On 07/23/20 at 10:36am, Anshuman Khandual wrote: > > > On 07/23/2020 08:52 AM, Baoquan He wrote: > > The checking is_migration_entry() and is_hwpoison_entry() are stricter > > than non_swap_entry(), means they have covered the conditional check > > which non_swap_entry() is doing. > > They are no stricter as such but implicitly contains non_swap_entry() in itself. > If a swap entry tests positive for either is_[migration|hwpoison]_entry(), then > its swap_type() is among SWP_MIGRATION_READ, SWP_MIGRATION_WRITE and SWP_HWPOISON. > All these types >= MAX_SWAPFILES, exactly what is asserted with non_swap_entry(). > > > > > Hence remove the unnecessary non_swap_entry() in is_hugetlb_entry_migration() > > and is_hugetlb_entry_hwpoisoned() to simplify code. > > > > Signed-off-by: Baoquan He <bhe@xxxxxxxxxx> > > Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > > Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> > > --- > > mm/hugetlb.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > index 3569e731e66b..c14837854392 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -3748,7 +3748,7 @@ bool is_hugetlb_entry_migration(pte_t pte) > > if (huge_pte_none(pte) || pte_present(pte)) > > return false; > > swp = pte_to_swp_entry(pte); > > - if (non_swap_entry(swp) && is_migration_entry(swp)) > > + if (is_migration_entry(swp)) > > return true; > > else > > return false; > > @@ -3761,7 +3761,7 @@ static bool is_hugetlb_entry_hwpoisoned(pte_t pte) > > if (huge_pte_none(pte) || pte_present(pte)) > > return false; > > swp = pte_to_swp_entry(pte); > > - if (non_swap_entry(swp) && is_hwpoison_entry(swp)) > > + if (is_hwpoison_entry(swp)) > > return true; > > else > > return false; > > > > It would be better if the commit message contains details about > the existing redundant check. But either way. Thanks for your advice. Do you think updating the log as below is OK? ~~~~~~~~ If a swap entry tests positive for either is_[migration|hwpoison]_entry(), then its swap_type() is among SWP_MIGRATION_READ, SWP_MIGRATION_WRITE and SWP_HWPOISON. All these types >= MAX_SWAPFILES, exactly what is asserted with non_swap_entry(). So the checking non_swap_entry() in is_hugetlb_entry_migration() and is_hugetlb_entry_hwpoisoned() is redundant. Let's remove it to optimize code. ~~~~~~~~ Thanks Baoquan
