if (!sc->may_unmap && folio_mapped(folio))
goto keep_locked;
+ /* folio_update_gen() tried to promote this page? */
+ if (lru_gen_enabled() && !ignore_references &&
+ folio_mapped(folio) && folio_test_referenced(folio))
+ goto keep_locked;
+
/*
* The number of dirty pages determines if a node is marked
* reclaim_congested. kswapd will stall and start writing
* the aging
******************************************************************************/
+/* promote pages accessed through page tables */
+static int folio_update_gen(struct folio *folio, int gen)
+{
+ unsigned long new_flags, old_flags = READ_ONCE(folio->flags);
+
+ VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);
+ VM_WARN_ON_ONCE(!rcu_read_lock_held());
+
+ do {
+ /* lru_gen_del_folio() has isolated this page? */
+ if (!(old_flags & LRU_GEN_MASK)) {
+ /* for shrink_page_list() */
+ new_flags = old_flags | BIT(PG_referenced);
+ continue;
+ }
+
+ new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_MASK | LRU_REFS_FLAGS);
+ new_flags |= (gen + 1UL) << LRU_GEN_PGOFF;
+ } while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
+
+ return ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
+}
+
/* protect pages accessed multiple times through file descriptors */
static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
{
VM_WARN_ON_ONCE_FOLIO(!(old_flags & LRU_GEN_MASK), folio);
do {
+ new_gen = ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
+ /* folio_update_gen() has promoted this page? */
+ if (new_gen >= 0 && new_gen != old_gen)
+ return new_gen;
+
new_gen = (old_gen + 1) % MAX_NR_GENS;
new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_MASK | LRU_REFS_FLAGS);
return new_gen;
}
+static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr)
+{
+ unsigned long pfn = pte_pfn(pte);
+
+ VM_WARN_ON_ONCE(addr < vma->vm_start || addr >= vma->vm_end);
+
+ if (!pte_present(pte) || is_zero_pfn(pfn))
+ return -1;
+
+ if (WARN_ON_ONCE(pte_devmap(pte) || pte_special(pte)))
+ return -1;
+
+ if (WARN_ON_ONCE(!pfn_valid(pfn)))
+ return -1;
+
+ return pfn;
+}
+
+static struct folio *get_pfn_folio(unsigned long pfn, struct mem_cgroup *memcg,
+ struct pglist_data *pgdat)
+{
+ struct folio *folio;
+
+ /* try to avoid unnecessary memory loads */
+ if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat))
+ return NULL;
+
+ folio = pfn_folio(pfn);
+ if (folio_nid(folio) != pgdat->node_id)
+ return NULL;
+
+ if (folio_memcg_rcu(folio) != memcg)
+ return NULL;
+
+ return folio;
+}
+
static void inc_min_seq(struct lruvec *lruvec, int type)
{
struct lru_gen_struct *lrugen = &lruvec->lrugen;
} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
}
+/*
+ * This function exploits spatial locality when shrink_page_list() walks the
+ * rmap. It scans the adjacent PTEs of a young PTE and promotes hot pages.
