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Mon, 07 Sep 2026 08:14:40 +0000 X-Mizu-Trace-ID: a8a672054efb182f X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Miaohe Lin , Andrew Morton Cc: Ye Liu , Michal Hocko , peterz@infradead.org, paulmck@kernel.org, mingo@redhat.com, rostedt@goodmis.org, jpoimboe@kernel.org, mic@digikod.net, oleg@redhat.com, tglx@kernel.org, david@kernel.org, nao.horiguchi@gmail.com, rafael@kernel.org, gnoack3000@gmail.com, ljs@kernel.org, sj@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, 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 Subject: [PATCH v2 4/8] mm/memory-failure: convert process iterator to for_each_process_rculock Date: Mon, 7 Sep 2026 16:13:30 +0800 Message-Id: <20260907081334.1152889-5-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260907081334.1152889-1-ye.liu@linux.dev> References: <20260907081334.1152889-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 558F8C0003 X-Stat-Signature: pgc6fyrnseqbjgu86omk6n6r7r8xbre6 X-HE-Tag: 1788768882-496080 X-HE-Meta: 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 K3kVZseu J1KVHhv8DQUaf2weLbiS7hRptNKmirEOzsh+7wqAAawk5LGEvR6QfB9dTarkVoakgGwgpzTKHOXgVAyP++CTafskHsZsx9X+Fb4pTCijrnc52vdyCTNE8mR8fzxteIa3/6HQV6UOamYWvsapba3pdVMJis/I5PruUtY3Ow10odJs91t07F2mgMvRGIENKWQyDeuCy5e8pqtZ8vGzfnRo34HyvrWz69nFfPfDOw9ikWQWRrJ2Xly5RU87TufLRr8ikHYHErtQze9JJU6t8d/do/YWGaiSKhFIv8/92xP65P6uXLqb9vCYGlcwirK4HFzU4KmdB7USfEqUKCUYImLLJ160c3cjjDyQawXVnSqWFwHJcEMpJqosb4jJDjia7OXO3vL8mPZ/ZgS4Y/lS8hJDaz9lQ5M/tYQzAL76jGi7Wlw1m3lxzJ9gOV8TQvXushS6vqHBdVp1fwmX6h8wUUwZbSiDI3Nt1EgZfyWJa Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ye Liu Replace the manual rcu_read_lock()/rcu_read_unlock() pairs combined with for_each_process() loop in mm/memory-failure.c with for_each_process_rculock(), which scopes the RCU read lock to the loop body via scoped_guard(rcu). In collect_procs_file(), the page_pgoff() call now falls outside the RCU read-side critical section. This is safe because page_pgoff() only reads folio->index and does not traverse any RCU-protected structures. Signed-off-by: Ye Liu Acked-by: Michal Hocko Acked-by: Miaohe Lin --- Changes in v2: - Rename *_rcu to *_rculock - Clarify page_pgoff() safety outside RCU lock (SJ Park) mm/memory-failure.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index a8b03e2920ba..7d93deb1f7b3 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -555,8 +555,7 @@ static void collect_procs_anon(const struct folio *folio, return; pgoff = page_pgoff(folio, page); - rcu_read_lock(); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct vm_area_struct *vma; struct anon_vma_chain *vmac; struct task_struct *t = task_early_kill(tsk, force_early); @@ -572,7 +571,6 @@ static void collect_procs_anon(const struct folio *folio, add_to_kill_anon_file(t, page, vma, to_kill, addr); } } - rcu_read_unlock(); anon_vma_unlock_read(av); } @@ -589,9 +587,8 @@ static void collect_procs_file(const struct folio *folio, pgoff_t pgoff; i_mmap_lock_read(mapping); - rcu_read_lock(); pgoff = page_pgoff(folio, page); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct task_struct *t = task_early_kill(tsk, force_early); unsigned long addr; @@ -611,7 +608,6 @@ static void collect_procs_file(const struct folio *folio, add_to_kill_anon_file(t, page, vma, to_kill, addr); } } - rcu_read_unlock(); i_mmap_unlock_read(mapping); } @@ -635,8 +631,7 @@ static void collect_procs_fsdax(const struct page *page, struct task_struct *tsk; i_mmap_lock_read(mapping); - rcu_read_lock(); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct task_struct *t = tsk; /* @@ -653,7 +648,6 @@ static void collect_procs_fsdax(const struct page *page, add_to_kill_fsdax(t, page, vma, to_kill, pgoff); } } - rcu_read_unlock(); i_mmap_unlock_read(mapping); } #endif /* CONFIG_FS_DAX */ @@ -2288,8 +2282,7 @@ static void collect_procs_pfn(struct pfn_address_space *pfn_space, struct address_space *mapping = pfn_space->mapping; i_mmap_lock_read(mapping); - rcu_read_lock(); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct task_struct *t = tsk; t = task_early_kill(tsk, true); @@ -2303,7 +2296,6 @@ static void collect_procs_pfn(struct pfn_address_space *pfn_space, add_to_kill_pgoff(t, vma, to_kill, pgoff); } } - rcu_read_unlock(); i_mmap_unlock_read(mapping); } -- 2.25.1