changeset 48945:d09be0adcf78

8191985: JDK-8190862 work for arch arm Summary: Fixed Interpreter never refills TLAB Reviewed-by: dsamersoff, aph
author jcbeyler
date Tue, 19 Dec 2017 20:14:52 -0800
parents 5f86c562a39e
children 9f6f48d4f9a1
files src/hotspot/cpu/arm/templateTable_arm.cpp
diffstat 1 files changed, 41 insertions(+), 38 deletions(-) [+]
line wrap: on
line diff
--- a/src/hotspot/cpu/arm/templateTable_arm.cpp	Tue Jan 09 16:52:25 2018 -0500
+++ b/src/hotspot/cpu/arm/templateTable_arm.cpp	Tue Dec 19 20:14:52 2017 -0800
@@ -4345,7 +4345,6 @@
   Label done;
   Label initialize_header;
   Label initialize_object;  // including clearing the fields
-  Label allocate_shared;
 
   const bool allow_shared_alloc =
     Universe::heap()->supports_inline_contig_alloc();
@@ -4390,13 +4389,19 @@
   // Klass::_lh_instance_slow_path_bit is really a bit mask, not bit number
   __ tbnz(Rsize, exact_log2(Klass::_lh_instance_slow_path_bit), slow_case);
 
+  // Allocate the instance:
+  //  If TLAB is enabled:
+  //    Try to allocate in the TLAB.
+  //    If fails, go to the slow path.
+  //  Else If inline contiguous allocations are enabled:
+  //    Try to allocate in eden.
+  //    If fails due to heap end, go to slow path.
   //
-  // Allocate the instance
-  // 1) Try to allocate in the TLAB
-  // 2) if fail and the object is large allocate in the shared Eden
-  // 3) if the above fails (or is not applicable), go to a slow case
-  // (creates a new TLAB, etc.)
-
+  //  If TLAB is enabled OR inline contiguous is enabled:
+  //    Initialize the allocation.
+  //    Exit.
+  //
+  //  Go to slow path.
   if (UseTLAB) {
     const Register Rtlab_top = R1_tmp;
     const Register Rtlab_end = R2_tmp;
@@ -4406,7 +4411,7 @@
     __ ldr(Rtlab_end, Address(Rthread, in_bytes(JavaThread::tlab_end_offset())));
     __ add(Rtlab_top, Robj, Rsize);
     __ cmp(Rtlab_top, Rtlab_end);
-    __ b(allow_shared_alloc ? allocate_shared : slow_case, hi);
+    __ b(slow_case, hi);
     __ str(Rtlab_top, Address(Rthread, JavaThread::tlab_top_offset()));
     if (ZeroTLAB) {
       // the fields have been already cleared
@@ -4415,45 +4420,43 @@
       // initialize both the header and fields
       __ b(initialize_object);
     }
-  }
-
-  // Allocation in the shared Eden, if allowed.
-  if (allow_shared_alloc) {
-    __ bind(allocate_shared);
-
-    const Register Rheap_top_addr = R2_tmp;
-    const Register Rheap_top = R5_tmp;
-    const Register Rheap_end = Rtemp;
-    assert_different_registers(Robj, Rklass, Rsize, Rheap_top_addr, Rheap_top, Rheap_end, LR);
-
-    // heap_end now (re)loaded in the loop since also used as a scratch register in the CAS
-    __ ldr_literal(Rheap_top_addr, Lheap_top_addr);
-
-    Label retry;
-    __ bind(retry);
+  } else {
+    // Allocation in the shared Eden, if allowed.
+    if (allow_shared_alloc) {
+      const Register Rheap_top_addr = R2_tmp;
+      const Register Rheap_top = R5_tmp;
+      const Register Rheap_end = Rtemp;
+      assert_different_registers(Robj, Rklass, Rsize, Rheap_top_addr, Rheap_top, Rheap_end, LR);
+
+      // heap_end now (re)loaded in the loop since also used as a scratch register in the CAS
+      __ ldr_literal(Rheap_top_addr, Lheap_top_addr);
+
+      Label retry;
+      __ bind(retry);
 
 #ifdef AARCH64
-    __ ldxr(Robj, Rheap_top_addr);
+      __ ldxr(Robj, Rheap_top_addr);
 #else
-    __ ldr(Robj, Address(Rheap_top_addr));
+      __ ldr(Robj, Address(Rheap_top_addr));
 #endif // AARCH64
 
-    __ ldr(Rheap_end, Address(Rheap_top_addr, (intptr_t)Universe::heap()->end_addr()-(intptr_t)Universe::heap()->top_addr()));
-    __ add(Rheap_top, Robj, Rsize);
-    __ cmp(Rheap_top, Rheap_end);
-    __ b(slow_case, hi);
-
-    // Update heap top atomically.
-    // If someone beats us on the allocation, try again, otherwise continue.
+      __ ldr(Rheap_end, Address(Rheap_top_addr, (intptr_t)Universe::heap()->end_addr()-(intptr_t)Universe::heap()->top_addr()));
+      __ add(Rheap_top, Robj, Rsize);
+      __ cmp(Rheap_top, Rheap_end);
+      __ b(slow_case, hi);
+
+      // Update heap top atomically.
+      // If someone beats us on the allocation, try again, otherwise continue.
 #ifdef AARCH64
-    __ stxr(Rtemp2, Rheap_top, Rheap_top_addr);
-    __ cbnz_w(Rtemp2, retry);
+      __ stxr(Rtemp2, Rheap_top, Rheap_top_addr);
+      __ cbnz_w(Rtemp2, retry);
 #else
-    __ atomic_cas_bool(Robj, Rheap_top, Rheap_top_addr, 0, Rheap_end/*scratched*/);
-    __ b(retry, ne);
+      __ atomic_cas_bool(Robj, Rheap_top, Rheap_top_addr, 0, Rheap_end/*scratched*/);
+      __ b(retry, ne);
 #endif // AARCH64
 
-    __ incr_allocated_bytes(Rsize, Rtemp);
+      __ incr_allocated_bytes(Rsize, Rtemp);
+    }
   }
 
   if (UseTLAB || allow_shared_alloc) {