Messages in this thread | | | Subject | Re: [linux-next PATCH 1/2] mm: khugepaged: add exceed_max_ptes_* helpers | From | Yang Shi <> | Date | Thu, 30 Apr 2020 16:59:29 -0700 |
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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@linux.intel.com> >> Cc: Hugh Dickins <hughd@google.com> >> Cc: Andrea Arcangeli <aarcange@redhat.com> >> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> >> --- >> 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.
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