Messages in this thread | | | Subject | RE: [2.6.25-rc5-mm1][regression] ia64: hackbench doesn't finish >12 hour | Date | Tue, 18 Mar 2008 17:14:39 -0700 | From | "Yu, Fenghua" <> |
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>this paramter mean use all physical memory and about 1GB swap space. >Could you expand swap space?
We can reproduce the soft lockup issue now and root cause the issue as well.
Since the ptc.g patch uses semaphore ptcg_sem to serialize multiple ptc.g instructions in ia64_global_tlb_purge(). This requires the code path should be safe to sleep in down(). But the code path can not sleep during swap because it holds some spin locks (e.g. anon_vma_lock). Going to sleep finally causes soft lockup.
Actually we though of this issue before releasing the ptcg patch and wrote some non-sleeping versions of ptcg patches. But since we couldn't see the sleeping issue during our testing, we didn't release a non-sleeping ptcg patch. If replacing the ptcg patch in -mm1 tree with one of our non-sleeping ptcg patches, the issue goes away.
Tony and I are working on releasing a final ptcg patch to solve the issue.
Thanks.
-Fenghua
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