Prepare khugepaged to see compound pages mapped with pte. For now we
won't collapse the pmd table with such pte.
khugepaged is subject for future rework wrt new refcounting.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Tested-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Acked-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
---
include/trace/events/huge_memory.h | 1 +
mm/huge_memory.c | 11 +++++++++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
index 1efc7f1dc9bd..11c59ca5e145 100644
--- a/include/trace/events/huge_memory.h
+++ b/include/trace/events/huge_memory.h
@@ -22,6 +22,7 @@
EM( SCAN_PAGE_LRU, "page_not_in_lru") \
EM( SCAN_PAGE_LOCK, "page_locked") \
EM( SCAN_PAGE_ANON, "page_not_anon") \
+ EM( SCAN_PAGE_COMPOUND, "page_compound") \
EM( SCAN_ANY_PROCESS, "no_process_for_page") \
EM( SCAN_VMA_NULL, "vma_null") \
EM( SCAN_VMA_CHECK, "vma_check_failed") \
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1e87739ceefc..44472136a67f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -46,6 +46,7 @@ enum scan_result {
SCAN_PAGE_LRU,
SCAN_PAGE_LOCK,
SCAN_PAGE_ANON,
+ SCAN_PAGE_COMPOUND,
SCAN_ANY_PROCESS,
SCAN_VMA_NULL,
SCAN_VMA_CHECK,
@@ -2887,6 +2888,13 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
result = SCAN_PAGE_NULL;
goto out_unmap;
}
+
+ /* TODO: teach khugepaged to collapse THP mapped with pte */
+ if (PageCompound(page)) {
+ result = SCAN_PAGE_COMPOUND;
+ goto out_unmap;
+ }
+
/*
* Record which node the original page is from and save this
* information to khugepaged_node_load[].
@@ -2899,9 +2907,8 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
goto out_unmap;
}
khugepaged_node_load[node]++;
- VM_BUG_ON_PAGE(PageCompound(page), page);
if (!PageLRU(page)) {
- result = SCAN_SCAN_ABORT;
+ result = SCAN_SCAN_ABORT;
goto out_unmap;
}
if (PageLocked(page)) {
--
2.5.1
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