From: Liew Rui Yan <aethernet65535@gmail.com>
To: Liew Rui Yan <aethernet65535@gmail.com>
Cc: damon@lists.linux.dev, linux-mm@kvack.org, SJ Park <sj@kernel.org>
Subject: Re: [RFC] mm/damon/damo: saving damon sysfs configuration
Date: Thu, 8 Oct 2026 20:09:05 +0800 [thread overview]
Message-ID: <20261008120916.4612-1-aethernet65535@gmail.com> (raw)
In-Reply-To: <20260930100031.7338-1-aethernet65535@gmail.com>
Hi SJ,
Just a reminder, I think you might have missed the question I asked.
On Wed, 30 Sep 2026 17:58:54 +0800 Liew Rui Yan <aethernet65535@gmail.com> wrote:
> On Tue, 29 Sep 2026 00:43:00 -0700 SJ Park <sj@kernel.org> wrote:
>
> > Hi Liew,
> >
> > On Tue, 29 Sep 2026 03:13:06 +0800 Liew Rui Yan <aethernet65535@gmail.com> wrote:
> >
> > > Hi SJ and Community,
> > >
> > > I've noticed that damo [1] doesn't seem to have a feature for saving
> > > DAMON SYSFS configuration. I tried 'damo args damon', but it doesn't
> > > save the DAMOS schemes information.
> >
> > If so, it is a bug. Could you share more details including how the issue can
> > be reproduced? Directly sending a PR should also be fine.
>
> Yes, this can be reproduced easily.
>
> # make sure DAMON is started
> $ sudo ./damo args damon > damo_args_damon.json
> $ sudo ./damo report damon --json > damo_report_damon.json
>
> $ sudo ./damo stop
>
> $ sudo ./damo start --kdamonds damo_args_damon.json
> $ sudo ./damo report damon --json > damo_report_damon_after.json
>
> $ diff damo_report_damon.json damo_report_damon_after.json
> 4c4
> < "pid": "4959",
> ---
> > "pid": "5582",
> 16,17c16,17
> < "start": "4,294,967,296",
> < "end": "15,807,283,199"
> ---
> > "start": "4,096",
> > "end": "15,807,283,200"
> 25c25
> < "ops_update_us": "1 m",
> ---
> > "ops_update_us": "1 s",
> 46,159c46
> < "schemes": [
> < {
> < "action": "pageout",
> < "dests": [],
> < "access_pattern": {
> < "sz_bytes": {
> < "min": "4.000 KiB",
> < "max": "max"
> < },
> < "nr_accesses": {
> < "min": "0 samples",
> < "max": "0 samples"
> < },
> < "age": {
> < "min": "60,000 aggr_intervals",
> < "max": "18,446,744,073,709,551,615 aggr_intervals"
> < }
> < },
> < "apply_interval_us": "0 ns",
> < "quotas": {
> < "time_ms": "0 ns",
> < "sz_bytes": "16.000 MiB",
> < "reset_interval_ms": "1 s",
> < "fail_charge_num": "0",
> < "fail_charge_denom": "0",
> < "goals": [
> < {
> < "metric": "user_input",
> < "nid": "0",
> < "memcg_path": "",
> < "target_value": "3,000",
> < "current_value": "7,855"
> < }
> < ],
> < "goal_tuner": "temporal\n",
> < "effective_sz_bytes": "0 B",
> < "weights": {
> < "sz_permil": "0 %",
> < "nr_accesses_permil": "0 %",
> < "age_permil": "0 %"
> < }
> < },
> < "watermarks": {
> < "metric": "none",
> < "interval_us": "0 ns",
> < "high_permil": "0 %",
> < "mid_permil": "0 %",
> < "low_permil": "0 %"
> < },
> < "filters": [],
> < "stats": {
> < "nr_tried": "0",
> < "sz_tried": "0 B",
> < "nr_applied": "0",
> < "sz_applied": "0 B",
> < "sz_ops_filter_passed": "0 B",
> < "qt_exceeds": "19",
> < "nr_snapshots": "0",
> < "max_nr_snapshots": "0"
> < }
> < },
> < {
> < "action": "stat",
> < "dests": [],
> < "access_pattern": {
> < "sz_bytes": {
> < "min": "0 B",
> < "max": "max"
> < },
> < "nr_accesses": {
> < "min": "0 samples",
> < "max": "18,446,744,073,709,551,615 samples"
> < },
> < "age": {
> < "min": "0 aggr_intervals",
> < "max": "18,446,744,073,709,551,615 aggr_intervals"
