@@ -294,6 +294,7 @@ enum lruvec_flags {
};
struct lruvec;
+struct page_vma_mapped_walk;
#define LRU_GEN_MASK ((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF)
#define LRU_USAGE_MASK ((BIT(LRU_USAGE_WIDTH) - 1) << LRU_USAGE_PGOFF)
@@ -382,6 +383,7 @@ struct lrugen {
void lru_gen_init_lruvec(struct lruvec *lruvec);
void lru_gen_set_state(bool enable, bool main, bool swap);
+void lru_gen_scan_around(struct page_vma_mapped_walk *pvmw);
#else /* CONFIG_LRU_GEN */
@@ -393,6 +395,10 @@ static inline void lru_gen_set_state(bool enable, bool main, bool swap)
{
}
+static inline void lru_gen_scan_around(struct page_vma_mapped_walk *pvmw)
+{
+}
+
#endif /* CONFIG_LRU_GEN */
struct lruvec {
@@ -72,6 +72,7 @@
#include <linux/page_idle.h>
#include <linux/memremap.h>
#include <linux/userfaultfd_k.h>
+#include <linux/mm_inline.h>
#include <asm/tlbflush.h>
@@ -792,6 +793,11 @@ static bool page_referenced_one(struct page *page, struct vm_area_struct *vma,
}
if (pvmw.pte) {
+ /* the multigenerational lru exploits the spatial locality */
+ if (lru_gen_enabled() && pte_young(*pvmw.pte)) {
+ lru_gen_scan_around(&pvmw);
+ referenced++;
+ }
if (ptep_clear_flush_young_notify(vma, address,
pvmw.pte)) {
/*
@@ -50,6 +50,8 @@
#include <linux/dax.h>
#include <linux/psi.h>
#include <linux/memory.h>
+#include <linux/pagewalk.h>
+#include <linux/shmem_fs.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -3186,6 +3188,788 @@ static bool get_next_mm(struct mm_walk_args *args, struct mm_struct **iter)
return last;
}
+/******************************************************************************
+ * the aging
+ ******************************************************************************/
+
+static void update_batch_size(struct page *page, int old_gen, int new_gen,
+ struct mm_walk_args *args)
+{
+ int type = page_is_file_lru(page);
+ int zone = page_zonenum(page);
+ int delta = thp_nr_pages(page);
+
+ VM_BUG_ON(old_gen >= MAX_NR_GENS);
+ VM_BUG_ON(new_gen >= MAX_NR_GENS);
+
+ args->batch_size++;
+
+ args->nr_pages[old_gen][type][zone] -= delta;
+ args->nr_pages[new_gen][type][zone] += delta;
+}
+
+static void reset_batch_size(struct lruvec *lruvec, struct mm_walk_args *args)
+{
+ int gen, type, zone;
+ struct lrugen *lrugen = &lruvec->evictable;
+
+ if (!args->batch_size)
+ return;
+
+ args->batch_size = 0;
+
+ spin_lock_irq(&lruvec->lru_lock);
+
+ for_each_gen_type_zone(gen, type, zone) {
+ enum lru_list lru = type * LRU_FILE;
+ int total = args->nr_pages[gen][type][zone];
+
+ if (!total)
+ continue;
+
+ args->nr_pages[gen][type][zone] = 0;
+ WRITE_ONCE(lrugen->sizes[gen][type][zone],
+ lrugen->sizes[gen][type][zone] + total);
+
+ if (lru_gen_is_active(lruvec, gen))
+ lru += LRU_ACTIVE;
+ update_lru_size(lruvec, lru, zone, total);
+ }
+
+ spin_unlock_irq(&lruvec->lru_lock);
+}
