linux-kernel - Re: [PATCH 0/2] Don't show PF_IO

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Message-ID: <97c7c790-35ab-9dbd-78d7-f299f150b3ea@kernel.dk>
Date:   Thu, 25 Mar 2021 13:40:58 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Cc:     io-uring <io-uring@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Oleg Nesterov <oleg@...hat.com>,
        Stefan Metzmacher <metze@...ba.org>
Subject: Re: [PATCH 0/2] Don't show PF_IO_WORKER in /proc/<pid>/task/

On 3/25/21 1:38 PM, Linus Torvalds wrote:
> On Thu, Mar 25, 2021 at 12:34 PM Eric W. Biederman
> <ebiederm@...ssion.com> wrote:
>>
>> A quick skim shows that these threads are not showing up anywhere in
>> proc which appears to be a problem, as it hides them from top.
>>
>> Sysadmins need the ability to dig into a system and find out where all
>> their cpu usage or io's have gone when there is a problem.  I general I
>> think this argues that these threads should show up as threads of the
>> process so I am not even certain this is the right fix to deal with gdb.
> 
> Yeah, I do think that hiding them is the wrong model, because it also
> hides them from "ps" etc, which is very wrong.

Totally agree.

> I don't know what the gdb logic is, but maybe there's some other
> option that makes gdb not react to them?

Guess it's time to dig out the gdb source... I'll take a look.

-- 
Jens Axboe