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smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-c45ff70000001609-c3-68ec55dc0baf Date: Mon, 13 Oct 2025 10:28:55 +0900 From: Byungchul Park To: Bagas Sanjaya Cc: linux-kernel@vger.kernel.org, kernel_team@skhynix.com, torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, jack@suse.cz, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, harry.yoo@oracle.com, chris.p.wilson@intel.com, gwan-gyeong.mun@intel.com, max.byungchul.park@gmail.com, boqun.feng@gmail.com, longman@redhat.com, yunseong.kim@ericsson.com, ysk@kzalloc.com, yeoreum.yun@arm.com, netdev@vger.kernel.org, matthew.brost@intel.com, her0gyugyu@gmail.com, corbet@lwn.net, catalin.marinas@arm.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, sumit.semwal@linaro.org, gustavo@padovan.org, christian.koenig@amd.com, andi.shyti@kernel.org, arnd@arndb.de, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, surenb@google.com, mcgrof@kernel.org, petr.pavlu@suse.com, da.gomez@kernel.org, samitolvanen@google.com, paulmck@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, josh@joshtriplett.org, urezki@gmail.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, chuck.lever@oracle.com, neil@brown.name, okorniev@redhat.com, Dai.Ngo@oracle.com, tom@talpey.com, trondmy@kernel.org, anna@kernel.org, kees@kernel.org, bigeasy@linutronix.de, clrkwllms@kernel.org, mark.rutland@arm.com, ada.coupriediaz@arm.com, kristina.martsenko@arm.com, wangkefeng.wang@huawei.com, broonie@kernel.org, kevin.brodsky@arm.com, dwmw@amazon.co.uk, shakeel.butt@linux.dev, ast@kernel.org, ziy@nvidia.com, yuzhao@google.com, baolin.wang@linux.alibaba.com, usamaarif642@gmail.com, joel.granados@kernel.org, richard.weiyang@gmail.com, geert+renesas@glider.be, tim.c.chen@linux.intel.com, linux@treblig.org, alexander.shishkin@linux.intel.com, lillian@star-ark.net, chenhuacai@kernel.org, francesco@valla.it, guoweikang.kernel@gmail.com, link@vivo.com, jpoimboe@kernel.org, masahiroy@kernel.org, brauner@kernel.org, thomas.weissschuh@linutronix.de, oleg@redhat.com, mjguzik@gmail.com, andrii@kernel.org, wangfushuai@baidu.com, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-i2c@vger.kernel.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, rcu@vger.kernel.org, linux-nfs@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH v17 28/47] dept: add documentation for dept Message-ID: <20251013012855.GB52546@system.software.com> References: <20251002081247.51255-1-byungchul@sk.com> <20251002081247.51255-29-byungchul@sk.com> Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA02Se0xTZxjG853Ldw4N1WNl4VNiiF3IhESxC+o754VptpwlGjRG3dSojRxt lYspysREbcPFimNTlmIojktKkLFGpSioKCmNgkRbLip2g1FuIkTLH1oqWCCjGKP//d7ned4n 7x8vTyvc7EJem3JM0qWok5RYxsi8oWVLu7e/1iz3N30LnQY7A0ZbIQueMSOCqfwmDnwTXRyY DAhMfYMYLo0YGDAPFXHg9dSzMFVwBALOVhoumdoQDF8/i2D0Oob2V5PUTBRDQXU4TFRUcfDY 0s1AkfMJC5N9Kmj6+yUHV72tLNj+eYDA97SPAuuvQzSU5ZQzUFjcjcE45UOgL3rHQpv9EQuP mh4y0Nfrnhkv5rHgvvACgaHRwsCbcj8DzXl2Cs4O12PIKa+moMHYS8H9a3UU2KydGGpsJhpM k0YMhrceBIHxyxj+9KniVWJ2xxQWrcVWJAbe5yPxtvk/Tsxq+JcTS23Hxaz7XlasqYwRLXdH KNFWdQ6Loy4XJ5bpTbRY3LJV7JoeoMW8zFEs3s72sFvCd8nWJEpJ2nRJF7tuv0xzb9zFHD0f dsJflIn0yDInF4XwRIgjnaWt6COX9DvYIDNCFPE6G2Z1LHxF3O4JOshhwhLSUjPO5SIZTwt1 EaT9xsCsMV9YT1zPrLMLcgGIr64EBUMKwYCIK+8G88GYR1oKB2eZFmKIe3qEykX8DEeQK9N8 UA4RoonH6cVB/kL4kthrm6lgDxH6Q0hPiRt/uHQBaax0MxeQYP6s1vxZrflTbSmiq5BCm5Ke rNYmxS3TZKRoTyw7kJpsQzP/VnFqcvct9KZtmwMJPFKGyjX1rzQKVp2elpHsQISnlWHyiznD GoU8UZ1xUtKl7tMdT5LSHCiCZ5Th8q/9vyQqhEPqY9IRSToq6T66FB+yUI/iv4l1/Lz3+WKc r1q52bVh400cGZqwrrry6rsHcwM9fHT2zjP31iyKGk+ODhyO+uG3xJxTrvZbe9pr167yDODf