+
+static int page_update_gen(struct page *page, int new_gen)
+{
+ int old_gen;
+ unsigned long old_flags, new_flags;
+
+ VM_BUG_ON(new_gen >= MAX_NR_GENS);
+
+ do {
+ old_flags = READ_ONCE(page->flags);
+
+ old_gen = ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
+ if (old_gen < 0) {
+ new_flags = old_flags | BIT(PG_referenced);
+ continue;
+ }
+
+ new_flags = (old_flags & ~(LRU_GEN_MASK | LRU_USAGE_MASK | LRU_TIER_FLAGS)) |
+ ((new_gen + 1UL) << LRU_GEN_PGOFF);
+ } while (new_flags != old_flags &&
+ cmpxchg(&page->flags, old_flags, new_flags) != old_flags);
+
+ return old_gen;
+}
+
+static int should_skip_vma(unsigned long start, unsigned long end, struct mm_walk *walk)
+{
+ struct address_space *mapping;
+ struct vm_area_struct *vma = walk->vma;
+ struct mm_walk_args *args = walk->private;
+
+ if (!vma_is_accessible(vma) || is_vm_hugetlb_page(vma) ||
+ (vma->vm_flags & (VM_LOCKED | VM_SPECIAL)))
+ return true;
+
+ if (vma_is_anonymous(vma))
+ return !args->swappiness;
+
+ if (WARN_ON_ONCE(!vma->vm_file || !vma->vm_file->f_mapping))
+ return true;
+
+ mapping = vma->vm_file->f_mapping;
+ if (!mapping->a_ops->writepage)
+ return true;
+
+ return (shmem_mapping(mapping) && !args->swappiness) || mapping_unevictable(mapping);
+}
+
+/*
+ * Some userspace memory allocators create many single-page VMAs. So instead of
+ * returning back to the PGD table for each of such VMAs, we finish at least an
+ * entire PMD table and therefore avoid many zigzags. This optimizes page table
+ * walks for workloads that have large numbers of tiny VMAs.
+ *
+ * We scan PMD tables in two passes. The first pass reaches to PTE tables and
+ * doesn't take the PMD lock. The second pass clears the accessed bit on PMD
+ * entries and needs to take the PMD lock. The second pass is only done on the
+ * PMD entries that first pass has found the accessed bit is set, namely
+ * 1) leaf entries mapping huge pages from the node under reclaim, and
+ * 2) non-leaf entries whose leaf entries only map pages from the node under
+ * reclaim, when CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG=y.
+ */
+static bool get_next_vma(struct mm_walk *walk, unsigned long mask, unsigned long size,
+ unsigned long *start, unsigned long *end)
+{
+ unsigned long next = round_up(*end, size);
+ struct mm_walk_args *args = walk->private;
+
+ VM_BUG_ON(mask & size);
+ VM_BUG_ON(*start >= *end);
+ VM_BUG_ON((next & mask) != (*start & mask));
+
+ while (walk->vma) {
+ if (next >= walk->vma->vm_end) {
+ walk->vma = walk->vma->vm_next;
+ continue;
+ }
+
+ if ((next & mask) != (walk->vma->vm_start & mask))
+ return false;
+
+ if (should_skip_vma(walk->vma->vm_start, walk->vma->vm_end, walk)) {
+ walk->vma = walk->vma->vm_next;
+ continue;
+ }
+
+ *start = max(next, walk->vma->vm_start);
