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mm-damon-vaddr-respect-folio-end-for-damos_migrate_hotcold.patch removed from -mm tree

merged mm-stable Andrew Morton 1 participant 1 message Oct 7 Stable branch

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The quilt patch titled

     Subject: mm/damon/vaddr: respect folio end for DAMOS_MIGRATE_{HOT,COLD}

has been removed from the -mm tree. Its filename was
mm-damon-vaddr-respect-folio-end-for-damos_migrate_hotcold.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: SJ Park <[email protected]>
Subject: mm/damon/vaddr: respect folio end for DAMOS_MIGRATE_{HOT,COLD}
Date: Tue, 1 Sep 2026 06:18:46 -0700

For applying DAMOS_MIGRATE_{HOT,COLD} actions to a region, DAMON virtual address space operation set (vaddr) calls walk_page_range[_vma]() for the region. The pmd walk entry function, namely damon_va_migrate_pmd_entry(), collects folios of addresses of the region in the pmd. It starts from the walking address and advances the address by the size of the folio of the address until it goes out of the pmd or the region.

Let's suppose it is for the first pmd of the region, and the region start address is in the middle of a large folio. Also, the next folios are small. Then, some of the next folios could be skipped. Fix the issue by advancing the address to exactly the start address of the next folio.

The user impact is that DAMOS action is applied to less than expected amount of memory. Given the best effort nature of DAMON, it is no big problem, but it is clearly a bug that is better to be fixed.

The issue was discovered [1] by Sashiko.

Fixes 09efc56a3b1c ("mm/damon/vaddr: consistently use only pmd_entry for damos_migrate")
Cc Usama Arif <[email protected]>
Cc <[email protected]> # 6.19.x

---

 mm/damon/vaddr.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
mm/damon/vaddr.c renamed from mm/damon/vaddr.c~mm-damon-vaddr-respect-folio-end-for-damos_migrate_hotcold +4 -1
@@ -676,6 +676,8 @@ huge_out:
 		return 0;
 
 	for (; addr < next; pte += nr, addr += nr * PAGE_SIZE) {
+		unsigned long page_idx;
+
 		nr = 1;
 		ptent = ptep_get(pte);
 
@@ -688,7 +690,8 @@ huge_out:
 			continue;
 		damos_va_migrate_dests_add(folio, walk->vma, addr, dests,
 				migration_lists);
-		nr = folio_nr_pages(folio);
+		page_idx = folio_page_idx(folio, pte_page(ptent));
+		nr = folio_nr_pages(folio) - page_idx;
 	}
 	pte_unmap_unlock(start_pte, ptl);
 	return 0;

