait for the completion of
access from both sleepable and non-sleepable bpf program: calling
call_rcu_tasks_trace() firstly to wait for a RCU-tasks-trace grace
period, then in its callback calls call_rcu() or kfree_rcu() to wait for
a normal RCU grace period.
According to the implementation of RCU Tasks Trace, it inovkes
->postscan_func() to wait for one RCU-tasks-trace grace period and
rcu_tasks_trace_postscan() inovkes synchronize_rcu() to wait for one
normal RCU grace period in turn, so one RCU-tasks-trace grace period
will imply one normal RCU grace period. And it also means there is no
need to do call_rcu() or kfree_rcu() again in the callback of
call_rcu_tasks_trace() in these grace period chains, so just remove the
unnecessary call_rcu() or kfree_rcu() calls.
Comments are always welcome.
Hou Tao (3):
bpf: Free elements after one RCU-tasks-trace grace period
bpf: Free local storage memory after one RCU-tasks-trace grace period
bpf: Free trace program array after one RCU-tasks-trace grace period
kernel/bpf/bpf_local_storage.c | 10 ++++++++--
kernel/bpf/core.c | 5 ++++-
kernel/bpf/memalloc.c | 17 ++++++-----------
3 files changed, 18 insertions(+), 14 deletions(-)
--
2.29.2
next reply other threads:[~2022-10-11 6:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-11 7:11 Hou Tao [this message]
2022-10-11 7:11 ` [PATCH bpf-next 1/3] bpf: Free elements after one RCU-tasks-trace grace period Hou Tao
2022-10-11 9:07 ` Paul E. McKenney
2022-10-11 11:31 ` Hou Tao
2022-10-12 6:36 ` Paul E. McKenney
2022-10-12 9:26 ` Hou Tao
2022-10-12 16:11 ` Paul E. McKenney
2022-10-13 1:25 ` Hou Tao
2022-10-13 5:07 ` Martin KaFai Lau
2022-10-13 9:02 ` Hou Tao
2022-10-13 19:00 ` Paul E. McKenney
2022-10-14 4:20 ` Hou Tao
2022-10-14 12:15 ` Paul E. McKenney
2022-10-17 6:55 ` Hou Tao
2022-10-17 10:23 ` Paul E. McKenney
2022-10-13 1:41 ` Hou Tao
2022-10-13 19:04 ` Paul E. McKenney
2022-10-14 4:04 ` Hou Tao
2022-10-11 7:11 ` [PATCH bpf-next 2/3] bpf: Free local storage memory " Hou Tao
2022-10-11 9:09 ` Paul E. McKenney
2022-10-11 7:11 ` [PATCH bpf-next 3/3] bpf: Free trace program array " Hou Tao
2022-10-11 9:09 ` Paul E. McKenney
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