Messages in this thread | | | Date | Wed, 28 May 2014 11:27:17 +0200 | From | Borislav Petkov <> | Subject | Re: [RFC 2/2] x86_64: expand kernel stack to 16K |
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On Wed, May 28, 2014 at 03:53:59PM +0900, Minchan Kim wrote: > While I play inhouse patches with much memory pressure on qemu-kvm, > 3.14 kernel was randomly crashed. The reason was kernel stack overflow. > > When I investigated the problem, the callstack was a little bit deeper > by involve with reclaim functions but not direct reclaim path. > > I tried to diet stack size of some functions related with alloc/reclaim > so did a hundred of byte but overflow was't disappeard so that I encounter > overflow by another deeper callstack on reclaim/allocator path. > > Of course, we might sweep every sites we have found for reducing > stack usage but I'm not sure how long it saves the world(surely, > lots of developer start to add nice features which will use stack > agains) and if we consider another more complex feature in I/O layer > and/or reclaim path, it might be better to increase stack size( > meanwhile, stack usage on 64bit machine was doubled compared to 32bit > while it have sticked to 8K. Hmm, it's not a fair to me and arm64 > already expaned to 16K. )
Hmm, stupid question: what happens when 16K is not enough too, do we increase again? When do we stop increasing? 1M, 2M... ?
Sounds like we want to make it a config option with a couple of sizes for everyone to be happy. :-)
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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