_

Patches currently in -mm which might be from [email protected] are

mm-damon-core-use-damon_nr_samples_per_aggr-for-max-merge-threshold.patch mm-damon-core-remove-debug-messages.patch mm-damon-core-remove-debug-messages-fix.patch mm-damon-vaddr-remove-a-debug-message.patch mm-damon-core-validate-number-of-probes-in-valid_probe_params.patch mm-damon-sysfs-remove-probes-number-validation.patch mm-damon-tests-core-kunit-extend-set_regions-test-for-error-case.patch mm-damon-tests-core-kunit-test-=0-size-damon_set_regions-inputs.patch mm-damon-tests-core-kunit-test-overlapping-ranges-for-set_regions.patch mm-damon-tests-core-kunit-test-damon_nr_samples_per_aggr.patch selftests-damon-sysfssh-test-hugepage_mem_bp-quota-goal.patch docs-mm-damon-maintainer-profile-update-ai-review-for-sashiko-replies.patch docs-abi-damon-recommend-subsystem-doc-instead-of-admin-guide.patch mm-damon-core-error-damos_commit_quota_goal-for-zero-target_value.patch revert-mm-damon-lru_sort-error-out-for-10000-active_mem_bp.patch revert-samples-damon-mtier-error-out-for-zero-quota-goal-target-values.patch mm-damon-core-handle-null-ctx-parameter-in-damon_call.patch mm-damon-core-set-ctx-call_controls_obsolete-in-damon_new_ctx.patch mm-damon-reclaim-remove-unnecessary-damon_call-param-validation.patch mm-damon-lru_sort-remove-unnecessary-damon_call-param-validation.patch mm-damon-vaddr-support-prep_probes.patch mm-damon-paddr-move-probe-filter-handling-to-ops-common.patch mm-damon-vaddr-support-apply_probe.patch mm-damon-vaddr-extend-apply_probes-for-hugetlb.patch mm-damon-vaddr-support-pgidle_unset-probe-filter-type.patch mm-damon-api-introduce-damon_filter_type_pgidle_set.patch mm-damon-paddr-support-damon_filter_type_pgidle_set.patch mm-damon-vaddr-support-damon_filter_type_pgidle_set.patch mm-damon-sysfs-support-damon_filter_type_pgidle_set.patch docs-mm-damon-design-update-for-pgidle_set-probe-filter.patch mm-damon-api-introduce-damos_filter_type_probe_hits_wsum.patch mm-damon-api-introduce-damos_filter_type_probe_hits_wsum-fix.patch mm-damon-core-extend-probe_hits_wsum-for-moving-sum-based-calculation.patch mm-damon-core-support-probe_hits_wsum-damos-core-filter.patch mm-damon-sysfs-schemes-rename-sysfs_filter-sz_range-to-range_minmax.patch mm-damon-sysfs-schemes-support-probe_hits_wsum-damos-core-filter.patch docs-mm-damon-design-update-for-probe_hits_wsum-damos-core-filter.patch docs-admin-guide-mm-damon-usage-update-for-probe_hits_wsum-damos-filter.patch mm-damon-sysfs-schemes-read-sysfs_filter-addr_range-only-once.patch mm-damon-sysfs-schemes-read-sysfs_filter-sz_range-only-once.patch mm-damon-core-return-an-error-from-damos_commit_filter_arg.patch mm-damon-core-disallow-max-min-damos-filter-range-arguments-commit.patch mm-damon-sysfs-schemes-drop-centralized-filter-range-arg-validations.patch mm-damon-sysfs-schemes-use-switch-case-in-add_scheme_filters.patch mm-damon-core-kunit-extend-damos_commit_filter_for-for-wrong-input.patch mm-damon-core-kunit-test-invalid-damos-filter-commits.patch mm-damon-api-introduce-damon_filter_type_hugepage_size.patch mm-damon-core-commit-hugepage_size-type-damon-filter.patch mm-damon-ops-common-support-hugepage_size-damon-filter-matching.patch mm-damon-sysfs-add-minmax-files-under-probe-filter-directory.patch mm-damon-sysfs-support-hugepage_size-probe-filter.patch docs-mm-damon-design-update-for-hugepage_size-probe-filter.patch docs-admin-guide-mm-damon-usage-update-for-hugepage_size.patch docs-abi-damon-update-for-hugepage_size-probe-filter.patch mm-damon-api-remove-nr_damos_filter_types.patch mm-damon-core-use-abs_diff-in-damon_feed_loop_next_input.patch mm-damon-core-use-mult_frac-in-damon_feed_loop_next_input.patch mm-damon-core-set-damon_ctx-walk_control_obsolete-in-damon_new_ctx.patch mm-damon-core-document-damon_call-damon_start-race-hang-issue.patch mm-damon-paddr-remove-pa-parameter-from-damon_pa_filter_pass.patch mm-damon-tests-core-kunit-test-eligible_mem_bp-commitment.patch mm-damon-tests-core-kunit-add-probe_hits_wsum-damos-filter-commit-test.patch selftests-damon-sysfs_memcg_path_leak-fail-only-for-real-damon-leak.patch docs-mm-damon-design-clarify-bp-is-basis-point.patch mm-damon-core-introduce-damos_quota_goal-complement.patch mm-damon-core-add-complement-argument-to-damos_new_quota_goal.patch mm-damon-sysfs-schemes-support-quota-goal-complement-flag.patch mm-damon-tests-core-kunit-test-quota_goal-complement-commit.patch selftests-damon-sysfssh-test-quota-goal-complement-flag-file.patch docs-mm-damon-design-document-damos-quota-goal-complement-flag.patch docs-admin-guide-mm-damon-usage-update-for-quota-goal-complement-file.patch docs-abi-damon-update-for-quota-goal-metric-complement-sysfs-file.patch