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bh=oWel6s+C+uqagn6K4/nTnPlyC70jxGXPY+vOwAK6HE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G20KdsROA4xaDU+ubwGVzeWYkmacNQkMqQ4YtlsG3dtqaGC+E8CQgaQwummAeQMcc EeGWMhI5Iu9NJsMiAfk51CttGuCrnuvyYKGcyriowNrINWnSBcB70XvoGUC2VsRK/G nBFwDkBGuujxpcdJtVmuR3gKy9yjBhnDQhfGGTQFjhKE2pD97hT0px1pVgHPsO9bYC dy4tu4JKtM9QmetkVrP7AA1bRkxLdzKVCPgDN1WIkpsL29WAcfLsgIyxplNJcMyAXq lXMvV7MAdfHKVx50WgOinTprAkIUYmCoFlJ4dmn40le4uqbMwtNPmaolldwbkUeUk3 WeWopPJAQbdGA== From: SeongJae Park To: Matthew Wilcox Cc: SeongJae Park , akpm@linux-foundation.org, vbabka@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] mm/slab: break up RCU readers on SLAB_TYPESAFE_BY_RCU example code Date: Sat, 15 Apr 2023 03:04:52 +0000 Message-Id: <20230415030452.3223-1-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 11B9B180007 X-Stat-Signature: 1s3ef8nqmn97hkueym5zuxczan39a8zo X-HE-Tag: 1681527895-52588 X-HE-Meta: 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 a5KkyjAR Pc7FJV8pagjLbp+ZYkKZ/Z2zoaEdeuwTE8VN6hVN/XU8XYsdtfwOjLeyezg17zpyQrSZC9Q6maRBYYHA+CkHj/Wjc+kvKe6q3m6ifEiLMomaftrYkvu4ssYElLfbF/8yEtIN5NIgP9K0soLLafVNIlLMFUo62qjkTfCApNKz566POC1c5i1PA2QdFph6qcIUtAp7BOkG2E04/uBbwre96SyVUn9AXzEgKArz8D3dkwPOFf1ttM0i4Lvtz4WhF1ebWPgfBqVGbOy2he7hzgS4DisaIsi4UeTAIgdkzT6GCXycQ9hnG0045ZxRN55sdV4xQ8UwmSwf5GimIRwu/GwJ/xmbSQe36x6DgIEHKV68hxvCVW5Fym+POmOu3qQxXnIbgsi9eLNfKK+AMlGRO+wXI5Cu3ug== 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: On Sat, 15 Apr 2023 03:51:54 +0100 Matthew Wilcox wrote: > On Sat, Apr 15, 2023 at 12:37:53AM +0000, SeongJae Park wrote: > > * > > + * begin: > > * rcu_read_lock(); > > - * again: > > * obj = lockless_lookup(key); > > * if (obj) { > > * if (!try_get_ref(obj)) // might fail for free objects > > - * goto again; > > + * goto begin; > > * > > * if (obj->key != key) { // not the object we expected > > * put_ref(obj); > > + * rcu_read_unlock(); > > * goto again; > > - * goto again; > + * goto begin; Oops, thank you for catching, Matthew! Thanks, SJ