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src/coreclr/gc/gc.cpp

@@ -783,9 +783,10 @@ class t_join
         return join_struct.n_threads;
     }
 
+    // This is for instrumentation only.
     int get_join_lock()
     {
-        return join_struct.join_lock;
+        return VolatileLoadWithoutBarrier (&join_struct.join_lock);
     }
 
     void destroy ()
@@ -2425,7 +2426,7 @@ last_recorded_gc_info gc_heap::last_full_blocking_gc_info;
 
 uint64_t    gc_heap::last_alloc_reset_suspended_end_time = 0;
 size_t      gc_heap::max_peak_heap_size = 0;
-size_t      gc_heap::llc_size = 0;
+VOLATILE(size_t) gc_heap::llc_size = 0;
 
 #ifdef BACKGROUND_GC
 last_recorded_gc_info gc_heap::last_bgc_info[2];

src/coreclr/gc/gcpriv.h

@@ -5193,8 +5193,6 @@ class gc_heap
     PER_HEAP_ISOLATED_FIELD_MAINTAINED size_t current_total_soh_stable_size;
     PER_HEAP_ISOLATED_FIELD_MAINTAINED uint64_t last_suspended_end_time;
     PER_HEAP_ISOLATED_FIELD_MAINTAINED uint64_t change_heap_count_time;
-    PER_HEAP_ISOLATED_FIELD_MAINTAINED uint64_t total_change_heap_count;
-    PER_HEAP_ISOLATED_FIELD_MAINTAINED uint64_t total_change_heap_count_time;
 
     // If the last full GC is blocking, this is that GC's index; for BGC, this is the settings.gc_index
     // when the BGC ended.
@@ -5408,8 +5406,8 @@ class gc_heap
     PER_HEAP_ISOLATED_FIELD_DIAG_ONLY size_t max_peak_heap_size;
 
     // Sometimes it's difficult to figure out why we get the gen0 min/max budget.
-    // These fields help figure those out.
-    PER_HEAP_ISOLATED_FIELD_DIAG_ONLY size_t llc_size;
+    // These fields help figure those out. Making it volatile so it doesn't get optimized out.
+    PER_HEAP_ISOLATED_FIELD_DIAG_ONLY VOLATILE(size_t) llc_size;
 
 #ifdef BACKGROUND_GC
     PER_HEAP_ISOLATED_FIELD_DIAG_ONLY gc_history_global bgc_data_global;
@@ -5442,6 +5440,8 @@ class gc_heap
 #ifdef DYNAMIC_HEAP_COUNT
     // Number of times we bailed from check_heap_count because we didn't have enough memory for the preparation
     PER_HEAP_ISOLATED_FIELD_DIAG_ONLY size_t hc_change_cancelled_count_prep;
+    PER_HEAP_ISOLATED_FIELD_DIAG_ONLY uint64_t total_change_heap_count;
+    PER_HEAP_ISOLATED_FIELD_DIAG_ONLY uint64_t total_change_heap_count_time;
 
 #ifdef BACKGROUND_GC
     // We log an entry whenever we needed to create new BGC threads.