Re: [GIT TREE] Unified NUMA balancing tree, v3

[Ingo Molnar <mingo@kernel.org>]

* Ingo Molnar <mingo@kernel.org> wrote:

> > If you had read that report, you would know that I didn't 
> > have results for specjbb with THP enabled due to the JVM 
> > crashing with null pointer exceptions.
> 
> Hm, it's the unified tree where most of the mm/ bits are the 
> AutoNUMA bits from your tree. (It does not match 100%, because 
> your tree has an ancient version of key memory usage 
> statistics that the scheduler needs for its convergence model. 
> I'll take a look at the differences.)

Beyond the difference in page frame statistics and the 
difference in the handling of "4K-EMU", the bits below are the 
difference I found (on the THP side) between numa/base-v3 and 
your -v10 tree - but I'm not sure it should have effect on your 
JVM segfault under THP ...

I tried with preemption on/off, debugging on/off, tried your 
.config - none triggers JVM segfaults with 4x JVM or 1x JVM 
SPECjbb tests.

Thanks,

	Ingo

------------------------->
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c25e37c..409b2f3 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -711,8 +711,7 @@ out:
 	 * run pte_offset_map on the pmd, if an huge pmd could
 	 * materialize from under us from a different thread.
 	 */
-	if (unlikely(pmd_none(*pmd)) &&
-	    unlikely(__pte_alloc(mm, vma, pmd, address)))
+	if (unlikely(__pte_alloc(mm, vma, pmd, address)))
 		return VM_FAULT_OOM;
 	/* if an huge pmd materialized from under us just retry later */
 	if (unlikely(pmd_trans_huge(*pmd)))
diff --git a/mm/memory.c b/mm/memory.c
index 8022526..30e1335 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3845,8 +3750,7 @@ retry:
 	 * run pte_offset_map on the pmd, if an huge pmd could
 	 * materialize from under us from a different thread.
 	 */
-	if (unlikely(pmd_none(*pmd)) &&
-	    unlikely(__pte_alloc(mm, vma, pmd, address)))
+	if (unlikely(pmd_none(*pmd)) && __pte_alloc(mm, vma, pmd, address))
 		return VM_FAULT_OOM;
 	/* if an huge pmd materialized from under us just retry later */
 	if (unlikely(pmd_trans_huge(*pmd)))

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