Dynamic heap count

src/coreclr/gc/gcconfig.h

@@ -137,7 +137,8 @@ class GCConfigStringHolder
     INT_CONFIG   (GCConserveMem,             "GCConserveMemory",          "System.GC.ConserveMemory",          0,                  "Specifies how hard GC should try to conserve memory - values 0-9")                       \
     INT_CONFIG   (GCWriteBarrier,            "GCWriteBarrier",            NULL,                                0,                  "Specifies whether GC should use more precise but slower write barrier")                  \
     STRING_CONFIG(GCName,                    "GCName",                    "System.GC.Name",                                        "Specifies the path of the standalone GC implementation.")                                \
-    INT_CONFIG   (GCSpinCountUnit,           "GCSpinCountUnit",           0,                                   0,                  "Specifies the spin count unit used by the GC.")
+    INT_CONFIG   (GCSpinCountUnit,           "GCSpinCountUnit",           0,                                   0,                  "Specifies the spin count unit used by the GC.")                                          \
+    BOOL_CONFIG  (GCDynamicAdaptation,       "GCDynamicAdaptation",       NULL,                                false,              "Enables varying the heap count dynamically in Server GC.")
 // This class is responsible for retreiving configuration information
 // for how the GC should operate.
 class GCConfig

src/coreclr/gc/gcinterface.h

@@ -1033,6 +1033,7 @@ struct ScanContext
 {
     Thread* thread_under_crawl;
     int thread_number;
+    int thread_count;
     uintptr_t stack_limit; // Lowest point on the thread stack that the scanning logic is permitted to read
     bool promotion; //TRUE: Promotion, FALSE: Relocation.
     bool concurrent; //TRUE: concurrent scanning
@@ -1050,6 +1051,7 @@ struct ScanContext
 
         thread_under_crawl = 0;
         thread_number = -1;
+        thread_count = -1;
         stack_limit = 0;
         promotion = false;
         concurrent = false;