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@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
}
/*
- * 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