From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B56B113C9C4 for ; Sun, 3 May 2026 13:16:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777814162; cv=none; b=i/8K2FoI1DPbQde3NLnfQAKQcS8wrpDCdV1iKnQDKJbETVNcE+QNzKGQsYx0JM68s/14mSlUbqCVVpyhuhaf6IM/2t9xNIwwcJqvYjxsUMXJbbLd2jZ4a7fJXSuTizYMEubMZLriwLKYTH2j8wMKlc7D74JVAjX0JtZRqHR6Id4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777814162; c=relaxed/simple; bh=lrQiPgbSnjz82j8AIFeSVulP8S/jWN/FGlt2hZXNvJY=; h=Date:To:From:Subject:Message-Id; b=G7cET0z0cxZwzHC5p//qQ317/Psp/U6CNCk6d/Re4sW2BrLsfmZ/had0YCWNkK/94OG8gyzouDoJvfLad+c5mRY/hwTPAzp+Ms4jesvOWKH+YdUbv3Uf4h9LTt2MlUEX/yx5XpJ4xbLmxTZ+VkmLRtBsotIMR9KqbVwXDj/c49Q= 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=D3c4S6k9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="D3c4S6k9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFE75C2BCB4; Sun, 3 May 2026 13:16:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777814162; bh=lrQiPgbSnjz82j8AIFeSVulP8S/jWN/FGlt2hZXNvJY=; h=Date:To:From:Subject:From; b=D3c4S6k9DSehyXWRyd7OCBwsH9tZTP4Xdvyv+1W7nxN7OfqPh18KFIewHbGLnWUUb wMO86BKsE3Qpw9mmC8h81srmP5BsXHCCpxIf67qhLeceCClvGD2JUiTEjVDmX/ZtF1 XW9hk8gBpgNhkr4pCFbejgnbjTkzln3hC4VFMWqs= Date: Sun, 03 May 2026 06:15:58 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,surenb@google.com,rppt@kernel.org,mhocko@suse.com,ljs@kernel.org,liam@infradead.org,david@kernel.org,corbet@lwn.net,sj@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-damon-stat-add-a-parameter-for-reading-kdamond-pid.patch added to mm-new branch Message-Id: <20260503131601.CFE75C2BCB4@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/stat: add a parameter for reading kdamond pid has been added to the -mm mm-new branch. Its filename is mm-damon-stat-add-a-parameter-for-reading-kdamond-pid.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-stat-add-a-parameter-for-reading-kdamond-pid.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: SeongJae Park Subject: mm/damon/stat: add a parameter for reading kdamond pid Date: Fri, 1 May 2026 19:05:03 -0700 Patch series "mm/damon/stat: add kdamond_pid parameter". DAMON_STAT doesn't provide the pid of its kdamond, unlike DAMON_RECLAIM and DAMON_LRU_SORT. This makes user-space management of DAMON_STAT unnecessarily complicated. Provide the information via a new parameter, namely kdamond_pid, and document it. This patch (of 2): Knowing the pid of the kdamonds can help user-space management including monitoring of DAMON's system resource consumption. To make it easier, DAMON_SYSFS, DAMON_RECLAIM and DAMON_LRU_SORT provide the pid information. DAMON_STAT is not providing it, though. Expose the pid of DAMON_STAT kdamond via a new read-only module parameter, namely kdamond_pid. This also makes DAMON modules usage more standardized, because DAMON_RECLAIM and DAMON_LRU_SORT also provide the information via their read-only parameters of the same name. Link: https://lore.kernel.org/20260502020505.80822-1-sj@kernel.org Link: https://lore.kernel.org/20260502020505.80822-2-sj@kernel.org Signed-off-by: SeongJae Park Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/damon/stat.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) --- a/mm/damon/stat.c~mm-damon-stat-add-a-parameter-for-reading-kdamond-pid +++ a/mm/damon/stat.c @@ -266,6 +266,45 @@ static int damon_stat_enabled_load(char return sprintf(buffer, "%c\n", damon_stat_enabled() ? 