Bug 1529265 Comment 0 Edit History

Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.

Original comment by
on 
This field:

  /* Number of zones collected in this GC. */
  int collectedZoneCount = 0;

Is used here:

  bool isFullCollection() const {
    return collectedZoneCount == collectableZoneCount;
  }

Both of these fields are computed in GCRuntime::scanZonesBeforeGC:

    if (zone->canCollect()) {
      zoneStats.collectableZoneCount++;
    }
    if (zone->isGCScheduled()) {
      zoneStats.collectedZoneCount++;
      ...

It's possible however for a zone to have isGCScheduled() with canCollect() == false (via JS::PrepareForFullGC for example).

This can result in repeatedly triggering full GCs in Gecko:

https://searchfox.org/mozilla-central/rev/93905b660fc99a5d52b683690dd26471daca08c8/dom/base/nsJSEnvironment.cpp#2214
Revision 1 by
on 
This field:
```
  /* Number of zones collected in this GC. */
  int collectedZoneCount = 0;
```
Is used here:
```
  bool isFullCollection() const {
    return collectedZoneCount == collectableZoneCount;
  }
```
Both of these fields are computed in GCRuntime::scanZonesBeforeGC:
```
    if (zone->canCollect()) {
      zoneStats.collectableZoneCount++;
    }
    if (zone->isGCScheduled()) {
      zoneStats.collectedZoneCount++;
      ...
```
It's possible however for a zone to have isGCScheduled() with canCollect() == false (via JS::PrepareForFullGC for example).

This can result in repeatedly triggering full GCs in Gecko:

https://searchfox.org/mozilla-central/rev/93905b660fc99a5d52b683690dd26471daca08c8/dom/base/nsJSEnvironment.cpp#2214

Back to Bug 1529265 Comment 0