Change the code cache remembered sets data structure from a GrowableArray to a chunked list of nmethods. This makes the data structure more amenable to parallelization, and decreases freeing time.
Reviewed-by: mgerdin, brutisso
Revert JDK-6976350 because it does not improve PLAB fragmentation. To the contrary, it tends to increase the amount of wasted space with many threads.
Reviewed-by: brutisso
Remove the assumption that G1CollectedHeap::in_cset_fast_test needs to check for NULL references. Most of the time this is not required, making the code doing this check multiple times.
Reviewed-by: stefank, mgerdin, jmasa
Remove the above mentioned template parameter and related unused code. Also remove some classes that are never used.
Reviewed-by: stefank, mgerdin, jwilhelm
8027455: Improve symbol table scan times during gc pauses
Parallelize string table and symbol table scan during remark and full GC. Some additional statistics output if the experimental flag G1TraceStringSymbolTableScrubbing is set.
Reviewed-by: mgerdin, coleenp, brutisso
Use conservative assumptions of required alignment for the various garbage collector components into account when determining the maximum heap size that supports compressed oops. Using this conservative value avoids several circular dependencies in the calculation.
Reviewed-by: stefank, dholmes
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
Create G1ParGCAllocBufferContainer to contain two buffers instead of previously using one buffer, in order to hold the first priority buffer longer. Thus, when some large objects hits the value of free space left in the first priority buffer it has an alternative to fit in the second priority buffer while the first priority buffer is given more chances to try allocating smaller objects. Overall, it will improve heap space efficiency.
Reviewed-by: johnc, jmasa, brutisso
Reset the fields in ParGCAllocBuffer, that are used for accumulating values for the ResizePLAB sensors in PLABStats, to zero after flushing the values to the PLABStats fields. Flush PLABStats values only when retiring the final allocation buffers prior to disposing of a G1ParScanThreadState object, rather than when retiring every allocation buffer.
Reviewed-by: jwilhelm, jmasa, ysr
Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes
Co-authored-by: Stefan Karlsson <stefan.karlsson@oracle.com>
Co-authored-by: Mikael Gerdin <mikael.gerdin@oracle.com>
Co-authored-by: Tom Rodriguez <tom.rodriguez@oracle.com>
Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland
Add the flags G1EvacuationFailureALot flag (and supporting flags) to force trigger evacuation failures. The support flags control how often to trigger an evacuation failure and during which types of evacuation pause. This functionality is analogous to that of PromotionFailureALot for the other collectors.
Reviewed-by: brutisso
Correct the result value of G1CollectedHeap::pending_card_num(). Change the code that calculates the GC efficiency of a non-young heap region to use historical data from mixed GCs and the actual number of live bytes when predicting how long it would take to collect the region. Changes were also reviewed by Thomas Schatzl.
Reviewed-by: azeemj, brutisso
Employ PLABStats instances to record information about survivor and old PLABs, and use the recorded stats to adjust the sizes of survivor and old PLABS.
Reviewed-by: johnc, ysr
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
Revamp of the mechanism that chooses old regions for inclusion in the CSet. It simplifies the code and introduces min and max bounds on the number of old regions added to the CSet at each mixed GC to avoid pathological cases. It also ensures that when we do a mixed GC we'll always find old regions to add to the CSet (i.e., it eliminates the case where a mixed GC will collect no old regions which can happen today).
Reviewed-by: johnc, brutisso
If we try to schedule an initial-mark GC in order to explicit start a conc mark cycle and it gets pre-empted by antoher GC, we should retry the attempt as long as it's appropriate for the GC cause.
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
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
Parallelize the removal of self forwarding pointers etc. by wrapping in a HeapRegion closure, which is then wrapped inside an AbstractGangTask.
Reviewed-by: tonyp, iveresov
Introduce a flag that is set when a heap expansion attempt during a GC fails so that we do not consantly attempt to expand the heap when it's going to fail anyway. This not only prevents the excessive ergo output (which is generated when a region allocation fails) but also avoids excessive and ultimately unsuccessful expansion attempts.
Reviewed-by: jmasa, johnc
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
