mm,ksm: swapoff might need to copy

[karo-tx-linux.git] / mm / swapfile.c

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9b51266413cd92e24e07841fbc6228313a266b2c..c72c648f750c8dbeea3b5d93e7642208aab66466 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -874,11 +874,17 @@ unsigned int count_swap_pages(int type, int free)
 static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
                unsigned long addr, swp_entry_t entry, struct page *page)
 {
+       struct page *swapcache;
        struct mem_cgroup *memcg;
        spinlock_t *ptl;
        pte_t *pte;
        int ret = 1;
 
+       swapcache = page;
+       page = ksm_might_need_to_copy(page, vma, addr);
+       if (unlikely(!page))
+               return -ENOMEM;
+
        if (mem_cgroup_try_charge_swapin(vma->vm_mm, page,
                                         GFP_KERNEL, &memcg)) {
                ret = -ENOMEM;
@@ -897,7 +903,10 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
        get_page(page);
        set_pte_at(vma->vm_mm, addr, pte,
                   pte_mkold(mk_pte(page, vma->vm_page_prot)));
-       page_add_anon_rmap(page, vma, addr);
+       if (page == swapcache)
+               page_add_anon_rmap(page, vma, addr);
+       else /* ksm created a completely new copy */
+               page_add_new_anon_rmap(page, vma, addr);
        mem_cgroup_commit_charge_swapin(page, memcg);
        swap_free(entry);
        /*
@@ -908,6 +917,10 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 out:
        pte_unmap_unlock(pte, ptl);
 out_nolock:
+       if (page != swapcache) {
+               unlock_page(page);
+               put_page(page);
+       }
        return ret;
 }