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[209.85.218.44]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a90610962d1sm676892566b.32.2024.09.18.23.46.44 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Sep 2024 23:46:44 -0700 (PDT) Received: by mail-ej1-f44.google.com with SMTP id a640c23a62f3a-a8d43657255so64711566b.0 for ; Wed, 18 Sep 2024 23:46:44 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCVq6WVqyzp+7RXor7hG0BuJe5TUv24NRceKtnK5yqytwHES3wz3C6fztq4QUlwa2Dze7llCLyaVqA==@kvack.org X-Received: by 2002:a17:907:9484:b0:a86:9d3d:edef with SMTP id a640c23a62f3a-a9047b50447mr2106944466b.12.1726728403730; Wed, 18 Sep 2024 23:46:43 -0700 (PDT) MIME-Version: 1.0 References: <20240917143402.930114-1-boqun.feng@gmail.com> <050d17f6-7db4-4a05-b4a5-6d5ab4f361cf@amd.com> In-Reply-To: <050d17f6-7db4-4a05-b4a5-6d5ab4f361cf@amd.com> From: Linus Torvalds Date: Thu, 19 Sep 2024 08:46:26 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH 0/4] Add hazard pointers to kernel To: Neeraj Upadhyay , John Johansen Cc: Boqun Feng , linux-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, lkmm@vger.kernel.org, "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Mark Rutland , Thomas Gleixner , Kent Overstreet , Vlastimil Babka , maged.michael@gmail.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 0E9711C0002 X-Stat-Signature: rbmtgsbh3snsxawr74brwota6jwjspa1 X-HE-Tag: 1726728407-849057 X-HE-Meta: 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 KQo/xk7N 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 19 Sept 2024 at 00:44, Neeraj Upadhyay wrote: > > While we were working on this problem, this refcount scalability issue got > resolved recently with conditional ref acquisition [3] (however, there are new > developments in apparmor code which might bring back the refcount problem [4]). Honestly, the various security layers should be a whole lot more careful about their horrid performance issues, and I think that [4] you point at needs to just be headed off at the pass. No more "the security layer is so bad at performance that we have to introduce new ref mechanisms", please. Let's push back on bad security layer code instead. Linus