From: Alan Huang <mmpgouride@gmail.com>
To: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>,
linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
x86@kernel.org, Lai Jiangshan <jiangshan.ljs@antgroup.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Josh Triplett <josh@joshtriplett.org>,
Boqun Feng <boqun.feng@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Zqiang <qiang.zhang1211@gmail.com>
Subject: Re: [PATCH 02/10] rcu: Move rcu_preempt_depth_set() to rcupdate.h
Date: Mon, 1 Apr 2024 19:57:40 +0800 [thread overview]
Message-ID: <60BB1971-38D3-4FE2-BB45-2DE228C6F370@gmail.com> (raw)
In-Reply-To: <073E72BD-63AF-4D88-95F8-9A002252C554@gmail.com>
2024年4月1日 19:40，Alan Huang <mmpgouride@gmail.com> wrote：
>
> 2024年4月1日 00:16，Lai Jiangshan <jiangshanlai@gmail.com> wrote：
>>
>> On Sun, Mar 31, 2024 at 7:10 PM Joel Fernandes <joel@joelfernandes.org> wrote:
>>>
>>>
>>>
>>>> On Mar 28, 2024, at 1:20 PM, Lai Jiangshan <jiangshanlai@gmail.com> wrote:
>>>>
>>>> From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
>>>>
>>>> Prepare for arch-specific-defined rcu_preempt_depth_set().
>>>>
>>>> No functionality change intended, but it has to be defined as a macro
>>>> as rcupdate.h is a very low level header included from areas that don't
>>>> even know about the task struct "current".
>>>
>>> Sorry I did not follow changelog. If some rcupdate.h includers do not know
>>> about task_struct, how does adding a macro that uses current help?
>>>
>>
>> Hello
>>
>> This is how macro works and it expands blindly based on tokens on the
>> usage-sites.
>
> But ‘current’ still needs to be expanded at last, it seems to me that it only affects
> the including order of the header files？
>
> Or what am I missing?
Get the missing part: if the user don’t need to use rcu_preempt_depth()
and rcu_preempt_depth_set() but other parts of rcupdate.h, then the two
has to be defined as a macro to avoid including linux/sched.h.
Sorry for the bother.
>
>>
>> And rcu_preempt_depth() & rcu_preempt_depth_set() are not universally
>> used wrappers, the user can simply also include linux/sched.h to make
>> they work.
>>
>> Thanks
>> Lai
next prev parent reply other threads:[~2024-04-01 11:57 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-28 7:53 [PATCH 00/10] rcu/x86: Use per-cpu rcu preempt count Lai Jiangshan
2024-03-28 7:53 ` [PATCH 01/10] lib: Use rcu_preempt_depth() to replace current->rcu_read_lock_nesting Lai Jiangshan
2024-03-28 7:53 ` [PATCH 02/10] rcu: Move rcu_preempt_depth_set() to rcupdate.h Lai Jiangshan
2024-03-31 11:09 ` Joel Fernandes
2024-03-31 16:16 ` Lai Jiangshan
2024-04-01 2:27 ` Joel Fernandes
2024-04-01 11:40 ` Alan Huang
2024-04-01 11:57 ` Alan Huang [this message]
2024-03-28 7:53 ` [PATCH 03/10] rcu: Reorder tree_exp.h after tree_plugin.h Lai Jiangshan
2024-03-28 7:53 ` [PATCH 04/10] rcu: Add macros set_rcu_preempt_special() and clear_rcu_preempt_special() Lai Jiangshan
2024-03-28 7:53 ` [PATCH 05/10] rcu: Make rcu_read_unlock_special() global Lai Jiangshan
2024-03-28 7:53 ` [PATCH 06/10] rcu: Rename marco __LINUX_RCU_H to __KERNEL_RCU_H Lai Jiangshan
2024-03-28 7:53 ` [PATCH 07/10] sched/core: Add rcu_preempt_switch() Lai Jiangshan
2024-03-28 7:53 ` [PATCH 08/10] rcu: Implement PCPU_RCU_PREEMPT_COUNT framework Lai Jiangshan
2024-04-22 10:41 ` Frederic Weisbecker
2024-03-28 7:53 ` [PATCH 09/10] x86/rcu: Add rcu_preempt_count Lai Jiangshan
2024-03-29 7:37 ` kernel test robot
2024-03-29 7:48 ` kernel test robot
2024-04-22 11:05 ` Frederic Weisbecker
2024-04-23 9:02 ` Lai Jiangshan
2024-04-23 11:33 ` Frederic Weisbecker
2024-03-28 7:53 ` [PATCH 10/10] x86/rcu: Add THUNK rcu_read_unlock_special_thunk Lai Jiangshan
2024-03-29 14:46 ` kernel test robot
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