+ x86-add-support-for-pud-sized-transparent-hugepages-checkpatch-fixes.patch added to -mm tree

On Wed, Mar 09, 2016 at 01:45:40PM -0500, Matthew Wilcox wrote:
> > In fact even before starting to fix the comment, I would recommend to
> > try again to call native_local_pmdp_get_and_clear and
> > native_local_ptep_get_and_clear to verify if it still breaks, just in
> > case the include ordering got fixed by accident in the meanwhile (that
> > was a comment in 2.6.25 when arch/x86/include/asm didn't even exist
> > yet, it was still in include/asm-x86). If it would manage to build
> > without the manual expansion, the comment could go and the duplication
> > as well.
>
> The ordering problem is still there.  native_local_ptep_get_and_clear()
> is declared at line 726 of asm/pgtable.h and asm/pgtable_64.h is included
> at line 466 of asm/pgtable.h.
>
> I'll have a little play; see if I can resolve this ...

asm/pgtable.h:466

asm/pgtable.h:726
static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
{
        pte_t res = *ptep;

        /* Pure native function needs no input for mm, addr */
        native_pte_clear(NULL, 0, ptep);
        return res;
}

asm/pgtable_64.h:47
static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr,
                                    pte_t *ptep)
{
        *ptep = native_make_pte(0);
}

asm/pgtable_64.h:73
static inline pte_t native_ptep_get_and_clear(pte_t *xp)
{
        return native_make_pte(xchg(&xp->pte, 0));
        /* native_local_ptep_get_and_clear,
           but duplicated because of cyclic dependency */
        pte_t ret = *xp;
        native_pte_clear(NULL, 0, xp);
        return ret;
}

Why don't we just convert native_ptep_get_and_clear to work the same way that
pgtable-2level and pgtable-3level work?  ie:

static inline pte_t native_ptep_get_and_clear(pte_t *xp)
{
        return native_make_pte(xchg(&xp->pte, 0));
}

Or perhaps better, centralise the non-SMP definitions:

 arch/x86/include/asm/pgtable-2level.h |  6 ------
 arch/x86/include/asm/pgtable-3level.h |  7 +------
 arch/x86/include/asm/pgtable.h        |  5 +++++
 arch/x86/include/asm/pgtable_64.h     | 18 ++----------------
 4 files changed, 8 insertions(+), 28 deletions(-)

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
4 files changed