<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div><span></span></div><div><div><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div>Hi All,</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature"> I have fixed a bug in the compactor that accounts for the two cases I've analysed and the two fairly repeatable crashes I have at hand (three cases in all). I hope that all those who have been experiencing crashes can start using the latest build asap.</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">It is fixed in these commits:</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature"><span style="background-color: rgba(255, 255, 255, 0);">Name: VMMaker.oscog-eem.2187<br>Author: eem<br>Time: 27 March 2017, 3:00:06.676146 pm<br>UUID: 2259d299-65a4-42d0-a01b-4b25f5a89745<br>Ancestors: VMMaker.oscog-rsf.2186<br><br>SpurPlanningCompactor:<br>Fix a big in resetting the free chunk used for the firstUnusedFieldsSpace after non-final pasxses (i.e. on snapshot). The old code didn't check to see if a free chunk was actually found(!!).</span></div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">and</div><div id="AppleMailSignature"><br><span style="background-color: rgba(255, 255, 255, 0);">Branch: refs/heads/Cog<br> Home: <a href="https://github.com/OpenSmalltalk/opensmalltalk-vm" dir="ltr" x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="0">https://github.com/OpenSmalltalk/opensmalltalk-vm</a><br> Commit: 4ceff23323bcd0f2d3d0a4a43c2995f43d09c98a<br> <a href="https://github.com/OpenSmalltalk/opensmalltalk-vm/commit/4ceff23323bcd0f2d3d0a4a43c2995f43d09c98a" dir="ltr" x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="1">https://github.com/OpenSmalltalk/opensmalltalk-vm/commit/4ceff23323bcd0f2d3d0a4a43c2995f43d09c98a</a><br> Author: Eliot Miranda <<a href="mailto:eliot.miranda@gmail.com" dir="ltr" x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="2">eliot.miranda@gmail.com</a>><br> Date: 2017-03-27 (Mon, 27 Mar 2017)</span></div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">The bintray files are here:</div><div id="AppleMailSignature"><a href="https://bintray.com/opensmalltalk/vm/cog/201703272314">https://bintray.com/opensmalltalk/vm/cog/201703272314</a><br><span style="background-color: rgba(255, 255, 255, 0);">_,,,^..^,,,_ (phone)</span></div><div><br>On Mar 25, 2017, at 1:27 PM, Eliot Miranda <<a href="mailto:eliot.miranda@gmail.com">eliot.miranda@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div><div dir="ltr">Hi All,<div><br></div><div> a number of people are being affected by crashes on snapshotting the image, the worst possible time for a crash. There is a bug in the new compactor that unfortunately bites when saving. The compactor is invoked as part of a full garbage collect after the garbage collector has feed unreachable objects. Normally the new compactor makes only a single pass through the heap, which may not move all the objects that are possible to move. (The amount of objects that can be moved in a single pass is limited by available free space.) But on snapshot the compactor makes as may passes as are necessary to slide all movable objects down as far as possible. Unfortunately there is a bug in this second pass.</div><div><br></div><div>Fixing this bug is now my priority. I have an example image from Esteban Lorenzano to test. I am asking anyone else that can provide an image that reliably crashes when trying to save it to make the image and changes available to me for testing if possible.</div><div><br></div><div>In the mean time one may be able to work around the problem by doing a full garbage collect before snapshot. This should do a GC with a single compaction pass which should not fail, and then make it much more likely that the GC during snapshot will do a single compaction pass, since fewer objects should be mobile after the single pass compaction in the explicit GC.</div><div><br></div><div>To do this in Pharo I would put a full gc here:</div><div><br></div><div><div>SessionManager>>snapshot: save andQuit: quit</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>| isImageStarting snapshotResult |</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>ChangesLog default logSnapshot: save andQuit: quit.</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"><br></span></div><div><span class="gmail-Apple-tab-span" style="white-space:pre">>> SmalltalkImage current primitiveGarbageCollect.</span></div><div><span class="gmail-Apple-tab-span" style="white-space:pre"><br></span></div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>self currentSession stop: quit.<span class="gmail-Apple-tab-span" style="white-space:pre"> </span>"Image not usable from here until the session is restarted!"</div></div><div>...</div><div><br></div><div>In Squeak I would put a full GC here:</div><div><br></div><div><div>snapshot: save andQuit: quit withExitCode: exitCode embedded: embeddedFlag</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>"Mark the changes file and close all files as part of #processShutdownList.</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>If save is true, save the current state of this Smalltalk in the image file.</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>If quit is true, then exit to the outer OS shell.</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>If exitCode is not nil, then use it as exit code.</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>The latter part of this method runs when resuming a previously saved image. This resume logic checks for a document file to process when starting up."</div><div><br></div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>| resuming msg |</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>Object flushDependents.</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>Object flushEvents.</div><div><br></div><div><span style="white-space:pre">...</span></div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>Smalltalk processShutDownList: quit.</div><div>>><span style="white-space:pre"> SmalltalkImage current primitiveGarbageCollect.</span></div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>Cursor write show.</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>save ifTrue: [resuming := embeddedFlag </div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>ifTrue: [self snapshotEmbeddedPrimitive] </div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>ifFalse: [self snapshotPrimitive]] "<-- PC frozen here on image file"</div><div><span class="gmail-Apple-tab-span" style="white-space:pre"> </span>ifFalse: [resuming := false].</div></div><div><br></div><div>I do apologise for the bug. I hope it will be fixed within a few days.</div><div><br></div><div class="gmail_signature"><div dir="ltr"><div><span style="font-size:small;border-collapse:separate"><div>_,,,^..^,,,_<br></div><div>best, Eliot</div></span></div></div></div>
</div>
</div></blockquote></div></div></body></html>