<div dir="ltr">I think the fact that RamFilter can't deal with huge pages is a bug , duo to this limit, we have to set a balance between normal memory and huge pages to use RamFilter and <span style="color:rgb(80,0,80)">NUMATopologyFilter. what do you think Jay?</span><div><font color="#500050"><br></font><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Sep 6, 2017 at 9:22 PM, Jay Pipes <span dir="ltr"><<a href="mailto:jaypipes@gmail.com" target="_blank">jaypipes@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span class="gmail-">On 09/06/2017 01:21 AM, Weichih Lu wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Thanks for your response.<br>
<br>
Is this mean if I want to create an instance with flavor: 16G memory (hw:mem_page_size=large), I need to preserve memory more than 16GB ?<br>
This instance consume hugepages resource.<br>
</blockquote>
<br></span>
You need to reserve fewer 1GB huge pages than 50 if you want to launch a 16GB instance on a host with 64GB of RAM. Try reserving 32 1GB huge pages.<br>
<br>
Best,<br>
-jay<br>
<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
2017-09-06 1:47 GMT+08:00 Jay Pipes <<a href="mailto:jaypipes@gmail.com" target="_blank">jaypipes@gmail.com</a> <mailto:<a href="mailto:jaypipes@gmail.com" target="_blank">jaypipes@gmail.com</a>>>:<div><div class="gmail-h5"><br>
<br>
Please remember to add a topic [nova] marker to your subject line.<br>
Answer below.<br>
<br>
On 09/05/2017 04:45 AM, Weichih Lu wrote:<br>
<br>
Dear all,<br>
<br>
I have a compute node with 64GB ram. And I set 50 hugepages wiht<br>
1GB hugepage size. I used command "free", it shows free memory<br>
is about 12GB. And free hugepages is 50.<br>
<br>
<br>
Correct. By assigning hugepages, you use the memory allocated to the<br>
hugepages.<br>
<br>
Then I launch an instance with 16GB memory, set flavor tag :<br>
hw:mem_page_size=large. It show Error: No valid host was found.<br>
There are not enough hosts available.<br>
<br>
<br>
Right, because you have only 12G of RAM available after<br>
creating/allocating 50G out of your 64G.<br>
<br>
Huge pages are entirely separate from the normal memory that a<br>
flavor consumes. The 16GB memory in your flavor is RAM consumed on<br>
the host. The huge pages are individual things that are consumed by<br>
the NUMA topology that your instance will take. RAM != huge pages.<br>
Totally different things.<br>
<br>
And I check nova-scheduler log. My<br>
<br>
compute is removed by RamFilter. I can launch an instance with<br>
8GB memory successfully, or I can launch an instance with 16GB<br>
memory sucessfully by remove RamFilter.<br>
<br>
<br>
That's because RamFilter doesn't deal with huge pages. Because huge<br>
pages are a different resource than memory. The page itself is the<br>
resource.<br>
<br>
The NUMATopologyFilter is the scheduler filter that evaluates the<br>
huge page resources on a compute host and determines if the there<br>
are enough *pages* available for the instance. Note that I say<br>
*pages* because the unit of resource consumption for huge pages is<br>
not MB of RAM. It's a single memory page.<br>
<br>
Please read this excellent article by Steve Gordon for information<br>
on what NUMA and huge pages are and how to use them in Nova:<br>
<br>
<a href="http://redhatstackblog.redhat.com/2015/09/15/driving-in-the-fast-lane-huge-page-support-in-openstack-compute/" rel="noreferrer" target="_blank">http://redhatstackblog.redhat.<wbr>com/2015/09/15/driving-in-the-<wbr>fast-lane-huge-page-support-in<wbr>-openstack-compute/</a><br>
<<a href="http://redhatstackblog.redhat.com/2015/09/15/driving-in-the-fast-lane-huge-page-support-in-openstack-compute/" rel="noreferrer" target="_blank">http://redhatstackblog.redhat<wbr>.com/2015/09/15/driving-in-<wbr>the-fast-lane-huge-page-suppor<wbr>t-in-openstack-compute/</a>><br>
<br>
Best,<br>
-jay<br>
<br>
Does RamFilter only check free memory but not free hugepages?<br>
How can I solve this problem?<br>
<br>
I use openstack mitaka version.<br>
<br>
thanks<br>
<br>
WeiChih, Lu.<br>
<br>
Best Regards.<br>
<br>
<br>
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</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div>Tang Yaguang</div><div><br></div><br><div> </div></div></div>
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