0005945: Mix-up of Minor_heap_min and Minor_heap_max units

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0005945

OCaml

runtime system and C interface

public

2013-03-12 17:23

2013-07-17 13:51

Reporter

bvaugon

Assigned To

doligez

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

4.00.1

Target Version

4.01.0+dev

Fixed in Version

4.01.0+dev

Summary

0005945: Mix-up of Minor_heap_min and Minor_heap_max units

Description

In the OCaml runtime, the contants representing the minor heap bounds Minor_heap_min and Minor_heap_max are sometimes used as byte number and sometimes as word number.

The comments near declarations of these constants (from config.h) tells that Minor_heap_* should be word numbers.

The attached patch fixes this problem.

Steps To Reproduce

This problem can be observed in two different ways:

1/ Break an assertion with a valid minor heap size initialization:

$ grep Minor_heap_max [OCAML_PATH]/byterun/config.h
#define Minor_heap_max (1 << 28)
$ ocamlc -use-runtime [OCAML_PATH]/byterun/ocamlrund hw.ml -o hw
$ CAMLRUNPARAM=s=200000000 ./hw
file minor_gc.d.c; line 82 ### Assertion failed: size <= Minor_heap_max

2/ Impossibility to dynamically change minor heap size to a valid value:

With the same Minor_heap_max (1 << 28) from config.h, run this OCaml program:

Gc.set { (Gc.get ()) with Gc.minor_heap_size = 200000000 };;
Printf.printf "%d\n" (Gc.get ()).Gc.minor_heap_size;;

-> 67108864

Additional Information

This problem comes from gc_ctrl.c and minor_gc.c, see ocaml-4.00.1-minor-heap-sizes.diff.

Tags

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Attached Files

ocaml-4.00.1-minor-heap-sizes.diff [^] (1,380 bytes) 2013-03-12 17:23 [Show Content] [Hide Content]

diff -Naur ocaml-4.00.1/byterun/gc_ctrl.c ocaml-4.00.1-minor-heap-sizes/byterun/gc_ctrl.c
--- ocaml-4.00.1/byterun/gc_ctrl.c	2013-03-12 16:51:15.826348301 +0100
+++ ocaml-4.00.1-minor-heap-sizes/byterun/gc_ctrl.c	2013-03-12 16:50:48.904348123 +0100
@@ -396,7 +396,7 @@
 
     /* Minor heap size comes last because it will trigger a minor collection
        (thus invalidating [v]) and it can raise [Out_of_memory]. */
-  newminsize = norm_minsize (Bsize_wsize (Long_val (Field (v, 0))));
+  newminsize = Bsize_wsize (norm_minsize (Long_val (Field (v, 0))));
   if (newminsize != caml_minor_heap_size){
     caml_gc_message (0x20, "New minor heap size: %luk bytes\n",
                      newminsize/1024);
diff -Naur ocaml-4.00.1/byterun/minor_gc.c ocaml-4.00.1-minor-heap-sizes/byterun/minor_gc.c
--- ocaml-4.00.1/byterun/minor_gc.c	2013-03-12 16:51:15.826348301 +0100
+++ ocaml-4.00.1-minor-heap-sizes/byterun/minor_gc.c	2013-03-12 16:50:48.904348123 +0100
@@ -78,8 +78,8 @@
   char *new_heap;
   void *new_heap_base;
 
-  Assert (size >= Minor_heap_min);
-  Assert (size <= Minor_heap_max);
+  Assert (size >= Bsize_wsize(Minor_heap_min));
+  Assert (size <= Bsize_wsize(Minor_heap_max));
   Assert (size % sizeof (value) == 0);
   if (caml_young_ptr != caml_young_end) caml_minor_collection ();
                                     Assert (caml_young_ptr == caml_young_end);

Relationships

Notes
(0009798) doligez (administrator) 2013-07-17 13:51	patch applied to 4.01 branch (rev 13899)

Issue History
Date Modified	Username	Field	Change
2013-03-12 17:23	bvaugon	New Issue
2013-03-12 17:23	bvaugon	File Added: ocaml-4.00.1-minor-heap-sizes.diff
2013-03-17 17:30	gasche	Assigned To	=> doligez
2013-03-17 17:30	gasche	Status	new => assigned
2013-07-12 09:42	doligez	Target Version	=> 4.01.0+dev
2013-07-17 13:51	doligez	Note Added: 0009798
2013-07-17 13:51	doligez	Status	assigned => closed
2013-07-17 13:51	doligez	Resolution	open => fixed
2013-07-17 13:51	doligez	Fixed in Version	=> 4.01.0+dev
2017-02-23 16:43	doligez	Category	OCaml runtime system => runtime system
2017-03-03 17:45	doligez	Category	runtime system => runtime system and C interface