[PATCH v1] mm/rmap: cleanup partially-mapped handling in __folio_remove_rmap()
From: David Hildenbrand
Date: Tue Jun 18 2024 - 11:11:49 EST
Let's simplify and reduce code indentation. In the RMAP_LEVEL_PTE case, we
already check for nr when computing partially_mapped.
For RMAP_LEVEL_PMD, it's a bit more confusing. Likely, we don't need the
"nr" check, but we could have "nr < nr_pmdmapped" also if we stumbled
into the "/* Raced ahead of another remove and an add? */" case. So
let's simply move the nr check in there.
Note that partially_mapped is always false for small folios.
No functional change intended.
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
mm/rmap.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index afec4b6800caf..aa900e46cdf82 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1551,11 +1551,12 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
}
}
- partially_mapped = nr < nr_pmdmapped;
+ partially_mapped = nr && nr < nr_pmdmapped;
break;
}
- if (nr) {
+ if (partially_mapped && folio_test_anon(folio) &&
+ list_empty(&folio->_deferred_list))
/*
* Queue anon large folio for deferred split if at least one
* page of the folio is unmapped and at least one page
@@ -1563,10 +1564,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
*
* Check partially_mapped first to ensure it is a large folio.
*/
- if (folio_test_anon(folio) && partially_mapped &&
- list_empty(&folio->_deferred_list))
- deferred_split_folio(folio);
- }
+ deferred_split_folio(folio);
__folio_mod_stat(folio, -nr, -nr_pmdmapped);
/*
--
2.45.2