HTTP client mem leak when socket hang up?

[Filirom1]

Hi,

In production we have a serious memory leak. I tried to figure it out using the module weak.
When I remove HTTP clients in my code, I don't have mem leaks. So I thought there was something strange in the HTTP client.

I started with #3179, and found something else when the socket hang up (socket hang up happens in our production code).

When executing this gist, weak tell us that some of our objects are not GC.

# node --expose-gc leak.js
webkit-devtools-agent started on 127.0.0.1:1337
We should do 18 requests
3MB used
Done: 0/18, not yet GC: 0
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up 
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
90MB used
Done: 18/18, not yet GC: 7
all requests done, memory should be collected by now ?
39MB used
Done: 18/18, not yet GC: 7
all requests done, memory should be collected by now ?

Using webkit-devtools-agent, I found that the leak is retained by an HTTPParser. So i tried this :

exports.FreeList.prototype.free = function(obj) {
  //debug("free " + this.name + " " + this.list.length);
  if (this.list.length < this.max) {
-    this.list.push(obj);
+    // this.list.push(obj);
  }
};

And the leak in the gist disappear.

$ node --expose-gc gistfile1.js 
We should do 18 requests
2MB used
Done: 0/18, not yet GC: 0
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
Got error: socket hang up
89MB used
Done: 18/18, not yet GC: 0
all requests done, memory should be collected by now ?
2MB used
Done: 18/18, not yet GC: 0
all requests done, memory should be collected by now ?
2MB used
Done: 18/18, not yet GC: 0
all requests done, memory should be collected by now ?
2MB used
Done: 18/18, not yet GC: 0
all requests done, memory should be collected by now ?

I tried to do something smarter in this pull request. The http tests still works. I hope this pull-request will help.

Thanks for node. It rocks !

[crickeys]

still seeing if it helps memory leak, but at first run it seems to slow things down a lot

[Filirom1]

Tomorrow I will try it in real life, and I will keep an eye on performance. But it's strange because I have just added a call on removeAllListeners();

[crickeys]

nevermind, I think the performance is on my end, still testing memory leak

[isaacs]

We've been tracking down an error that looks suspiciously like this at @joyent that @mranney is encountering at @Voxer.

If bfe9cdb doesn't fix it, then we'll look into other things.

e25611e is not acceptable, because it puts http-specific logic into FreeList, which is not where it belongs.

[isaacs]

Closing this pull req, because it's not the right solution.