<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small;color:rgb(0,0,0)">It sounds like it was doing just a partial RAM defrag. Otherwise, there should be a single large contig (hopefully > 4GB) right after the defrag.<br> <br></div><div class="gmail_extra"><div><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><font size="2"><span style="font-family:verdana,sans-serif">Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701, +1-204-515-1700, +1-810-471-4600, +1-909-361-6005<br></span></font><br></div></div></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On 4 January 2016 at 12:54, Trevor Cordes <span dir="ltr"><<a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 2016-01-04 Hartmut W Sager wrote:<br>
> I am surprised. Doesn't a current high-grade OS like Linux (maybe not<br>
> Windows) routinely close the gaps in RAM by relocating running code<br>
> and data? This is quite efficiently do-able in CPU architectures<br>
<br>
I just read an article about this. Supposedly modern linux (not sure<br>
about RHEL6) does mem "defrag" only on oom condition (going from vague<br>
memory). Discussions always crop up about having a kthread that can do<br>
periodic defrag outside of oom condition but I don't think this is<br>
being done at present.<br>
<br>
Defrag on oom does sound like what I just saw today, because when the<br>
oom happened there was almost no contig ram left, but when I checked<br>
the server a while later there were lots of bigger contigs, but still<br>
not enough for a 4G alloc.<br>
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