From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/writeback: minor clean up for highmem_dirtyable_memory
Since commit a804552b9a15 ("mm/page-writeback.c: fix dirty_balance_reserve
subtraction from dirtyable memory"), local variable x can not be negative.
And it can not overflow when it is the total number of dirtyable highmem
pages. Thus remove the unneeded comment and overflow check.
Link: https://lkml.kernel.org/r/20220224115416.46089-1-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page-writeback.c | 12 ------------
1 file changed, 12 deletions(-)
--- a/mm/page-writeback.c~mm-writeback-minor-clean-up-for-highmem_dirtyable_memory
+++ a/mm/page-writeback.c
@@ -324,18 +324,6 @@ static unsigned long highmem_dirtyable_m
}
/*
- * Unreclaimable memory (kernel memory or anonymous memory
- * without swap) can bring down the dirtyable pages below
- * the zone's dirty balance reserve and the above calculation
- * will underflow. However we still want to add in nodes
- * which are below threshold (negative values) to get a more
- * accurate calculation but make sure that the total never
- * underflows.
- */
- if ((long)x < 0)
- x = 0;
-
- /*
* Make sure that the number of highmem pages is never larger
* than the number of the total dirtyable memory. This can only
* occur in very strange VM situations but we want to make sure
_