+ next = (next | ~mask) + 1;
+ /* rounded-up boundaries can wrap to 0 */
+ *end = next && next < walk->vma->vm_end ? next : walk->vma->vm_end;
+
+ args->mm_stats[MM_VMA_INTERVAL]++;
+
+ return true;
+ }
+
+ return false;
+}
+
+static bool walk_pte_range(pmd_t *pmd, unsigned long start, unsigned long end,
+ struct mm_walk *walk)
+{
+ int i;
+ pte_t *pte;
+ spinlock_t *ptl;
+ unsigned long addr;
+ int remote = 0;
+ struct mm_walk_args *args = walk->private;
+ int old_gen, new_gen = lru_gen_from_seq(args->max_seq);
+
+ VM_BUG_ON(pmd_leaf(*pmd));
+
+ pte = pte_offset_map_lock(walk->mm, pmd, start & PMD_MASK, &ptl);
+ arch_enter_lazy_mmu_mode();
+restart:
+ for (i = pte_index(start), addr = start; addr != end; i++, addr += PAGE_SIZE) {
+ struct page *page;
+ unsigned long pfn = pte_pfn(pte[i]);
+
+ if (!pte_present(pte[i]) || is_zero_pfn(pfn)) {
+ args->mm_stats[MM_LEAF_HOLE]++;
+ continue;
+ }
+
+ if (WARN_ON_ONCE(pte_devmap(pte[i]) || pte_special(pte[i])))
+ continue;
+
+ if (!pte_young(pte[i])) {
+ args->mm_stats[MM_LEAF_OLD]++;
+ continue;
+ }
+
+ VM_BUG_ON(!pfn_valid(pfn));
+ if (pfn < args->start_pfn || pfn >= args->end_pfn) {
+ args->mm_stats[MM_LEAF_OTHER_NODE]++;
+ remote++;
+ continue;
+ }
+
+ page = compound_head(pfn_to_page(pfn));
+ if (page_to_nid(page) != args->node_id) {
+ args->mm_stats[MM_LEAF_OTHER_NODE]++;
+ remote++;
+ continue;
+ }
+
+ if (page_memcg_rcu(page) != args->memcg) {
+ args->mm_stats[MM_LEAF_OTHER_MEMCG]++;
+ continue;
+ }
+
+ VM_BUG_ON(addr < walk->vma->vm_start || addr >= walk->vma->vm_end);
+ if (!ptep_test_and_clear_young(walk->vma, addr, pte + i))
+ continue;
+
+ if (pte_dirty(pte[i]) && !PageDirty(page) &&
+ !(PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page))) {
+ set_page_dirty(page);
+ args->mm_stats[MM_LEAF_DIRTY]++;
+ }
+
+ old_gen = page_update_gen(page, new_gen);
+ if (old_gen >= 0 && old_gen != new_gen)
+ update_batch_size(page, old_gen, new_gen, args);
+ args->mm_stats[MM_LEAF_YOUNG]++;
+ }
+
+ if (i < PTRS_PER_PTE && get_next_vma(walk, PMD_MASK, PAGE_SIZE, &start, &end))
+ goto restart;
+
+ arch_leave_lazy_mmu_mode();
+ pte_unmap_unlock(pte, ptl);
+
+ return IS_ENABLED(CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG) && !remote;
+}
+
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG)
+static void __walk_pmd_range(pud_t *pud, unsigned long start,
+ struct vm_area_struct *vma, struct mm_walk *walk)
+{
+ int i;
+ pmd_t *pmd;
+ spinlock_t *ptl;
+ struct mm_walk_args *args = walk->private;
+ int old_gen, new_gen = lru_gen_from_seq(args->max_seq);
+
+ VM_BUG_ON(pud_leaf(*pud));
+
+ start &= PUD_MASK;
+ pmd = pmd_offset(pud, start);
+ ptl = pmd_lock(walk->mm, pmd);
+ arch_enter_lazy_mmu_mode();
+
+ for_each_set_bit(i, args->bitmap, PTRS_PER_PMD) {
+ struct page *page;
+ unsigned long pfn = pmd_pfn(pmd[i]);
