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McKenney" , Ingo Molnar , Steven Rostedt , Josh Poimboeuf , =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= , Oleg Nesterov , Thomas Gleixner Cc: Ye Liu , David Hildenbrand , Miaohe Lin , Naoya Horiguchi , "Rafael J. Wysocki" , =?UTF-8?q?G=C3=BCnther=20Noack?= , Lorenzo Stoakes , SJ Park , Gregory Price , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, rientjes@google.com, shakeel.butt@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, will@kernel.org, boqun@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, josh@joshtriplett.org, urezki@gmail.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, tony.luck@intel.com, reinette.chatre@intel.com, x86@kernel.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, pavel@kernel.org, lance.yang@linux.dev, mhiramat@kernel.org, pmladek@suse.com, longman@redhat.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, mark.rutland@arm.com, Dave.Martin@arm.com, james.morse@arm.com, babu.moger@amd.com Subject: [PATCH v4 00/15] sched: introduce for_each_process_rculock and for_each_thread_rculock Date: Mon, 21 Sep 2026 17:20:46 +0800 Message-Id: <20260921092101.89285-1-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 6C2AD160005 X-Stat-Signature: ocaj75uid3denrtrmcraidz8m1rx7cq9 X-Rspam-User: X-HE-Tag: 1789982484-69150 X-HE-Meta: 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 Q9Y+gBmD W5ssiWgXJTxndnhN99V/Oe23dfCVy2R7arJ9sdZrtRk9Gf5f+uIqPlWyZCWo9dlDrkt0ocNGzukY0iYr65B7+/sP6+OYTz3+iUSh1KRDAGhOcTEToM0Obk3qa7HiBcT0iFCTX6Sd11KVDcHXABY9axgPTrgM9wDC5VqPazpf2uu3ErMO1MdiSIemHpFN7tdA96iYWe2gA/DVUl/Pg8gtYZelnhgEsCqUCCJdkLLrGj4EEvSou41yvH5eLAfr8wnIBfJsTcddmAgMyIRyg6fbD7xgGijO57pCJLeu1tnuo0nCzjcCD6XjU54poCwnDoo/S84KAyL62p6QHHDhM8HfZYH1qmwlF5CSFLUxoHG1zE1USVKwzAyMonZ64TafCA+fHJpKCzBcybLMUOHqz0Kq2HyLmG4j/+ii37MOY Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ye Liu Introduce for_each_process_rculock(), for_each_thread_rculock() and for_each_process_thread_rculock() macros that combine the existing iteration macros with scoped_guard(rcu), so that the RCU read lock is automatically acquired before iteration and released when the loop exits — including via break, goto, or return. The rest of the series converts manual rcu_read_lock()/ rcu_read_unlock() and guard(rcu)() pairs across mm/, kernel/, fs/, lib/ and security/ to use the new macros. Suggested by Michal Hocko for the oom_kill path [2]. Signed-off-by: Ye Liu --- Changes since v3 [4]: - Fix patch 5 (cpu/hotplug): title and commit message incorrectly said "thread iterator" and "for_each_thread_rculock" while the code converts for_each_process() to for_each_process_rculock(). Note: Patches 4, 11, and 13 received automated reviews from sashiko-bot in the v3 thread [4] that were verified as false positives: - Patch 4: claimed the folio lock is dropped before collect_procs(), leading to a NULL deref on folio->mapping; the lock is held in all call paths. - Patch 11: claimed mixing goto/scope-based cleanup in alloc_retstack_tasklist(); the goto free label handles memory cleanup, not lock management. - Patch 13: claimed mixing goto/scope-based cleanup in __set_oom_adj(); goto err_unlock manages oom_adj_mutex while scoped_guard(rcu) manages the RCU read lock — different resources. Changes since v2 [3]: - Split the kernel/ patch into per-subsystem patches, as the combined patch could not be applied (Peter Zijlstra, Steven Rostedt). - Move changelog below the --- separator so it is excluded from the commit message (Lorenzo Stoakes). - Indent loop body in macro definitions to show scoped_guard scope (Lorenzo Stoakes). Changes since v1 [1]: - Rename macros from *_rcu to *_rculock, as suggested by Steven Rostedt and acked by Thomas Gleixner, to avoid confusion with existing *_rcu() list iterators that expect the caller to hold the RCU read lock. - Improve the comment on for_each_process_thread_rculock() to document that 'break' only exits the inner loop and 'goto' is needed to exit both loops (Thomas Gleixner). - Rename the stale 'unlock:' label to 'out:' in hung_task.c, as noted by Günther Noack. - Clarify in patch 4 that page_pgoff() is safe outside the RCU read-side critical section (SJ Park). - CC all relevant maintainers on every patch (Lorenzo Stoakes). - Drop the mm: prefix from patch 1, as the macros are in include/linux/sched/signal.h (Michal Hocko). [1] https://lore.kernel.org/all/20260904083001.553587-1-ye.liu@linux.dev/ [2] https://lore.kernel.org/all/20260813092933.562028-1-ye.liu@linux.dev/ [3] https://lore.kernel.org/all/20260907081334.1152889-1-ye.liu@linux.dev/ [4] https://lore.kernel.org/all/20260911075800.491472-1-ye.liu@linux.dev/ Ye Liu (15): sched: introduce for_each_process_rculock and for_each_thread_rculock mm/oom_kill: convert process/thread iterators to for_each_*_rculock mm/ksm: convert process iterator to for_each_process_rculock mm/memory-failure: convert process iterator to for_each_process_rculock cpu/hotplug: convert process iterator to for_each_process_rculock freezer: convert thread iterator to for_each_thread_rculock hung_task: convert process/thread iterators to for_each_*_rculock locking/lockdep: convert process/thread iterators to for_each_*_rculock rcu: convert process/thread iterator to for_each_process_thread_rculock sched: convert process/thread iterators to for_each_*_rculock tracing/fgraph: convert process/thread iterator to for_each_process_thread_rculock unwind: convert process/thread iterator to for_each_process_thread_rculock fs: convert process/thread iterators to for_each_*_rculock lib: convert process iterator to for_each_process_rculock security/landlock: convert thread iterator to for_each_thread_rculock fs/proc/base.c | 4 +--- fs/resctrl/rdtgroup.c | 8 ++------ include/linux/sched/signal.h | 26 ++++++++++++++++++++++++++ kernel/cpu.c | 4 +--- kernel/freezer.c | 4 +--- kernel/hung_task.c | 11 ++++------- kernel/locking/lockdep.c | 4 +--- kernel/rcu/update.c | 4 +--- kernel/sched/core.c | 3 +-- kernel/sched/debug.c | 4 +--- kernel/trace/fgraph.c | 8 ++------ kernel/unwind/deferred.c | 3 +-- lib/is_single_threaded.c | 5 +---- mm/ksm.c | 4 +--- mm/memory-failure.c | 16 ++++------------ mm/oom_kill.c | 20 +++++--------------- security/landlock/tsync.c | 8 ++------ 17 files changed, 55 insertions(+), 81 deletions(-) -- 2.25.1