516 pointer_delta(aligned_upper_new_high, upper_high(), sizeof(char));
517 }
518
519 // Check contiguity.
520 assert(low_boundary() <= lower_high() &&
521 lower_high() <= lower_high_boundary(),
522 "high address must be contained within the region");
523 assert(lower_high_boundary() <= middle_high() &&
524 middle_high() <= middle_high_boundary(),
525 "high address must be contained within the region");
526 assert(middle_high_boundary() <= upper_high() &&
527 upper_high() <= upper_high_boundary(),
528 "high address must be contained within the region");
529
530 // Commit regions
531 if (lower_needs > 0) {
532 assert(low_boundary() <= lower_high() &&
533 lower_high() + lower_needs <= lower_high_boundary(),
534 "must not expand beyond region");
535 if (!os::commit_memory(lower_high(), lower_needs, _executable)) {
536 debug_only(warning("os::commit_memory failed"));
537 return false;
538 } else {
539 _lower_high += lower_needs;
540 }
541 }
542 if (middle_needs > 0) {
543 assert(lower_high_boundary() <= middle_high() &&
544 middle_high() + middle_needs <= middle_high_boundary(),
545 "must not expand beyond region");
546 if (!os::commit_memory(middle_high(), middle_needs, middle_alignment(),
547 _executable)) {
548 debug_only(warning("os::commit_memory failed"));
549 return false;
550 }
551 _middle_high += middle_needs;
552 }
553 if (upper_needs > 0) {
554 assert(middle_high_boundary() <= upper_high() &&
555 upper_high() + upper_needs <= upper_high_boundary(),
556 "must not expand beyond region");
557 if (!os::commit_memory(upper_high(), upper_needs, _executable)) {
558 debug_only(warning("os::commit_memory failed"));
559 return false;
560 } else {
561 _upper_high += upper_needs;
562 }
563 }
564
565 if (pre_touch || AlwaysPreTouch) {
566 int vm_ps = os::vm_page_size();
567 for (char* curr = previous_high;
568 curr < unaligned_new_high;
569 curr += vm_ps) {
570 // Note the use of a write here; originally we tried just a read, but
571 // since the value read was unused, the optimizer removed the read.
572 // If we ever have a concurrent touchahead thread, we'll want to use
573 // a read, to avoid the potential of overwriting data (if a mutator
574 // thread beats the touchahead thread to a page). There are various
575 // ways of making sure this read is not optimized away: for example,
576 // generating the code for a read procedure at runtime.
577 *curr = 0;
578 }
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516 pointer_delta(aligned_upper_new_high, upper_high(), sizeof(char));
517 }
518
519 // Check contiguity.
520 assert(low_boundary() <= lower_high() &&
521 lower_high() <= lower_high_boundary(),
522 "high address must be contained within the region");
523 assert(lower_high_boundary() <= middle_high() &&
524 middle_high() <= middle_high_boundary(),
525 "high address must be contained within the region");
526 assert(middle_high_boundary() <= upper_high() &&
527 upper_high() <= upper_high_boundary(),
528 "high address must be contained within the region");
529
530 // Commit regions
531 if (lower_needs > 0) {
532 assert(low_boundary() <= lower_high() &&
533 lower_high() + lower_needs <= lower_high_boundary(),
534 "must not expand beyond region");
535 if (!os::commit_memory(lower_high(), lower_needs, _executable)) {
536 debug_only(warning("INFO: os::commit_memory(" PTR_FORMAT
537 ", lower_needs=" SIZE_FORMAT ", %d) failed",
538 lower_high(), lower_needs, _executable);)
539 return false;
540 } else {
541 _lower_high += lower_needs;
542 }
543 }
544 if (middle_needs > 0) {
545 assert(lower_high_boundary() <= middle_high() &&
546 middle_high() + middle_needs <= middle_high_boundary(),
547 "must not expand beyond region");
548 if (!os::commit_memory(middle_high(), middle_needs, middle_alignment(),
549 _executable)) {
550 debug_only(warning("INFO: os::commit_memory(" PTR_FORMAT
551 ", middle_needs=" SIZE_FORMAT ", " SIZE_FORMAT
552 ", %d) failed", middle_high(), middle_needs,
553 middle_alignment(), _executable);)
554 return false;
555 }
556 _middle_high += middle_needs;
557 }
558 if (upper_needs > 0) {
559 assert(middle_high_boundary() <= upper_high() &&
560 upper_high() + upper_needs <= upper_high_boundary(),
561 "must not expand beyond region");
562 if (!os::commit_memory(upper_high(), upper_needs, _executable)) {
563 debug_only(warning("INFO: os::commit_memory(" PTR_FORMAT
564 ", upper_needs=" SIZE_FORMAT ", %d) failed",
565 upper_high(), upper_needs, _executable);)
566 return false;
567 } else {
568 _upper_high += upper_needs;
569 }
570 }
571
572 if (pre_touch || AlwaysPreTouch) {
573 int vm_ps = os::vm_page_size();
574 for (char* curr = previous_high;
575 curr < unaligned_new_high;
576 curr += vm_ps) {
577 // Note the use of a write here; originally we tried just a read, but
578 // since the value read was unused, the optimizer removed the read.
579 // If we ever have a concurrent touchahead thread, we'll want to use
580 // a read, to avoid the potential of overwriting data (if a mutator
581 // thread beats the touchahead thread to a page). There are various
582 // ways of making sure this read is not optimized away: for example,
583 // generating the code for a read procedure at runtime.
584 *curr = 0;
585 }
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