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<div style="font-size: 12px;">This is so interesting, I am trying to implement the idea of extend maxheapsize at a ratio at </div>
<div style="font-size: 12px;">runtime based on G1，which could more or less help to avoid the OOM/fullGC cause online service hang</div>
<div style="font-size: 12px;">in my BigData scenario.</div>
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<div style="font-size: 12px;">It seems the design is similar with the SoftMaxHeapSize，So maybe I could help to contribute in G1 part of this.</div>
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<div style="font-size: 12px;">BRs,</div>
<div style="font-size: 12px;">Lin</div>
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<blockquote type="cite" class="">
<div class="">在 2019年4月10日，下午11:57，Per Liden <<a href="mailto:per.liden@oracle.com" class="">per.liden@oracle.com</a>> 写道：</div>
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<div class="">Thanks for reviewing, Thomas!<br class="">
<br class="">
/Per<br class="">
<br class="">
On 04/10/2019 05:52 PM, Thomas Schatzl wrote:<br class="">
<blockquote type="cite" class="">Hi,<br class="">
On Wed, 2019-04-10 at 14:06 +0200, Per Liden wrote:<br class="">
<blockquote type="cite" class="">Introduce a manageable SoftMaxHeapSize flag. When set, the GC should<br class="">
strive to not grow heap size beyond the specified size. But as the<br class="">
flag name suggests, this is a soft limit. In other words, the GC is<br class="">
allowed to grow the heap size beyond SoftMaxHeapSize if needed.<br class="">
<br class="">
There are a few different use cases where this flag could be useful.<br class="">
For example, when you want to keep the heap footprint down, while<br class="">
retaining the capability to deal with a temporary increase in heap<br class="">
space requirement. Or when you want to play it safe, with lots of<br class="">
margin, to increase confidence that you will not run into an<br class="">
allocation stall because of an unforeseen increase in allocation<br class="">
rate.<br class="">
<br class="">
The SoftMaxHeapSize should not be allowed to be set to a value<br class="">
smaller than min heap size (-Xms) or greater than max heap size (-<br class="">
Xmx). When not set on the command-line, this flag should default to<br class="">
the max heap size.<br class="">
<br class="">
Bug: <a href="https://bugs.openjdk.java.net/browse/JDK-8222145" class="">https://bugs.openjdk.java.net/browse/JDK-8222145</a><br class="">
CSR: <a href="https://bugs.openjdk.java.net/browse/JDK-8222181" class="">https://bugs.openjdk.java.net/browse/JDK-8222181</a><br class="">
Webrev: <a href="http://cr.openjdk.java.net/~pliden/8222145/webrev.1" class="">http://cr.openjdk.java.net/~pliden/8222145/webrev.1</a><br class="">
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</blockquote>
looks good to me.<br class="">
Thomas<br class="">
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