+ unsigned long addr = start + i * PMD_SIZE;
+
+ if (!pmd_present(pmd[i]) || is_huge_zero_pmd(pmd[i])) {
+ args->mm_stats[MM_LEAF_HOLE]++;
+ continue;
+ }
+
+ if (WARN_ON_ONCE(pmd_devmap(pmd[i])))
+ continue;
+
+ if (!pmd_young(pmd[i])) {
+ args->mm_stats[MM_LEAF_OLD]++;
+ continue;
+ }
+
+ if (!pmd_trans_huge(pmd[i])) {
+ if (IS_ENABLED(CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG) &&
+ pmdp_test_and_clear_young(vma, addr, pmd + i))
+ args->mm_stats[MM_NONLEAF_YOUNG]++;
+ continue;
+ }
+
+ VM_BUG_ON(!pfn_valid(pfn));
+ if (pfn < args->start_pfn || pfn >= args->end_pfn) {
+ args->mm_stats[MM_LEAF_OTHER_NODE]++;
+ continue;
+ }
+
+ page = pfn_to_page(pfn);
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ if (page_to_nid(page) != args->node_id) {
+ args->mm_stats[MM_LEAF_OTHER_NODE]++;
+ continue;
+ }
+
+ if (page_memcg_rcu(page) != args->memcg) {
+ args->mm_stats[MM_LEAF_OTHER_MEMCG]++;
+ continue;
+ }
+
+ VM_BUG_ON(addr < vma->vm_start || addr >= vma->vm_end);
+ if (!pmdp_test_and_clear_young(vma, addr, pmd + i))
+ continue;
+
+ if (pmd_dirty(pmd[i]) && !PageDirty(page) &&
+ !(PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page))) {
+ set_page_dirty(page);
+ args->mm_stats[MM_LEAF_DIRTY]++;
+ }
+
+ old_gen = page_update_gen(page, new_gen);
+ if (old_gen >= 0 && old_gen != new_gen)
+ update_batch_size(page, old_gen, new_gen, args);
+ args->mm_stats[MM_LEAF_YOUNG]++;
+ }
+
+ arch_leave_lazy_mmu_mode();
+ spin_unlock(ptl);
+
+ bitmap_zero(args->bitmap, PTRS_PER_PMD);
+}
+#else
+static void __walk_pmd_range(pud_t *pud, unsigned long start,
+ struct vm_area_struct *vma, struct mm_walk *walk)
+{
+}
+#endif
+
+static void walk_pmd_range(pud_t *pud, unsigned long start, unsigned long end,
+ struct mm_walk *walk)
+{
+ int i;
+ pmd_t *pmd;
+ unsigned long next;
+ unsigned long addr;
+ struct vm_area_struct *vma;
+ int leaf = 0;
+ int nonleaf = 0;
+ struct mm_walk_args *args = walk->private;
+
+ VM_BUG_ON(pud_leaf(*pud));
+
+ pmd = pmd_offset(pud, start & PUD_MASK);
+restart:
+ vma = walk->vma;
+ for (i = pmd_index(start), addr = start; addr != end; i++, addr = next) {
+ pmd_t val = pmd_read_atomic(pmd + i);
+
+ /* for pmd_read_atomic() */
+ barrier();
+
+ next = pmd_addr_end(addr, end);
+
+ if (!pmd_present(val)) {
+ args->mm_stats[MM_LEAF_HOLE]++;
+ continue;
+ }
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ if (pmd_trans_huge(val)) {
+ unsigned long pfn = pmd_pfn(val);
+
+ if (is_huge_zero_pmd(val)) {
+ args->mm_stats[MM_LEAF_HOLE]++;
+ continue;
+ }
+
+ if (!pmd_young(val)) {
+ args->mm_stats[MM_LEAF_OLD]++;
+ continue;
+ }
+
+ if (pfn < args->start_pfn || pfn >= args->end_pfn) {
+ args->mm_stats[MM_LEAF_OTHER_NODE]++;
+ continue;
+ }
+
+ __set_bit(i, args->bitmap);
+ leaf++;
+ continue;
+ }
+#endif
+
+#ifdef CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG
