When checking for humongous objects to reclaim, we dirty cards that might belong to freed regions. Fixed by checking the region before dirtying.
Reviewed-by: tschatzl, brutisso
Push the remembered sets of large objects with few referenced into the dirty card queue at the beginning of the evacuation so that they may end up with zero remembered set entries at the end of the collection, and are potentially reclaimed. Also improve timing measurements of the early reclaim mechanism, and shorten flag names.
Reviewed-by: brutisso, jmasa, dfazunen
Some verification code iterated over the heap using the region mapping array. This is not allowed. Changed to use the regular iteration method with closure.
Reviewed-by: jwilhelm, brutisso
Evaluate and improve object copy time by micro-optimizations and splitting out slow and fast paths aggressively.
Co-authored-by: Tony Printezis <tprintezis@twitter.com>
Reviewed-by: kbarrett, mgerdin, jmasa
Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso
Support for segmentation of the code cache. Separate code heaps are created and used to store code of different types.
Reviewed-by: kvn, iveresov, roland, anoll, egahlin, sla
Remove -XX:-G1DeferredRSUpdate functionality as it is racy. During evacuation failure handling, threads where evacuation failure handling occurred may try to add remembered sets to regions which remembered sets are currently being scanned. The iterator to handle the remembered set scan does not support addition of entries during scan and so may skip valid references.
Reviewed-by: iveresov, brutisso, mgerdin
Splitting out a g1 allocator class to simply specialized allocators which can associate each allocation with a given context.
Reviewed-by: mgerdin, brutisso
Replace G1CodeRootSet with a Hashtable based implementation, merge Code Root Migration phase into Code Root Scanning
Reviewed-by: jmasa, brutisso, tschatzl
Extend the WhiteBox API to provide information about the size and age of objects. Further add a mechanism to trigger a young GC.
Reviewed-by: tschatzl, sjohanss
Allow G1 to decommit memory of arbitrary regions within the heap and their associated auxiliary data structures card table, BOT, hot card cache, and mark bitmaps.
Reviewed-by: mgerdin, brutisso, jwilhelm
Let HeapRegionSeq manage the heap region and auxiliary data to decrease the amount of responsibilities of G1CollectedHeap, and encapsulate this work from other code.
Reviewed-by: jwilhelm, jmasa, mgerdin, brutisso
