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From: "H. Peter Anvin" <hpa@zytor.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Xie Yuanbin <qq570070308@gmail.com>,
	david@redhat.com, tglx@linutronix.de, segher@kernel.crashing.org,
	riel@surriel.com, linux@armlinux.org.uk,
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	will@kernel.org
Subject: Re: [PATCH v2 3/4] Provide the always inline version of some functions
Date: Mon, 10 Nov 2025 15:21:52 -0800	[thread overview]
Message-ID: <128b82ff-d304-41d6-b914-a44706d8781f@zytor.com> (raw)
In-Reply-To: <20251109115152.GD2545891@noisy.programming.kicks-ass.net>

On 2025-11-09 03:51, Peter Zijlstra wrote:
> On Sat, Nov 08, 2025 at 02:14:44PM -0800, H. Peter Anvin wrote:
> 
>>> +static struct rq *finish_task_switch(struct task_struct *prev)
>>> +{
>>> +	return finish_task_switch_ainline(prev);
>>> +}
>>> +
>>> /**
>>>  * schedule_tail - first thing a freshly forked thread must call.
>>>  * @prev: the thread we just switched away from.
>>
>> There is, in fact: you have to have an always_inline version, and wrap it in a noinline version.
> 
> Yes, but all of this is particularly retarded, there are exactly _2_
> callers of this function. Keeping an out-of-line copy for one while
> inlineing the other makes 0 sense.
> 
> Also, the amount of crap he needs to mark __always_inline doesn't make
> much sense to me, is he building with -Os or something?

That's another issue -- unless the second instance of the function is on a
slow path which wants to be isolated from the rest of its function (unlikely.)

I was merely commenting on the claim that there is no way to control inlining
on a call site basis - there is.

	-hpa


  reply	other threads:[~2025-11-10 23:23 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-08 17:23 [PATCH v2 0/4] Optimize code generation during context switching Xie Yuanbin
2025-11-08 17:23 ` [PATCH v2 1/4] Make enter_lazy_tlb inline on x86 Xie Yuanbin
2025-11-08 17:23 ` [PATCH v2 2/4] Make raw_spin_rq_unlock inline Xie Yuanbin
2025-11-08 17:23 ` [PATCH v2 3/4] Provide the always inline version of some functions Xie Yuanbin
2025-11-08 22:14   ` H. Peter Anvin
2025-11-09 11:51     ` Peter Zijlstra
2025-11-10 23:21       ` H. Peter Anvin [this message]
2025-11-09 11:31   ` Peter Zijlstra
2025-11-09 17:04     ` Xie Yuanbin
2025-11-09 17:35       ` Arnd Bergmann
2025-11-10 15:43         ` Xie Yuanbin
2025-11-08 17:23 ` [PATCH v2 4/4] Make finish_task_switch and its subfuncs inline in context switching Xie Yuanbin
2025-11-09 11:35   ` Peter Zijlstra

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