+ if (!pmd_young(val)) {
+ args->mm_stats[MM_NONLEAF_OLD]++;
+ continue;
+ }
+#endif
+ if (walk_pte_range(&val, addr, next, walk)) {
+ __set_bit(i, args->bitmap);
+ nonleaf++;
+ }
+ }
+
+ if (leaf) {
+ __walk_pmd_range(pud, start, vma, walk);
+ leaf = nonleaf = 0;
+ }
+
+ if (i < PTRS_PER_PMD && get_next_vma(walk, PUD_MASK, PMD_SIZE, &start, &end))
+ goto restart;
+
+ if (nonleaf)
+ __walk_pmd_range(pud, start, vma, walk);
+}
+
+static int walk_pud_range(p4d_t *p4d, unsigned long start, unsigned long end,
+ struct mm_walk *walk)
+{
+ int i;
+ pud_t *pud;
+ unsigned long addr;
+ unsigned long next;
+ struct mm_walk_args *args = walk->private;
+
+ VM_BUG_ON(p4d_leaf(*p4d));
+
+ pud = pud_offset(p4d, start & P4D_MASK);
+restart:
+ for (i = pud_index(start), addr = start; addr != end; i++, addr = next) {
+ pud_t val = READ_ONCE(pud[i]);
+
+ next = pud_addr_end(addr, end);
+
+ if (!pud_present(val) || WARN_ON_ONCE(pud_leaf(val)))
+ continue;
+
+ walk_pmd_range(&val, addr, next, walk);
+
+ if (args->batch_size >= MAX_BATCH_SIZE) {
+ end = (addr | ~PUD_MASK) + 1;
+ goto done;
+ }
+ }
+
+ if (i < PTRS_PER_PUD && get_next_vma(walk, P4D_MASK, PUD_SIZE, &start, &end))
+ goto restart;
+
+ end = round_up(end, P4D_SIZE);
+done:
+ /* rounded-up boundaries can wrap to 0 */
+ args->next_addr = end && walk->vma ? max(end, walk->vma->vm_start) : 0;
+
+ return -EAGAIN;
+}
+
+static void walk_mm(struct mm_walk_args *args, struct mm_struct *mm)
+{
+ static const struct mm_walk_ops mm_walk_ops = {
+ .test_walk = should_skip_vma,
+ .p4d_entry = walk_pud_range,
+ };
+
+ int err;
+ struct mem_cgroup *memcg = args->memcg;
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(args->node_id));
+
+ args->next_addr = FIRST_USER_ADDRESS;
+
+ do {
+ unsigned long start = args->next_addr;
+ unsigned long end = mm->highest_vm_end;
+
+ err = -EBUSY;
+
+ preempt_disable();
+ rcu_read_lock();
+
+#ifdef CONFIG_MEMCG
+ if (memcg && atomic_read(&memcg->moving_account)) {
+ args->mm_stats[MM_LOCK_CONTENTION]++;
+ goto contended;
+ }
+#endif
+ if (!mmap_read_trylock(mm)) {
+ args->mm_stats[MM_LOCK_CONTENTION]++;
+ goto contended;
+ }
+
+ err = walk_page_range(mm, start, end, &mm_walk_ops, args);
+
+ mmap_read_unlock(mm);
+
+ reset_batch_size(lruvec, args);
+contended:
+ rcu_read_unlock();
+ preempt_enable();
+
+ cond_resched();
+ } while (err == -EAGAIN && args->next_addr &&
+ !mm_is_oom_victim(mm) && !mm_has_migrated(mm, memcg));
+}
+
+static void page_inc_gen(struct page *page, struct lruvec *lruvec, bool front)
+{
+ int old_gen, new_gen;
+ unsigned long old_flags, new_flags;
+ int type = page_is_file_lru(page);
+ int zone = page_zonenum(page);
+ struct lrugen *lrugen = &lruvec->evictable;
+
+ old_gen = lru_gen_from_seq(lrugen->min_seq[type]);
+
+ do {