O/pdmZl3Vm+3D46N1Pq78CZ9XcJ3BwsSLC0vT1f8NBbZ4di647KlN/59bNaCoUjLH9831/c4 U+c2rlj541/quHO7whVKJk2jVsXQujT1/6oVpudrAwAA X-Brightmail-Tracker: H4sIAAAAAAAAA02SbUxTZxTHfe69vffSUHLtSngUh0mNuhGBmWh2si2bn+aNi8ZoFqNmmTfz xjaUYlpXxYWEWtkYvqx0aZFWpULoDNSBpaiM1DR1q0Eo2oFKJtDhqoLQsYzyJhTWsizzy8nv nN/5J+fDYUl5QrKaVWuPiTqtoFHSUkq6631T3sCn46p3JhtWwSOjn4KpeAUFF5vdNFR4aiTw 4McmBJGpCgQz8w4SytuXKEhYggzE554wYDUiWPIFEdjCFhLcXiMBky2LNIzd+RuBdThKQ/Wo kYIJ11kE9ucOBkZ/2Q6xSIcElgZfEPB4ehyBK7pIQNT/DYKErRBq61ppmA/dJ6Ha+gDBleFB EkZaktIbHELgu3qKhmfmNhJ6oxnQNzVBQ6f1DA2x8EUC/myhwXnKJ4FLDgsCU30zDbZLHgra f/+JgfDYAgEDNgsBTZ6dEHE9p6DLXEck70tuXc8CR7WJSJYRAqzXOgiYczUy0F0/QIGrbD04 Qr0SeHrVzsDC8GZYchZDsOkFA4PfWaltNsTPlJ+n+MbWGwRf/muC5t2X3Yiff2VBfLzBRPLl 5mR7Z3yC5E+3HucbusZp/tXUQ5r3TTsp/l4d5qtCeXy7fZDhT9/+jdn93gHpB4dFjdog6go+ PCRV+WZ7qKNnFCemHSZUhuozKlEai7ktuPZpQJJiiluPY6HbKMU0txH398+RKVZwb+HO1lmm EklZkruZjcPeP5bFG9xHuOehezkg4wDHb9ai1JKcMyLcc85L/StW4s6a6DKTXC7uXxwlKhGb 5Gz8wyKbGqdxb+NIKEanOJNbh/037hJmJLO/lra/lrb/n3YishEp1FpDkaDWbM3XF6pKtOoT +V8UF3lQ8ildpQtVt1C8d3sAcSxSpstUHWMquUQw6EuKAgizpFIhq/p6RCWXHRZKToq64s91 X2pEfQBls5QyS7Zjn3hIzh0RjomFonhU1P1nCTZtdRny1e4xXT8y9MRW9RJrMrW33u14PNTd pzj4cYH35Q5DW9Ce2RxOLzDTipx9e3M/c3hItrt4Y9aKPZIN/q41+7e9uTUnbl678EhIK32m adty4ORfm2LpwmT27NkLBuf3gcim46Ur/TUVI4nRn2fOF+Wv+KTh2wtfhWN5fTmGtXczVlUO KSm9SticS+r0wj/gdz/3kAMAAA== X-CFilter-Loop: Reflected On Fri, Oct 03, 2025 at 09:44:28AM +0700, Bagas Sanjaya wrote: > On Thu, Oct 02, 2025 at 05:12:28PM +0900, Byungchul Park wrote: > > This document describes the concept and APIs of dept. > > > > Signed-off-by: Byungchul Park > > --- > > Documentation/dependency/dept.txt | 735 ++++++++++++++++++++++++++ > > Documentation/dependency/dept_api.txt | 117 ++++ > > 2 files changed, 852 insertions(+) > > create mode 100644 Documentation/dependency/dept.txt > > create mode 100644 Documentation/dependency/dept_api.txt > > What about writing dept docs in reST (like the rest of kernel documentation)? Sorry for late reply, but sure. I should and will. Thank you! > ---- >8 ---- > diff --git a/Documentation/dependency/dept.txt b/Documentation/locking/dept.rst > similarity index 92% > rename from Documentation/dependency/dept.txt > rename to Documentation/locking/dept.rst > index 5dd358b96734e6..7b90a0d95f0876 100644 > --- a/Documentation/dependency/dept.txt > +++ b/Documentation/locking/dept.rst However, I'm not sure if dept is about locking. dept is about general waits e.g. wait_for_completion(), wait_event(), and so on, rather than just waits involved in typical locking mechanisms e.g. spin lock, mutex, and so on. [snip] > > + > > + context X context Y > > + /* * Acquired A. */ > > + mutex_lock A /* * Request something that will be handled * through e.g. wq, deamon or any its own * way, and then do 'complete B'. */ request_xxx_and_complete_B(); /* * The request from * context Y has been * done. So running * toward 'complete B'. */ /* * Wait for A to be * released, but will * never happen. */ > > + mutex_lock A <- DEADLOCK /* * Wait for 'complete B' to happen, but * will never happen. */ > > + wait_for_complete B <- DEADLOCK /* * Never reachable. */ > > + complete B /* * Never reachable. */ > > + mutex_unlock A > > + mutex_unlock A > > Can you explain how DEPT detects deadlock on the second example above (like > the first one being described in "How DEPT works" section)? Sure. I added the explanation inline above. Don't hesitate if you have any questions. Thanks. Byungchul > > Confused... > > -- > An old man doll... just what I always wanted! - Clara