diff options
Diffstat (limited to 'mm/ksm.c')
| -rw-r--r-- | mm/ksm.c | 135 |
1 files changed, 21 insertions, 114 deletions
@@ -1891,21 +1891,24 @@ struct page *ksm_might_need_to_copy(struct page *page, return new_page; } -int page_referenced_ksm(struct page *page, struct mem_cgroup *memcg, - unsigned long *vm_flags) +int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc) { struct stable_node *stable_node; struct rmap_item *rmap_item; - unsigned int mapcount = page_mapcount(page); - int referenced = 0; + int ret = SWAP_AGAIN; int search_new_forks = 0; - VM_BUG_ON(!PageKsm(page)); - VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON_PAGE(!PageKsm(page), page); + + /* + * Rely on the page lock to protect against concurrent modifications + * to that page's node of the stable tree. + */ + VM_BUG_ON_PAGE(!PageLocked(page), page); stable_node = page_stable_node(page); if (!stable_node) - return 0; + return ret; again: hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) { struct anon_vma *anon_vma = rmap_item->anon_vma; @@ -1928,113 +1931,16 @@ again: if ((rmap_item->mm == vma->vm_mm) == search_new_forks) continue; - if (memcg && !mm_match_cgroup(vma->vm_mm, memcg)) - continue; - - referenced += page_referenced_one(page, vma, - rmap_item->address, &mapcount, vm_flags); - if (!search_new_forks || !mapcount) - break; - } - anon_vma_unlock_read(anon_vma); - if (!mapcount) - goto out; - } - if (!search_new_forks++) - goto again; -out: - return referenced; -} - -int try_to_unmap_ksm(struct page *page, enum ttu_flags flags) -{ - struct stable_node *stable_node; - struct rmap_item *rmap_item; - int ret = SWAP_AGAIN; - int search_new_forks = 0; - - VM_BUG_ON(!PageKsm(page)); - VM_BUG_ON(!PageLocked(page)); - - stable_node = page_stable_node(page); - if (!stable_node) - return SWAP_FAIL; -again: - hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) { - struct anon_vma *anon_vma = rmap_item->anon_vma; - struct anon_vma_chain *vmac; - struct vm_area_struct *vma; - - anon_vma_lock_read(anon_vma); - anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, - 0, ULONG_MAX) { - vma = vmac->vma; - if (rmap_item->address < vma->vm_start || - rmap_item->address >= vma->vm_end) - continue; - /* - * Initially we examine only the vma which covers this - * rmap_item; but later, if there is still work to do, - * we examine covering vmas in other mms: in case they - * were forked from the original since ksmd passed. - */ - if ((rmap_item->mm == vma->vm_mm) == search_new_forks) + if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg)) continue; - ret = try_to_unmap_one(page, vma, - rmap_item->address, flags); - if (ret != SWAP_AGAIN || !page_mapped(page)) { + ret = rwc->rmap_one(page, vma, + rmap_item->address, rwc->arg); + if (ret != SWAP_AGAIN) { anon_vma_unlock_read(anon_vma); goto out; } - } - anon_vma_unlock_read(anon_vma); - } - if (!search_new_forks++) - goto again; -out: - return ret; -} - -#ifdef CONFIG_MIGRATION -int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *, - struct vm_area_struct *, unsigned long, void *), void *arg) -{ - struct stable_node *stable_node; - struct rmap_item *rmap_item; - int ret = SWAP_AGAIN; - int search_new_forks = 0; - - VM_BUG_ON(!PageKsm(page)); - VM_BUG_ON(!PageLocked(page)); - - stable_node = page_stable_node(page); - if (!stable_node) - return ret; -again: - hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) { - struct anon_vma *anon_vma = rmap_item->anon_vma; - struct anon_vma_chain *vmac; - struct vm_area_struct *vma; - - anon_vma_lock_read(anon_vma); - anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, - 0, ULONG_MAX) { - vma = vmac->vma; - if (rmap_item->address < vma->vm_start || - rmap_item->address >= vma->vm_end) - continue; - /* - * Initially we examine only the vma which covers this - * rmap_item; but later, if there is still work to do, - * we examine covering vmas in other mms: in case they - * were forked from the original since ksmd passed. - */ - if ((rmap_item->mm == vma->vm_mm) == search_new_forks) - continue; - - ret = rmap_one(page, vma, rmap_item->address, arg); - if (ret != SWAP_AGAIN) { + if (rwc->done && rwc->done(page)) { anon_vma_unlock_read(anon_vma); goto out; } @@ -2047,17 +1953,18 @@ out: return ret; } +#ifdef CONFIG_MIGRATION void ksm_migrate_page(struct page *newpage, struct page *oldpage) { struct stable_node *stable_node; - VM_BUG_ON(!PageLocked(oldpage)); - VM_BUG_ON(!PageLocked(newpage)); - VM_BUG_ON(newpage->mapping != oldpage->mapping); + VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage); + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); + VM_BUG_ON_PAGE(newpage->mapping != oldpage->mapping, newpage); stable_node = page_stable_node(newpage); if (stable_node) { - VM_BUG_ON(stable_node->kpfn != page_to_pfn(oldpage)); + VM_BUG_ON_PAGE(stable_node->kpfn != page_to_pfn(oldpage), oldpage); stable_node->kpfn = page_to_pfn(newpage); /* * newpage->mapping was set in advance; now we need smp_wmb() @@ -2438,4 +2345,4 @@ out_free: out: return err; } -module_init(ksm_init) +subsys_initcall(ksm_init); |