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From: Jens Axboe <>
To: Miroslav Benes <>, Oleg Nesterov <>
Subject: Re: [PATCHSET RFC v3 0/6] Add support for TIF_NOTIFY_SIGNAL
Date: Sat, 10 Oct 2020 10:53:44 -0600	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 10/9/20 9:21 AM, Jens Axboe wrote:
> On 10/9/20 2:01 AM, Miroslav Benes wrote:
>> On Thu, 8 Oct 2020, Oleg Nesterov wrote:
>>> On 10/05, Jens Axboe wrote:
>>>> Hi,
>>>> The goal is this patch series is to decouple TWA_SIGNAL based task_work
>>>> from real signals and signal delivery.
>>> I think TIF_NOTIFY_SIGNAL can have more users. Say, we can move
>>> try_to_freeze() from get_signal() to tracehook_notify_signal(), kill
>>> fake_signal_wake_up(), and remove freezing() from recalc_sigpending().
>>> Probably the same for TIF_PATCH_PENDING, klp_send_signals() can use
>>> set_notify_signal() rather than signal_wake_up().
>> Yes, that was my impression from the patch set too, when I accidentally 
>> noticed it.
>> Jens, could you CC our live patching ML when you submit v4, please? It 
>> would be a nice cleanup.
> Definitely, though it'd be v5 at this point. But we really need to get
> all archs supporting TIF_NOTIFY_SIGNAL first. Once we have that, there's
> a whole slew of cleanups that'll fall out naturally:
> - Removal of JOBCTL_TASK_WORK
> - Removal of special path for TWA_SIGNAL in task_work
> - TIF_PATCH_PENDING can be converted and then removed
> - try_to_freeze() cleanup that Oleg mentioned
> And probably more I'm not thinking of right now :-)

Here's the current series, I took a stab at converting all archs to
support TIF_NOTIFY_SIGNAL so we have a base to build on top of. Most
of them were straight forward, but I need someone to fixup powerpc,
verify arm and s390.

But it's a decent start I think, and means that we can drop various
bits as is done at the end of the series. I could swap things around
a bit and avoid having the intermediate step, but I envision that
getting this in all archs will take a bit longer than just signing off
on the generic/x86 bits. So probably best to keep the series as it is
for now, and work on getting the arch bits verified/fixed/tested.

Jens Axboe

  reply	other threads:[~2020-10-10 23:07 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
     [not found] ` <>
2020-10-09  8:01   ` [PATCHSET RFC v3 0/6] Add support for TIF_NOTIFY_SIGNAL Miroslav Benes
2020-10-09 15:21     ` Jens Axboe
2020-10-10 16:53       ` Jens Axboe [this message]
2020-10-12 17:27         ` Miroslav Benes
2020-10-13 19:39           ` Jens Axboe
2020-10-13 23:34             ` Thomas Gleixner
2020-10-13 23:37               ` Jens Axboe

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