mm: catch memory commitment underflow

PATCH New Konstantin Khlebnikov 1 participant 1 message Sep 13, 2013

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Memory management Memory mapping

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Konstantin Khlebnikov

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2013-09-13 11:03 UTC #0 lore raw

PATCH 1/1 mm: catch memory commitment underflow

This adds debug for vm_committed_as under CONFIG_DEBUG_VM=y

Signed-off-by Konstantin Khlebnikov <[email protected]>

---
 mm/mmap.c |    6 ++++++
 1 file changed, 6 insertions(+)

mm/mmap.c +6 -0

index 9d54851..2c7e6aa 100644
@@ -131,6 +131,12 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 
 	vm_acct_memory(pages);
 
+#ifdef CONFIG_DEBUG_VM
+	WARN_ONCE(percpu_counter_read(&vm_committed_as) <
+			-(s64)vm_committed_as_batch * num_online_cpus(),
+			"memory commitment underflow");
+#endif
+
 	/*
 	 * Sometimes we want to use more memory than we have
 	 */

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