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Wed, 18 Feb 2026 15:08:27 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 4AnNIevVlWkRRwAAD6G6ig (envelope-from ); Wed, 18 Feb 2026 15:08:27 +0000 Message-ID: <7765df86-b08a-4f70-900d-4b4d85c07d49@suse.com> Date: Wed, 18 Feb 2026 16:08:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v18 34/42] dept: add module support for struct dept_event_site and dept_event_site_dep To: Byungchul Park Cc: 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, 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, 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, 2407018371@qq.com, dakr@kernel.org, miguel.ojeda.sandonis@gmail.com, neilb@ownmail.net, bagasdotme@gmail.com, wsa+renesas@sang-engineering.com, dave.hansen@intel.com, geert@linux-m68k.org, ojeda@kernel.org, alex.gaynor@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org References: <20251205071855.72743-1-byungchul@sk.com> <20251205071855.72743-35-byungchul@sk.com> <7afb6666-43b6-4d17-b875-e585c7a5ac99@suse.com> <20260213055006.GA55430@system.software.com> Content-Language: en-US From: Petr Pavlu In-Reply-To: <20260213055006.GA55430@system.software.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Rspam-User: X-Stat-Signature: x7z4b4focw67q59a3hegyzrcttabkp9i X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 0D3BE80012 X-HE-Tag: 1771427309-793222 X-HE-Meta: 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 rxRfCCUw A/rU4gZTF6OE/zWzl5Xg/EEezWppwPOWWBhxkkpZAZbvA8Uef+ydAYEgqOyvR9jBhL75jP0N7LOOnMIMCXE1QD2K43f0N50sagDQX7cIMwEF59uzGT1sTtslqcHFwM7359A4tUqQ/Xpv7xZPsgyYdyhqYD7wH1FSgVWT3oaJadB7J0rCsE13TrV09aitVvMgXyy2WnCf+9TZDAYG7cwBtwYkAL9Wgw6s8vVAwDticDdx2BM4LCnygwMrSe2A9dLaPle0iMH22Y4tDk0rSn5ARDlJ/SECHIU8EeSFv9i1XKDpdKuvTmEQz0RZIuxeEwb3JGfgk9DyDImbLKlCpsolOq6xn7044mhDVFDIbTdNSqIPerHiiDGOZyp/jGbvbZ9mz9FLgok3LxXqYGtLhHhczTOYuJTQVv4h9nY12o9urFc6vdOpjGFghYC0g9ECrh+zAxfQliRsasdbFYXnm8sLBbvZgXg== 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 2/13/26 6:50 AM, Byungchul Park wrote: > On Wed, Jan 07, 2026 at 01:19:00PM +0100, Petr Pavlu wrote: >> On 12/5/25 8:18 AM, Byungchul Park wrote: >>> struct dept_event_site and struct dept_event_site_dep have been >>> introduced to track dependencies between multi event sites for a single >>> wait, that will be loaded to data segment. Plus, a custom section, >>> '.dept.event_sites', also has been introduced to keep pointers to the >>> objects to make sure all the event sites defined exist in code. >>> >>> dept should work with the section and segment of module. Add the >>> support to handle the section and segment properly whenever modules are >>> loaded and unloaded. >>> >>> Signed-off-by: Byungchul Park >> >> Below are a few comments from the module loader perspective. > > Sorry about the late reply. I've been going through some major life > changes lately. :( > > Thank you sooooo~ much for your helpful feedback. I will leave my > opinion below. > [...] >>> diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c >>> index b14400c4f83b..07d883579269 100644 >>> --- a/kernel/dependency/dept.c >>> +++ b/kernel/dependency/dept.c >>> @@ -984,6 +984,9 @@ static void bfs(void *root, struct bfs_ops *ops, void *in, void **out) >>> * event sites. >>> */ >>> >>> +static LIST_HEAD(dept_event_sites); >>> +static LIST_HEAD(dept_event_site_deps); >>> + >>> /* >>> * Print all events in the circle. >>> */ >>> @@ -2043,6 +2046,33 @@ static void del_dep_rcu(struct rcu_head *rh) >>> preempt_enable(); >>> } >>> >>> +/* >>> + * NOTE: Must be called with dept_lock held. >>> + */ >>> +static void disconnect_event_site_dep(struct dept_event_site_dep *esd) >>> +{ >>> + list_del_rcu(&esd->dep_node); >>> + list_del_rcu(&esd->dep_rev_node); >>> +} >>> + >>> +/* >>> + * NOTE: Must be called with dept_lock held. >>> + */ >>> +static void disconnect_event_site(struct dept_event_site *es) >>> +{ >>> + struct dept_event_site_dep *esd, *next_esd; >>> + >>> + list_for_each_entry_safe(esd, next_esd, &es->dep_head, dep_node) { >>> + list_del_rcu(&esd->dep_node); >>> + list_del_rcu(&esd->dep_rev_node); >>> + } >>> + >>> + list_for_each_entry_safe(esd, next_esd, &es->dep_rev_head, dep_rev_node) { >>> + list_del_rcu(&esd->dep_node); >>> + list_del_rcu(&esd->dep_rev_node); >>> + } >>> +} >>> + >>> /* >>> * NOTE: Must be called with dept_lock held. >>> */ >>> @@ -2384,6 +2414,8 @@ void dept_free_range(void *start, unsigned int sz) >>> { >>> struct dept_task *dt = dept_task(); >>> struct dept_class *c, *n; >>> + struct dept_event_site_dep *esd, *next_esd; >>> + struct dept_event_site *es, *next_es; >>> unsigned long flags; >>> >>> if (unlikely(!dept_working())) >>> @@ -2405,6 +2437,24 @@ void dept_free_range(void *start, unsigned int sz) >>> while (unlikely(!dept_lock())) >>> cpu_relax(); >>> >>> + list_for_each_entry_safe(esd, next_esd, &dept_event_site_deps, all_node) { >>> + if (!within((void *)esd, start, sz)) >>> + continue; >>> + >>> + disconnect_event_site_dep(esd); >>> + list_del(&esd->all_node); >>> + } >>> + >>> + list_for_each_entry_safe(es, next_es, &dept_event_sites, all_node) { >>> + if (!within((void *)es, start, sz) && >>> + !within(es->name, start, sz) && >>> + !within(es->func_name, start, sz)) >>> + continue; >>> + >>> + disconnect_event_site(es); >>> + list_del(&es->all_node); >>> + } >>> + >>> list_for_each_entry_safe(c, n, &dept_classes, all_node) { >>> if (!within((void *)c->key, start, sz) && >>> !within(c->name, start, sz)) >>> @@ -3337,6 +3387,7 @@ void __dept_recover_event(struct dept_event_site_dep *esd, >>> >>> list_add(&esd->dep_node, &es->dep_head); >>> list_add(&esd->dep_rev_node, &rs->dep_rev_head); >>> + list_add(&esd->all_node, &dept_event_site_deps); >>> check_recover_dl_bfs(esd); >>> unlock: >>> dept_unlock(); >>> @@ -3347,6 +3398,23 @@ EXPORT_SYMBOL_GPL(__dept_recover_event); >>> >>> #define B2KB(B) ((B) / 1024) >>> >>> +void dept_mark_event_site_used(void *start, void *end) >> >> Nit: I suggest that dept_mark_event_site_used() take pointers to >> dept_event_site_init, which would catch the type mismatch with > > IMO, this is the easiest way to get all the pointers from start to the > end, or I can't get the number of the pointers. It's similar to the > initcalls section for device drivers. This was a minor suggestion.. The idea is to simply change the function signature to: void dept_mark_event_site_used(struct dept_event_site_init **start, struct dept_event_site_init **end)) This way, the compiler can provide proper type checking to ensure that correct pointers are passed to dept_mark_event_site_used(). It would catch the type mismatch with module::dept_event_sites. > >> module::dept_event_sites. >> >>> +{ >>> + struct dept_event_site_init **evtinitpp; >>> + >>> + for (evtinitpp = (struct dept_event_site_init **)start; >>> + evtinitpp < (struct dept_event_site_init **)end; >>> + evtinitpp++) { >>> + (*evtinitpp)->evt_site->used = true; >>> + (*evtinitpp)->evt_site->func_name = (*evtinitpp)->func_name; >>> + list_add(&(*evtinitpp)->evt_site->all_node, &dept_event_sites); >>> + >>> + pr_info("dept_event_site %s@%s is initialized.\n", >>> + (*evtinitpp)->evt_site->name, >>> + (*evtinitpp)->evt_site->func_name); >>> + } >>> +} >>> + >>> extern char __dept_event_sites_start[], __dept_event_sites_end[]; >> >> Related to the above, __dept_event_sites_start and >> __dept_event_sites_end can already be properly typed here. > > How can I get the number of the pointers? Similarly here, changing the code to: extern struct dept_event_site_init *__dept_event_sites_start[], *__dept_event_sites_end[]; It is the same for the initcalls you mentioned. The declarations of their start/end symbols are also already properly typed as initcall_entry_t[] in include/linux/init.h. -- Thanks, Petr