> < }
> < },
> < "apply_interval_us": "0 ns",
> < "quotas": {
> < "time_ms": "0 ns",
> < "sz_bytes": "0 B",
> < "reset_interval_ms": "0 ns",
> < "fail_charge_num": "0",
> < "fail_charge_denom": "0",
> < "goals": [],
> < "goal_tuner": "consist\n",
> < "effective_sz_bytes": "0 B",
> < "weights": {
> < "sz_permil": "0 %",
> < "nr_accesses_permil": "0 %",
> < "age_permil": "0 %"
> < }
> < },
> < "watermarks": {
> < "metric": "none",
> < "interval_us": "0 ns",
> < "high_permil": "0 %",
> < "mid_permil": "0 %",
> < "low_permil": "0 %"
> < },
> < "filters": [],
> < "stats": {
> < "nr_tried": "2,000",
> < "sz_tried": "1.801 TiB",
> < "nr_applied": "0",
> < "sz_applied": "0 B",
> < "sz_ops_filter_passed": "0 B",
> < "qt_exceeds": "0",
> < "nr_snapshots": "172",
> < "max_nr_snapshots": "0"
> < }
> < }
> < ]
> ---
> > "schemes": []
>
> >
> > > 'damo report damon --json' provides
> > > more detailed information, but its output cannot be read by 'damo start
> > > --kdamonds'.
> >
> > Maybe this is also an issue that we could fix.
>
> In my opinion, this is not an issue, since there's no documentation
> recommending we use the 'damo report damon --json' to generate
> configuration for 'damo start --kdamonds'.
>
> >
> > >
> > > I'd like to know if there is currently any way in damo to save the DAMON
> > > SYSFS configuration that can be correctly read by 'damo start
> > > --kdamonds'. If not, would it be worth adding one?
> >
> > I believe it would be useful. Please feel free to send a PR.
> >
> > Nonetheless, we added the json/yaml kdamonds config support mainly because
> > there was no good way to flexibly configure kdamonds with the command line
> > interface. Now it is much more improved [1].
>
> Thank you for clarifying this!
>
> >
> > I'd recommend using the command line interface. That is, you could copy your
> > command line setup in a bash script and modify/reuse it.
> >
> > Is there a use case that it cannot work or suboptimum?
>
> No, CLI (Command Line Interface) do very convenience. I can write my
> configuration in CLI and it is very readable. Thank you for letting me
> know this feature!
>
> #!/bin/bash
>
> # update-damon-config.sh
>
> ./damo args damon \
> --kdamond --damon_ctx --ops paddr \
> --monitoring_intervals 5000 100000 1000000 \
> --damon_target --regions 4294967296-15807283199 \
> --damos_scheme --damos_action pageout \
> --damos_sz_region 4096 18446744073709551615 \
> --damos_access_rate 0 0 \
> --damos_age 600000000 18446744073709551615 \
> --damos_quota_goal user_input 3000 10000 \
> --damos_quota_goal_tuner temporal \
> --damos_quota_interval 1000 \
> --damos_quota_time 0 \
> --damos_quota_space 16777216 \
> --damos_quota_weights 0 0 0 \
> > config.json
>
> >
> > [1] https://github.com/damonitor/damo/issues/3#issuecomment-5655965736
>
> [...]
>
> Best regards,
> Rui Yan
>
next prev parent reply other threads:[~2026-10-08 12:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-28 19:13 [RFC] mm/damon/damo: saving damon sysfs configuration Liew Rui Yan
2026-09-29 7:43 ` SJ Park
2026-09-30 9:58 ` Liew Rui Yan
2026-10-08 12:09 ` Liew Rui Yan [this message]
2026-10-08 12:32 ` SJ Park
2026-10-08 13:44 ` Liew Rui Yan
2026-10-08 15:00 ` SJ Park
2026-10-08 16:14 ` Liew Rui Yan
2026-10-09 8:01 ` SJ Park
2026-10-09 12:08 ` Liew Rui Yan
2026-10-09 14:00 ` SJ Park
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