https://bugs.dragonflybsd.org/https://bugs.dragonflybsd.org/favicon.ico?16293952082010-10-18T05:37:24ZDragonFlyBSD bugtrackerDragonFlyBSD - Bug #1878: dsched_fq and occasional console freezehttps://bugs.dragonflybsd.org/issues/1878?journal_id=91312010-10-18T05:37:24Zelekktretterr
<ul></ul><blockquote>
<p>Hi.<br />When the current dsched policy is set to fq, the console (or ssh<br />connection)<br />occasionally freezes (becomes unresponsive, even to ctrl+T). However,<br />I can still switch between ttyvN terminals by pressing Alt+Fn keys,<br />and drop to DDB (I remember reading a similar description in the past,<br />but I couldn't find the message in my mailbox).</p>
<p>Unfortunately, the kernel dumping locks up too in that case<br />(no progress is printed on the screen), so no vmcore is available<br />at the moment. FWIW, dsched_fq is loaded as kernel module and the policy<br />is set via /etc/rc.d/sysctl.</p>
<p>This is on an Atom D510 with 4G bytes of RAM and running a very recent<br />-DEVELOPMENT x86_64 kernel; I haven't tried it on a PC running 32-bit<br />version yet.</p>
</blockquote>
<p>I wonder if this:<br /><a class="external" href="http://leaf.dragonflybsd.org/mailarchive/bugs/2010-10/msg00085.html">http://leaf.dragonflybsd.org/mailarchive/bugs/2010-10/msg00085.html</a></p>
<p>is related, I did enable DSCHED_FQ via sysctl just before I ran "hammer<br />cleanup" I remember now, and the symptoms are same - freeze but can switch<br />between terminals, but can't actually execute any command because they are<br />all "hanging", for about 5 minutes and eventually freeze completely but<br />without a kernel dump.</p>
<p>Petr</p> DragonFlyBSD - Bug #1878: dsched_fq and occasional console freezehttps://bugs.dragonflybsd.org/issues/1878?journal_id=91332010-10-18T06:09:17Zdillon
<ul></ul><p>:I wonder if this:<br />:http://leaf.dragonflybsd.org/mailarchive/bugs/2010-10/msg00085.html<br />:<br />:is related, I did enable DSCHED_FQ via sysctl just before I ran "hammer<br />:cleanup" I remember now, and the symptoms are same - freeze but can switch<br />:between terminals, but can't actually execute any command because they are<br />:all "hanging", for about 5 minutes and eventually freeze completely but<br />:without a kernel dump.<br />:<br />:Petr</p>
<pre><code>I think it might be. A bug in DSCHED_FQ could cause the I/O to not<br /> get properly completed and stall the NFS server.</code></pre>
<pre><code>-Matt<br /> Matthew Dillon <br /> &lt;<a class="email" href="mailto:dillon@backplane.com">dillon@backplane.com</a>&gt;</code></pre> DragonFlyBSD - Bug #1878: dsched_fq and occasional console freezehttps://bugs.dragonflybsd.org/issues/1878?journal_id=93182010-11-23T02:41:09Zalexh
<ul></ul><p>Well, I fail to find anything that might be causing this in dsched_fq. The code <br />is only around 600 lines, so it'd be good if more people would take a look at it <br />to see if anyone finds issues.</p>
<p>Cheers,<br />Alex Hornung</p>
<p>PS: dsched is a framework, so please, people, write some (better fair-share) <br />disk scheduler!</p> DragonFlyBSD - Bug #1878: dsched_fq and occasional console freezehttps://bugs.dragonflybsd.org/issues/1878?journal_id=142172021-11-27T16:51:44Ztuxillo
<ul><li><strong>Description</strong> updated (<a title="View differences" href="/journals/14217/diff?detail_id=3755">diff</a>)</li><li><strong>Category</strong> set to <i>Kernel</i></li><li><strong>Status</strong> changed from <i>New</i> to <i>Closed</i></li><li><strong>Assignee</strong> deleted (<del><i>0</i></del>)</li></ul><p>dsched removed in <a class="changeset" title="kernel - Remove dsched * After consultation, remove dsched from the kernel. The original idea ..." href="https://bugs.dragonflybsd.org/projects/dragonfly/repository/dragonflybsd/revisions/3573cf7bf66147ca2e7b19f6d8db6b50b21cd63a">3573cf7bf66147ca2e7b19f6d8db6b50b21cd63a</a></p>