On 4/30/20 2:59 PM, Kirill A. Shutemov wrote:
On Thu, Apr 30, 2020 at 06:56:21AM +0800, Yang Shi wrote:The max_ptes_{swap|none|shared} are defined to tune the behavior of khugepaged. The are checked at a couple of places with open coding. Replace the opencoding to exceed_pax_ptes_{swap|none_shared} helpers to improve the readability. Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> --- mm/khugepaged.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index a02a4c5..0c8d30b 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -339,6 +339,21 @@ struct attribute_group khugepaged_attr_group = { }; #endif /* CONFIG_SYSFS */+static inline bool exceed_max_ptes_none(unsigned int *nr_ptes)+{ + return (++(*nr_ptes) > khugepaged_max_ptes_none); +} + +static inline bool exceed_max_ptes_swap(unsigned int *nr_ptes) +{ + return (++(*nr_ptes) > khugepaged_max_ptes_swap); +} + +static inline bool exceed_max_ptes_shared(unsigned int *nr_ptes) +{ + return (++(*nr_ptes) > khugepaged_max_ptes_shared); +} +Frankly, I find this ugly and confusing. Open-coded version is more readable to me.
I'm sorry you feel that way. I tend to agree that dereference looks not good. The open-coded version is not hard to understand to me either.
They are checked at a couple of different places with different variables, i.e. unmapped vs swap, and with different comparisons, > vs <=. I just thought the helpers with unified name started with "exceed_" may make it more self-explained and readable. Anyway this totally depends on taste and I really don't insist on this change.
