public inbox for [email protected]
 help / color / mirror / Atom feed
From: Jens Axboe <[email protected]>
To: Linus Torvalds <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>,
	io-uring <[email protected]>,
	Linux Kernel Mailing List <[email protected]>,
	Oleg Nesterov <[email protected]>,
	Stefan Metzmacher <[email protected]>
Subject: Re: [PATCH 0/2] Don't show PF_IO_WORKER in /proc/<pid>/task/
Date: Thu, 25 Mar 2021 18:08:11 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAHk-=wgmHRvoYdsA2ZL4aEOYvNx-5c7typsUbFcqq+GmOMcoDQ@mail.gmail.com>

On 3/25/21 4:37 PM, Linus Torvalds wrote:
> On Thu, Mar 25, 2021 at 2:44 PM Jens Axboe <[email protected]> wrote:
>>
>> In the spirit of "let's just try it", I ran with the below patch. With
>> that, I can gdb attach just fine to a test case that creates an io_uring
>> and a regular thread with pthread_create(). The regular thread uses
>> the ring, so you end up with two iou-mgr threads. Attach:
>>
>> [root@archlinux ~]# gdb -p 360
>> [snip gdb noise]
>> Attaching to process 360
>> [New LWP 361]
>> [New LWP 362]
>> [New LWP 363]
> [..]
> 
> Looks fairly sane to me.
> 
> I think this ends up being the right approach - just the final part
> (famous last words) of "io_uring threads act like normal threads".
> 
> Doing it for VM and FS got rid of all the special cases there, and now
> doing it for signal handling gets rid of all these ptrace etc issues.
> 
> And the fact that a noticeable part of the patch was removing the
> PF_IO_WORKER tests again looks like a very good sign to me.

I agree, and in fact there are more PF_IO_WORKER checks that can go
too. The patch is just the bare minimum.

> In fact, I think you could now remove all the freezer hacks too -
> because get_signal() will now do the proper try_to_freeze(), so all
> those freezer things are stale as well.

Yep

> Yeah, it's still going to be different in that there's no real user
> space return, and so it will never look _entirely_ like a normal
> thread, but on the whole I really like how this does seem to get rid
> of another batch of special cases.

That's what makes me feel better too. I think was so hung up on the
"never take signals" that it just didn't occur to me to go this
route instead.

I'll send out a clean series.

-- 
Jens Axboe


  reply	other threads:[~2021-03-26  0:09 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-25 16:43 [PATCH 0/2] Don't show PF_IO_WORKER in /proc/<pid>/task/ Jens Axboe
2021-03-25 16:43 ` [PATCH 1/2] kernel: don't include PF_IO_WORKERs as part of same_thread_group() Jens Axboe
2021-03-25 16:43 ` [PATCH 2/2] proc: don't show PF_IO_WORKER threads as threads in /proc/<pid>/task/ Jens Axboe
2021-03-25 19:33 ` [PATCH 0/2] Don't show PF_IO_WORKER " Eric W. Biederman
2021-03-25 19:38   ` Linus Torvalds
2021-03-25 19:40     ` Jens Axboe
2021-03-25 19:42     ` Linus Torvalds
2021-03-25 19:46       ` Jens Axboe
2021-03-25 20:21         ` Eric W. Biederman
2021-03-25 20:40           ` Oleg Nesterov
2021-03-25 20:43             ` Jens Axboe
2021-03-25 20:48             ` Eric W. Biederman
2021-03-25 20:42           ` Jens Axboe
2021-03-25 20:12       ` Linus Torvalds
2021-03-25 20:40         ` Jens Axboe
2021-03-25 21:44           ` Jens Axboe
2021-03-25 21:57             ` Stefan Metzmacher
2021-03-26  0:11               ` Jens Axboe
2021-03-26 11:59                 ` Stefan Metzmacher
2021-04-01 14:40                   ` Stefan Metzmacher
2021-03-25 22:37             ` Linus Torvalds
2021-03-26  0:08               ` Jens Axboe [this message]
2021-03-25 20:43         ` Eric W. Biederman
2021-03-25 21:50           ` Jens Axboe
2021-03-25 20:44         ` Oleg Nesterov
2021-03-25 20:55           ` Eric W. Biederman
2021-03-25 21:20             ` Stefan Metzmacher
2021-03-25 21:48               ` Stefan Metzmacher
2021-03-25 19:40   ` Jens Axboe
2021-03-25 20:32     ` Oleg Nesterov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox