And how many of these you have ? Sorry for all the questions :(
> On 20 Jul 2016, at 19:19, Chris Conroy <[email protected]> wrote: > > Here's an example leaked buf > > <Screen Shot 2016-07-20 at 1.18.24 PM.png> > > On Wed, Jul 20, 2016 at 1:17 PM, 'Norman Maurer' via Netty discussions > <[email protected] <mailto:[email protected]>> wrote: > One last thing… > > Can you tell me what the capacity() of the “leaked” buffer is ? > >> On 20 Jul 2016, at 19:11, Norman Maurer <[email protected] >> <mailto:[email protected]>> wrote: >> >> Thanks Chris, >> >> this sounds really “fishy”. Let me try to debug this a bit more (not sure >> yet how tho). >> >>> On 20 Jul 2016, at 19:06, Chris Conroy <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> This leak resulted in exhaustion of 4G of NIO memory. The same application >>> under Netty 3 only ever uses <200MB of NIO memory. I have run several >>> experiments where I take some traffic, disable the node from serving >>> traffic, and then force a full GC. The allocated NIO memory does not return >>> to normal levels. >>> >>> Spot checking the byte buf handles from my heap dump, I see lots (all?) >>> `recycle` and `lastRecycleIds` of `int -2147483648 <tel:2147483648> = >>> 0x80000000` >>> >>> The experiment yesterday with the recycler disabled did not result in any >>> such leaks over several hours of traffic. >>> >>> On Wed, Jul 20, 2016 at 12:41 AM, 'Norman Maurer' via Netty discussions >>> <[email protected] <mailto:[email protected]>> wrote: >>> Are you actually sure these are really leaked ? >>> >>> The point of the “ThreadLocalUnsafeDirectByteBuf” is that it can be reused >>> so it is expected that it not gets released after its written but put back >>> in the recycler. Or you saying there are too many of these ? >>> >>> >>>> On 19 Jul 2016, at 22:39, Chris Conroy <[email protected] >>>> <mailto:[email protected]>> wrote: >>>> >>>> Yes all the leaked buffers look to be ThreadLocalUnsafeDirectByteBuf >>>> >>>> Disabling the recycler w/o backpressure on slow readers resulted in >>>> several massive allocation events. I was able to free them by forcing GC >>>> so no leaks there. Memory usage with backpressure on slow readers is back >>>> down to Netty 3 w/o backpressure levels. I don't see any leaks so far. >>>> >>>> Assuming that disabling the recycler does indeed prevent leaks, where do >>>> we go from there? Any ideas of things to look for in my application that >>>> might cause the recycler to get into a bad state? >>>> >>>> On Tue, Jul 19, 2016 at 3:40 PM, 'Norman Maurer' via Netty discussions >>>> <[email protected] <mailto:[email protected]>> wrote: >>>> Btw all the “leaking” buffers are always: >>>> >>>> ThreadLocalUnsafeDirectByteBuf >>>> >>>> ? >>>> >>>> >>>>> On 19 Jul 2016, at 21:29, Chris Conroy <[email protected] >>>>> <mailto:[email protected]>> wrote: >>>>> >>>>> I ran with paranoid while observing the leak and got no messages from the >>>>> ResourceLeakDetector. >>>>> >>>>> Initial results from recycler maxCapacity of 0 are looking positive with >>>>> respect to the leak. However, I did see a large spike of NIO memory >>>>> allocated (1G) where the Netty 3 version of this app receiving similar >>>>> traffic peaks at about 1/10th that. I'll let this run for a while and >>>>> report back later with the full results. >>>>> >>>>> On Tue, Jul 19, 2016 at 2:59 PM, 'Norman Maurer' via Netty discussions >>>>> <[email protected] <mailto:[email protected]>> wrote: >>>>> Can you do me a favour and run with: >>>>> >>>>> -Dio.netty.recycler.maxCapacity=0 >>>>> >>>>> And let me know if you still see some leaks ? >>>>> >>>>> >>>>> >>>>>> On 19 Jul 2016, at 20:50, Chris Conroy <[email protected] >>>>>> <mailto:[email protected]>> wrote: >>>>>> >>>>>> 4.1.0.Final >>>>>> >>>>>> On Tue, Jul 19, 2016 at 2:48 PM, 'Norman Maurer' via Netty discussions >>>>>> <[email protected] <mailto:[email protected]>> wrote: >>>>>> Are you using 4.0 or 4.1 ? >>>>>> >>>>>>> On 19 Jul 2016, at 20:42, Chris Conroy <[email protected] >>>>>>> <mailto:[email protected]>> wrote: >>>>>>> >>>>>>> I have not been able to reproduce locally yet, but I do see it in a >>>>>>> cluster that takes a lot of varied traffic. The leak detector has not >>>>>>> fired for this under advanced. I will give paranoid a shot to be safe, >>>>>>> but it's my understanding that the leak detection framework is more for >>>>>>> dealing with pooled byte buf misuse, but in this case I am exclusively >>>>>>> using unpooled heap byte bufs: these are just the socket direct byte >>>>>>> bufs