+ old_flags = READ_ONCE(page->flags);
+
+ /* in case the aging has updated old_gen */
+ new_gen = ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
+ VM_BUG_ON_PAGE(new_gen < 0, page);
+ if (new_gen >= 0 && new_gen != old_gen)
+ goto sort;
+
+ new_gen = (old_gen + 1) % MAX_NR_GENS;
+
+ new_flags = (old_flags & ~(LRU_GEN_MASK | LRU_USAGE_MASK | LRU_TIER_FLAGS)) |
+ ((new_gen + 1UL) << LRU_GEN_PGOFF);
+ /* mark the page for reclaim if it's pending writeback */
+ if (front)
+ new_flags |= BIT(PG_reclaim);
+ } while (cmpxchg(&page->flags, old_flags, new_flags) != old_flags);
+
+ lru_gen_update_size(page, lruvec, old_gen, new_gen);
+sort:
+ if (front)
+ list_move(&page->lru, &lrugen->lists[new_gen][type][zone]);
+ else
+ list_move_tail(&page->lru, &lrugen->lists[new_gen][type][zone]);
+}
+
+static bool try_inc_min_seq(struct lruvec *lruvec, int type)
+{
+ int gen, zone;
+ bool success = false;
+ struct lrugen *lrugen = &lruvec->evictable;
+
+ VM_BUG_ON(!seq_is_valid(lruvec));
+
+ while (get_nr_gens(lruvec, type) > MIN_NR_GENS) {
+ gen = lru_gen_from_seq(lrugen->min_seq[type]);
+
+ for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+ if (!list_empty(&lrugen->lists[gen][type][zone]))
+ return success;
+ }
+
+ reset_controller_pos(lruvec, gen, type);
+ WRITE_ONCE(lrugen->min_seq[type], lrugen->min_seq[type] + 1);
+
+ success = true;
+ }
+
+ return success;
+}
+
+static bool inc_min_seq(struct lruvec *lruvec, int type)
+{
+ int gen, zone;
+ int batch_size = 0;
+ struct lrugen *lrugen = &lruvec->evictable;
+
+ VM_BUG_ON(!seq_is_valid(lruvec));
+
+ if (get_nr_gens(lruvec, type) != MAX_NR_GENS)
+ return true;
+
+ gen = lru_gen_from_seq(lrugen->min_seq[type]);
+
+ for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+ struct list_head *head = &lrugen->lists[gen][type][zone];
+
+ while (!list_empty(head)) {
+ struct page *page = lru_to_page(head);
+
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ VM_BUG_ON_PAGE(PageUnevictable(page), page);
+ VM_BUG_ON_PAGE(PageActive(page), page);
+ VM_BUG_ON_PAGE(page_is_file_lru(page) != type, page);
+ VM_BUG_ON_PAGE(page_zonenum(page) != zone, page);
+
+ prefetchw_prev_lru_page(page, head, flags);
+
+ page_inc_gen(page, lruvec, false);
+
+ if (++batch_size == MAX_BATCH_SIZE)
+ return false;
+ }
+
+ VM_BUG_ON(lrugen->sizes[gen][type][zone]);
+ }
+
+ reset_controller_pos(lruvec, gen, type);
+ WRITE_ONCE(lrugen->min_seq[type], lrugen->min_seq[type] + 1);
+
+ return true;
+}
+
+static void inc_max_seq(struct lruvec *lruvec)
+{
+ int gen, type, zone;
+ struct lrugen *lrugen = &lruvec->evictable;
+
+ spin_lock_irq(&lruvec->lru_lock);
+
+ VM_BUG_ON(!seq_is_valid(lruvec));
+
+ for (type = 0; type < ANON_AND_FILE; type++) {
+ if (try_inc_min_seq(lruvec, type))
+ continue;
+
+ while (!inc_min_seq(lruvec, type)) {
+ spin_unlock_irq(&lruvec->lru_lock);
