On Thu, Jun 21, 2018 at 8:55 PM Huang, Ying <ying.huang@xxxxxxxxx> wrote: > > From: Huang Ying <ying.huang@xxxxxxxxx> > > Previously, the PMD swap operations are only enabled for > CONFIG_ARCH_ENABLE_THP_MIGRATION. Because they are only used by the > THP migration support. We will support PMD swap mapping to the huge > swap cluster and swapin the THP as a whole. That will be enabled via > CONFIG_THP_SWAP and needs these PMD swap operations. So enable the > PMD swap operations for CONFIG_THP_SWAP too. > > Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> > Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > Cc: Shaohua Li <shli@xxxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > Cc: Zi Yan <zi.yan@xxxxxxxxxxxxxx> > Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> > --- > arch/x86/include/asm/pgtable.h | 2 +- > include/asm-generic/pgtable.h | 2 +- > include/linux/swapops.h | 44 ++++++++++++++++++++++-------------------- > 3 files changed, 25 insertions(+), 23 deletions(-) > > diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h > index 99ecde23c3ec..13bf58838daf 100644 > --- a/arch/x86/include/asm/pgtable.h > +++ b/arch/x86/include/asm/pgtable.h > @@ -1224,7 +1224,7 @@ static inline pte_t pte_swp_clear_soft_dirty(pte_t pte) > return pte_clear_flags(pte, _PAGE_SWP_SOFT_DIRTY); > } > > -#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION > +#if defined(CONFIG_ARCH_ENABLE_THP_MIGRATION) || defined(CONFIG_THP_SWAP) How about introducing a new config symbol representing the common infrastructure between the two and have them select that symbol. Would that also allow us to clean up the usage of CONFIG_ARCH_ENABLE_THP_MIGRATION in fs/proc/task_mmu.c? In other words, what's the point of having nice ifdef'd alternatives in header files when ifdefs are still showing up in C files, all of it should be optionally determined by header files.
