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copied!<p>It looks like you are entering <em>The Lost World</em> here. I don’t think the problem is with c-bindings in <code>racc</code> either.</p> <p>Ruby memory management is both elegant and cumbersome. It stores objects (named <code>RVALUE</code>s) in so-called <em>heaps</em> of size of approx 16KB. On a low level, <code>RVALUE</code> is a c-struct, containing a <code>union</code> of different standard ruby object representations.</p> <p>So, heaps store <code>RVALUE</code> objects, which size is not more than 40 bytes. For such objects as <code>String</code>, <code>Array</code>, <code>Hash</code> etc. this means that small objects can fit in the heap, but as soon as they reach a threshold, an extra memory outside of the Ruby heaps will be allocated.</p> <p><strong>This extra memory is flexible; is will be freed as soon as an object became GC’ed.</strong> That’s why your testcase with <code>big_string</code> shows the memory up-down behaviour:</p> <pre><code>def report puts 'Memory ' + `ps ax -o pid,rss | grep -E "^[[:space:]]*#{$$}"` .strip.split.map(&:to_i)[1].to_s + 'KB' end report big_var = " " * 10000000 report big_var = nil report ObjectSpace.garbage_collect sleep 1 report # ⇒ Memory 11788KB # ⇒ Memory 65188KB # ⇒ Memory 65188KB # ⇒ Memory 11788KB </code></pre> <p>But the heaps (see <code>GC[:heap_length]</code>) themselves <strong>are not released</strong> back to OS, once acquired. Look, I’ll make a humdrum change to your testcase:</p> <pre><code>- big_var = " " * 10000000 + big_var = 1_000_000.times.map(&:to_s) </code></pre> <p>And, voilá:</p> <pre><code># ⇒ Memory 11788KB # ⇒ Memory 65188KB # ⇒ Memory 65188KB # ⇒ Memory 57448KB </code></pre> <p>The memory is not released back to OS anymore, because each element of the array I introduced <em>suits</em> the <code>RVALUE</code> size and <em>is stored</em> in the ruby heap.</p> <p>If you’ll examine the output of <code>GC.stat</code> after the GC was run, you’ll find that <code>GC[:heap_used]</code> value is decreased as expected. Ruby now has a lot of empty heaps, ready.</p> <p><strong>The summing up:</strong> I don’t think, the <code>c</code> code leaks. I think the problem is within base64 representation of huge image in your <code>css</code>. I have no clue, what’s happening inside parser, but it looks like the huge string forces the ruby heap count to increase.</p> <p>Hope it helps. </p>

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