YJIT: Include actual memory region size in stats (#6736)

yjit.rb

@@ -262,6 +262,7 @@ module RubyVM::YJIT
       $stderr.puts "inline_code_size:      " + ("%10d" % stats[:inline_code_size])
       $stderr.puts "outlined_code_size:    " + ("%10d" % stats[:outlined_code_size])
       $stderr.puts "freed_code_size:       " + ("%10d" % stats[:freed_code_size])
+      $stderr.puts "code_region_size:      " + ("%10d" % stats[:code_region_size])
       $stderr.puts "yjit_alloc_size:       " + ("%10d" % stats[:yjit_alloc_size]) if stats.key?(:yjit_alloc_size)
       $stderr.puts "live_page_count:       " + ("%10d" % stats[:live_page_count])
       $stderr.puts "freed_page_count:      " + ("%10d" % stats[:freed_page_count])

yjit/src/asm/mod.rs

@@ -210,12 +210,15 @@ impl CodeBlock {
         self.page_size
     }
 
+    pub fn mapped_region_size(&self) -> usize {
+        self.mem_block.borrow().mapped_region_size()
+    }
+
     /// Return the number of code pages that have been mapped by the VirtualMemory.
     pub fn num_mapped_pages(&self) -> usize {
-        let mapped_region_size = self.mem_block.borrow().mapped_region_size();
         // CodeBlock's page size != VirtualMem's page size on Linux,
         // so mapped_region_size % self.page_size may not be 0
-        ((mapped_region_size - 1) / self.page_size) + 1
+        ((self.mapped_region_size() - 1) / self.page_size) + 1
     }
 
     /// Return the number of code pages that have been reserved by the VirtualMemory.

yjit/src/stats.rs

@@ -402,6 +402,9 @@ fn rb_yjit_gen_stats_dict() -> VALUE {
         // Code GC count
         hash_aset_usize!(hash, "code_gc_count", CodegenGlobals::get_code_gc_count());
 
+        // Size of memory region allocated for JIT code
+        hash_aset_usize!(hash, "code_region_size", cb.mapped_region_size());
+
         // Rust global allocations in bytes
         #[cfg(feature="stats")]
         hash_aset_usize!(hash, "yjit_alloc_size", global_allocation_size());