diff options
| -rw-r--r-- | gc.c | 69 | ||||
| -rw-r--r-- | gc.rb | 3 | ||||
| -rw-r--r-- | test/ruby/test_gc_compact.rb | 112 |
3 files changed, 134 insertions, 50 deletions
@@ -682,7 +682,7 @@ typedef struct rb_objspace { unsigned int dont_gc : 1; unsigned int dont_incremental : 1; unsigned int during_gc : 1; - unsigned int during_compacting : 1; + unsigned int during_compacting : 2; unsigned int gc_stressful: 1; unsigned int has_hook: 1; unsigned int during_minor_gc : 1; @@ -3090,6 +3090,17 @@ Init_heap(void) { rb_objspace_t *objspace = &rb_objspace; +#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE) + /* If Ruby's heap pages are not a multiple of the system page size, we + * cannot use mprotect for the read barrier, so we must disable automatic + * compaction. */ + int pagesize; + pagesize = (int)sysconf(_SC_PAGE_SIZE); + if ((HEAP_PAGE_SIZE % pagesize) != 0) { + ruby_enable_autocompact = 0; + } +#endif + objspace->next_object_id = INT2FIX(OBJ_ID_INITIAL); objspace->id_to_obj_tbl = st_init_table(&object_id_hash_type); objspace->obj_to_id_tbl = st_init_numtable(); @@ -4389,6 +4400,11 @@ static VALUE gc_move(rb_objspace_t *objspace, VALUE scan, VALUE free); static void lock_page_body(rb_objspace_t *objspace, struct heap_page_body *body) { + /* If this is an explicit compaction (GC.compact), we don't need a read + * barrier, so just return early. */ + if (objspace->flags.during_compacting >> 1) { + return; + } #if defined(_WIN32) DWORD old_protect; @@ -4405,6 +4421,11 @@ lock_page_body(rb_objspace_t *objspace, struct heap_page_body *body) static void unlock_page_body(rb_objspace_t *objspace, struct heap_page_body *body) { + /* If this is an explicit compaction (GC.compact), we don't need a read + * barrier, so just return early. */ + if (objspace->flags.during_compacting >> 1) { + return; + } #if defined(_WIN32) DWORD old_protect; @@ -4624,8 +4645,12 @@ gc_compact_finish(rb_objspace_t *objspace, rb_heap_t *heap) { GC_ASSERT(heap->sweeping_page == heap->compact_cursor); - gc_unprotect_pages(objspace, heap); - uninstall_handlers(); + /* If this is an explicit compaction (GC.compact), no read barrier was set + * so we don't need to unprotect pages or uninstall the SEGV handler */ + if (!(objspace->flags.during_compacting >> 1)) { + gc_unprotect_pages(objspace, heap); + uninstall_handlers(); + } /* The mutator is allowed to run during incremental sweeping. T_MOVED * objects can get pushed on the stack and when the compaction process @@ -5134,6 +5159,12 @@ gc_compact_start(rb_objspace_t *objspace, rb_heap_t *heap) memset(objspace->rcompactor.considered_count_table, 0, T_MASK * sizeof(size_t)); memset(objspace->rcompactor.moved_count_table, 0, T_MASK * sizeof(size_t)); + /* If this is an explicit compaction (GC.compact), we don't need a read + * barrier, so just return early. */ + if (objspace->flags.during_compacting >> 1) { + return; + } + /* Set up read barrier for pages containing MOVED objects */ install_handlers(); } @@ -7030,7 +7061,7 @@ gc_marks_start(rb_objspace_t *objspace, int full_mark) #endif objspace->flags.during_minor_gc = FALSE; if (ruby_enable_autocompact) { - objspace->flags.during_compacting = TRUE; + objspace->flags.during_compacting |= TRUE; } objspace->profile.major_gc_count++; objspace->rgengc.uncollectible_wb_unprotected_objects = 0; @@ -8057,7 +8088,9 @@ gc_start(rb_objspace_t *objspace, int reason) /* reason may be clobbered, later, so keep set immediate_sweep here */ objspace->flags.immediate_sweep = !!((unsigned)reason & GPR_FLAG_IMMEDIATE_SWEEP); - objspace->flags.during_compacting = !!((unsigned)reason & GPR_FLAG_COMPACT); + + /* Explicitly enable compaction (GC.compact) */ + objspace->flags.during_compacting = (!!((unsigned)reason & GPR_FLAG_COMPACT) << 1); if (!heap_allocated_pages) return FALSE; /* heap is not ready */ if (!