8365306: Provide OS Process Size and Libc statistic metrics to JFR

src/hotspot/os/aix/os_aix.cpp

@@ -2716,5 +2716,8 @@ void os::print_memory_mappings(char* addr, size_t bytes, outputStream* st) {}
 #if INCLUDE_JFR
 
 void os::jfr_report_memory_info() {}
+void os::jfr_report_process_size() {}
+void os::jfr_report_libc_statistics() {}
+int os::num_process_threads() { return -1; }
 
 #endif // INCLUDE_JFR

src/hotspot/os/aix/os_aix.inline.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2025, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2018 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -54,6 +54,6 @@ inline void os::map_stack_shadow_pages(address sp) {
 
 // Trim-native support, stubbed out for now, may be enabled later
 inline bool os::can_trim_native_heap() { return false; }
-inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
+inline bool os::trim_native_heap(os::size_change_t& rss_change) { return false; }
 
 #endif // OS_AIX_OS_AIX_INLINE_HPP

src/hotspot/os/bsd/os_bsd.cpp

@@ -207,20 +207,32 @@ julong os::physical_memory() {
   return Bsd::physical_memory();
 }
 
-size_t os::rss() {
-  size_t rss = 0;
 #ifdef __APPLE__
+bool os::Bsd::query_process_memory_info(os::Bsd::process_info_t* pi) {
   mach_task_basic_info info;
   mach_msg_type_number_t count = MACH_TASK_BASIC_INFO_COUNT;
-
   kern_return_t ret = task_info(mach_task_self(), MACH_TASK_BASIC_INFO,
                                 (task_info_t)&info, &count);
   if (ret == KERN_SUCCESS) {
-    rss = info.resident_size;
+    pi->vsize = info.virtual_size;
+    pi->rss = info.resident_size;
+    // We've seen that resident_size_max sometimes trails resident_size with one page.
+    // Make sure we always report size <= peak
+    pi->rssmax = MAX2(info.resident_size_max, info.resident_size);
+    return true;
   }
-#endif // __APPLE__
+  return false;
+}
+#endif
 
-  return rss;
+size_t os::rss() {
+#ifdef __APPLE__
+  os::Bsd::process_info_t info;
+  if (os::Bsd::query_process_memory_info(&info)) {
+    return info.rss;
+  }
+#endif // __APPLE__
+  return 0;
 }
 
 // Cpu architecture string
@@ -2447,32 +2459,52 @@ void os::print_memory_mappings(char* addr, size_t bytes, outputStream* st) {}
 
 #if INCLUDE_JFR
 
-void os::jfr_report_memory_info() {
-#ifdef __APPLE__
-  mach_task_basic_info info;
-  mach_msg_type_number_t count = MACH_TASK_BASIC_INFO_COUNT;
+#define JFR_WARN_ONCE(text) { \
+  static bool first_warning = true; \
+  if (first_warning) { \
+    log_warning(jfr)(text); \
+    first_warning = false; \
+  } \
+}
 
-  kern_return_t ret = task_info(mach_task_self(), MACH_TASK_BASIC_INFO, (task_info_t)&info, &count);
-  if (ret == KERN_SUCCESS) {
-    // Send the RSS JFR event
+#ifdef __APPLE__
+void os::jfr_report_memory_info() {
+  os::Bsd::process_info_t info;
+  if (os::Bsd::query_process_memory_info(&info)) {
     EventResidentSetSize event;
-    event.set_size(info.resident_size);
-    // We've seen that resident_size_max sometimes trails resident_size with one page.
-    // Make sure we always report size <= peak
-    event.set_peak(MAX2(info.resident_size_max, info.resident_size));
+    event.set_size(info.rss);
+    event.set_peak(info.rssmax);
     event.commit();
   } else {
-    // Log a warning
-    static bool first_warning = true;
-    if (first_warning) {
-      log_warning(jfr)("Error fetching RSS values: task_info failed");
-      first_warning = false;
-    }
+    JFR_WARN_ONCE("Error fetching RSS values: task_info failed");
+  }
+}
+
+void os::jfr_report_process_size() {
+  os::Bsd::process_info_t info;
+  if (os::Bsd::query_process_memory_info(&info)) {
+    EventProcessSize e;
+    e.set_vsize(info.vsize);
+    e.set_rss(info.rss);
+    e.set_rssPeak(info.rssmax);
+    e.set_rssAnon(0);
+    e.set_rssFile(0);
+    e.set_rssShmem(0);
+    e.set_committed(0);
+    e.set_pagetable(0);
+    e.set_swap(0);
+    e.commit();
+  } else {
+    JFR_WARN_ONCE("Error fetching RSS values: task_info failed");
   }
-
-#endif // __APPLE__
 }
+#else
+void os::jfr_report_memory_info() {}
+void os::jfr_report_process_size() {}
+#endif // __APPLE__
 
