Added a new API to provide memory information that GC records. This (#17326)

is to be used by BCL for deciding when to trim memory usage in pooling code

8 files changed, 114 insertions, 7 deletions

diff --git a/src/gc/gc.cpp b/src/gc/gc.cpp
index a23edb9dff..ef9058e6ab 100644
--- a/src/gc/gc.cpp
+++ b/src/gc/gc.cpp
@@ -2467,13 +2467,19 @@ double       gc_heap::short_plugs_pad_ratio = 0;
 size_t      gc_heap::youngest_gen_desired_th;
 #endif //BIT64
 
-uint64_t    gc_heap::mem_one_percent;
+uint32_t    gc_heap::last_gc_memory_load = 0;
 
-uint32_t    gc_heap::high_memory_load_th;
+size_t      gc_heap::last_gc_heap_size = 0;
 
-uint64_t    gc_heap::total_physical_mem;
+size_t      gc_heap::last_gc_fragmentation = 0;
 
-uint64_t    gc_heap::entry_available_physical_mem;
+uint64_t    gc_heap::mem_one_percent = 0;
+
+uint32_t    gc_heap::high_memory_load_th = 0;
+
+uint64_t    gc_heap::total_physical_mem = 0;
+
+uint64_t    gc_heap::entry_available_physical_mem = 0;
 
 #ifdef BACKGROUND_GC
 GCEvent     gc_heap::bgc_start_event;
@@ -5755,9 +5761,8 @@ void gc_mechanisms::init_mechanisms()
     allocations_allowed = TRUE;
 #endif //BACKGROUND_GC
 
-#ifdef BIT64
     entry_memory_load = 0;
-#endif // BIT64
+    exit_memory_load = 0;
 
 #ifdef STRESS_HEAP
     stress_induced = FALSE;
@@ -19096,6 +19101,28 @@ size_t gc_heap::get_total_heap_size()
     return total_heap_size;
 }
 
+size_t gc_heap::get_total_fragmentation()
+{
+    size_t total_fragmentation = 0;
+
+#ifdef MULTIPLE_HEAPS
+    for (int i = 0; i < gc_heap::n_heaps; i++)
+    {
+        gc_heap* hp = gc_heap::g_heaps[i];
+#else //MULTIPLE_HEAPS
+    {
+        gc_heap* hp = pGenGCHeap;
+#endif //MULTIPLE_HEAPS
+        for (int i = 0; i <= (max_generation + 1); i++)
+        {
+            generation* gen = hp->generation_of (i);
+            total_fragmentation += (generation_free_list_space (gen) + generation_free_obj_space (gen));
+        }
+    }
+
+    return total_fragmentation;
+}
+
 size_t gc_heap::committed_size()
 {
     generation* gen = generation_of (max_generation);
@@ -29663,8 +29690,11 @@ size_t gc_heap::desired_new_allocation (dynamic_data* dd,
             }
             else //large object heap
             {
+                uint32_t memory_load = 0;
                 uint64_t available_physical = 0;
-                get_memory_info (NULL, &available_physical);
+                get_memory_info (&memory_load, &available_physical);
+                if (heap_number == 0)
+                    settings.exit_memory_load = memory_load;
                 if (available_physical > 1024*1024)
                     available_physical -= 1024*1024;
 
@@ -29899,6 +29929,7 @@ size_t gc_heap::joined_youngest_desired (size_t new_allocation)
         {
             uint32_t memory_load = 0;
             get_memory_info (&memory_load);
+            settings.exit_memory_load = memory_load;
             dprintf (2, ("Current emory load: %d", memory_load));
 
             size_t final_total = 
@@ -34882,6 +34913,14 @@ void gc_heap::do_post_gc()
         settings.condemned_generation,
         (settings.concurrent ? "BGC" : "GC")));
 
+    if (settings.exit_memory_load != 0)
+        last_gc_memory_load = settings.exit_memory_load;
+    else if (settings.entry_memory_load != 0)
+        last_gc_memory_load = settings.entry_memory_load;
+
+    last_gc_heap_size = get_total_heap_size();
+    last_gc_fragmentation = get_total_fragmentation();
+
     GCHeap::UpdatePostGCCounters();
 #ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
     //if (g_fEnableARM)
@@ -35266,6 +35305,19 @@ unsigned int GCHeap::GetCondemnedGeneration()
     return gc_heap::settings.condemned_generation;
 }
 
