From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-242.mta0.migadu.com [91.218.175.242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E88EC45C70F for ; Fri, 11 Sep 2026 08:01:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.242 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789113700; cv=none; b=oYumqJ0kybo6LkqEsvA+heDLG0q3FYnS9Z1hTUjdy/Usi+wrzJcZKpnEpO3CoydSNY3/Vf9qPxlX4E1BlpRgeFTUqHtR883ZALBQL0YtjDirbUN11IXVXXLglpbeP+yZT02Qmt57pLhurSv/+r3hRFZVlNbXlF7FP6MHmoVQ5Og= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789113700; c=relaxed/simple; bh=IUi1QxJJO9OkJwG+5y62kZo0PP6tS0vKjCkbB/pQE7o=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hP0rFjqH0ChnbkaVQRvCK7R5m4K7SaPnWDf6H6+hiNTL2UIM3cCWZ4USdOxqIaVo4xrLvVB5AaCH9multAlPaoma6eSzNd3R0R5VnxB7Lhc95TB6p0qDu0PhNCbS/WPXfppwFgQUHvAo5iNkfWybDtlPcJkC1xRAJ96fXzXNoKs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ITKbw41G; arc=none smtp.client-ip=91.218.175.242 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ITKbw41G" X-Envelope-To: linux-trace-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=IUi1QxJJO9OkJwG+5y62kZo0PP6tS0vKjCkbB/pQE7o=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789113696; v=1; x=1789718496; b=ITKbw41GIqoryyNdtt8qpmC83viNLQyMmuoZW8dWz8JcJc0unVQ8J/nZdm9KxTFgnButgmGJ wiCYmtwrdxbb97eNtf9+weSiTGw+PYTAPRWcmIxdXGmrRf7AdeO2fEl1oddISNtk4J+GRgfSs0j TvtyaW+rSUFOPeoVoko6zkWc= X-Envelope-To: linux-trace-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id e9627d939de7aa3b; 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> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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