Re: [PATCH 1/4] thp: clean up __collapse_huge_page_isolate

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On 10/18/2012 06:20 PM, Bob Liu wrote:
Sorry, should be to linux-mm instead of linux-kernel.
It's strange linux-mm not in the result by using
./scripts/get_maintainer.pl -f ./mm/huge_memory.c

On Thu, Oct 18, 2012 at 6:12 PM, Bob Liu <lliubbo@xxxxxxxxx> wrote:
There are duplicated place using release_pte_pages().
And release_all_pte_pages() can also be removed.

this cleanup looks reasonable to me.


Signed-off-by: Bob Liu <lliubbo@xxxxxxxxx>
---
  mm/huge_memory.c |   37 +++++++++++--------------------------
  1 file changed, 11 insertions(+), 26 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a863af2..462d6ea 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1700,64 +1700,49 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte)
         }
  }

-static void release_all_pte_pages(pte_t *pte)
-{
-       release_pte_pages(pte, pte + HPAGE_PMD_NR);
-}
-
  static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
                                         unsigned long address,
                                         pte_t *pte)
  {
         struct page *page;
         pte_t *_pte;
-       int referenced = 0, isolated = 0, none = 0;
+       int referenced = 0, isolated = 1, none = 0;
         for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
              _pte++, address += PAGE_SIZE) {
                 pte_t pteval = *_pte;
                 if (pte_none(pteval)) {
                         if (++none <= khugepaged_max_ptes_none)
                                 continue;
-                       else {
-                               release_pte_pages(pte, _pte);
+                       else
                                 goto out;
-                       }
                 }
-               if (!pte_present(pteval) || !pte_write(pteval)) {
-                       release_pte_pages(pte, _pte);
+               if (!pte_present(pteval) || !pte_write(pteval))
                         goto out;
-               }
                 page = vm_normal_page(vma, address, pteval);
-               if (unlikely(!page)) {
-                       release_pte_pages(pte, _pte);
+               if (unlikely(!page))
                         goto out;
-               }
+
                 VM_BUG_ON(PageCompound(page));
                 BUG_ON(!PageAnon(page));
                 VM_BUG_ON(!PageSwapBacked(page));

                 /* cannot use mapcount: can't collapse if there's a gup pin */
-               if (page_count(page) != 1) {
-                       release_pte_pages(pte, _pte);
+               if (page_count(page) != 1)
                         goto out;
-               }
                 /*
                  * We can do it before isolate_lru_page because the
                  * page can't be freed from under us. NOTE: PG_lock
                  * is needed to serialize against split_huge_page
                  * when invoked from the VM.
                  */
-               if (!trylock_page(page)) {
-                       release_pte_pages(pte, _pte);
+               if (!trylock_page(page))
                         goto out;
-               }
                 /*
                  * Isolate the page to avoid collapsing an hugepage
                  * currently in use by the VM.
                  */
                 if (isolate_lru_page(page)) {
                         unlock_page(page);
-                       release_pte_pages(pte, _pte);
                         goto out;
                 }
                 /* 0 stands for page_is_file_cache(page) == false */
@@ -1770,11 +1755,11 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
                     mmu_notifier_test_young(vma->vm_mm, address))
                         referenced = 1;
         }
-       if (unlikely(!referenced))
-               release_all_pte_pages(pte);
-       else
-               isolated = 1;
+       if (unlikely(!referenced)) {
  out:
+               release_pte_pages(pte, _pte);
+               isolated = 0;
+       }
         return isolated;
  }

--
1.7.9.5





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