On Friday 27 of August 2010 15:48:02 Hedi Berriche wrote: > On Fri, Aug 27, 2010 at 14:38 Petr Tesarik wrote: > | Hi everybody, > | > | SGI has recently experienced failures with the new ticket spinlock > | implementation. Hedi Berriche sent me a simple test case that can > | trigger the failure on the siglock. > > One more fact, the problem was introduced by commit > > commit 9d40ee200a527ce08ab8c793ba8ae3e242edbb0e > Author: Tony Luck <tony.luck@xxxxxxxxx> > Date: Wed Oct 7 10:54:19 2009 -0700 > > [IA64] Squeeze ticket locks back into 4 bytes. > > Reverting the patch makes the problem go away. > > IOW, and as far as testing shows, the first incarnation of the ticket locks > implementation on IA64 (commit 2c8696), the one that used 8 bytes, does not > exhibit this problem. I wouldn't be so sure about it. Given that I have only observed the problem when the spinlock value wraps around, then an 8-byte spinlock might only need much more time to trigger the bug. Just my two cents, Petr Tesarik L3 International Novell, Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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