netdev - [PATCH bpf-next 0/2] Remove unnecessary synchronizations in cpumap

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Message-Id: <20230816045959.358059-1-houtao@huaweicloud.com>
Date: Wed, 16 Aug 2023 12:59:56 +0800
From: Hou Tao <houtao@...weicloud.com>
To: bpf@...r.kernel.org,
	netdev@...r.kernel.org,
	Toke Høiland-Jørgensen <toke@...hat.com>
Cc: "David S . Miller" <davem@...emloft.net>,
	Jakub Kicinski <kuba@...nel.org>,
	Jesper Dangaard Brouer <hawk@...nel.org>,
	John Fastabend <john.fastabend@...il.com>,
	Björn Töpel <bjorn.topel@...il.com>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Alexei Starovoitov <alexei.starovoitov@...il.com>,
	Andrii Nakryiko <andrii@...nel.org>,
	Song Liu <song@...nel.org>,
	Hao Luo <haoluo@...gle.com>,
	Yonghong Song <yonghong.song@...ux.dev>,
	Daniel Borkmann <daniel@...earbox.net>,
	KP Singh <kpsingh@...nel.org>,
	Stanislav Fomichev <sdf@...gle.com>,
	Jiri Olsa <jolsa@...nel.org>,
	houtao1@...wei.com
Subject: [PATCH bpf-next 0/2] Remove unnecessary synchronizations in cpumap

From: Hou Tao <houtao1@...wei.com>

Hi,

This is the formal patchset to remove unnecessary synchronizations in
cpu-map after address comments and collect Rvb tags from Toke
Høiland-Jørgensen (Big thanks to Toke). Patch #1 removes the unnecessary
rcu_barrier() when freeing bpf_cpu_map_entry and replaces it by
queue_rcu_work(). Patch #2 removes the unnecessary call_rcu() and
queue_work() when destroying cpu-map and does the freeing directly.

Test the patchset by using xdp_redirect_cpu and virtio-net. Both
xdp-mode and skb-mode have been exercised and no issues were reported.
As ususal, comments and suggestions are always welcome.

Change Log:
v1:
  * address comments from Toke Høiland-Jørgensen
  * add Rvb tags from Toke Høiland-Jørgensen
  * update outdated comment in cpu_map_delete_elem()

RFC: https://lore.kernel.org/bpf/20230728023030.1906124-1-houtao@huaweicloud.com

Hou Tao (2):
  bpf, cpumap: Use queue_rcu_work() to remove unnecessary rcu_barrier()
  bpf, cpumask: Clean up bpf_cpu_map_entry directly in cpu_map_free

 kernel/bpf/cpumap.c | 113 ++++++++++++++------------------------------
 1 file changed, 35 insertions(+), 78 deletions(-)

-- 
2.29.2