On Wed, Sep 26, 2018 at 03:11:41PM +0200, Peter Zijlstra wrote:
> On Wed, Sep 26, 2018 at 01:53:35PM +0100, Will Deacon wrote:
> > > +static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
> > > +{
> > > + if (tlb->fullmm)
> > > + return;
> > > +
> > > + /*
> > > + * flush_tlb_range() implementations that look at VM_HUGETLB (tile,
> > > + * mips-4k) flush only large pages.
> > > + *
> > > + * flush_tlb_range() implementations that flush I-TLB also flush D-TLB
> > > + * (tile, xtensa, arm), so it's ok to just add VM_EXEC to an existing
> > > + * range.
> > > + *
> > > + * We rely on tlb_end_vma() to issue a flush, such that when we reset
> > > + * these values the batch is empty.
> > > + */
> > > + tlb->vma_huge = !!(vma->vm_flags & VM_HUGETLB);
> > > + tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);
> >
> > Hmm, does this result in code generation for archs that don't care about the
> > vm_flags?
>
> Yes. It's not much code, but if you deeply care we could frob things to
> get rid of it.
Something a little like the below... not particularly pretty but should
work.
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -305,7 +305,8 @@ static inline void __tlb_reset_range(str
#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma()
#endif
-#define tlb_flush tlb_flush
+#define generic_tlb_flush
+
static inline void tlb_flush(struct mmu_gather *tlb)
{
if (tlb->fullmm || tlb->need_flush_all) {
@@ -391,12 +392,12 @@ static inline unsigned long tlb_get_unma
* the vmas are adjusted to only cover the region to be torn down.
*/
#ifndef tlb_start_vma
-#define tlb_start_vma tlb_start_vma
static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
{
if (tlb->fullmm)
return;
+#ifdef generic_tlb_flush
/*
* flush_tlb_range() implementations that look at VM_HUGETLB (tile,
* mips-4k) flush only large pages.
@@ -410,13 +411,13 @@ static inline void tlb_start_vma(struct
*/
tlb->vma_huge = !!(vma->vm_flags & VM_HUGETLB);
tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);
+#endif
flush_cache_range(vma, vma->vm_start, vma->vm_end);
}
#endif
#ifndef tlb_end_vma
-#define tlb_end_vma tlb_end_vma
static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
{
if (tlb->fullmm)
