From: "tmm1 (Aman Gupta)" <ruby@...1.net>
Date: 2013-03-14T18:46:13+09:00
Subject: [ruby-core:53405] [ruby-trunk - Bug #8095][Open] [patch] gc: fix unlimited memory growth with large values of RUBY_FREE_MIN


Issue #8095 has been reported by tmm1 (Aman Gupta).

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Bug #8095: [patch] gc: fix unlimited memory growth with large values of RUBY_FREE_MIN
https://bugs.ruby-lang.org/issues/8095

Author: tmm1 (Aman Gupta)
Status: Open
Priority: Normal
Assignee: authorNari (Narihiro Nakamura)
Category: core
Target version: 
ruby -v: ruby 2.1.0dev (2013-03-14 trunk 39748) [x86_64-darwin12.2.1]


Normally, do_heap_free is set to 65% of total slots available.

But if you specify a very large RUBY_FREE_MIN, then do_heap_free is always set to 100%. This results in a memory leak over time.
Instead of forcing do_heap_free = 100%, the following patch sets do_heap_free = max( RUBY_FREE_MIN, 65% )

diff --git a/gc.c b/gc.c
index bd95073..4103af6 100644
--- a/gc.c
+++ b/gc.c
@@ -1973,8 +1973,9 @@ before_gc_sweep(rb_objspace_t *objspace)
     objspace->heap.do_heap_free = (size_t)((heaps_used * HEAP_OBJ_LIMIT) * 0.65);
     objspace->heap.free_min = (size_t)((heaps_used * HEAP_OBJ_LIMIT)  * 0.2);
     if (objspace->heap.free_min < initial_free_min) {
-       objspace->heap.do_heap_free = heaps_used * HEAP_OBJ_LIMIT;
         objspace->heap.free_min = initial_free_min;
+        if (objspace->heap.do_heap_free < initial_free_min)
+            objspace->heap.do_heap_free = initial_free_min;
     }
     objspace->heap.sweep_slots = heaps;
     objspace->heap.free_num = 0;


-- 
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