Auxiliary data structures should have knowledge of their own requirements for virtual memory reservations instead of getting these values directly from various places.
Reviewed-by: stefank, kbarrett
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
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
Add a list of nmethods to the RSet for a region that contain references into the region. Skip scanning the code cache during root scanning and scan the nmethod lists during RSet scanning instead.
Reviewed-by: tschatzl, brutisso, mgerdin, twisti, kvn
Skip reference processing if the global marking stack overflows during remark. Refactor and rename set_phase(); move code that sets the concurrency level into its own routine. Do not call set_phase() from within parallel reference processing; use the concurrency level routine instead. The marking state should only set reset by CMTask[0] during the concurrent phase of the marking cycle; if an overflow occurs at any stage during the remark, the marking state will be reset after reference processing.
Reviewed-by: brutisso, jmasa
In CMTask::do_marking_step(), Skip offering termination and entering the first and second synchronization barriers if called from a serial context, i.e. the VM thread.
Reviewed-by: brutisso, tschatzl
Update the task local finger to the start of the next object when marking aborts, in order to avoid the redundant scanning of all 0's when the marking task restarts, if otherwise updating to the next word. In addition, reuse the routine nextObject() in routine iterate().
Reviewed-by: johnc, ysr
Check that the concurrent marking worker gang exists in ConcurrentMark::print_worker_threads_on(). Changes were also reviewed by Vitaly Davidovich <vitalyd@gmail.com>.
Reviewed-by: brutisso
Reset the marking state, including the mark stack overflow flag, in the event of a marking stack overflow during serial reference processing.
Reviewed-by: jmasa
Set the value of MarkStackSize to a value based on the number of parallel marking threads with a reasonable minimum. Expand the marking stack if we have to restart marking due to an overflow up to a reasonable maximum. Allocate the underlying space for the marking stack from virtual memory.
Reviewed-by: jmasa, brutisso
Change the type of various task num fields, parameters etc to unsigned and rename them to be more consistent with the other collectors. Code changes were also reviewed by Vitaly Davidovich.
Reviewed-by: johnc
The clipping code in the routine that sets the bits for a range of cards, in the liveness accounting verification code was incorrect. It set all the bits in the card bitmap from the given starting index which would lead to spurious marking verification failures.
Reviewed-by: brutisso, jwilhelm, jmasa
7151532: DCmd for hotspot native memory tracking
Implementation of native memory tracking phase 1, which tracks VM native memory usage, and related DCmd
Reviewed-by: acorn, coleenp, fparain
Change the type of fields / variables / etc. that represent region counts and indeces from size_t to uint.
Reviewed-by: iveresov, brutisso, jmasa, jwilhelm
Re-enable survivors during the initial-mark pause. Afterwards, the concurrent marking threads have to scan them and mark everything reachable from them. The next GC will have to wait for the survivors to be scanned.
Reviewed-by: brutisso, johnc
Remove the separate counting phase of concurrent marking by tracking the amount of marked bytes and the cards spanned by marked objects in marking task/worker thread local data structures, which are updated as individual objects are marked.
Reviewed-by: brutisso, tonyp
There is a high number of mispredicted branches associated with calling BitMap::iteratate() from within CMBitMapRO::iterate(). Implement a version of CMBitMapRO::iterate() directly using inline-able routines.
Reviewed-by: tonyp, iveresov
This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object).
Reviewed-by: johnc, brutisso
Change variables representing the number of GC workers to uint from int and size_t. Change the parameter in work(int i) to work(uint worker_id).
Reviewed-by: brutisso, tonyp
Running G1 with ParallelGCThreads==0 results in various crashes and asserts. Most of these are caused by unguarded references to the worker threads array or an incorrect number of active workers.
Reviewed-by: jmasa, tonyp
Parallelize the serial code that was used to mark objects reachable from survivor objects in the collection set. Some minor improvments in the timers used to track the freeing of the collection set along with some tweaks to PrintGCDetails.
Reviewed-by: tonyp, brutisso
