Re: [PATCH RESEND v5 1/4] mm/rmap: remove duplicated exit code in pagewalk loop

From: Lance Yang
Date: Tue May 14 2024 - 03:43:43 EST


Hi Baolin,

Thanks for taking time to review!

Best,
Lance

On Tue, May 14, 2024 at 2:26 PM Baolin Wang
<baolin.wang@xxxxxxxxxxxxxxxxx> wrote:
>
>
>
> On 2024/5/13 15:47, Lance Yang wrote:
> > Introduce the labels walk_done and walk_done_err as exit points to
> > eliminate duplicated exit code in the pagewalk loop.
> >
> > Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
> > Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx>
>
> LGTM.
> Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
>
> > ---
> > mm/rmap.c | 40 +++++++++++++++-------------------------
> > 1 file changed, 15 insertions(+), 25 deletions(-)
> >
> > diff --git a/mm/rmap.c b/mm/rmap.c
> > index e8fc5ecb59b2..ddffa30c79fb 100644
> > --- a/mm/rmap.c
> > +++ b/mm/rmap.c
> > @@ -1679,9 +1679,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > /* Restore the mlock which got missed */
> > if (!folio_test_large(folio))
> > mlock_vma_folio(folio, vma);
> > - page_vma_mapped_walk_done(&pvmw);
> > - ret = false;
> > - break;
> > + goto walk_done_err;
> > }
> >
> > pfn = pte_pfn(ptep_get(pvmw.pte));
> > @@ -1719,11 +1717,8 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > */
> > if (!anon) {
> > VM_BUG_ON(!(flags & TTU_RMAP_LOCKED));
> > - if (!hugetlb_vma_trylock_write(vma)) {
> > - page_vma_mapped_walk_done(&pvmw);
> > - ret = false;
> > - break;
> > - }
> > + if (!hugetlb_vma_trylock_write(vma))
> > + goto walk_done_err;
> > if (huge_pmd_unshare(mm, vma, address, pvmw.pte)) {
> > hugetlb_vma_unlock_write(vma);
> > flush_tlb_range(vma,
> > @@ -1738,8 +1733,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > * actual page and drop map count
> > * to zero.
> > */
> > - page_vma_mapped_walk_done(&pvmw);
> > - break;
> > + goto walk_done;
> > }
> > hugetlb_vma_unlock_write(vma);
> > }
> > @@ -1811,9 +1805,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > if (unlikely(folio_test_swapbacked(folio) !=
> > folio_test_swapcache(folio))) {
> > WARN_ON_ONCE(1);
> > - ret = false;
> > - page_vma_mapped_walk_done(&pvmw);
> > - break;
> > + goto walk_done_err;
> > }
> >
> > /* MADV_FREE page check */
> > @@ -1852,23 +1844,17 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > */
> > set_pte_at(mm, address, pvmw.pte, pteval);
> > folio_set_swapbacked(folio);
> > - ret = false;
> > - page_vma_mapped_walk_done(&pvmw);
> > - break;
> > + goto walk_done_err;
> > }
> >
> > if (swap_duplicate(entry) < 0) {
> > set_pte_at(mm, address, pvmw.pte, pteval);
> > - ret = false;
> > - page_vma_mapped_walk_done(&pvmw);
> > - break;
> > + goto walk_done_err;
> > }
> > if (arch_unmap_one(mm, vma, address, pteval) < 0) {
> > swap_free(entry);
> > set_pte_at(mm, address, pvmw.pte, pteval);
> > - ret = false;
> > - page_vma_mapped_walk_done(&pvmw);
> > - break;
> > + goto walk_done_err;
> > }
> >
> > /* See folio_try_share_anon_rmap(): clear PTE first. */
> > @@ -1876,9 +1862,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > folio_try_share_anon_rmap_pte(folio, subpage)) {
> > swap_free(entry);
> > set_pte_at(mm, address, pvmw.pte, pteval);
> > - ret = false;
> > - page_vma_mapped_walk_done(&pvmw);
> > - break;
> > + goto walk_done_err;
> > }
> > if (list_empty(&mm->mmlist)) {
> > spin_lock(&mmlist_lock);
> > @@ -1918,6 +1902,12 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > if (vma->vm_flags & VM_LOCKED)
> > mlock_drain_local();
> > folio_put(folio);
> > + continue;
> > +walk_done_err:
> > + ret = false;
> > +walk_done:
> > + page_vma_mapped_walk_done(&pvmw);
> > + break;
> > }
> >
> > mmu_notifier_invalidate_range_end(&range);