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SubjectRe: linux-next: manual merge of the akpm-current tree with the tip tree
On Fri, Aug 11, 2017 at 01:56:07PM +0200, Ingo Molnar wrote:
> I've done a minimal conflict resolution merge locally. Peter, could you please
> double check my resolution, in:
>
> 040cca3ab2f6: Merge branch 'linus' into locking/core, to resolve conflicts

That merge is a bit wonky, but not terminally broken afaict.

It now does two TLB flushes, the below cleans that up.

---
mm/huge_memory.c | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ce883459e246..08f6c1993832 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1410,7 +1410,6 @@ int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
int page_nid = -1, this_nid = numa_node_id();
int target_nid, last_cpupid = -1;
- bool need_flush = false;
bool page_locked;
bool migrated = false;
bool was_writable;
@@ -1497,22 +1496,18 @@ int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
}

/*
- * The page_table_lock above provides a memory barrier
- * with change_protection_range.
- */
- if (mm_tlb_flush_pending(vma->vm_mm))
- flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);
-
- /*
* Since we took the NUMA fault, we must have observed the !accessible
* bit. Make sure all other CPUs agree with that, to avoid them
* modifying the page we're about to migrate.
*
* Must be done under PTL such that we'll observe the relevant
- * set_tlb_flush_pending().
+ * inc_tlb_flush_pending().
+ *
+ * We are not sure a pending tlb flush here is for a huge page
+ * mapping or not. Hence use the tlb range variant
*/
if (mm_tlb_flush_pending(vma->vm_mm))
- need_flush = true;
+ flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);

/*
* Migrate the THP to the requested node, returns with page unlocked
@@ -1520,13 +1515,6 @@ int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
*/
spin_unlock(vmf->ptl);

- /*
- * We are not sure a pending tlb flush here is for a huge page
- * mapping or not. Hence use the tlb range variant
- */
- if (need_flush)
- flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);
-
migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma,
vmf->pmd, pmd, vmf->address, page, target_nid);
if (migrated) {
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