(reason & GPR_FLAG_METHOD) && !ready_to_gc(objspace)) return TRUE; /* GC is not allowed */ @@ -9248,10 +9281,26 @@ heap_check_moved_i(void *vstart, void *vend, size_t stride, void *data) } static VALUE +gc_compact(rb_execution_context_t *ec, VALUE self) +{ + /* Clear the heap. */ + gc_start_internal(ec, self, Qtrue, Qtrue, Qtrue, Qfalse); + + /* At this point, all references are live and the mutator is not allowed + * to run, so we don't need a read barrier. */ + gc_start_internal(ec, self, Qtrue, Qtrue, Qtrue, Qtrue); + + return gc_compact_stats(ec, self); +} + +static VALUE gc_verify_compaction_references(rb_execution_context_t *ec, VALUE self, VALUE double_heap, VALUE toward_empty) { rb_objspace_t *objspace = &rb_objspace; + /* Clear the heap. */ + gc_start_internal(ec, self, Qtrue, Qtrue, Qtrue, Qfalse); + RB_VM_LOCK_ENTER(); { gc_rest(objspace); @@ -9865,6 +9914,16 @@ gc_disable(rb_execution_context_t *ec, VALUE _) static VALUE gc_set_auto_compact(rb_execution_context_t *ec, VALUE _, VALUE v) { +#if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE) + /* If Ruby's heap pages are not a multiple of the system page size, we + * cannot use mprotect for the read barrier, so we must disable automatic + * compaction. */ + int pagesize; + pagesize = (int)sysconf(_SC_PAGE_SIZE); + if ((HEAP_PAGE_SIZE % pagesize) != 0) { + rb_raise(rb_eNotImpError, "Automatic compaction isn't available on this platform"); + } +#endif ruby_enable_autocompact = RTEST(v); return v; } @@ -199,8 +199,7 @@ module GC end def self.compact - Primitive.gc_start_internal true, true, true, true - Primitive.gc_compact_stats + Primitive.gc_compact end # call-seq: diff --git a/test/ruby/test_gc_compact.rb b/test/ruby/test_gc_compact.rb index 3aad9e6d5f..4a8cff33f4 100644 --- a/test/ruby/test_gc_compact.rb +++ b/test/ruby/test_gc_compact.rb @@ -1,56 +1,82 @@ # frozen_string_literal: true require 'test/unit' require 'fiddle' +require 'etc' class TestGCCompact < Test::Unit::TestCase - def test_enable_autocompact - before = GC.auto_compact - GC.auto_compact = true - assert GC.auto_compact - ensure - GC.auto_compact = before - end + class AutoCompact < Test::Unit::TestCase + def setup + skip "autocompact not supported on this platform" unless supports_auto_compact? + super + end - def test_disable_autocompact - before = GC.auto_compact - GC.auto_compact = false - refute GC.auto_compact - ensure - GC.auto_compact = before - end + def test_enable_autocompact + before = GC.auto_compact + GC.auto_compact = true + assert GC.auto_compact + ensure + GC.auto_compact = before + end - def test_major_compacts - before = GC.auto_compact - GC.auto_compact = true - compact = GC.stat :compact_count - GC.start - assert_operator GC.stat(:compact_count), :>, compact - ensure - GC.auto_compact = before - end + def test_disable_autocompact + before = GC.auto_compact + GC.auto_compact = false + refute GC.auto_compact + ensure + GC.auto_compact = before + end - def test_implicit_compaction_does_something - before = GC.auto_compact - list = [] - list2 = [] + def test_major_compacts + before = GC.auto_compact + GC.auto_compact = true + compact = GC.stat :compact_count + GC.start + assert_operator GC.stat(:compact_count), :>, compact + ensure + GC.auto_compact = before + end - # Try to make some fragmentation - 500.times { - list << Object.new - Object.new - Object.new - } - count = GC.stat :compact_count - GC.auto_compact = true - loop do - break if count < GC.stat(:compact_count) - list2 << Object.new + def test_implicit_compaction_does_something + before = GC.auto_compact + list = [] + list2 = [] + + # Try to make some fragmentation + 500.times { + list << Object.new + Object.new + Object.new + } + count = GC.stat :compact_count + GC.auto_compact = true + loop do + break if count < GC.stat(:compact_count) + list2 << Object.new + end + compact_stats = GC.latest_compact_info + refute_predicate compact_stats[:considered], :empty? + refute_predicate compact_stats[:moved], :empty? + ensure + GC.auto_compact = before end - compact_stats = GC.latest_compact_info - refute_predicate compact_stats[:considered], :empty? - refute_predicate compact_stats[:moved], :empty? - ensure - GC.auto_compact = before + + private + + def supports_auto_compact? + return true unless defined?(Etc::SC_PAGE_SIZE) + + begin + return GC::INTERNAL_CONSTANTS[:HEAP_PAGE_SIZE] % Etc.sysconf(Etc::SC_PAGE_SIZE) == 0 + rescue NotImplementedError + rescue ArgumentError + end + + true + end + end + + def os_page_size + return true unless defined?(Etc::SC_PAGE_SIZE) end def test_gc_compact_stats |