'Y' : 'N'); } +static int damon_stat_kdamond_pid_store( + const char *val, const struct kernel_param *kp) +{ + /* + * kdamond_pid is read-only, but kernel command line could write it. + * Do nothing here. + */ + return 0; +} + +static int damon_stat_kdamond_pid_load( + char *buffer, const struct kernel_param *kp) +{ + int pid; + + if (!damon_stat_context) { + pid = -1; + } else { + pid = damon_kdamond_pid(damon_stat_context); + if (pid < 1) + pid = -1; + } + return sprintf(buffer, "%d\n", pid); +} + +static const struct kernel_param_ops kdamond_pid_param_ops = { + .set = damon_stat_kdamond_pid_store, + .get = damon_stat_kdamond_pid_load, +}; + +/* + * PID of the DAMON thread + * + * If DAMON_STAT is enabled, this becomes the PID of the worker thread. + * Else, -1. + */ +module_param_cb(kdamond_pid, &kdamond_pid_param_ops, NULL, 0400); +MODULE_PARM_DESC(kdamond_pid, "pid of the kdamond"); + static int __init damon_stat_init(void) { int err = 0; _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-sysfs-schemes-call-missing-mem_cgroup_iter_break.patch mm-damon-fix-damos_stat-tracepoint-format-for-sz_applied.patch mm-damon-core-make-charge_addr_from-aware-of-end-address-exclusivity.patch mm-damon-core-handle-min_region_sz-remaining-quota-as-empty.patch mm-damon-core-merge-regions-after-applying-damos-schemes.patch mm-damon-core-introduce-failed-region-quota-charge-ratio.patch mm-damon-sysfs-schemes-implement-fail_charge_numdenom-files.patch docs-mm-damon-design-document-fail_charge_numdenom.patch docs-admin-guide-mm-damon-usage-document-fail_charge_numdenom-files.patch docs-abi-damon-document-fail_charge_numdenom.patch mm-damon-tests-core-kunit-test-fail_charge_numdenom-committing.patch selftests-damon-_damon_sysfs-support-failed-region-quota-charge-ratio.patch selftests-damon-drgn_dump_damon_status-support-failed-region-quota-charge-ratio.patch selftests-damon-sysfspy-test-failed-region-quota-charge-ratio.patch docs-mm-damon-maintainer-profile-add-ai-review-usage-guideline.patch mm-damon-core-introduce-damon_ctx-paused.patch mm-damon-sysfs-add-pause-file-under-context-dir.patch docs-mm-damon-design-update-for-context-pause-resume-feature.patch docs-admin-guide-mm-damon-usage-update-for-pause-file.patch docs-abi-damon-update-for-pause-sysfs-file.patch mm-damon-tests-core-kunit-test-pause-commitment.patch selftests-damon-_damon_sysfs-support-pause-file-staging.patch selftests-damon-drgn_dump_damon_status-dump-pause.patch selftests-damon-sysfspy-check-pause-on-assert_ctx_committed.patch selftests-damon-sysfspy-pause-damon-before-dumping-status.patch mm-damon-introduce-damon_set_region_system_rams_default.patch mm-damon-reclaim-cover-all-system-rams.patch mm-damon-lru_sort-cover-all-system-rams.patch mm-damon-core-remove-damon_set_region_biggest_system_ram_default.patch mm-damon-stat-use-damon_set_region_system_rams_default.patch docs-admin-guide-mm-damon-reclaim-update-for-entire-memory-monitoring.patch docs-admin-guide-mm-damon-lru_sort-update-for-entire-memory-monitoring.patch docs-admin-guide-mm-damon-usage-mark-scheme-filters-sysfs-dir-as-deprecated.patch docs-abi-damon-mark-schemes-s-filters-deprecated.patch mm-damon-reclaim-add-autotune_monitoring_intervals-parameter.patch docs-admin-guide-mm-damon-reclaim-update-for-autotune_monitoring_intervals.patch mm-damon-stat-add-a-parameter-for-reading-kdamond-pid.patch docs-admin-guide-mm-damon-stat-document-kdamond_pid-parameter.patch