On Fri, Nov 22, 2013 at 12:37 PM, Steve Freegard <st...@stevefreegard.com> wrote: > Hi, > > I'm trying to debug and understand an issue on several of my Haraka servers > after a recent update. > > I'm seeing large amounts of memory being used and never returned back to the > operating system causing the machine to swap and eventually the Linux OOM > killer shooting the processes. > > I thought that there must be a memory leak somewhere - but I've used > node-heapdump and taken multiple snapshots and compared them and whilst I'm > seeing a small growth I'm not seeing anything major. However the heapdump > reports the size at ~97Mb whereas the RSS of the process at the time of the > dump was 1.1Gb which is what I really don't understand at all. > > Would such a disparity between heap and RSS indicate that an external C++ > module that is being used is leaking memory?? If so, what is the best way > of finding out which? > > I've tried the mtrace module - but it caused the process to completely hang > after only a few minutes of running so I had to kill it. The output that I > got from it is attached - I'm not really sure it tells me anything though. > > Any suggestions as to how to work out what is going on here and how to fix > it would be gratefully received. > > Kind regards, > Steve.
Tracking down memory leaks in garbage-collected environments is one of the great unsolved problems of our generation. Okay, maybe not really but there is no one-size-fits-all solution. Here are some things you can try: * The mtrace log suggests you're using node.js v0.8. Consider upgrading. * Use Valgrind. Drawback: it's really, really slow and it uses a lot of memory itself. * SystemTap. Write a small stap script that collects malloc/free/etc. call graphs and aggregates them into histograms. Strong disparities between calls to malloc() and free() generally show up quickly that way. Apropos that heap snapshot, did you look at the self size or the retained size? Buffer objects tend to have small self sizes (usually on the order of a few hundred bytes) but can have massive retained sizes. Note that Buffers in snapshots taken with node.js <= v0.8.11 don't report the true retained size. -- -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to nodejs@googlegroups.com To unsubscribe from this group, send email to nodejs+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en --- You received this message because you are subscribed to the Google Groups "nodejs" group. To unsubscribe from this group and stop receiving emails from it, send an email to nodejs+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
