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-rw-r--r--include/linux/mm.h15
1 files changed, 7 insertions, 8 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index af2904aeb163..bf660d5b6e97 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -532,28 +532,27 @@ extern unsigned int kobjsize(const void *objp);
* possesses it but the other does not, the merged VMA should nonetheless have
* applied to it:
*
+ * VM_SOFTDIRTY - if a VMA is marked soft-dirty, that is has not had its
+ * references cleared via /proc/$pid/clear_refs, any merged VMA
+ * should be considered soft-dirty also as it operates at a VMA
+ * granularity.
+ *
* VM_MAYBE_GUARD - If a VMA may have guard regions in place it implies that
* mapped page tables may contain metadata not described by the
* VMA and thus any merged VMA may also contain this metadata,
* and thus we must make this flag sticky.
*/
-#define VM_STICKY VM_MAYBE_GUARD
+#define VM_STICKY (VM_SOFTDIRTY | VM_MAYBE_GUARD)
/*
* VMA flags we ignore for the purposes of merge, i.e. one VMA possessing one
* of these flags and the other not does not preclude a merge.
*
- * VM_SOFTDIRTY - Should not prevent from VMA merging, if we match the flags but
- * dirty bit -- the caller should mark merged VMA as dirty. If
- * dirty bit won't be excluded from comparison, we increase
- * pressure on the memory system forcing the kernel to generate
- * new VMAs when old one could be extended instead.
- *
* VM_STICKY - When merging VMAs, VMA flags must match, unless they are
* 'sticky'. If any sticky flags exist in either VMA, we simply
* set all of them on the merged VMA.
*/
-#define VM_IGNORE_MERGE (VM_SOFTDIRTY | VM_STICKY)
+#define VM_IGNORE_MERGE VM_STICKY
/*
* Flags which should result in page tables being copied on fork. These are