src/hotspot/share/services/nmtCommon.hpp

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 * accompanied this code).
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#ifndef SHARE_SERVICES_NMTCOMMON_HPP
#define SHARE_SERVICES_NMTCOMMON_HPP

#include "memory/allocation.hpp" // for MEMFLAGS only
#include "utilities/align.hpp"
#include "utilities/globalDefinitions.hpp"

// Native memory tracking level
//
// The meaning of the different states:
//
// "unknown": pre-init phase (before parsing NMT arguments)
//
// "off":     after initialization - NMT confirmed off.
//             - nothing is tracked
//             - no malloc headers are used
//
// "summary": after initialization with NativeMemoryTracking=summary - NMT in summary mode
//             - category summaries per tag are tracked
//             - thread stacks are tracked
//             - malloc headers are used
//             - malloc call site table is allocated and used
//
// "detail":  after initialization with NativeMemoryTracking=detail - NMT in detail mode
//             - category summaries per tag are tracked
//             - malloc details per call site are tracked
//             - virtual memory mapping info is tracked
//             - thread stacks are tracked
//             - malloc headers are used
//             - malloc call site table is allocated and used
//


// Please keep relation of numerical values!
// unknown < off < summary < detail
//
enum NMT_TrackingLevel {
  NMT_unknown,
  NMT_off,
  NMT_summary,
  NMT_detail
};

// Number of stack frames to capture. This is a
// build time decision.
const int NMT_TrackingStackDepth = 4;

// A few common utilities for native memory tracking
class NMTUtil : AllStatic {
 public:
  // Check if index is a valid MEMFLAGS enum value (including mtNone)
  static inline bool flag_index_is_valid(int index) {
    return index >= 0 && index < mt_number_of_types;
  }

  // Check if flag value is a valid MEMFLAGS enum value (including mtNone)
  static inline bool flag_is_valid(MEMFLAGS flag) {
    const int index = static_cast<int>(flag);
    return flag_index_is_valid(index);
  }

  // Map memory type to index
  static inline int flag_to_index(MEMFLAGS flag) {
    assert(flag_is_valid(flag), "Invalid flag (%u)", (unsigned)flag);
    return static_cast<int>(flag);
  }

  // Map memory type to human readable name
  static const char* flag_to_name(MEMFLAGS flag) {
    return _strings[flag_to_index(flag)].human_readable;
  }

  // Map memory type to literalized enum name (e.g. "mtTest")
  static const char* flag_to_enum_name(MEMFLAGS flag) {
    return _strings[flag_to_index(flag)].enum_s;
  }

  // Map an index to memory type
  static MEMFLAGS index_to_flag(int index) {
    assert(flag_index_is_valid(index), "Invalid flag index (%d)", index);
    return static_cast<MEMFLAGS>(index);
  }

  // Memory size scale
  static const char* scale_name(size_t scale);
  static size_t scale_from_name(const char* scale);

  // Translate memory size in specified scale
  static size_t amount_in_scale(size_t amount, size_t scale) {
    return (amount + scale / 2) / scale;
  }

  // Parses the tracking level from a string. Returns NMT_unknown if
  // string is not a valid level.
  static NMT_TrackingLevel parse_tracking_level(const char* s);

  // Given a string, return associated flag. mtNone if name is invalid.
  // String can be either the human readable name or the
  // stringified enum (with or without leading "mt". In all cases, case is ignored.
  static MEMFLAGS string_to_flag(const char* name);

  // Returns textual representation of a tracking level.
  static const char* tracking_level_to_string(NMT_TrackingLevel level);

 private:
  struct S {
    const char* enum_s; // e.g. "mtNMT"
    const char* human_readable; // e.g. "Native Memory Tracking"
  };
  static S _strings[mt_number_of_types];
};


#endif // SHARE_SERVICES_NMTCOMMON_HPP