that appear to be leaking. >>>>>>> >>>>>>> I meant to add this earlier: The path to GC root goes: >>>>>>> >>>>>>> io.netty.buffer.ByteBufUtil$ThreadLocalUnsafeDirectByteBuf >>>>>>> io.netty.util.Recycler$DefaultHandle >>>>>>> io.netty.util.Recycler$DefaultHandle[] >>>>>>> io.netty.util.Recycler#Stack >>>>>>> java.lang.Object[] >>>>>>> io.netty.util.internal.InternalThreadLocalMap >>>>>>> ... (more thread local map refs up to java.lang.Thread) >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Tuesday, July 19, 2016 at 2:17:25 PM UTC-4, Norman Maurer wrote: >>>>>>> Can you provide a reproducer? Also did you try to run with paranoid >>>>>>> leak detection >>>>>>> >>>>>>> Am 19.07.2016 um 20:04 schrieb Chris Conroy <[email protected] <>>: >>>>>>> >>>>>>>> Ah okay: I didn't see the calls to failFlushed since they occur above >>>>>>>> the stanza I found suspicious. >>>>>>>> >>>>>>>> So, the above explanation is probably not correct. Still, I am seeing >>>>>>>> a leak where DirectByteBufs are rooted to the recycler, and the speed >>>>>>>> at which these buffers leak appears to be correlated with slow/partial >>>>>>>> readers. >>>>>>>> >>>>>>>> On Monday, July 18, 2016 at 4:36:31 PM UTC-4, Norman Maurer wrote: >>>>>>>> failFlushed(...) should be called to fail and release all flushed >>>>>>>> messages. >>>>>>>> >>>>>>>> Are you saying this not happens? >>>>>>>> >>>>>>>> Am 18.07.2016 um 22:02 schrieb Chris Conroy <[email protected] <>>: >>>>>>>> >>>>>>>>> I’ve been trying to track down a NIO memory leak that occurs in a >>>>>>>>> Netty application I am porting from Netty 3 to Netty 4. This leak >>>>>>>>> does not occur in the Netty 3 version of the application. >>>>>>>>> >>>>>>>>> For now, I’m using only unpooled heap buffers in Netty 4, but NIO >>>>>>>>> buffers do come into play for socket communication. >>>>>>>>> >>>>>>>>> I’ve captured a few heap dumps from affected instances, and in each >>>>>>>>> it appears that the leaked DirectByteBuf java objects are rooted in >>>>>>>>> an io.netty.util.Recycler. >>>>>>>>> >>>>>>>>> These buffers remain indefinitely: I can disable the application to >>>>>>>>> drain traffic and force GCs, but the # of NIO buffers and NIO >>>>>>>>> allocated space stays flat. >>>>>>>>> >>>>>>>>> The issue is likely related to slow readers. However, the leak >>>>>>>>> persists long after all channels have been closed. >>>>>>>>> >>>>>>>>> I implemented a writability listener and the leak does appear to go >>>>>>>>> away if I stop writing to a channel after it goes unwritable. This is >>>>>>>>> good, but I’m still worried that this just makes the problem less >>>>>>>>> likely since it’s still possible to write/flush and have pending >>>>>>>>> data: writability just limits how much data will be buffered. >>>>>>>>> >>>>>>>>> Digging into ChannelOutBoundBuffer I see the following stanza in >>>>>>>>> close: >>>>>>>>> >>>>>>>>> >>>>>>>>> // Release all unflushed messages. >>>>>>>>> try { >>>>>>>>> Entry e = unflushedEntry; >>>>>>>>> while (e != null) { >>>>>>>>> // Just decrease; do not trigger any events via >>>>>>>>> decrementPendingOutboundBytes() >>>>>>>>> int size = e.pendingSize; >>>>>>>>> TOTAL_PENDING_SIZE_UPDATER.addAndGet(this, -size); >>>>>>>>> >>>>>>>>> if (!e.cancelled) { >>>>>>>>> ReferenceCountUtil.safeRelease(e.msg); >>>>>>>>> safeFail(e.promise, cause); >>>>>>>>> } >>>>>>>>> e = e.recycleAndGetNext(); >>>>>>>>> } >>>>>>>>> } finally { >>>>>>>>> inFail = false; >>>>>>>>> } >>>>>>>>> clearNioBuffers(); >>>>>>>>> This seems a bit curious to me: why are flushed buffers not released >>>>>>>>> here? Since the leak seems to be rooted in the Recycler, this could >>>>>>>>> be the culprit…What do you think? >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> You received this message because you are subscribed to the Google >>>>>>>>> Groups "Netty discussions" group. >>>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>>> send an email to [email protected] <>. >>>>>>>>> To view this discussion on the web visit >>>>>>>>> https://groups.google.com/d/msgid/netty/CA%2B%3DgZKADssKFcs-WCc8%2Br2RWrvbgg3csaJPdcsXL_mCD5yG2bg%40mail.gmail.com >>>>>>>>> >>>>>>>>> <https://groups.google.com/d/msgid/netty/CA%2B%3DgZKADssKFcs-WCc8%2Br2RWrvbgg3csaJPdcsXL_mCD5yG2bg%40mail.gmail.com?utm_medium=email&utm_source=footer>. >>>>>>>>> For more options, visit https://groups.google.com/d/optout >>>>>>>>> <https://groups.google.com/d/optout>. >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "Netty discussions" group. 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