+ cond_resched();
+ spin_lock_irq(&lruvec->lru_lock);
+ }
+ }
+
+ gen = lru_gen_from_seq(lrugen->max_seq - 1);
+ for_each_type_zone(type, zone) {
+ enum lru_list lru = type * LRU_FILE;
+ long total = lrugen->sizes[gen][type][zone];
+
+ if (!total)
+ continue;
+
+ WARN_ON_ONCE(total != (int)total);
+
+ update_lru_size(lruvec, lru, zone, total);
+ update_lru_size(lruvec, lru + LRU_ACTIVE, zone, -total);
+ }
+
+ gen = lru_gen_from_seq(lrugen->max_seq + 1);
+ for_each_type_zone(type, zone) {
+ VM_BUG_ON(lrugen->sizes[gen][type][zone]);
+ VM_BUG_ON(!list_empty(&lrugen->lists[gen][type][zone]));
+ }
+
+ for (type = 0; type < ANON_AND_FILE; type++)
+ reset_controller_pos(lruvec, gen, type);
+
+ WRITE_ONCE(lrugen->timestamps[gen], jiffies);
+ /* make sure all preceding modifications appear first */
+ smp_store_release(&lrugen->max_seq, lrugen->max_seq + 1);
+
+ spin_unlock_irq(&lruvec->lru_lock);
+}
+
+/* Main function used by the foreground, the background and the user-triggered aging. */
+static bool walk_mm_list(struct lruvec *lruvec, unsigned long max_seq,
+ struct scan_control *sc, int swappiness, struct mm_walk_args *args)
+{
+ bool last;
+ bool alloc = !args;
+ struct mm_struct *mm = NULL;
+ struct lrugen *lrugen = &lruvec->evictable;
+ struct pglist_data *pgdat = lruvec_pgdat(lruvec);
+ int nid = pgdat->node_id;
+ struct mem_cgroup *memcg = lruvec_memcg(lruvec);
+ struct lru_gen_mm_list *mm_list = get_mm_list(memcg);
+
+ VM_BUG_ON(max_seq > READ_ONCE(lrugen->max_seq));
+
+ if (alloc) {
+ args = kvzalloc_node(size_of_mm_walk_args(), GFP_KERNEL, nid);
+ if (WARN_ON_ONCE(!args))
+ return false;
+ }
+
+ args->memcg = memcg;
+ args->max_seq = max_seq;
+ args->start_pfn = pgdat->node_start_pfn;
+ args->end_pfn = pgdat_end_pfn(pgdat);
+ args->node_id = nid;
+ args->swappiness = swappiness;
+
+ do {
+ last = get_next_mm(args, &mm);
+ if (mm)
+ walk_mm(args, mm);
+
+ cond_resched();
+ } while (mm);
+
+ if (alloc)
+ kvfree(args);
+
+ if (!last) {
+ /* the foreground aging prefers not to wait */
+ if (!current_is_kswapd() && sc->priority < DEF_PRIORITY - 2)
+ wait_event_killable(mm_list->nodes[nid].wait,
+ max_seq < READ_ONCE(lrugen->max_seq));
+
+ return max_seq < READ_ONCE(lrugen->max_seq);
+ }
+
+ VM_BUG_ON(max_seq != READ_ONCE(lrugen->max_seq));
+
+ inc_max_seq(lruvec);
+
+ /* order against inc_max_seq() */
+ smp_mb();
+ /* either we see any waiters or they will see updated max_seq */
+ if (waitqueue_active(&mm_list->nodes[nid].wait))
+ wake_up_all(&mm_list->nodes[nid].wait);
+
+ wakeup_flusher_threads(WB_REASON_VMSCAN);
+
+ return true;
+}
+
+void lru_gen_scan_around(struct page_vma_mapped_walk *pvmw)
+{
+ int i;
+ pte_t *pte;
+ int old_gen, new_gen;
+ unsigned long start;
+ unsigned long end;
+ unsigned long addr;
+ struct lruvec *lruvec;
