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From: Jens Axboe <axboe@kernel.dk>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org, io-uring@vger.kernel.org,
	peterz@infradead.org, tglx@linutronix.de
Subject: Re: [PATCH 3/5] kernel: add support for TIF_NOTIFY_SIGNAL
Date: Thu, 15 Oct 2020 08:33:37 -0600	[thread overview]
Message-ID: <5d231aa1-b8c7-ae4e-90bb-211f82b57547@kernel.dk> (raw)
In-Reply-To: <20201015143151.GB24156@redhat.com>

On 10/15/20 8:31 AM, Oleg Nesterov wrote:
> On 10/15, Jens Axboe wrote:
>>
>>  static inline int signal_pending(struct task_struct *p)
>>  {
>> +#if defined(CONFIG_GENERIC_ENTRY) && defined(TIF_NOTIFY_SIGNAL)
>> +	/*
>> +	 * TIF_NOTIFY_SIGNAL isn't really a signal, but it requires the same
>> +	 * behavior in terms of ensuring that we break out of wait loops
>> +	 * so that notify signal callbacks can be processed.
>> +	 */
>> +	if (unlikely(test_tsk_thread_flag(p, TIF_NOTIFY_SIGNAL)))
>> +		return 1;
>> +#endif
>>  	return task_sigpending(p);
>>  }
> 
> I don't understand why does this version requires CONFIG_GENERIC_ENTRY.
> 
> Afaics, it is very easy to change all the non-x86 arches to support
> TIF_NOTIFY_SIGNAL, but it is not trivial to change them all to use
> kernel/entry/common.c ?

I think that Thomas wants to gate TIF_NOTIFY_SIGNAL on conversion to
the generic entry code? Because you are right, it's usually pretty
trivial to wire up the arch code, regardless of whether it uses the
generic entry handling or not.

-- 
Jens Axboe


  reply	other threads:[~2020-10-15 14:33 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 [this message]
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
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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