YJIT: Make Code GC metrics available for non-stats builds (#6665)

Merged-By: maximecb <maximecb@ruby-lang.org>

NEWS.md

@@ -330,6 +330,9 @@ The following deprecated APIs are removed.
   memory pages until actually utilized by JIT code.
 * Introduce Code GC that frees all code pages when the memory consumption
   by JIT code reaches `--yjit-exec-mem-size`.
+* `RubyVM::YJIT.runtime_stats` returns Code GC metrics in addition to
+  existing `inline_code_size` and `outlined_code_size` keys:
+  `code_gc_count`, `live_page_count`, `freed_page_count`, and `freed_code_size`.
 
 ### MJIT
 

test/ruby/test_yjit.rb

@@ -837,7 +837,7 @@ class TestYJIT < Test::Unit::TestCase
       return :not_compiled2 unless compiles { nil } # should be JITable again
 
       code_gc_count = RubyVM::YJIT.runtime_stats[:code_gc_count]
-      return :"code_gc_#{code_gc_count}" if code_gc_count && code_gc_count != 2
+      return :"code_gc_#{code_gc_count}" if code_gc_count != 2
 
       :ok
     RUBY
@@ -858,7 +858,7 @@ class TestYJIT < Test::Unit::TestCase
       return :broken_resume2 if fiber.resume != 0 # The code should be still callable
 
       code_gc_count = RubyVM::YJIT.runtime_stats[:code_gc_count]
-      return :"code_gc_#{code_gc_count}" if code_gc_count && code_gc_count != 1
+      return :"code_gc_#{code_gc_count}" if code_gc_count != 1
 
       :ok
     RUBY
@@ -890,7 +890,7 @@ class TestYJIT < Test::Unit::TestCase
       return :not_paged4 unless add_pages(100) # check everything still works
 
       code_gc_count = RubyVM::YJIT.runtime_stats[:code_gc_count]
-      return :"code_gc_#{code_gc_count}" if code_gc_count && code_gc_count != 3
+      return :"code_gc_#{code_gc_count}" if code_gc_count != 3
 
       :ok
     RUBY
@@ -912,7 +912,7 @@ class TestYJIT < Test::Unit::TestCase
       return :broken_resume2 if fiber.resume != 0 # on-stack code should be callable
 
       code_gc_count = RubyVM::YJIT.runtime_stats[:code_gc_count]
-      return :"code_gc_#{code_gc_count}" if code_gc_count && code_gc_count == 0
+      return :"code_gc_#{code_gc_count}" if code_gc_count == 0
 
       :ok
     RUBY

yjit/src/asm/mod.rs

@@ -10,7 +10,6 @@ use crate::core::IseqPayload;
 use crate::core::for_each_off_stack_iseq_payload;
 use crate::core::for_each_on_stack_iseq_payload;
 use crate::invariants::rb_yjit_tracing_invalidate_all;
-use crate::stats::incr_counter;
 use crate::virtualmem::WriteError;
 
 #[cfg(feature = "disasm")]
@@ -605,7 +604,6 @@ impl CodeBlock {
         }
 
         CodegenGlobals::set_freed_pages(freed_pages);
-        incr_counter!(code_gc_count);
     }
 
     pub fn inline(&self) -> bool {

yjit/src/codegen.rs

@@ -6724,6 +6724,9 @@ pub struct CodegenGlobals {
 
     /// Freed page indexes. None if code GC has not been used.
     freed_pages: Option<Vec<usize>>,
+
+    /// How many times code GC has been executed.
+    code_gc_count: usize,
 }
 
 /// For implementing global code invalidation. A position in the inline
@@ -6816,6 +6819,7 @@ impl CodegenGlobals {
             method_codegen_table: HashMap::new(),
             ocb_pages,
             freed_pages: None,
+            code_gc_count: 0,
         };
 
         // Register the method codegen functions
@@ -6961,7 +6965,12 @@ impl CodegenGlobals {
     }
 
     pub fn set_freed_pages(freed_pages: Vec<usize>) {
-        CodegenGlobals::get_instance().freed_pages = Some(freed_pages)
+        CodegenGlobals::get_instance().freed_pages = Some(freed_pages);
+        CodegenGlobals::get_instance().code_gc_count += 1;
+    }
+
+    pub fn get_code_gc_count() -> usize {
+        CodegenGlobals::get_instance().code_gc_count
     }
 }
 

yjit/src/stats.rs

@@ -261,7 +261,6 @@ make_counters! {
     compiled_block_count,
     compilation_failure,
     freed_iseq_count,
-    code_gc_count,
 
     exit_from_branch_stub,
 
@@ -391,6 +390,9 @@ fn rb_yjit_gen_stats_dict() -> VALUE {
 
         // Live pages
         hash_aset_usize!(hash, "live_page_count", cb.num_mapped_pages() - freed_page_count);
+
+        // Code GC count
+        hash_aset_usize!(hash, "code_gc_count", CodegenGlobals::get_code_gc_count());
     }
 
     // If we're not generating stats, the hash is done