+void GCHeap::GetMemoryInfo(uint32_t* highMemLoadThreshold, 
+                           uint64_t* totalPhysicalMem, 
+                           uint32_t* lastRecordedMemLoad,
+                           size_t* lastRecordedHeapSize,
+                           size_t* lastRecordedFragmentation)
+{
+    *highMemLoadThreshold = gc_heap::high_memory_load_th;
+    *totalPhysicalMem = gc_heap::total_physical_mem;
+    *lastRecordedMemLoad = gc_heap::last_gc_memory_load;
+    *lastRecordedHeapSize = gc_heap::last_gc_heap_size;
+    *lastRecordedFragmentation = gc_heap::last_gc_fragmentation;
+}
+
 int GCHeap::GetGcLatencyMode()
 {
     return (int)(pGenGCHeap->settings.pause_mode);
diff --git a/src/gc/gcimpl.h b/src/gc/gcimpl.h
index 261e26e9aa..54aee1a2ed 100644
--- a/src/gc/gcimpl.h
+++ b/src/gc/gcimpl.h
@@ -168,6 +168,12 @@ public:
 
     unsigned GetCondemnedGeneration();
 
+    void GetMemoryInfo(uint32_t* highMemLoadThreshold, 
+                       uint64_t* totalPhysicalMem, 
+                       uint32_t* lastRecordedMemLoad,
+                       size_t* lastRecordedHeapSize,
+                       size_t* lastRecordedFragmentation);
+
     int GetGcLatencyMode();
     int SetGcLatencyMode(int newLatencyMode);
 
diff --git a/src/gc/gcinterface.h b/src/gc/gcinterface.h
index c7c6424d00..d532c8a13a 100644
--- a/src/gc/gcinterface.h
+++ b/src/gc/gcinterface.h
@@ -608,6 +608,20 @@ public:
     ===========================================================================
     */
 
+    // Gets memory related information -
+    // highMemLoadThreshold - physical memory load (in percentage) when GC will start to 
+    // react aggressively to reclaim memory.
+    // totalPhysicalMem - the total amount of phyiscal memory available on the machine and the memory
+    // limit set on the container if running in a container.
+    // lastRecordedMemLoad - physical memory load in percentage recorded in the last GC
+    // lastRecordedHeapSize - total managed heap size recorded in the last GC
+    // lastRecordedFragmentation - total fragmentation in the managed heap recorded in the last GC
+    virtual void GetMemoryInfo(uint32_t* highMemLoadThreshold, 
+                               uint64_t* totalPhysicalMem, 
+                               uint32_t* lastRecordedMemLoad,
+                               size_t* lastRecordedHeapSize,
+                               size_t* lastRecordedFragmentation) = 0;
+
     // Gets the current GC latency mode.
     virtual int GetGcLatencyMode() = 0;
 
diff --git a/src/gc/gcpriv.h b/src/gc/gcpriv.h
index 2c66acef4a..90717420ce 100644
--- a/src/gc/gcpriv.h
+++ b/src/gc/gcpriv.h
@@ -489,7 +489,9 @@ public:
     BOOL stress_induced;
 #endif // STRESS_HEAP
 
+    // These are opportunistically set
     uint32_t entry_memory_load;
+    uint32_t exit_memory_load;
 
     void init_mechanisms(); //for each GC
     void first_init(); // for the life of the EE
@@ -2479,6 +2481,8 @@ protected:
     size_t get_total_heap_size ();
     PER_HEAP_ISOLATED
     size_t get_total_committed_size();
+    PER_HEAP_ISOLATED
+    size_t get_total_fragmentation();
 
     PER_HEAP_ISOLATED
     void get_memory_info (uint32_t* memory_load, 
@@ -2969,6 +2973,15 @@ public:
 #endif //BIT64
 
     PER_HEAP_ISOLATED
+    uint32_t last_gc_memory_load;
+
+    PER_HEAP_ISOLATED
+    size_t last_gc_heap_size;
+
+    PER_HEAP_ISOLATED
+    size_t last_gc_fragmentation;
+
+    PER_HEAP_ISOLATED
     uint32_t high_memory_load_th;
 