+void os::jfr_report_libc_statistics() {}
+int os::num_process_threads() { return -1; }
 #endif // INCLUDE_JFR
 
 bool os::pd_dll_unload(void* libhandle, char* ebuf, int ebuflen) {

src/hotspot/os/bsd/os_bsd.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2025, 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
@@ -36,6 +36,17 @@ class os::Bsd {
   // mach_absolute_time
   static mach_timebase_info_data_t _timebase_info;
   static volatile uint64_t         _max_abstime;
+
+  // Output structure for query_process_memory_info()
+  struct process_info_t {
+    // see mach_task_basic_info_data_t
+    size_t vsize;      // current virtual size
+    size_t rss;        // current resident set size
+    size_t rssmax;     // max resident set size
+  };
+
+  // Attempts to query memory information about the current process and return it in the output structure.
+  static bool query_process_memory_info(process_info_t* info);
 #endif
 
   static GrowableArray<int>* _cpu_to_node;

src/hotspot/os/bsd/os_bsd.inline.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2025, 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
@@ -57,6 +57,6 @@ inline void os::map_stack_shadow_pages(address sp) {
 
 // Trim-native support, stubbed out for now, may be enabled later
 inline bool os::can_trim_native_heap() { return false; }
-inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
+inline bool os::trim_native_heap(os::size_change_t& rss_change) { return false; }
 
 #endif // OS_BSD_OS_BSD_INLINE_HPP

src/hotspot/os/linux/os_linux.cpp

@@ -351,8 +351,8 @@ julong os::physical_memory() {
 
 size_t os::rss() {
   size_t size = 0;
-  os::Linux::meminfo_t info;
-  if (os::Linux::query_process_memory_info(&info)) {
+  os::Linux::process_info_t info;
+  if (os::Linux::query_process_info(&info)) {
     size = info.vmrss * K;
   }
   return size;
@@ -2313,13 +2313,14 @@ void os::Linux::print_system_memory_info(outputStream* st) {
                       "/sys/kernel/mm/transparent_hugepage/defrag", st);
 }
 
-bool os::Linux::query_process_memory_info(os::Linux::meminfo_t* info) {
+bool os::Linux::query_process_info(os::Linux::process_info_t* info) {
   FILE* f = os::fopen("/proc/self/status", "r");
-  const int num_values = sizeof(os::Linux::meminfo_t) / sizeof(size_t);
-  int num_found = 0;
   char buf[256];
   info->vmsize = info->vmpeak = info->vmrss = info->vmhwm = info->vmswap =
-      info->rssanon = info->rssfile = info->rssshmem = -1;
+      info->rssanon = info->rssfile = info->rssshmem = info->vmpte = -1;
+  info->threads = info->fdsize = -1;
+  constexpr int num_values = 11;
+  int num_found = 0;
   if (f != nullptr) {
     while (::fgets(buf, sizeof(buf), f) != nullptr && num_found < num_values) {
       if ( (info->vmsize == -1    && sscanf(buf, "VmSize: %zd kB", &info->vmsize) == 1) ||
@@ -2329,7 +2330,10 @@ bool os::Linux::query_process_memory_info(os::Linux::meminfo_t* info) {
            (info->vmrss == -1     && sscanf(buf, "VmRSS: %zd kB", &info->vmrss) == 1) ||
            (info->rssanon == -1   && sscanf(buf, "RssAnon: %zd kB", &info->rssanon) == 1) || // Needs Linux 4.5
            (info->rssfile == -1   && sscanf(buf, "RssFile: %zd kB", &info->rssfile) == 1) || // Needs Linux 4.5
-           (info->rssshmem == -1  && sscanf(buf, "RssShmem: %zd kB", &info->rssshmem) == 1)  // Needs Linux 4.5
+           (info->rssshmem == -1  && sscanf(buf, "RssShmem: %zd kB", &info->rssshmem) == 1) || // Needs Linux 4.5
+           (info->vmpte == -1     && sscanf(buf, "VmPTE: %zd kB", &info->vmpte) == 1) || // Needs Linux 2.6.10
+           (info->fdsize == -1    && sscanf(buf, "FDSize: %d", &info->fdsize) == 1) ||
+           (info->threads == -1   && sscanf(buf, "Threads: %d", &info->threads) == 1)
            )
       {
         num_found ++;
@@ -2375,8 +2379,8 @@ void os::Linux::print_process_memory_info(outputStream* st) {
 
   // Print virtual and resident set size; peak values; swap; and for
   //  rss its components if the kernel is recent enough.
-  meminfo_t info;
-  if (query_process_memory_info(&info)) {
+  process_info_t info;
+  if (query_process_info(&info)) {
     st->print_cr("Virtual Size: %zdK (peak: %zdK)", info.vmsize, info.vmpeak);
     st->print("Resident Set Size: %zdK (peak: %zdK)", info.vmrss, info.vmhwm);
     if (info.rssanon != -1) { // requires kernel >= 4.5
@@ -2660,26 +2664,73 @@ void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
 
 #if INCLUDE_JFR
 
+#define JFR_WARN_ONCE(text) { \
+  static bool first_warning = true; \
+  if (first_warning) { \
+    log_warning(jfr)(text); \
+    first_warning = false; \
+  } \
+}
+
 void os::jfr_report_memory_info() {
-  os::Linux::meminfo_t info;
-  if (os::Linux::query_process_memory_info(&info)) {
+  os::Linux::process_info_t info;
+  if (os::Linux::query_process_info(&info)) {
     // Send the RSS JFR event
     EventResidentSetSize event;
     event.set_size(info.vmrss * K);
     event.set_peak(info.vmhwm * K);
     event.commit();
   } else {
-    // Log a warning
-    static bool first_warning = true;
-    if (first_warning) {
-      log_warning(jfr)("Error fetching RSS values: query_process_memory_info failed");
-      first_warning = false;
-    }
+    JFR_WARN_ONCE("Error fetching RSS values: query_process_memory_info failed");
+  }
+}
+
+void os::jfr_report_process_size() {
+  os::Linux::process_info_t info;
+  if (os::Linux::query_process_info(&info)) {
+    EventProcessSize e;
+    e.set_vsize(info.vmsize * K);
+    e.set_rss(info.vmrss * K);
+    e.set_rssPeak(info.vmhwm * K);
+    e.set_rssAnon(info.rssanon * K);
+    e.set_rssFile(info.rssfile * K);
+    e.set_rssShmem(info.rssshmem * K);
+    e.set_committed(0);
+    e.set_pagetable(info.vmpte * K);
+    e.set_swap(info.vmswap * K);
+    e.commit();
+  } else {
+    JFR_WARN_ONCE("Error fetching ProcessSize: query_process_memory_info failed");
+  }
+}
+
+void os::jfr_report_libc_statistics() {
+#ifdef __GLIBC__
+  bool might_have_wrapped = false;
+  os::Linux::glibc_mallinfo mi;
+  os::Linux::get_mallinfo(&mi, &might_have_wrapped);
+  if (!might_have_wrapped) {
+    EventLibcStatistics e;
+    e.set_mallocOutstanding(mi.uordblks + mi.hblkhd);
+    e.set_mallocRetained(mi.fordblks);
+    e.set_trims(mi.num_trims);
+    e.commit();
+  } else {
+    JFR_WARN_ONCE("Error libc statistics: too old glibc");
   }
+#endif
 }
 
