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[90.235.25.230]) by smtp.gmail.com with ESMTPSA id w13-20020a05651c118d00b0026c42f67eb8sm1164863ljo.7.2022.12.05.03.09.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Dec 2022 03:09:19 -0800 (PST) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 5 Dec 2022 12:09:16 +0100 To: Eric Dumazet Cc: paulmck@kernel.org, Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, eric.dumazet@gmail.com, Dmitry Safonov , rcu@vger.kernel.org Subject: Re: [PATCH net-next] tcp: use 2-arg optimal variant of kfree_rcu() Message-ID: References: <21A10014-22D8-4107-8C6C-14102478D19B@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <21A10014-22D8-4107-8C6C-14102478D19B@joelfernandes.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hello, Eric. > +rcu for archives > > > On Dec 2, 2022, at 7:16 PM, Joel Fernandes wrote: > > > > On Sat, Dec 3, 2022 at 12:12 AM Joel Fernandes wrote: > >> > >>> On Sat, Dec 3, 2022 at 12:03 AM Paul E. McKenney wrote: > >>> > >>> On Fri, Dec 02, 2022 at 11:49:59PM +0000, Joel Fernandes wrote: > >>>> On Fri, Dec 02, 2022 at 05:28:47AM +0000, Eric Dumazet wrote: > >>>>> kfree_rcu(1-arg) should be avoided as much as possible, > >>>>> since this is only possible from sleepable contexts, > >>>>> and incurr extra rcu barriers. > >>>>> > >>>>> I wish the 1-arg variant of kfree_rcu() would > >>>>> get a distinct name, like kfree_rcu_slow() > >>>>> to avoid it being abused. > tcp: use 2-arg optimal variant of kfree_rcu() Date: Fri, 2 Dec 2022 05:28:47 +0000 [thread overview] Message-ID: <20221202052847.2623997-1-edumazet@google.com> (raw) kfree_rcu(1-arg) should be avoided as much as possible, since this is only possible from sleepable contexts, and incurr extra rcu barriers. I wish the 1-arg variant of kfree_rcu() would get a distinct name, like kfree_rcu_slow() to avoid it being abused. Fixes: 459837b522f7 ("net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction") Signed-off-by: Eric Dumazet Cc: Dmitry Safonov Cc: Paul E. McKenney Could you please clarify a little bit about why/how have you came up with a patch that you posted with "Fixes" tag? I mean you run into: - performance degrade; - simple typo; - etc. Thank you. -- Uladzislau Rezki