Messages in this thread | | | Date | Fri, 7 Mar 2008 11:48:49 +0000 | From | Mel Gorman <> | Subject | Re: [BUG] 2.6.25-rc4 hang/softlockups after freeing hugepages |
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On (06/03/08 12:23), Lee Schermerhorn didst pronounce: > Test platform: HP Proliant DL585 server - 4 socket, dual core AMD with > 32GB memory. > > I first saw this on 25-rc2-mm1 with Mel's zonelist patches, while > investigating the interaction of hugepages and cpusets. Thinking that > it might be caused by the zonelist patches, I went back to 25-rc2-mm1 > w/o the patches and saw the same thing. It sometimes takes a while for > the softlockups to start appearing, and I wanted to find a fairly > minimal duplicator. Meanwhile 25-rc3 and rc4 have come out, so I tried > the latest upstream kernel and see the same thing. > > To duplicate the problem, I need only: > > + log into the platform as root in one window and: > > echo N >/proc/sys/vm/nr_hugepages > echo 0 >proc/sys/vm/nr_hugepages >
Uncool, I am going to try and find a machine to reproduce this one but in case I have no luck, can you try setting the following in your .config which may rattle out something please?
CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_DEBUG_SPINLOCK_SLEEP=y CONFIG_DEBUG_VM=y
and as you have DEBUG_INFO, can you say what line is ffffffff8027b693 ?
> In my case, N=64. If I look, before echoing 0, I see 16 hugepages > allocated on each of the 4 nodes, as expected. > > + then in another window, log in again. > > Sometimes it will hang during the 2nd login and I'll never see a shell > prompt.
My initial guess was that is is something to do with page_table_lock but as you didn't get to fault in huge pages, it doesn't make much sense.
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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