From: Abel Wu <wuyun.abel@bytedance.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Muchun Song <muchun.song@linux.dev>,
Simon Horman <simon.horman@corigine.com>,
netdev@vger.kernel.org, linux-mm@kvack.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Re: [PATCH net-next v5 1/3] net-memcg: Fold dependency into memcg pressure cond
Date: Mon, 5 Jun 2023 19:52:10 +0800 [thread overview]
Message-ID: <2a45da69-b164-0a4f-eb45-fe57f301bc4b@bytedance.com> (raw)
In-Reply-To: <20230602202549.7nvrv4bx4cu7qxdn@google.com>
On 6/3/23 4:25 AM, Shakeel Butt wrote:
> On Fri, Jun 02, 2023 at 04:11:33PM +0800, Abel Wu wrote:
>> The callers of mem_cgroup_under_socket_pressure() should always make
>> sure that (mem_cgroup_sockets_enabled && sk->sk_memcg) is true. So
>> instead of coding around all the callsites, put the dependencies into
>> mem_cgroup_under_socket_pressure() to avoid redundancy and possibly
>> bugs.
>>
>> This change might also introduce slight function call overhead *iff*
>> the function gets expanded in the future. But for now this change
>> doesn't make binaries different (checked by vimdiff) except the one
>> net/ipv4/tcp_input.o (by scripts/bloat-o-meter), which is probably
>> negligible to performance:
>>
>> add/remove: 0/0 grow/shrink: 1/2 up/down: 5/-5 (0)
>> Function old new delta
>> tcp_grow_window 573 578 +5
>> tcp_try_rmem_schedule 1083 1081 -2
>> tcp_check_space 324 321 -3
>> Total: Before=44647, After=44647, chg +0.00%
>>
>> So folding the dependencies into mem_cgroup_under_socket_pressure()
>> is generally a good thing and provides better readablility.
>>
>
> I don't see how it is improving readability. If you have removed the use
> of mem_cgroup_sockets_enabled completely from the networking then I can
> understand but this change IMHO will actually decrease the readability
> because the later readers will have to reason why we are doing this
> check at some places but not other.
Yes, I agree. I am trying to let networking get rid of this macro
entirely, but get stuck on inet_csk_accept().. :(
next prev parent reply other threads:[~2023-06-05 11:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 8:11 [PATCH net-next v5 0/3] sock: Improve condition on sockmem pressure Abel Wu
2023-06-02 8:11 ` [PATCH net-next v5 1/3] net-memcg: Fold dependency into memcg pressure cond Abel Wu
2023-06-02 20:25 ` Shakeel Butt
2023-06-05 11:52 ` Abel Wu [this message]
2023-06-02 8:11 ` [PATCH net-next v5 2/3] sock: Always take memcg pressure into consideration Abel Wu
2023-06-02 20:41 ` Shakeel Butt
2023-06-04 10:36 ` Willem de Bruijn
2023-06-05 3:44 ` Abel Wu
2023-06-05 8:27 ` Paolo Abeni
2023-06-05 9:57 ` Abel Wu
2023-06-02 8:11 ` [PATCH net-next v5 3/3] sock: Fix misuse of sk_under_memory_pressure() Abel Wu
2023-06-02 20:53 ` Shakeel Butt
2023-06-05 8:34 ` Abel Wu
2023-06-06 8:39 ` kernel test robot
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