# HG changeset patch
# User stuefe
# Date 1562740225 -7200
#      Wed Jul 10 08:30:25 2019 +0200
# Node ID a3c6b22da80181ead9d18bb2f8dab471e6e9ca2d
# Parent  8bff79035c7e4fe24bfb7bfa63cc8c9f0b9f2c3b
[mq]: 8227254-nestegg-buffer

diff -r 8bff79035c7e -r a3c6b22da801 src/hotspot/share/runtime/globals.hpp
--- a/src/hotspot/share/runtime/globals.hpp	Tue Jul 09 17:00:34 2019 +0200
+++ b/src/hotspot/share/runtime/globals.hpp	Wed Jul 10 08:30:25 2019 +0200
@@ -525,6 +525,10 @@
           "error log in case of a crash.")                                  \
           range(0, (uint64_t)max_jlong/1000)                                \
                                                                             \
+  diagnostic(intx, NesteggSize, 0,                                          \
+          "A preallocated buffer which is used in case a native OOM "       \
+          "to improve error reporting.")                                    \
+                                                                            \
   product_pd(bool, UseOSErrorReporting,                                     \
           "Let VM fatal error propagate to the OS (ie. WER on Windows)")    \
                                                                             \
diff -r 8bff79035c7e -r a3c6b22da801 src/hotspot/share/utilities/vmError.cpp
--- a/src/hotspot/share/utilities/vmError.cpp	Tue Jul 09 17:00:34 2019 +0200
+++ b/src/hotspot/share/utilities/vmError.cpp	Wed Jul 10 08:30:25 2019 +0200
@@ -1375,6 +1375,13 @@
     _error_reported = true;
 
     reporting_started();
+
+    // In case this is a native OOM, release the nestegg buffer - if there is one -
+    // to increase chance of error reporting functioning.
+    if (_id == (int)OOM_MALLOC_ERROR || _id == (int)OOM_MMAP_ERROR) {
+      release_nestegg();
+    }
+
     if (!TestUnresponsiveErrorHandler) {
       // Record reporting_start_time unless we're running the
       // TestUnresponsiveErrorHandler test. For that test we record
@@ -1723,6 +1730,16 @@
 
 }
 
+static void* nestegg = NULL;
+void VMError::prepare_nestegg() {
+  nestegg = os::malloc(NesteggSize, mtInternal);
+}
+
+void VMError::release_nestegg() {
+  os::free(nestegg);
+  nestegg = NULL;
+}
+
 #ifndef PRODUCT
 #if defined(__SUNPRO_CC) && __SUNPRO_CC >= 0x5140
 #pragma error_messages(off, SEC_NULL_PTR_DEREF)
diff -r 8bff79035c7e -r a3c6b22da801 src/hotspot/share/utilities/vmError.hpp
--- a/src/hotspot/share/utilities/vmError.hpp	Tue Jul 09 17:00:34 2019 +0200
+++ b/src/hotspot/share/utilities/vmError.hpp	Wed Jul 10 08:30:25 2019 +0200
@@ -195,5 +195,9 @@
   // returns an address which is guaranteed to generate a SIGSEGV on read,
   // for test purposes, which is not NULL and contains bits in every word
   static void* get_segfault_address();
+
+  static void prepare_nestegg();
+  static void release_nestegg();
+
 };
 #endif // SHARE_UTILITIES_VMERROR_HPP