The patch titled Subject: mm/damon/sysfs: fix wrong empty schemes assumption under online tuning in damon_sysfs_set_schemes() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-damon-sysfs-fix-wrong-empty-schemes-assumption-under-online-tuning-in-damon_sysfs_set_schemes.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: SeongJae Park sj@kernel.org Subject: mm/damon/sysfs: fix wrong empty schemes assumption under online tuning in damon_sysfs_set_schemes() Date: Tue, 22 Nov 2022 19:48:31 +0000

Commit da87878010e5 ("mm/damon/sysfs: support online inputs update") made 'damon_sysfs_set_schemes()' to be called for running DAMON context, which could have schemes. In the case, DAMON sysfs interface is supposed to update, remove, or add schemes to reflect the sysfs files. However, the code is assuming the DAMON context wouldn't have schemes at all, and therefore creates and adds new schemes. As a result, the code doesn't work as intended for online schemes tuning and could have more than expected memory footprint. The schemes are all in the DAMON context, so it doesn't leak the memory, though.

Remove the wrong asssumption (the DAMON context wouldn't have schemes) in 'damon_sysfs_set_schemes()' to fix the bug.

Link: https://lkml.kernel.org/r/20221122194831.3472-1-sj@kernel.org Fixes: da87878010e5 ("mm/damon/sysfs: support online inputs update") Signed-off-by: SeongJae Park sj@kernel.org Cc: stable@vger.kernel.org [5.19+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/damon/sysfs.c | 46 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 44 insertions(+), 2 deletions(-)

--- a/mm/damon/sysfs.c~mm-damon-sysfs-fix-wrong-empty-schemes-assumption-under-online-tuning-in-damon_sysfs_set_schemes +++ a/mm/damon/sysfs.c @@ -2283,12 +2283,54 @@ static struct damos *damon_sysfs_mk_sche &wmarks); }

+static void damon_sysfs_update_scheme(struct damos *scheme, + struct damon_sysfs_scheme *sysfs_scheme) +{ + struct damon_sysfs_access_pattern *access_pattern = + sysfs_scheme->access_pattern; + struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas; + struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights; + struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks; + + scheme->pattern.min_sz_region = access_pattern->sz->min; + scheme->pattern.max_sz_region = access_pattern->sz->max; + scheme->pattern.min_nr_accesses = access_pattern->nr_accesses->min; + scheme->pattern.max_nr_accesses = access_pattern->nr_accesses->max; + scheme->pattern.min_age_region = access_pattern->age->min; + scheme->pattern.max_age_region = access_pattern->age->max; + + scheme->action = sysfs_scheme->action; + + scheme->quota.ms = sysfs_quotas->ms; + scheme->quota.sz = sysfs_quotas->sz; + scheme->quota.reset_interval = sysfs_quotas->reset_interval_ms; + scheme->quota.weight_sz = sysfs_weights->sz; + scheme->quota.weight_nr_accesses = sysfs_weights->nr_accesses; + scheme->quota.weight_age = sysfs_weights->age; + + scheme->wmarks.metric = sysfs_wmarks->metric; + scheme->wmarks.interval = sysfs_wmarks->interval_us; + scheme->wmarks.high = sysfs_wmarks->high; + scheme->wmarks.mid = sysfs_wmarks->mid; + scheme->wmarks.low = sysfs_wmarks->low; +} + static int damon_sysfs_set_schemes(struct damon_ctx *ctx, struct damon_sysfs_schemes *sysfs_schemes) { - int i; + struct damos *scheme, *next; + int i = 0; + + damon_for_each_scheme_safe(scheme, next, ctx) { + if (i < sysfs_schemes->nr) + damon_sysfs_update_scheme(scheme, + sysfs_schemes->schemes_arr[i]); + else + damon_destroy_scheme(scheme); + i++; + }

- for (i = 0; i < sysfs_schemes->nr; i++) { + for (; i < sysfs_schemes->nr; i++) { struct damos *scheme, *next;

scheme = damon_sysfs_mk_scheme(sysfs_schemes->schemes_arr[i]); _

Patches currently in -mm which might be from sj@kernel.org are

mm-damon-sysfs-schemes-skip-stats-update-if-the-scheme-directory-is-removed.patch mm-damon-sysfs-fix-wrong-empty-schemes-assumption-under-online-tuning-in-damon_sysfs_set_schemes.patch mm-damon-core-split-out-damos-charged-region-skip-logic-into-a-new-function.patch mm-damon-core-split-damos-application-logic-into-a-new-function.patch mm-damon-core-split-out-scheme-stat-update-logic-into-a-new-function.patch mm-damon-core-split-out-scheme-quota-adjustment-logic-into-a-new-function.patch mm-damon-sysfs-use-damon_addr_range-for-regions-start-and-end-values.patch mm-damon-sysfs-remove-parameters-of-damon_sysfs_region_alloc.patch mm-damon-sysfs-move-sysfs_lock-to-common-module.patch mm-damon-sysfs-move-unsigned-long-range-directory-to-common-module.patch mm-damon-sysfs-split-out-kdamond-independent-schemes-stats-update-logic-into-a-new-function.patch mm-damon-sysfs-split-out-schemes-directory-implementation-to-separate-file.patch mm-damon-modules-deduplicate-init-steps-for-damon-context-setup.patch mm-damon-reclaimlru_sort-remove-unnecessarily-included-headers.patch mm-damon-reclaim-enable-and-disable-synchronously.patch selftests-damon-add-tests-for-damon_reclaims-enabled-parameter.patch mm-damon-lru_sort-enable-and-disable-synchronously.patch selftests-damon-add-tests-for-damon_lru_sorts-enabled-parameter.patch docs-admin-guide-mm-damon-usage-describe-the-rules-of-sysfs-region-directories.patch docs-admin-guide-mm-damon-usage-fix-wrong-usage-example-of-init_regions-file.patch mm-damon-core-add-a-callback-for-scheme-target-regions-check.patch mm-damon-sysfs-schemes-implement-schemes-tried_regions-directory.patch mm-damon-sysfs-schemes-implement-scheme-region-directory.patch mm-damon-sysfs-implement-damos-tried-regions-update-command.patch mm-damon-sysfs-implement-damos-tried-regions-update-command-fix.patch mm-damon-sysfs-schemes-implement-damos-tried-regions-clear-command.patch mm-damon-sysfs-schemes-implement-damos-tried-regions-clear-command-fix.patch tools-selftets-damon-sysfs-test-tried_regions-directory-existence.patch docs-admin-guide-mm-damon-usage-document-schemes-s-tried_regions-sysfs-directory.patch docs-abi-damon-document-schemes-s-tried_regions-sysfs-directory.patch selftests-damon-test-non-context-inputs-to-rm_contexts-file.patch