 #endif // INCLUDE_JFR
 
+int os::num_process_threads() {
+  os::Linux::process_info_t info;
+  if (os::Linux::query_process_info(&info)) {
+    return info.threads; // These are OS threads
+  }
+  return -1;
+}
+
 #if defined(AMD64) || defined(IA32) || defined(X32)
 const char* search_string = "model name";
 #elif defined(M68K)
@@ -4872,8 +4923,9 @@ int os::open(const char *path, int oflag, int mode) {
   // All file descriptors that are opened in the Java process and not
   // specifically destined for a subprocess should have the close-on-exec
   // flag set.  If we don't set it, then careless 3rd party native code
-  // might fork and exec without closing all appropriate file descriptors,
-  // and this in turn might:
+  // might fork and exec without closing all appropriate file descriptors
+  // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
+  // turn might:
   //
   // - cause end-of-file to fail to be detected on some file
   //   descriptors, resulting in mysterious hangs, or
@@ -5308,6 +5360,7 @@ void os::print_memory_mappings(char* addr, size_t bytes, outputStream* st) {
 }
 
 #ifdef __GLIBC__
+static unsigned g_num_trims = 0;
 void os::Linux::get_mallinfo(glibc_mallinfo* out, bool* might_have_wrapped) {
   if (g_mallinfo2) {
     new_mallinfo mi = g_mallinfo2();
@@ -5321,6 +5374,7 @@ void os::Linux::get_mallinfo(glibc_mallinfo* out, bool* might_have_wrapped) {
     out->uordblks = mi.uordblks;
     out->fordblks = mi.fordblks;
     out->keepcost =  mi.keepcost;
+    out->num_trims = g_num_trims;
     *might_have_wrapped = false;
   } else if (g_mallinfo) {
     old_mallinfo mi = g_mallinfo();
@@ -5335,6 +5389,7 @@ void os::Linux::get_mallinfo(glibc_mallinfo* out, bool* might_have_wrapped) {
     out->uordblks = (size_t)(unsigned)mi.uordblks;
     out->fordblks = (size_t)(unsigned)mi.fordblks;
     out->keepcost = (size_t)(unsigned)mi.keepcost;
+    out->num_trims = g_num_trims;
     *might_have_wrapped = NOT_LP64(false) LP64_ONLY(true);
   } else {
     // We should have either mallinfo or mallinfo2
@@ -5350,29 +5405,27 @@ int os::Linux::malloc_info(FILE* stream) {
 }
 #endif // __GLIBC__
 
-bool os::trim_native_heap(os::size_change_t* rss_change) {
+bool os::trim_native_heap(os::size_change_t& rss_change) {
 #ifdef __GLIBC__
-  os::Linux::meminfo_t info1;
-  os::Linux::meminfo_t info2;
+  os::Linux::process_info_t info1;
+  os::Linux::process_info_t info2;
 
-  bool have_info1 = rss_change != nullptr &&
-                    os::Linux::query_process_memory_info(&info1);
+  bool have_info1 = os::Linux::query_process_info(&info1);
   ::malloc_trim(0);
-  bool have_info2 = rss_change != nullptr && have_info1 &&
-                    os::Linux::query_process_memory_info(&info2);
+  bool have_info2 = have_info1 && os::Linux::query_process_info(&info2);
   ssize_t delta = (ssize_t) -1;
-  if (rss_change != nullptr) {
-    if (have_info1 && have_info2 &&
-        info1.vmrss != -1 && info2.vmrss != -1 &&
-        info1.vmswap != -1 && info2.vmswap != -1) {
-      // Note: query_process_memory_info returns values in K
-      rss_change->before = (info1.vmrss + info1.vmswap) * K;
-      rss_change->after = (info2.vmrss + info2.vmswap) * K;
-    } else {
-      rss_change->after = rss_change->before = SIZE_MAX;
-    }
+  if (have_info1 && have_info2 &&
+      info1.vmrss != -1 && info2.vmrss != -1 &&
+      info1.vmswap != -1 && info2.vmswap != -1) {
+    // Note: query_process_memory_info returns values in K
+    rss_change.before = (info1.vmrss + info1.vmswap) * K;
+    rss_change.after = (info2.vmrss + info2.vmswap) * K;
+  } else {
+    rss_change.after = rss_change.before = SIZE_MAX;
   }
 
+  g_num_trims ++;
+
   return true;
 #else
   return false; // musl