From: Dave Jones <davej@codemonkey.org.uk>
To: Jan Stancek <jstancek@redhat.com>
Cc: trinity@vger.kernel.org
Subject: Re: [bug] child processes stall forever and don't get killed
Date: Fri, 9 Sep 2016 09:32:36 -0400 [thread overview]
Message-ID: <20160909133236.qm32kmsz3wfby53y@codemonkey.org.uk> (raw)
In-Reply-To: <210078090.1267922.1473417016250.JavaMail.zimbra@redhat.com>
On Fri, Sep 09, 2016 at 06:30:16AM -0400, Jan Stancek wrote:
> Hi,
>
> I'm running v1.6-643-gecea2b06d5f3 on RHEL7.3 and I'm seeing an issue
> where all child processes stall and none of them is getting killed.
> They are usually in a syscalls like read, recv, nanosleep, etc.
>
> I suspect this commit introduced the problem, because any syscall
> that started but not completed is now considered to "make progress":
>
> commit ecf6dfd83d4c886d78d4605163cb8c3f1728db62
> Author: Dave Jones <davej@codemonkey.org.uk>
> Date: Fri Aug 12 15:05:01 2016 -0400
>
> if we haven't done a syscall yet, treat child as "making progress".
>
> Chances are that we haven't been scheduled because some other
> children are hogging the cpu.
>
> I'm seeing more the opposite of what commit above says. Most CPUs
> are idle, because N-1 children are stuck in recv/read/...
> and last child manages to keep going. Then by a chance it also hits
> a syscall that doesn't complete and system stays idle
> (after ~hour I gave up waiting).
Need to think some more on this, but as a quick guess...
try replacing the <= BEFORE with < BEFORE
I'll try and find some time to look into this soon. I'm surprised I
haven't also seen it happen though. How many CPUs & how many child
processes ?
Dave
next prev parent reply other threads:[~2016-09-09 13:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1139550397.1201862.1473415639192.JavaMail.zimbra@redhat.com>
2016-09-09 10:30 ` [bug] child processes stall forever and don't get killed Jan Stancek
2016-09-09 13:32 ` Dave Jones [this message]
2016-09-09 14:16 ` Jan Stancek
2016-09-10 1:46 ` Dave Jones
2016-09-13 12:00 ` Jan Stancek
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