Commit 63f39737 authored by Yueyang Pan's avatar Yueyang Pan Committed by Andrew Morton
Browse files

mm/damon/vaddr: support stat-purpose DAMOS filters

This patch extends DAMOS_STAT handling of the DAMON operations sets for
virtual address spaces for ops-level DAMOS filters.  It leverages the
walk_page_range to walk the page table and gets the folio from page table.
The last folio scanned is stored in damos->last_applied to prevent double
counting.

Link: https://lkml.kernel.org/r/264a4b5ea202fd73c01b349c9694d8bf9978c441.1754135312.git.pyyjason@gmail.com


Signed-off-by: default avatarYueyang Pan <pyyjason@gmail.com>
Reviewed-by: default avatarSeongJae Park <sj@kernel.org>
Cc: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 408b299a
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+102 −1
Original line number Diff line number Diff line
@@ -890,6 +890,107 @@ static unsigned long damos_va_migrate(struct damon_target *target,
	return applied * PAGE_SIZE;
}

struct damos_va_stat_private {
	struct damos *scheme;
	unsigned long *sz_filter_passed;
};

static inline bool damos_va_invalid_folio(struct folio *folio,
		struct damos *s)
{
	return !folio || folio == s->last_applied;
}

static int damos_va_stat_pmd_entry(pmd_t *pmd, unsigned long addr,
		unsigned long next, struct mm_walk *walk)
{
	struct damos_va_stat_private *priv = walk->private;
	struct damos *s = priv->scheme;
	unsigned long *sz_filter_passed = priv->sz_filter_passed;
	struct vm_area_struct *vma = walk->vma;
	struct folio *folio;
	spinlock_t *ptl;
	pte_t *start_pte, *pte, ptent;
	int nr;

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	if (pmd_trans_huge(*pmd)) {
		pmd_t pmde;

		ptl = pmd_trans_huge_lock(pmd, vma);
		if (!ptl)
			return 0;
		pmde = pmdp_get(pmd);
		if (!pmd_present(pmde))
			goto huge_unlock;

		folio = vm_normal_folio_pmd(vma, addr, pmde);

		if (damos_va_invalid_folio(folio, s))
			goto huge_unlock;

		if (!damos_va_filter_out(s, folio, vma, addr, NULL, pmd))
			*sz_filter_passed += folio_size(folio);
		s->last_applied = folio;

huge_unlock:
		spin_unlock(ptl);
		return 0;
	}
#endif
	start_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
	if (!start_pte)
		return 0;

	for (; addr < next; pte += nr, addr += nr * PAGE_SIZE) {
		nr = 1;
		ptent = ptep_get(pte);

		if (pte_none(ptent) || !pte_present(ptent))
			continue;

		folio = vm_normal_folio(vma, addr, ptent);

		if (damos_va_invalid_folio(folio, s))
			continue;

		if (!damos_va_filter_out(s, folio, vma, addr, pte, NULL))
			*sz_filter_passed += folio_size(folio);
		nr = folio_nr_pages(folio);
		s->last_applied = folio;
	}
	pte_unmap_unlock(start_pte, ptl);
	return 0;
}

static unsigned long damos_va_stat(struct damon_target *target,
		struct damon_region *r, struct damos *s,
		unsigned long *sz_filter_passed)
{
	struct damos_va_stat_private priv;
	struct mm_struct *mm;
	struct mm_walk_ops walk_ops = {
		.pmd_entry = damos_va_stat_pmd_entry,
		.walk_lock = PGWALK_RDLOCK,
	};

	priv.scheme = s;
	priv.sz_filter_passed = sz_filter_passed;

	if (!damos_ops_has_filter(s))
		return 0;

	mm = damon_get_mm(target);
	if (!mm)
		return 0;

	mmap_read_lock(mm);
	walk_page_range(mm, r->ar.start, r->ar.end, &walk_ops, &priv);
	mmap_read_unlock(mm);
	mmput(mm);
	return 0;
}

static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx,
		struct damon_target *t, struct damon_region *r,
		struct damos *scheme, unsigned long *sz_filter_passed)
@@ -916,7 +1017,7 @@ static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx,
	case DAMOS_MIGRATE_COLD:
		return damos_va_migrate(t, r, scheme, sz_filter_passed);
	case DAMOS_STAT:
		return 0;
		return damos_va_stat(t, r, scheme, sz_filter_passed);
	default:
		/*
		 * DAMOS actions that are not yet supported by 'vaddr'.