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Fri, 11 Sep 2026 08:01:34 +0000 X-Mizu-Trace-ID: e9627d939de7aa3b X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Steven Rostedt , Masami Hiramatsu Cc: Ye Liu , Michal Hocko , SJ Park , Lorenzo Stoakes , Oleg Nesterov , peterz@infradead.org, paulmck@kernel.org, mingo@redhat.com, jpoimboe@kernel.org, mic@digikod.net, tglx@kernel.org, akpm@linux-foundation.org, david@kernel.org, linmiaohe@huawei.com, nao.horiguchi@gmail.com, rafael@kernel.org, gnoack3000@gmail.com, gourry@gourry.net, 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, 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 v3 11/15] tracing/fgraph: convert process/thread iterator to for_each_process_thread_rculock Date: Fri, 11 Sep 2026 15:57:56 +0800 Message-Id: <20260911075800.491472-12-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260911075800.491472-1-ye.liu@linux.dev> References: <20260911075800.491472-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: 43re4fk71h5ripjt1uriewozhynq1kfi X-Rspamd-Queue-Id: AE6F3160007 X-HE-Tag: 1789113697-230972 X-HE-Meta: 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 n6wNP6rj 4XGDx9LgL00Qb+FUU5TuWTB6K9WbYvXK2mKdfnPlXB9XnQiKXkfXTgQC+2V/tmwSewgsTgdv+EjUAMQoPtho76KMZtCb8nSnXnHNE+GQ/hIC0ZPsZmyjuovXElCothGjSbbysUilytgnMbs+Lqh4ZmXkoehGNFW1/bSlcxlsOj2vhr6Yhd6ShJnlnNYvUp9E4drkeMoxDBXis3H4iG3exzilGIK5l20HJs2B1UWxL6L3hG4cpdjc/fAbodK6WUoyc27zKR9Xp4b1XegYqmP7KqX+dfRtN3+baEVGywA0kuusFc6wh9mkQzPJ1vbfIlTJ6Bm99g4UBWO3Ng8B/59MDjncy1x4jnnusJtfQCiLFL7+mYXj3hnGUbg/wnfbKPnBDnZtRVEke252oRc7lhoS0a+1l/p8Ho6mqubU1L1uPm+CJRw0qp8LIYK3rwLGfYDgYetrmhczlDilHni0= 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() pair combined with for_each_process_thread() loop in kernel/trace/fgraph.c with for_each_process_thread_rculock(), which scopes the RCU read lock to the loop body via scoped_guard(rcu). No functional change. Signed-off-by: Ye Liu Acked-by: Michal Hocko Reviewed-by: SJ Park Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: Oleg Nesterov --- Changes in v3: - Split from kernel/ patch in v2 (Peter Zijlstra, Steven Rostedt) Changes in v2: - Rename *_rcu to *_rculock kernel/trace/fgraph.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 40d373d65f9b..f797ce119223 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -1057,11 +1057,10 @@ static int alloc_retstack_tasklist(unsigned long **ret_stack_list) } } - rcu_read_lock(); - for_each_process_thread(g, t) { + for_each_process_thread_rculock(g, t) { if (start == end) { ret = -EAGAIN; - goto unlock; + goto free; } if (t->ret_stack == NULL) { @@ -1074,9 +1073,6 @@ static int alloc_retstack_tasklist(unsigned long **ret_stack_list) t->ret_stack = ret_stack_list[start++]; } } - -unlock: - rcu_read_unlock(); free: for (i = start; i < end; i++) kmem_cache_free(fgraph_stack_cachep, ret_stack_list[i]); -- 2.25.1