diff options
| -rw-r--r-- | mm/ksm.c | 48 |
1 files changed, 22 insertions, 26 deletions
@@ -41,6 +41,14 @@ #include <asm/tlbflush.h> #include "internal.h" +#ifdef CONFIG_NUMA +#define NUMA(x) (x) +#define DO_NUMA(x) do { (x); } while (0) +#else +#define NUMA(x) (0) +#define DO_NUMA(x) do { } while (0) +#endif + /* * A few notes about the KSM scanning process, * to make it easier to understand the data structures below: @@ -130,6 +138,7 @@ struct stable_node { * @mm: the memory structure this rmap_item is pointing into * @address: the virtual address this rmap_item tracks (+ flags in low bits) * @oldchecksum: previous checksum of the page at that virtual address + * @nid: NUMA node id of unstable tree in which linked (may not match page) * @node: rb node of this rmap_item in the unstable tree * @head: pointer to stable_node heading this list in the stable tree * @hlist: link into hlist of rmap_items hanging off that stable_node @@ -141,7 +150,7 @@ struct rmap_item { unsigned long address; /* + low bits used for flags below */ unsigned int oldchecksum; /* when unstable */ #ifdef CONFIG_NUMA - unsigned int nid; + int nid; #endif union { struct rb_node node; /* when node of unstable tree */ @@ -192,8 +201,12 @@ static unsigned int ksm_thread_pages_to_scan = 100; /* Milliseconds ksmd should sleep between batches */ static unsigned int ksm_thread_sleep_millisecs = 20; +#ifdef CONFIG_NUMA /* Zeroed when merging across nodes is not allowed */ static unsigned int ksm_merge_across_nodes = 1; +#else +#define ksm_merge_across_nodes 1U +#endif #define KSM_RUN_STOP 0 #define KSM_RUN_MERGE 1 @@ -456,10 +469,7 @@ out: page = NULL; */ static inline int get_kpfn_nid(unsigned long kpfn) { - if (ksm_merge_across_nodes) - return 0; - else - return pfn_to_nid(kpfn); + return ksm_merge_across_nodes ? 0 : pfn_to_nid(kpfn); } static void remove_node_from_stable_tree(struct stable_node *stable_node) @@ -479,7 +489,6 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node) } nid = get_kpfn_nid(stable_node->kpfn); - rb_erase(&stable_node->node, &root_stable_tree[nid]); free_stable_node(stable_node); } @@ -578,13 +587,8 @@ static void remove_rmap_item_from_tree(struct rmap_item *rmap_item) age = (unsigned char)(ksm_scan.seqnr - rmap_item->address); BUG_ON(age > 1); if (!age) -#ifdef CONFIG_NUMA rb_erase(&rmap_item->node, - &root_unstable_tree[rmap_item->nid]); -#else - rb_erase(&rmap_item->node, &root_unstable_tree[0]); -#endif - + &root_unstable_tree[NUMA(rmap_item->nid)]); ksm_pages_unshared--; rmap_item->address &= PAGE_MASK; } @@ -604,7 +608,7 @@ static void remove_trailing_rmap_items(struct mm_slot *mm_slot, } /* - * Though it's very tempting to unmerge in_stable_tree(rmap_item)s rather + * Though it's very tempting to unmerge rmap_items from stable tree rather * than check every pte of a given vma, the locking doesn't quite work for * that - an rmap_item is assigned to the stable tree after inserting ksm * page and upping mmap_sem. Nor does it fit with the way we skip dup'ing @@ -1058,7 +1062,7 @@ static struct page *stable_tree_search(struct page *page) } /* - * stable_tree_insert - insert rmap_item pointing to new ksm page + * stable_tree_insert - insert stable tree node pointing to new ksm page * into the stable tree. * * This function returns the stable tree node just allocated on success, @@ -1108,13 +1112,11 @@ static struct stable_node *stable_tree_insert(struct page *kpage) if (!stable_node) return NULL; - rb_link_node(&stable_node->node, parent, new); - rb_insert_color(&stable_node->node, &root_stable_tree[nid]); - INIT_HLIST_HEAD(&stable_node->hlist); - stable_node->kpfn = kpfn; set_page_stable_node(kpage, stable_node); + rb_link_node(&stable_node->node, parent, new); + rb_insert_color(&stable_node->node, &root_stable_tree[nid]); return stable_node; } @@ -1170,8 +1172,6 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, * If tree_page has been migrated to another NUMA node, it * will be flushed out and put into the right unstable tree * next time: only merge with it if merge_across_nodes. - * Just notice, we don't have similar problem for PageKsm - * because their migration is disabled now. (62b61f611e) */ if (!ksm_merge_across_nodes && page_to_nid(tree_page) != nid) { put_page(tree_page); @@ -1195,9 +1195,7 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, rmap_item->address |= UNSTABLE_FLAG; rmap_item->address |= (ksm_scan.seqnr & SEQNR_MASK); -#ifdef CONFIG_NUMA - rmap_item->nid = nid; -#endif + DO_NUMA(rmap_item->nid = nid); rb_link_node(&rmap_item->node, parent, new); rb_insert_color(&rmap_item->node, root); @@ -1213,13 +1211,11 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, static void stable_tree_append(struct rmap_item *rmap_item, struct stable_node *stable_node) { -#ifdef CONFIG_NUMA /* * Usually rmap_item->nid is already set correctly, * but it may be wrong after switching merge_across_nodes. */ - rmap_item->nid = get_kpfn_nid(stable_node->kpfn); -#endif + DO_NUMA(rmap_item->nid = get_kpfn_nid(stable_node->kpfn)); rmap_item->head = stable_node; rmap_item->address |= STABLE_FLAG; hlist_add_head(&rmap_item->hlist, &stable_node->hlist); |