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From: Oleg Nesterov <[email protected]>
To: Thomas Gleixner <[email protected]>
Cc: Jens Axboe <[email protected]>,
	[email protected], [email protected],
	[email protected]
Subject: Re: [PATCH 4/5] x86: wire up TIF_NOTIFY_SIGNAL
Date: Thu, 15 Oct 2020 17:17:56 +0200	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 10/15, Thomas Gleixner wrote:
>
> On Thu, Oct 15 2020 at 16:34, Oleg Nesterov wrote:
> > On 10/15, Thomas Gleixner wrote:
> >> Instead of adding this to every architectures signal magic, we can
> >> handle TIF_NOTIFY_SIGNAL in the core code:
> >>
> >> static void handle_singal_work(ti_work, regs)
> >> {
> >> 	if (ti_work & _TIF_NOTIFY_SIGNAL)
> >>         	tracehook_notify_signal();
> >>
> >>         arch_do_signal(ti_work, regs);
> >> }
> >>
> >>       loop {
> >>       		if (ti_work & (SIGPENDING | NOTIFY_SIGNAL))
> >>                 	handle_signal_work(ti_work, regs);
> >>       }
> >
> > To me this looks like unnecessary complication. We need to change
> > every architecture anyway, how can this helper help?
>
> You need to change ONE architecture because nobody else uses the common
> entry loop right now.

so we need to change other arches to use the common entry loop.

> For those who move over they have to supply
> arch_do_signal() anyway,

and this arch_do_signal() should be changed to check _TIF_SIGPENDING.



See also my replies to 3/5. I strongly disagree with CONFIG_GENERIC_ENTRY.
But even if we require CONFIG_GENERIC_ENTRY, why do we want this helper?

We can just change exit_to_user_mode_loop() to do

	if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
		if (ti_work & _TIF_NOTIFY_SIGNAL)
			tracehook_notify_signal();
		arch_do_signal(ti_work, regs);
	}

but I'd prefer to handle SIGPENDING/NOTIFY_SIGNAL in one place.

Oleg.


  reply	other threads:[~2020-10-15 15:18 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-15 13:16 [PATCHSET v5] Add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-15 13:16 ` [PATCH 1/5] tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume() Jens Axboe
2020-10-15 14:42   ` Oleg Nesterov
2020-10-15 14:43     ` Jens Axboe
2020-10-15 13:16 ` [PATCH 2/5] kernel: add task_sigpending() helper Jens Axboe
2020-10-15 14:42   ` Oleg Nesterov
2020-10-15 13:16 ` [PATCH 3/5] kernel: add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-15 14:31   ` Oleg Nesterov
2020-10-15 14:33     ` Jens Axboe
2020-10-15 14:37       ` Oleg Nesterov
2020-10-15 14:43         ` Jens Axboe
2020-10-15 14:47           ` Oleg Nesterov
2020-10-15 14:53             ` Oleg Nesterov
2020-10-15 14:56               ` Jens Axboe
2020-10-15 15:01         ` Thomas Gleixner
2020-10-15 15:27           ` Oleg Nesterov
2020-10-15 14:44   ` Oleg Nesterov
2020-10-15 13:17 ` [PATCH 4/5] x86: wire up TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-15 14:11   ` Thomas Gleixner
2020-10-15 14:31     ` Jens Axboe
2020-10-15 14:34       ` Thomas Gleixner
2020-10-15 14:35         ` Jens Axboe
2020-10-15 14:36       ` Oleg Nesterov
2020-10-15 14:42         ` Jens Axboe
2020-10-15 14:34     ` Oleg Nesterov
2020-10-15 14:54       ` Thomas Gleixner
2020-10-15 15:17         ` Oleg Nesterov [this message]
2020-10-16  9:55       ` Thomas Gleixner
2020-10-16 10:54         ` Oleg Nesterov
2020-10-16 13:07           ` Thomas Gleixner
2020-10-15 14:44   ` Oleg Nesterov
2020-10-20 10:57   ` introduce asm-generic/thread_info.h ? Oleg Nesterov
2020-10-15 13:17 ` [PATCH 5/5] task_work: use TIF_NOTIFY_SIGNAL if available Jens Axboe
2020-10-15 15:49   ` Oleg Nesterov
2020-10-15 18:39     ` Jens Axboe
2020-10-16  9:00       ` Thomas Gleixner
2020-10-16  9:39         ` Thomas Gleixner
2020-10-16 13:35           ` Jens Axboe
2020-10-16 14:17             ` Thomas Gleixner
2020-10-16 14:51               ` Oleg Nesterov
2020-10-16 14:53                 ` Jens Axboe
2020-10-16 18:03                   ` Thomas Gleixner
2020-10-16 18:05                     ` Jens Axboe
2020-10-16 13:33         ` Jens Axboe
2020-10-16 14:11           ` Thomas Gleixner
2020-10-16 14:22             ` Jens Axboe

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