port pool stats to 1.10 (#102)

* port pool stats to 1.10

* increment/decrement current_pg_count

---------

Co-authored-by: K Pamnany <[email protected]>

src/gc-pages.c

@@ -19,6 +19,31 @@ extern "C" {
 #define MIN_BLOCK_PG_ALLOC (1) // 16 KB
 
 static int block_pg_cnt = DEFAULT_BLOCK_PG_ALLOC;
+static _Atomic(size_t) current_pg_count = 0;
+
+// Julia allocates large blocks (64M) with mmap. These are never
+// released back but the underlying physical memory may be released
+// with calls to madvise(MADV_DONTNEED).
+// These large blocks are used to allocated jl_page_size sized
+// pages, that are tracked by current_pg_count.
+static uint64_t poolmem_bytes_allocated = 0;
+static uint64_t poolmem_blocks_allocated_total = 0;
+
+
+JL_DLLEXPORT uint64_t jl_poolmem_blocks_allocated_total(void)
+{
+    return poolmem_blocks_allocated_total;
+}
+
+JL_DLLEXPORT uint64_t jl_poolmem_bytes_allocated(void)
+{
+    return poolmem_bytes_allocated;
+}
+
+JL_DLLEXPORT uint64_t jl_current_pg_count(void)
+{
+    return (uint64_t)jl_atomic_load(&current_pg_count);
+}
 
 void jl_gc_init_page(void)
 {
@@ -47,6 +72,8 @@ char *jl_gc_try_alloc_pages_(int pg_cnt) JL_NOTSAFEPOINT
                             MAP_NORESERVE | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
     if (mem == MAP_FAILED)
         return NULL;
+    poolmem_bytes_allocated += pages_sz;
+    poolmem_blocks_allocated_total++;
 
 #ifdef MADV_NOHUGEPAGE
     madvise(mem, pages_sz, MADV_NOHUGEPAGE);
@@ -152,6 +179,7 @@ NOINLINE jl_gc_pagemeta_t *jl_gc_alloc_page(void) JL_NOTSAFEPOINT
     SetLastError(last_error);
 #endif
     errno = last_errno;
+    jl_atomic_fetch_add(&current_pg_count, 1);
     return meta;
 }
 
@@ -192,6 +220,7 @@ void jl_gc_free_page(jl_gc_pagemeta_t *pg) JL_NOTSAFEPOINT
     madvise(p, decommit_size, MADV_DONTNEED);
 #endif
     msan_unpoison(p, decommit_size);
+    jl_atomic_fetch_add(&current_pg_count, -1);
 }
 
 #ifdef __cplusplus