+ struct mem_cgroup *memcg;
+ struct pglist_data *pgdat = page_pgdat(pvmw->page);
+ unsigned long bitmap[BITS_TO_LONGS(SWAP_CLUSTER_MAX * 2)] = {};
+
+ lockdep_assert_held(pvmw->ptl);
+ VM_BUG_ON_PAGE(PageTail(pvmw->page), pvmw->page);
+
+ start = max(pvmw->address & PMD_MASK, pvmw->vma->vm_start);
+ end = pmd_addr_end(pvmw->address, pvmw->vma->vm_end);
+
+ if (end - start > SWAP_CLUSTER_MAX * 2 * PAGE_SIZE) {
+ if (pvmw->address - start < SWAP_CLUSTER_MAX * PAGE_SIZE)
+ end = start + SWAP_CLUSTER_MAX * 2 * PAGE_SIZE;
+ else if (end - pvmw->address < SWAP_CLUSTER_MAX * PAGE_SIZE)
+ start = end - SWAP_CLUSTER_MAX * 2 * PAGE_SIZE;
+ else {
+ start = pvmw->address - SWAP_CLUSTER_MAX * PAGE_SIZE;
+ end = pvmw->address + SWAP_CLUSTER_MAX * PAGE_SIZE;
+ }
+ }
+
+ pte = pvmw->pte - (pvmw->address - start) / PAGE_SIZE;
+
+ arch_enter_lazy_mmu_mode();
+
+ lock_page_memcg(pvmw->page);
+ lruvec = lock_page_lruvec_irq(pvmw->page);
+
+ memcg = page_memcg(pvmw->page);
+ new_gen = lru_gen_from_seq(lruvec->evictable.max_seq);
+
+ for (i = 0, addr = start; addr != end; i++, addr += PAGE_SIZE) {
+ struct page *page;
+ unsigned long pfn = pte_pfn(pte[i]);
+
+ if (!pte_present(pte[i]) || is_zero_pfn(pfn))
+ continue;
+
+ if (WARN_ON_ONCE(pte_devmap(pte[i]) || pte_special(pte[i])))
+ continue;
+
+ if (!pte_young(pte[i]))
+ continue;
+
+ VM_BUG_ON(!pfn_valid(pfn));
+ if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat))
+ continue;
+
+ page = compound_head(pfn_to_page(pfn));
+ if (page_to_nid(page) != pgdat->node_id)
+ continue;
+
+ if (page_memcg_rcu(page) != memcg)
+ continue;
+
+ VM_BUG_ON(addr < pvmw->vma->vm_start || addr >= pvmw->vma->vm_end);
+ if (!ptep_test_and_clear_young(pvmw->vma, addr, pte + i))
+ continue;
+
+ if (pte_dirty(pte[i]) && !PageDirty(page) &&
+ !(PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page)))
+ __set_bit(i, bitmap);
+
+ old_gen = page_update_gen(page, new_gen);
+ if (old_gen >= 0 && old_gen != new_gen)
+ lru_gen_update_size(page, lruvec, old_gen, new_gen);
+ }
+
+ unlock_page_lruvec_irq(lruvec);
+ unlock_page_memcg(pvmw->page);
+
+ arch_leave_lazy_mmu_mode();
+
+ for_each_set_bit(i, bitmap, SWAP_CLUSTER_MAX * 2)
+ set_page_dirty(pte_page(pte[i]));
+}
+
/******************************************************************************
* state change
******************************************************************************/
@@ -3415,6 +4199,10 @@ static int __init init_lru_gen(void)
BUILD_BUG_ON(BIT(LRU_GEN_WIDTH) <= MAX_NR_GENS);
BUILD_BUG_ON(sizeof(MM_STAT_CODES) != NR_MM_STATS + 1);
+ VM_BUG_ON(PMD_SIZE / PAGE_SIZE != PTRS_PER_PTE);
+ VM_BUG_ON(PUD_SIZE / PMD_SIZE != PTRS_PER_PMD);
+ VM_BUG_ON(P4D_SIZE / PUD_SIZE != PTRS_PER_PUD);
+
if (mem_cgroup_disabled()) {
global_mm_list = alloc_mm_list();
if (WARN_ON_ONCE(!global_mm_list))