+ */
+void lru_gen_look_around(struct page_vma_mapped_walk *pvmw)
+{
+ int i;
+ pte_t *pte;
+ unsigned long start;
+ unsigned long end;
+ unsigned long addr;
+ unsigned long bitmap[BITS_TO_LONGS(MIN_LRU_BATCH)] = {};
+ struct folio *folio = pfn_folio(pvmw->pfn);
+ struct mem_cgroup *memcg = folio_memcg(folio);
+ struct pglist_data *pgdat = folio_pgdat(folio);
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
+ DEFINE_MAX_SEQ(lruvec);
+ int old_gen, new_gen = lru_gen_from_seq(max_seq);
+
+ lockdep_assert_held(pvmw->ptl);
+ VM_WARN_ON_ONCE_FOLIO(folio_test_lru(folio), folio);
+
+ if (spin_is_contended(pvmw->ptl))
+ return;
+
+ start = max(pvmw->address & PMD_MASK, pvmw->vma->vm_start);
+ end = min(pvmw->address | ~PMD_MASK, pvmw->vma->vm_end - 1) + 1;
+
+ if (end - start > MIN_LRU_BATCH * PAGE_SIZE) {
+ if (pvmw->address - start < MIN_LRU_BATCH * PAGE_SIZE / 2)
+ end = start + MIN_LRU_BATCH * PAGE_SIZE;
+ else if (end - pvmw->address < MIN_LRU_BATCH * PAGE_SIZE / 2)
+ start = end - MIN_LRU_BATCH * PAGE_SIZE;
+ else {
+ start = pvmw->address - MIN_LRU_BATCH * PAGE_SIZE / 2;
+ end = pvmw->address + MIN_LRU_BATCH * PAGE_SIZE / 2;
+ }
+ }
+
+ pte = pvmw->pte - (pvmw->address - start) / PAGE_SIZE;
+
+ rcu_read_lock();
+ arch_enter_lazy_mmu_mode();
+
+ for (i = 0, addr = start; addr != end; i++, addr += PAGE_SIZE) {
+ unsigned long pfn;
+
+ pfn = get_pte_pfn(pte[i], pvmw->vma, addr);
+ if (pfn == -1)
+ continue;
+
+ if (!pte_young(pte[i]))
+ continue;
+
+ folio = get_pfn_folio(pfn, memcg, pgdat);
+ if (!folio)
+ continue;
+
+ if (!ptep_test_and_clear_young(pvmw->vma, addr, pte + i))
+ VM_WARN_ON_ONCE(true);
+
+ if (pte_dirty(pte[i]) && !folio_test_dirty(folio) &&
+ !(folio_test_anon(folio) && folio_test_swapbacked(folio) &&
+ !folio_test_swapcache(folio)))
+ folio_mark_dirty(folio);
+
+ old_gen = folio_lru_gen(folio);
+ if (old_gen < 0)
+ folio_set_referenced(folio);
+ else if (old_gen != new_gen)
+ __set_bit(i, bitmap);
+ }
+
+ arch_leave_lazy_mmu_mode();
+ rcu_read_unlock();
+
+ if (bitmap_weight(bitmap, MIN_LRU_BATCH) < PAGEVEC_SIZE) {
+ for_each_set_bit(i, bitmap, MIN_LRU_BATCH) {
+ folio = pfn_folio(pte_pfn(pte[i]));
+ folio_activate(folio);
+ }
+ return;
+ }
+
+ /* folio_update_gen() requires stable folio_memcg() */
+ if (!mem_cgroup_trylock_pages(memcg))
+ return;
+
+ spin_lock_irq(&lruvec->lru_lock);
+ new_gen = lru_gen_from_seq(lruvec->lrugen.max_seq);
+
+ for_each_set_bit(i, bitmap, MIN_LRU_BATCH) {
+ folio = pfn_folio(pte_pfn(pte[i]));
+ if (folio_memcg_rcu(folio) != memcg)
+ continue;
+
+ old_gen = folio_update_gen(folio, new_gen);
+ if (old_gen < 0 || old_gen == new_gen)
+ continue;
+
+ lru_gen_update_size(lruvec, folio, old_gen, new_gen);
+ }
+
+ spin_unlock_irq(&lruvec->lru_lock);
+
+ mem_cgroup_unlock_pages();
+}
+
/******************************************************************************
* the eviction
******************************************************************************/
return true;
}
+ /* promoted */
+ if (gen != lru_gen_from_seq(lrugen->min_seq[type])) {
+ list_move(&folio->lru, &lrugen->lists[gen][type][zone]);
+ return true;
+ }
+
/* protected */
if (tier > tier_idx) {
int hist = lru_hist_from_seq(lrugen->min_seq[type]);
projects / kernel.git / commitdiff