     PER_HEAP_ISOLATED
diff --git a/src/mscorlib/src/System/GC.cs b/src/mscorlib/src/System/GC.cs
index 7119302e27..848141f006 100644
--- a/src/mscorlib/src/System/GC.cs
+++ b/src/mscorlib/src/System/GC.cs
@@ -66,6 +66,14 @@ namespace System
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
         internal static extern int SetGCLatencyMode(int newLatencyMode);
 
+        [MethodImplAttribute(MethodImplOptions.InternalCall)]
+        internal static extern void GetMemoryInfo(out uint highMemLoadThreshold,
+                                                  out ulong totalPhysicalMem,
+                                                  out uint lastRecordedMemLoad,
+                                                  // The next two are size_t
+                                                  out UIntPtr lastRecordedHeapSize,
+                                                  out UIntPtr lastRecordedFragmentation);
+
         [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)]
         internal static extern int _StartNoGCRegion(long totalSize, bool lohSizeKnown, long lohSize, bool disallowFullBlockingGC);
 
diff --git a/src/vm/comutilnative.cpp b/src/vm/comutilnative.cpp
index 48efc11904..d564f9acd8 100644
--- a/src/vm/comutilnative.cpp
+++ b/src/vm/comutilnative.cpp
@@ -922,6 +922,18 @@ UINT64   GCInterface::m_remPressure[NEW_PRESSURE_COUNT] = {0, 0, 0, 0};   // his
 // (m_iteration % NEW_PRESSURE_COUNT) is used as an index into m_addPressure and m_remPressure
 UINT     GCInterface::m_iteration = 0;
 
+FCIMPL5(void, GCInterface::GetMemoryInfo, UINT32* highMemLoadThreshold, UINT64* totalPhysicalMem, UINT32* lastRecordedMemLoad, size_t* lastRecordedHeapSize, size_t* lastRecordedFragmentation)
+{
+    FCALL_CONTRACT;
+
+    FC_GC_POLL_NOT_NEEDED();
+    
+    return GCHeapUtilities::GetGCHeap()->GetMemoryInfo(highMemLoadThreshold, totalPhysicalMem, 
+                                                       lastRecordedMemLoad, 
+                                                       lastRecordedHeapSize, lastRecordedFragmentation);
+}
+FCIMPLEND
+
 FCIMPL0(int, GCInterface::GetGcLatencyMode)
 {
     FCALL_CONTRACT;
diff --git a/src/vm/comutilnative.h b/src/vm/comutilnative.h
index 3e63a0479c..c604811c9e 100644
--- a/src/vm/comutilnative.h
+++ b/src/vm/comutilnative.h
@@ -111,6 +111,7 @@ public:
     static FORCEINLINE UINT64 InterlockedAdd(UINT64 *pAugend, UINT64 addend);
     static FORCEINLINE UINT64 InterlockedSub(UINT64 *pMinuend, UINT64 subtrahend);
 
+    static FCDECL5(void,    GetMemoryInfo, UINT32* highMemLoadThreshold, UINT64* totalPhysicalMem, UINT32* lastRecordedMemLoad, size_t* lastRecordedHeapSize, size_t* lastRecordedFragmentation);
     static FCDECL0(int,     GetGcLatencyMode);
     static FCDECL1(int,     SetGcLatencyMode, int newLatencyMode);
     static FCDECL0(int,     GetLOHCompactionMode);
diff --git a/src/vm/ecalllist.h b/src/vm/ecalllist.h
index 92d75e3f90..998f62b908 100644
--- a/src/vm/ecalllist.h
+++ b/src/vm/ecalllist.h
@@ -840,6 +840,7 @@ FCFuncStart(gGCInterfaceFuncs)
     FCFuncElement("_WaitForFullGCApproach", GCInterface::WaitForFullGCApproach)
     FCFuncElement("_WaitForFullGCComplete", GCInterface::WaitForFullGCComplete)
     FCFuncElement("_CollectionCount", GCInterface::CollectionCount)
+    FCFuncElement("GetMemoryInfo", GCInterface::GetMemoryInfo)
     FCFuncElement("GetGCLatencyMode", GCInterface::GetGcLatencyMode)
     FCFuncElement("SetGCLatencyMode", GCInterface::SetGcLatencyMode)
     FCFuncElement("GetLOHCompactionMode", GCInterface::GetLOHCompactionMode)