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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white">Hi,
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white">Just going back to a technical point, did you manage to capture a stacktrace from the hang when running with -XX:OnError="jcmd %p GC.heap_dump
-overwrite filename.dmp" <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white">It would be great to know if that is a reliable hang, and what it looks like. Maybe gclocker should not be blocking us at the point OnError
commands are run. We should understand that before making the change, as it seems like a reasonable alternative..<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white">Do you still suggest HeapDumpOverwrite? Maybe we can think about if that suggests it applies to all heap dumps… Or, should we be handling
FIFOs specifically, and not need the overwrite flag?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white">Thanks!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#656D76;background:white">Kevin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Elon Azoulay <elon.azoulay@gmail.com>
<br>
<b>Sent:</b> 18 November 2023 05:20<br>
<b>To:</b> Kevin Walls <kevin.walls@oracle.com><br>
<b>Cc:</b> serviceability-dev@openjdk.org; jdk-dev@openjdk.org<br>
<b>Subject:</b> Re: [External] : Re: Proposal: Add overwrite heapdump flag to java<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi,<o:p></o:p></p>
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<p class="MsoNormal">I wanted to know what I can do to move <a href="https://urldefense.com/v3/__https:/github.com/openjdk/jdk/pull/13276__;!!ACWV5N9M2RV99hQ!MFC1RxlQIbT9S_VS7myYAin2-PCtJagecw_MNFTE6iYHgLvomoZzLN1mlqEe7LSifTKCzkIM2liNzyuTKBZuC68$">
https://github.com/openjdk/jdk/pull/13276</a> along.<o:p></o:p></p>
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<p class="MsoNormal">There was advice to create a CSR request, in order to do that there needs to be a jira <o:p></o:p></p>
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<p class="MsoNormal">but I don't think I have permissions to create one.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks for all the reviews, let me know what I can do, happy to follow your advice!<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Thu, May 25, 2023 at 11:39 PM Kevin Walls <<a href="mailto:kevin.walls@oracle.com">kevin.walls@oracle.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hi,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">(I put this in the PR, but maybe drafts don’t get updates put on the mailing list?)</span><o:p></o:p></p>
<p style="margin-bottom:12.0pt;background:white"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">HeapDumpOverwrite sounds quite general, there are different ways of heap dumping and this doesn't affect all of them. This could
be HeapDumpOnOutOfMemoryErrorOverwrite, which is a long option even for us 8-) so could be abbreviated perhaps, BUT that option might not be the way to do it…</span><o:p></o:p></p>
<p style="margin-bottom:12.0pt;background:white;box-sizing:border-box;font-variant-ligatures:normal;font-variant-caps:normal;text-align:start;text-decoration-style:initial;text-decoration-color:initial;word-spacing:0px">
<span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">Is it really that all heap dumps should be permitted to an existing file, IF that file is a FIFO? From the email I think that's the problem? ..and if so, we have:</span><o:p></o:p></p>
<p style="margin-bottom:12.0pt;background:white;box-sizing:border-box;font-variant-ligatures:normal;font-variant-caps:normal;text-align:start;text-decoration-style:initial;text-decoration-color:initial;word-spacing:0px">
<span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">8267666: Add option to jcmd GC.heap_dump to use existing file<br>
</span><a href="https://bugs.openjdk.org/browse/JDK-8267666" target="_blank"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;text-decoration:none">https://bugs.openjdk.org/browse/JDK-8267666</span></a><o:p></o:p></p>
<p style="margin-top:0cm;background:white;box-sizing:border-box;font-variant-ligatures:normal;font-variant-caps:normal;text-align:start;text-decoration-style:initial;text-decoration-color:initial;word-spacing:0px">
<span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">So if jcmd to create a dump can use an existing file, -XX:OnError= can trigger such a jcmd?
<br>
<br>
i.e. Maybe there is a way of doing what you want. A code change could still be required to make this easier for heap dumps on out of memory. Writing a JBS bug first is useful to define the problem.<br>
<br>
Thanks<br>
Kevin</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> jdk-dev
<</span><a href="mailto:jdk-dev-retn@openjdk.org" target="_blank"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">jdk-dev-retn@openjdk.org</span></a><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">>
<b>On Behalf Of </b>Elon Azoulay<br>
<b>Sent:</b> 25 May 2023 21:21<br>
<b>To:</b> Daniel Daugherty <</span><a href="mailto:daniel.daugherty@oracle.com" target="_blank"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">daniel.daugherty@oracle.com</span></a><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">><br>
<b>Cc:</b> </span><a href="mailto:serviceability-dev@openjdk.org" target="_blank"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">serviceability-dev@openjdk.org</span></a><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">;
</span><a href="mailto:jdk-dev@openjdk.org" target="_blank"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">jdk-dev@openjdk.org</span></a><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"><br>
<b>Subject:</b> Re: [External] : Re: Proposal: Add overwrite heapdump flag to java</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Sounds good, thanks so much!<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On Thu, May 25, 2023 at 12:13 PM <<a href="mailto:daniel.daugherty@oracle.com" target="_blank">daniel.daugherty@oracle.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;margin-bottom:12.0pt"><span style="font-family:"Courier New"">Pointing the older thread to this newer incarnation would be a good idea.<br>
<br>
Dan</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On 5/25/23 3:11 PM, Elon Azoulay wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hi Dan,
<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">That's great! Should I follow up in that thread as well?<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On Thu, May 25, 2023 at 12:04 PM <<a href="mailto:daniel.daugherty@oracle.com" target="_blank">daniel.daugherty@oracle.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;margin-bottom:12.0pt">Greetings,<br>
<br>
A similar request came up on the hotspot-dev alias back in 2022.11:<br>
<br>
<a href="https://mail.openjdk.org/pipermail/hotspot-dev/2022-November/066956.html" target="_blank">https://mail.openjdk.org/pipermail/hotspot-dev/2022-November/066956.html</a><br>
<br>
Dan<br>
<br>
<br>
On 5/25/23 1:48 AM, David Holmes wrote:<br>
> Hi Elon,<br>
><br>
> I would suggest taking this up on serviceability-dev - cc'd.<br>
><br>
> On 25/05/2023 3:46 am, Elon Azoulay wrote:<br>
>> Hi,<br>
>> I submitted a pull request <br>
>> <<a href="https://urldefense.com/v3/__https:/github.com/openjdk/jdk/pull/13276__;!!ACWV5N9M2RV99hQ!P4XNOUSVFXTWEIX8H89o1hhVY4MkuYC-SezupmhJPMkq4ytSpJqLz-jQjNkp906DjKBK_EuRIoL1MtBM2AGEbVqkI0M$" target="_blank">https://github.com/openjdk/jdk/pull/13276</a>>
to expose the overwrite <br>
>> flag to HeapDumpOnOutOfMemoryError.<br>
>> The flag is already exposed to jcmd as -overwrite.This is to <br>
>> facilitate creating a heapdump within a container native environment.<br>
>> We use this internally to dump the heap dump to a fifo so that we <br>
>> could read it in a separate container.Let me know what needs to be <br>
>> done in terms of creating an issue and getting my pr merged.<br>
><br>
> Have you gone through the guide:<br>
><br>
> <a href="https://openjdk.org/guide/" target="_blank">https://openjdk.org/guide/</a><br>
><br>
> ?<br>
><br>
> You will need a JBS issue and also a CSR request as this proposes to <br>
> add a new manageable product flag.<br>
><br>
> Cheers,<br>
> David<br>
><br>
>> I am a new contributor and would be happy to contribute more!<br>
>><br>
>> Cheers,<br>
>><br>
>> Elon<o:p></o:p></p>
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