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Mon, 21 Sep 2026 09:22:24 +0000 X-Mizu-Trace-ID: ae900405219d419d X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Miaohe Lin , Andrew Morton Cc: Ye Liu , Michal Hocko , Lorenzo Stoakes , SJ Park , Gregory Price , 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, 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 04/15] mm/memory-failure: convert process iterator to for_each_process_rculock Date: Mon, 21 Sep 2026 17:20:50 +0800 Message-Id: <20260921092101.89285-5-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260921092101.89285-1-ye.liu@linux.dev> References: <20260921092101.89285-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 338EB20007 X-Rspam-User: X-Stat-Signature: 46o4bkr8u8qb73gwdqwrxdojib95qdou X-HE-Tag: 1789982545-267015 X-HE-Meta: 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 gTNVsTw2 9LORNeTSjozCaZDDHfekc5QgkZgHtwppOgacebq54qLQ21h2h+KJaii7DtD8nRH++4gqfsix1oHH7ILp5ztaf2/6S1/FCr+K2urYXLvfZrBqv23KowHZPRqxGHDRBQbvp2DJ5UZsVNIML5HMfc6JLN+KMo5f77PuUpk9Tc51L6I/AvgyC3xCG3AwLMhBPEX7P0jKUxVZW29YucRdy+9cbEjzmmFLlURYEgWmEvMggCr2DV/DK/Igr1w8BqUIdOXsDZ6zQmLRq09EMPmsrHJtLFtcbpfsEk9QOXNP2oWidfFGDFnRxvJVI2ce/aO21IEu9D0XSpCKuzj6+2emGZTGPfEcdzkmpl0Xu+5ykH6bGnQVPuQ4u2/egKu3vIlbXTiEONdBbeQ2xa0podJX0L3XEWX3Pwz6XS5BvoghZqIAePRO3M/ADrCQCwJPkZwtya/EWzU1iHwIlOCqQYnsysI2acEq2DOXIBL/PItPiSeyhJ1c1lfM+swQDNkRmyOVZEEG9tC3JtczoZUJqx4n1nhza7KckTvk7mTtzu01/vAg/IgpgnRU/ml6tr9BFIA== 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 Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: SJ Park Reviewed-by: Gregory Price (Meta) --- 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