a3b7c323b0
- Initial and final marking no longer visit all of new-space, reducing the STW pause for major GC. - A scavenge during concurrent marking must forward / filter objects in the marking worklist that are moved / collected, increasing the STW pause for minor GC. - Unreachable intergenerational cycles and weak references are collected in the next mark-sweep instead of first requiring enough scavenges to promote the whole cycle or weak target into old-space. - Artificial minor GCs are no longer needed to avoid memory leaks from back-to-back major GCs. - reachabilityBarrier is now just a count of major GCs. TEST=ci Change-Id: Ic7754e8d972763654eae2b7faa8670735d9cda3f Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/340644 Reviewed-by: Siva Annamalai <asiva@google.com> Commit-Queue: Ryan Macnak <rmacnak@google.com>