Hi all, I know I'm very, very late to the party, but I'm building my first ever project with ARC instead of manual retain/release (which I was always very comfortable with). Frankly, I'm finding it frustrating because it seems much harder to know how memory is managed. Anyway. I will plough on - no doubt I'll get used to it.
I'm using NSURLSession and NSURLSessionDataTask to fetch chunks of data from a .m3u8 playlist. It works pretty well, but I'm seeing a gradual increase in memory usage as my app runs. Under classical memory management, I would probably have little difficulty in isolating the problem, but with ARC I'm finding it much harder to track down because it's unclear when certain objects come to the end of their lives. Anyway, running in Instruments shows a constant list of calls to malloc() from HTTPNetStreamInfo::_readStreamClientCallBack(__CFReadStream*, unsigned long) in the CFNetwork library, allocating 132KB. These blocks are allocated at a high rate (over 100x per second) as the app runs, and as far as I can see are never freed. I'm not directly using this API, it must be something internal to NSURLSession. How can I ensure that these blocks are freed? I'm assuming that a leak in the OS of this sort would have been spotted, so my assumption here is that I'm doing something wrong that prevents proper freeing. The way I'm using NSURLSession seems to be "normal", as far as I can tell. I have an object that allocates a NSURLSession and this session exists for as long as the task runs, which can be a very long time. Each "chunk" of data is added to the session as a NSURLSessionDataTask and I supply a completion block. The completion block simply appends the data it receives to a file and fires off some notifications. The completion block may or may not schedule the download of the following chunk, depending on various factors, but it doesn't do anything special to tell the task it has finished - as far as I can tell from documentation, the fact the completion block is called is because the task has finished, so I can just forget about it. The session itself is invalidated when the owning object is dealloced, but that might be hours or days later when the user decides to discard the task. Otherwise it stays alive indefinitely. I'm wondering if that's the right thing to do? The docs suggest that a NSURLSession is somewhat like a tab in a web browser, so it lives as long as that tab exists. Any clues as to how I can track down the leak or whether there's an obvious missing step that should free temporary buffers used by NSURLSessionDataTask would be gratefully received at this point. --Graham _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
