[PATCH v4 3/4] mm/util.c: remove the VM_WARN_ONCE for vm_committed_as underflow check

[Feng Tang]

As is explained by Michal Hocko:

: Looking at the history, this has been added by 82f71ae4a2b8
: ("mm: catch memory commitment underflow") to have a safety check
: for issues which have been fixed. There doesn't seem to be any bug
: reports mentioning this splat since then so it is likely just
: spending cycles for a hot path (yes many people run with DEBUG_VM)
: without a strong reason.

Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Andi Kleen <andi.kleen@xxxxxxxxx>
---
 mm/util.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/mm/util.c b/mm/util.c
index 3c7a08c..fe63271 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -814,14 +814,6 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 {
 	long allowed;
 
-	/*
-	 * A transient decrease in the value is unlikely, so no need
-	 * READ_ONCE() for vm_committed_as.count.
-	 */
-	VM_WARN_ONCE(data_race(percpu_counter_read(&vm_committed_as) <
-			-(s64)vm_committed_as_batch * num_online_cpus()),
-			"memory commitment underflow");
-
 	vm_acct_memory(pages);
 
 	/*
-- 
2.7.4