src/hotspot/os_cpu/linux_x86/gc/z/zPhysicalMemoryBacking_linux_x86.cpp

*** 1,7 ****
  /*
!  * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 23,32 ****
--- 23,33 ----
  
  #include "precompiled.hpp"
  #include "gc/z/zAddress.inline.hpp"
  #include "gc/z/zBackingFile_linux_x86.hpp"
  #include "gc/z/zErrno.hpp"
+ #include "gc/z/zGlobals.hpp"
  #include "gc/z/zLargePages.inline.hpp"
  #include "gc/z/zMemory.hpp"
  #include "gc/z/zNUMA.hpp"
  #include "gc/z/zPhysicalMemory.inline.hpp"
  #include "gc/z/zPhysicalMemoryBacking_linux_x86.hpp"
*** 45,71 ****
  #endif
  
  // Proc file entry for max map mount
  #define ZFILENAME_PROC_MAX_MAP_COUNT         "/proc/sys/vm/max_map_count"
  
! ZPhysicalMemoryBacking::ZPhysicalMemoryBacking(size_t max_capacity, size_t granule_size) :
      _manager(),
!     _file(),
!     _granule_size(granule_size) {
  
    if (!_file.is_initialized()) {
      return;
    }
  
    // Check and warn if max map count is too low
!   check_max_map_count(max_capacity, granule_size);
  
    // Check and warn if available space on filesystem is too low
    check_available_space_on_filesystem(max_capacity);
  }
  
! void ZPhysicalMemoryBacking::check_max_map_count(size_t max_capacity, size_t granule_size) const {
    const char* const filename = ZFILENAME_PROC_MAX_MAP_COUNT;
    FILE* const file = fopen(filename, "r");
    if (file == NULL) {
      // Failed to open file, skip check
      log_debug(gc, init)("Failed to open %s", filename);
--- 46,71 ----
  #endif
  
  // Proc file entry for max map mount
  #define ZFILENAME_PROC_MAX_MAP_COUNT         "/proc/sys/vm/max_map_count"
  
! ZPhysicalMemoryBacking::ZPhysicalMemoryBacking(size_t max_capacity) :
      _manager(),
!     _file() {
  
    if (!_file.is_initialized()) {
      return;
    }
  
    // Check and warn if max map count is too low
!   check_max_map_count(max_capacity);
  
    // Check and warn if available space on filesystem is too low
    check_available_space_on_filesystem(max_capacity);
  }
  
! void ZPhysicalMemoryBacking::check_max_map_count(size_t max_capacity) const {
    const char* const filename = ZFILENAME_PROC_MAX_MAP_COUNT;
    FILE* const file = fopen(filename, "r");
    if (file == NULL) {
      // Failed to open file, skip check
      log_debug(gc, init)("Failed to open %s", filename);
*** 84,94 ****
    // The required max map count is impossible to calculate exactly since subsystems
    // other than ZGC are also creating memory mappings, and we have no control over that.
    // However, ZGC tends to create the most mappings and dominate the total count.
    // In the worst cases, ZGC will map each granule three times, i.e. once per heap view.
    // We speculate that we need another 20% to allow for non-ZGC subsystems to map memory.
!   const size_t required_max_map_count = (max_capacity / granule_size) * 3 * 1.2;
    if (actual_max_map_count < required_max_map_count) {
      log_warning(gc, init)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
      log_warning(gc, init)("The system limit on number of memory mappings per process might be too low "
                            "for the given");
      log_warning(gc, init)("max Java heap size (" SIZE_FORMAT "M). Please adjust %s to allow for at",
--- 84,94 ----
    // The required max map count is impossible to calculate exactly since subsystems
    // other than ZGC are also creating memory mappings, and we have no control over that.
    // However, ZGC tends to create the most mappings and dominate the total count.
    // In the worst cases, ZGC will map each granule three times, i.e. once per heap view.
    // We speculate that we need another 20% to allow for non-ZGC subsystems to map memory.
!   const size_t required_max_map_count = (max_capacity / ZGranuleSize) * 3 * 1.2;
    if (actual_max_map_count < required_max_map_count) {
      log_warning(gc, init)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
      log_warning(gc, init)("The system limit on number of memory mappings per process might be too low "
                            "for the given");
      log_warning(gc, init)("max Java heap size (" SIZE_FORMAT "M). Please adjust %s to allow for at",
*** 133,161 ****
  }
  
  size_t ZPhysicalMemoryBacking::try_expand(size_t old_capacity, size_t new_capacity) {
    assert(old_capacity < new_capacity, "Invalid old/new capacity");
  
!   const size_t capacity = _file.try_expand(old_capacity, new_capacity - old_capacity, _granule_size);
    if (capacity > old_capacity) {
      // Add expanded capacity to free list
      _manager.free(old_capacity, capacity - old_capacity);
    }
  
    return capacity;
  }
  
  ZPhysicalMemory ZPhysicalMemoryBacking::alloc(size_t size) {
!   assert(is_aligned(size, _granule_size), "Invalid size");
  
    ZPhysicalMemory pmem;
  
    // Allocate segments
!   for (size_t allocated = 0; allocated < size; allocated += _granule_size) {
!     const uintptr_t start = _manager.alloc_from_front(_granule_size);
      assert(start != UINTPTR_MAX, "Allocation should never fail");
!     pmem.add_segment(ZPhysicalMemorySegment(start, _granule_size));
    }
  
    return pmem;
  }
  
--- 133,161 ----
  }
  
  size_t ZPhysicalMemoryBacking::try_expand(size_t old_capacity, size_t new_capacity) {
    assert(old_capacity < new_capacity, "Invalid old/new capacity");
  
!   const size_t capacity = _file.try_expand(old_capacity, new_capacity - old_capacity, ZGranuleSize);
    if (capacity > old_capacity) {
      // Add expanded capacity to free list
      _manager.free(old_capacity, capacity - old_capacity);
    }
  
    return capacity;
  }
  
  ZPhysicalMemory ZPhysicalMemoryBacking::alloc(size_t size) {
!   assert(is_aligned(size, ZGranuleSize), "Invalid size");
  
    ZPhysicalMemory pmem;
  
    // Allocate segments
!   for (size_t allocated = 0; allocated < size; allocated += ZGranuleSize) {
!     const uintptr_t start = _manager.alloc_from_front(ZGranuleSize);
      assert(start != UINTPTR_MAX, "Allocation should never fail");
!     pmem.add_segment(ZPhysicalMemorySegment(start, ZGranuleSize));
    }
  
    return pmem;
  }