src/hotspot/os/linux/os_linux.cpp

*** 126,137 ****
  #define MAX_SECS 100000000
  
  // for timer info max values which include all bits
  #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
  
! #define LARGEPAGES_BIT (1 << 6)
! #define DAX_SHARED_BIT (1 << 8)
  ////////////////////////////////////////////////////////////////////////////////
  // global variables
  julong os::Linux::_physical_memory = 0;
  
  address   os::Linux::_initial_thread_stack_bottom = NULL;
--- 126,141 ----
  #define MAX_SECS 100000000
  
  // for timer info max values which include all bits
  #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
  
! enum CoredumpFilterBit {
!   FILE_BACKED_PVT_BIT = 1 << 2,
!   LARGEPAGES_BIT = 1 << 6,
!   DAX_SHARED_BIT = 1 << 8
! };
! 
  ////////////////////////////////////////////////////////////////////////////////
  // global variables
  julong os::Linux::_physical_memory = 0;
  
  address   os::Linux::_initial_thread_stack_bottom = NULL;
*** 3397,3431 ****
  // - (bit 5) hugetlb private memory
  // - (bit 6) hugetlb shared memory
  // - (bit 7) dax private memory
  // - (bit 8) dax shared memory
  //
! static void set_coredump_filter(bool largepages, bool dax_shared) {
    FILE *f;
    long cdm;
-   bool filter_changed = false;
  
    if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
      return;
    }
  
    if (fscanf(f, "%lx", &cdm) != 1) {
      fclose(f);
      return;
    }
  
    rewind(f);
  
!   if (largepages && (cdm & LARGEPAGES_BIT) == 0) {
!     cdm |= LARGEPAGES_BIT;
!     filter_changed = true;
!   }
!   if (dax_shared && (cdm & DAX_SHARED_BIT) == 0) {
!     cdm |= DAX_SHARED_BIT;
!     filter_changed = true;
!   }
!   if (filter_changed) {
      fprintf(f, "%#lx", cdm);
    }
  
    fclose(f);
  }
--- 3401,3428 ----
  // - (bit 5) hugetlb private memory
  // - (bit 6) hugetlb shared memory
  // - (bit 7) dax private memory
  // - (bit 8) dax shared memory
  //
! static void set_coredump_filter(CoredumpFilterBit bit) {
    FILE *f;
    long cdm;
  
    if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
      return;
    }
  
    if (fscanf(f, "%lx", &cdm) != 1) {
      fclose(f);
      return;
    }
  
+   long saved_cdm = cdm;
    rewind(f);
+   cdm |= bit;
  
!   if (cdm != saved_cdm) {
      fprintf(f, "%#lx", cdm);
    }
  
    fclose(f);
  }
*** 3560,3570 ****
    }
  
    size_t large_page_size = Linux::setup_large_page_size();
    UseLargePages          = Linux::setup_large_page_type(large_page_size);
  
!   set_coredump_filter(true /*largepages*/, false /*dax_shared*/);
  }
  
  #ifndef SHM_HUGETLB
    #define SHM_HUGETLB 04000
  #endif
--- 3557,3567 ----
    }
  
    size_t large_page_size = Linux::setup_large_page_size();
    UseLargePages          = Linux::setup_large_page_type(large_page_size);
  
!   set_coredump_filter(LARGEPAGES_BIT);
  }
  
  #ifndef SHM_HUGETLB
    #define SHM_HUGETLB 04000
  #endif
*** 5064,5075 ****
  
    // initialize thread priority policy
    prio_init();
  
    if (!FLAG_IS_DEFAULT(AllocateHeapAt)) {
!     set_coredump_filter(false /*largepages*/, true /*dax_shared*/);
    }
    return JNI_OK;
  }
  
  // Mark the polling page as unreadable
  void os::make_polling_page_unreadable(void) {
--- 5061,5077 ----
  
    // initialize thread priority policy
    prio_init();
  
    if (!FLAG_IS_DEFAULT(AllocateHeapAt)) {
!     set_coredump_filter(DAX_SHARED_BIT);
    }
+ 
+   if (UseSharedSpaces) {
+     set_coredump_filter(FILE_BACKED_PVT_BIT);
+   }
+ 
    return JNI_OK;
  }
  
  // Mark the polling page as unreadable
  void os::make_polling_page_unreadable(void) {