From db87a4e236424249c7def768ba50b88699af2c0d Mon Sep 17 00:00:00 2001 From: Bijan Tabatabai Date: Tue, 8 Jul 2025 19:59:43 -0500 Subject: [PATCH] mm/damon/vaddr: apply filters in migrate_{hot/cold} The paddr versions of migrate_{hot/cold} filter out folios from migration based on the scheme's filters. This patch does the same for the vaddr versions of those schemes. The filtering code is mostly the same for the paddr and vaddr versions. The exception is the young filter. paddr determines if a page is young by doing a folio rmap walk to find the page table entries corresponding to the folio. However, vaddr schemes have easier access to the page tables, so we add some logic to avoid the extra work. Link: https://lkml.kernel.org/r/20250709005952.17776-14-bijan311@gmail.com Co-developed-by: Ravi Shankar Jonnalagadda Signed-off-by: Ravi Shankar Jonnalagadda Signed-off-by: Bijan Tabatabai Reviewed-by: SeongJae Park Cc: Jonathan Corbet Signed-off-by: Andrew Morton --- mm/damon/vaddr.c | 69 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 65 insertions(+), 4 deletions(-) diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index 47d5f33f89c88..7f5dc9c221a04 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -611,9 +611,60 @@ static unsigned int damon_va_check_accesses(struct damon_ctx *ctx) return max_nr_accesses; } +static bool damos_va_filter_young_match(struct damos_filter *filter, + struct folio *folio, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, pmd_t *pmdp) +{ + bool young = false; + + if (ptep) + young = pte_young(ptep_get(ptep)); + else if (pmdp) + young = pmd_young(pmdp_get(pmdp)); + + young = young || !folio_test_idle(folio) || + mmu_notifier_test_young(vma->vm_mm, addr); + + if (young && ptep) + damon_ptep_mkold(ptep, vma, addr); + else if (young && pmdp) + damon_pmdp_mkold(pmdp, vma, addr); + + return young == filter->matching; +} + +static bool damos_va_filter_out(struct damos *scheme, struct folio *folio, + struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep, pmd_t *pmdp) +{ + struct damos_filter *filter; + bool matched; + + if (scheme->core_filters_allowed) + return false; + + damos_for_each_ops_filter(filter, scheme) { + /* + * damos_folio_filter_match checks the young filter by doing an + * rmap on the folio to find its page table. However, being the + * vaddr scheme, we have direct access to the page tables, so + * use that instead. + */ + if (filter->type == DAMOS_FILTER_TYPE_YOUNG) + matched = damos_va_filter_young_match(filter, folio, + vma, addr, ptep, pmdp); + else + matched = damos_folio_filter_match(filter, folio); + + if (matched) + return !filter->allow; + } + return scheme->ops_filters_default_reject; +} + struct damos_va_migrate_private { struct list_head *migration_lists; - struct damos_migrate_dests *dests; + struct damos *scheme; }; /* @@ -673,7 +724,8 @@ static int damos_va_migrate_pmd_entry(pmd_t *pmd, unsigned long addr, { struct damos_va_migrate_private *priv = walk->private; struct list_head *migration_lists = priv->migration_lists; - struct damos_migrate_dests *dests = priv->dests; + struct damos *s = priv->scheme; + struct damos_migrate_dests *dests = &s->migrate_dests; struct folio *folio; spinlock_t *ptl; pmd_t pmde; @@ -691,9 +743,13 @@ static int damos_va_migrate_pmd_entry(pmd_t *pmd, unsigned long addr, if (!folio) goto unlock; + if (damos_va_filter_out(s, folio, walk->vma, addr, NULL, pmd)) + goto put_folio; + damos_va_migrate_dests_add(folio, walk->vma, addr, dests, migration_lists); +put_folio: folio_put(folio); unlock: spin_unlock(ptl); @@ -708,7 +764,8 @@ static int damos_va_migrate_pte_entry(pte_t *pte, unsigned long addr, { struct damos_va_migrate_private *priv = walk->private; struct list_head *migration_lists = priv->migration_lists; - struct damos_migrate_dests *dests = priv->dests; + struct damos *s = priv->scheme; + struct damos_migrate_dests *dests = &s->migrate_dests; struct folio *folio; pte_t ptent; @@ -720,9 +777,13 @@ static int damos_va_migrate_pte_entry(pte_t *pte, unsigned long addr, if (!folio) return 0; + if (damos_va_filter_out(s, folio, walk->vma, addr, pte, NULL)) + goto put_folio; + damos_va_migrate_dests_add(folio, walk->vma, addr, dests, migration_lists); +put_folio: folio_put(folio); return 0; } @@ -790,7 +851,7 @@ static unsigned long damos_va_migrate(struct damon_target *target, use_target_nid = dests->nr_dests == 0; nr_dests = use_target_nid ? 1 : dests->nr_dests; - priv.dests = dests; + priv.scheme = s; priv.migration_lists = kmalloc_array(nr_dests, sizeof(*priv.migration_lists), GFP_KERNEL); if (!priv.migration_lists) -- 2.47.2