All of lore.kernel.org
 help / color / mirror / Atom feed
From: Cyril Hrubis <chrubis@suse.cz>
To: ltp@lists.linux.it
Subject: [LTP] [PATCH/RFC] tst_process_state_wait: wait for schedstats to settle when state == S
Date: Thu, 7 Nov 2019 13:15:20 +0100	[thread overview]
Message-ID: <20191107121520.GC22352@rei.lan> (raw)
In-Reply-To: <598814762.10700788.1573034381847.JavaMail.zimbra@redhat.com>

Hi!
> hb->lock is locked at this point, and requeue takes it too, so I'm not
> sure what makes it fail. I've seen testcase fail in at least
> 2 different ways now. Here's the other one:

Here is another theory, some of the processes may be sleeping in a
different place in the kernel, somewhere between the fork() and the
futex(), and hence we think that they have been suspended on the futex
but aren't.

I guess that what we can do is to put a counter in a piece of shared
memory and increment it from each child just before the futex_wait()
call and wait in the parent until the counter reached num_waiters.

-- 
Cyril Hrubis
chrubis@suse.cz

  parent reply	other threads:[~2019-11-07 12:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-05 11:57 [LTP] [PATCH/RFC] tst_process_state_wait: wait for schedstats to settle when state == S Jan Stancek
2019-11-06  9:59 ` Jan Stancek
2019-11-07 11:39   ` Cyril Hrubis
2019-11-07 12:03     ` Cyril Hrubis
2019-11-07 12:15   ` Cyril Hrubis [this message]
2019-11-07 12:31     ` Jan Stancek

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 \
    --in-reply-to=20191107121520.GC22352@rei.lan \
    --to=chrubis@suse.cz \
    --cc=ltp@lists.linux.it \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.