From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B23C31F9AC; Wed, 2 Sep 2026 02:55:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788317749; cv=none; b=hYbaGvgYO627QX1YrCNFEMgjZRO6ZdtyK9tFUfLmalDhsjXcqudItm9b98MyYKWyENwr6ff6lPALwxZNuNDBG8fpvRgbjWx8C3donOa4VHSMqASk24D6lOPS9yZ6yZSssqqhp2LBnPAp/nmS/KU/nYgQhCLwl4VjDp9An5aoYEI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788317749; c=relaxed/simple; bh=NaoaSBlS+DgdYtL3sNFRga7o+bN4A787+ju70cdYb1Y=; h=Date:To:From:Subject:Message-Id; b=fj45XyjeZq5x85UP5cMpmrjXkZwcPeHQ1cv7jA9CpILgOmUXYPl7iV/Ky2YER1GRzMN1G9sLiYIrT8w/NAGgADeY6CeEgPlktw+iRt+XYyNgArF/BLFEmv9g5GU2PI7zpM52e70h4qYH57IWW8208HTrYId8rVyd1/Pif7CeRNI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=ijyciQKw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ijyciQKw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A441F1F000E9; Wed, 2 Sep 2026 02:55:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788317747; bh=XrH/boMVa4pLRXFR1JyiFi287EWlfnZXBEHMgPpi75c=; h=Date:To:From:Subject; b=ijyciQKw9foAlauhmpYtpjFmVRJ7qWJAQQeYfZJzjPe64Zh/15biGFImtDbP6w/Sm kFYWQvptIt/SOCPloAIgV7F4NuNJSKu5zfWvkPLUretP5+ErVLs0rbgyiLokLgsBQh wuTmWdzSMr/v72M9qoClRPZgnNFdD8jyxLdcp5Lw= Date: Tue, 01 Sep 2026 19:55:47 -0700 To: mm-commits@vger.kernel.org,yanquanmin1@huawei.com,stable@vger.kernel.org,davidgow@davidgow.net,brendan.higgins@linux.dev,sj@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch added to mm-new branch Message-Id: <20260902025547.A441F1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/damon/sysfs: set next refresh jiffies per sysfs context has been added to the -mm mm-new branch. Its filename is mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: SJ Park Subject: mm/damon/sysfs: set next refresh jiffies per sysfs context Date: Tue, 1 Sep 2026 17:27:23 -0700 When 'refresh_ms' is set, DAMON sysfs interface periodically updates auto-tuned parameters and DAMOS stats. The timestamp for the next refresh is initialized when a DAMON context starts, and updated in its damon_call() callback function. That is, each DAMON context updates it. However, the timestamp is a global variable that is shared with all the contexts. When there are multiple DAMON contexts having different refresh_ms, the update frequency will be changed, depending on the order of the contexts. When there are multiple kdamonds, it will be even more chaotic. Fix the problem by having the timestamp per each context. The user impact is not very critical. It does not leak, corrupt or crash. The update will not be faster or slower than the lowest and largest refresh_ms values of the contexts, respectively. The user can also manually ask the updates on demand using kdamond state commands. That said, clearly this is a bug and can easily be reproduced. Link: https://lore.kernel.org/20260902002725.108635-5-sj@kernel.org Fixes: 9fd7bb5083d1 ("mm/damon/sysfs: change next_update_jiffies to a global variable") Signed-off-by: SJ Park Cc: Brendan Higgins Cc: David Gow Cc: Quanmin Yan Cc: # 6.18.x Signed-off-by: Andrew Morton --- mm/damon/sysfs.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) --- a/mm/damon/sysfs.c~mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context +++ a/mm/damon/sysfs.c @@ -2034,6 +2034,7 @@ struct damon_sysfs_kdamond { struct damon_sysfs_contexts *contexts; struct damon_ctx *damon_ctx; unsigned int refresh_ms; + unsigned long next_refresh_jiffies; }; static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void) @@ -2484,17 +2485,15 @@ static struct damon_ctx *damon_sysfs_bui return ctx; } -static unsigned long damon_sysfs_next_update_jiffies; - static int damon_sysfs_repeat_call_fn(void *data) { struct damon_sysfs_kdamond *sysfs_kdamond = data; if (!sysfs_kdamond->refresh_ms) return 0; - if (time_before(jiffies, damon_sysfs_next_update_jiffies)) + if (time_before(jiffies, sysfs_kdamond->next_refresh_jiffies)) return 0; - damon_sysfs_next_update_jiffies = jiffies + + sysfs_kdamond->next_refresh_jiffies = jiffies + msecs_to_jiffies(sysfs_kdamond->refresh_ms); if (!mutex_trylock(&damon_sysfs_lock)) @@ -2542,8 +2541,8 @@ static int damon_sysfs_turn_damon_on(str } kdamond->damon_ctx = ctx; - damon_sysfs_next_update_jiffies = - jiffies + msecs_to_jiffies(kdamond->refresh_ms); + kdamond->next_refresh_jiffies = jiffies + + msecs_to_jiffies(kdamond->refresh_ms); repeat_call_control->fn = damon_sysfs_repeat_call_fn; repeat_call_control->data = kdamond; _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-core-skip-applying-scheme-if-region-split-for-quota-fails.patch mm-damon-paddr-respect-folio-end-for-damos_stat.patch mm-damon-paddr-respect-folio-end-for-damos-actions-except-stat.patch mm-damon-vaddr-respect-folio-end-for-damos_stat.patch mm-damon-vaddr-respect-folio-end-for-damos_migrate_hotcold.patch mm-damon-core-handle-extreme-memory-state-in-damon_get_node_mem_bp.patch mm-damon-core-handle-extreme-memory-state-in-get_node_memcg_used_bp.patch mm-damon-core-handle-extreme-memory-state-in-get_in_active_mem_bp.patch mm-damon-core-introduce-damon_filter_type_pgidle_unset.patch mm-damon-paddr-support-pgidle_unset-probe-filter-type.patch mm-damon-sysfs-support-pgidle_unset-probe-filter-type.patch docs-mm-damon-design-document-pgidle_unset-probe-filter-type.patch mm-damon-core-introduce-damon_prep-struct.patch mm-damon-core-commit-preps.patch mm-damon-core-introduce-damon_operations-prep_probes.patch mm-damon-paddr-support-damon_prep.patch mm-damon-sysfs-implement-preps-directory.patch mm-damon-sysfs-implement-preps-nr_preps-file.patch mm-damon-sysfs-create-directories-for-nr_preps-writes.patch mm-damon-sysfs-implement-prep_action-file.patch mm-damon-sysfs-pass-preps-to-damon-core.patch selftests-damon-sysfssh-test-probe-prep-sysfs-files.patch docs-mm-damon-design-document-probe-preps.patch docs-admin-guide-mm-damon-usage-document-probe-preps-sysfs-files.patch docs-abi-damon-document-probe-prep-sysfs-files.patch mm-damon-tests-core-kunit-test-committing-psi-goal-to-psi-goal.patch mm-damon-core-handle-uninitialized-damos_quota_goal-last_psi_total.patch mm-damon-core-copy-nid-for-eligible_mem_bp-damos-quota-goal-commit.patch mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch