From nobody Thu Dec 18 18:24:04 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07BC0EE7FF4 for ; Wed, 13 Sep 2023 02:21:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238164AbjIMCVE (ORCPT ); Tue, 12 Sep 2023 22:21:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238153AbjIMCVC (ORCPT ); Tue, 12 Sep 2023 22:21:02 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 147A3170A; Tue, 12 Sep 2023 19:20:59 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AD12C433C9; Wed, 13 Sep 2023 02:20:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694571658; bh=Ux09g9gvrxiM7e96gBaO1VxVbWHC7sVtSUZj+woij6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MWIXfpIYm9NEP1OadcLcMILX/yRVtaPGkZh+pKnN+/VGHmrzOeD87gZ9c50xSCL8T 8eeLui/pnMGyuouBdR24HUhiq47J7olFaCqiix8Kq4z/bAX4LnLOjmPKCHsgwkMHef 4vIcYFP6dYIErFnn1lFSQTnvXscr8IxyU4/DwmPe4YKJO9t+KHzR+SqXuFkaTXctaQ C7W+xMCx27zSpzYth6tRXZLtIyQRmZqV9TEcus8xqCmCTqqdJA1Drt/Q0F1eBMDPne jqOat7YDtf5VopmWMc2o5kWXNq+AEu4tnoYc2vCsMDbgqBzP1vYASGCIzoaHADaXz3 SWxmmlSa9FS4Q== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , Steven Rostedt , damon@lists.linux.dev, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH RESEND v2 1/2] mm/damon/core: add a tracepoint for damos apply target regions Date: Wed, 13 Sep 2023 02:20:49 +0000 Message-Id: <20230913022050.2109-2-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230913022050.2109-1-sj@kernel.org> References: <20230913022050.2109-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" DAMON provides damon_aggregated tracepoint, which exposes details of each region and its access monitoring results. It is useful for getting whole monitoring results, e.g., for recording purposes. For investigations of DAMOS, DAMON Sysfs interface provides DAMOS statistics and tried_regions directory. But, those provides only statistics and snapshots. If the scheme is frequently applied and if the user needs to know every detail of DAMOS behavior, the snapshot-based interface could be insufficient and expensive. As a last resort, userspace users need to record the all monitoring results via damon_aggregated tracepoint and simulate how DAMOS would worked. It is unnecessarily complicated. DAMON kernel API users, meanwhile, can do that easily via before_damos_apply() callback field of 'struct damon_callback', though. Add a tracepoint that will be called just after before_damos_apply() callback for more convenient investigations of DAMOS. The tracepoint exposes all details about each regions, similar to damon_aggregated tracepoint. Please note that DAMOS is currently not only for memory management but also for query-like efficient monitoring results retrievals (when 'stat' action is used). Until now, only statistics or snapshots were supported. Addition of this tracepoint allows efficient full recording of DAMOS-based filtered monitoring results. Signed-off-by: SeongJae Park Reviewed-by: Steven Rostedt (Google) --- include/trace/events/damon.h | 39 ++++++++++++++++++++++++++++++++++++ mm/damon/core.c | 32 ++++++++++++++++++++++++++++- 2 files changed, 70 insertions(+), 1 deletion(-) diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h index 0b8d13bde17a..19930bb7af9a 100644 --- a/include/trace/events/damon.h +++ b/include/trace/events/damon.h @@ -9,6 +9,45 @@ #include #include =20 +TRACE_EVENT_CONDITION(damos_before_apply, + + TP_PROTO(unsigned int context_idx, unsigned int scheme_idx, + unsigned int target_idx, struct damon_region *r, + unsigned int nr_regions, bool do_trace), + + TP_ARGS(context_idx, target_idx, scheme_idx, r, nr_regions, do_trace), + + TP_CONDITION(do_trace), + + TP_STRUCT__entry( + __field(unsigned int, context_idx) + __field(unsigned int, scheme_idx) + __field(unsigned long, target_idx) + __field(unsigned long, start) + __field(unsigned long, end) + __field(unsigned int, nr_accesses) + __field(unsigned int, age) + __field(unsigned int, nr_regions) + ), + + TP_fast_assign( + __entry->context_idx =3D context_idx; + __entry->scheme_idx =3D scheme_idx; + __entry->target_idx =3D target_idx; + __entry->start =3D r->ar.start; + __entry->end =3D r->ar.end; + __entry->nr_accesses =3D r->nr_accesses; + __entry->age =3D r->age; + __entry->nr_regions =3D nr_regions; + ), + + TP_printk("ctx_idx=3D%u scheme_idx=3D%u target_idx=3D%lu nr_regions=3D%u = %lu-%lu: %u %u", + __entry->context_idx, __entry->scheme_idx, + __entry->target_idx, __entry->nr_regions, + __entry->start, __entry->end, + __entry->nr_accesses, __entry->age) +); + TRACE_EVENT(damon_aggregated, =20 TP_PROTO(unsigned int target_id, struct damon_region *r, diff --git a/mm/damon/core.c b/mm/damon/core.c index ca631dd88b33..3ca34a252a3c 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -950,6 +950,33 @@ static void damos_apply_scheme(struct damon_ctx *c, st= ruct damon_target *t, struct timespec64 begin, end; unsigned long sz_applied =3D 0; int err =3D 0; + /* + * We plan to support multiple context per kdamond, as DAMON sysfs + * implies with 'nr_contexts' file. Nevertheless, only single context + * per kdamond is supported for now. So, we can simply use '0' context + * index here. + */ + unsigned int cidx =3D 0; + struct damos *siter; /* schemes iterator */ + unsigned int sidx =3D 0; + struct damon_target *titer; /* targets iterator */ + unsigned int tidx =3D 0; + bool do_trace =3D false; + + /* get indices for trace_damos_before_apply() */ + if (trace_damos_before_apply_enabled()) { + damon_for_each_scheme(siter, c) { + if (siter =3D=3D s) + break; + sidx++; + } + damon_for_each_target(titer, c) { + if (titer =3D=3D t) + break; + tidx++; + } + do_trace =3D true; + } =20 if (c->ops.apply_scheme) { if (quota->esz && quota->charged_sz + sz > quota->esz) { @@ -964,8 +991,11 @@ static void damos_apply_scheme(struct damon_ctx *c, st= ruct damon_target *t, ktime_get_coarse_ts64(&begin); if (c->callback.before_damos_apply) err =3D c->callback.before_damos_apply(c, t, r, s); - if (!err) + if (!err) { + trace_damos_before_apply(cidx, sidx, tidx, r, + damon_nr_regions(t), do_trace); sz_applied =3D c->ops.apply_scheme(c, t, r, s); + } ktime_get_coarse_ts64(&end); quota->total_charged_ns +=3D timespec64_to_ns(&end) - timespec64_to_ns(&begin); --=20 2.25.1 From nobody Thu Dec 18 18:24:04 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE578EEB57B for ; Wed, 13 Sep 2023 02:21:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238170AbjIMCVG (ORCPT ); Tue, 12 Sep 2023 22:21:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238166AbjIMCVF (ORCPT ); Tue, 12 Sep 2023 22:21:05 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1242E1716; Tue, 12 Sep 2023 19:21:01 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2810DC433C8; Wed, 13 Sep 2023 02:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694571660; bh=yCdyENSSr2jBoqcU5uuhQp9Eg5ZiZzpyIfgAEWQFG08=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G+l4nTmJpLTnnS7zeMq7sUR0wx9A3+mSu7hZCG0AI8qsphhiKn/LA+9HqEahsbJkW 0VIYo5N/jkiNWdz5mJ70XL49dQ1xejMgCB+uYW73vVraKzDPiM3zegf5Y/bgvYN7IZ GFK1gmEqs8YH7k18ckYgFZfPa9qs/iuxvztNwWFzkudCTmJxoaqxbL2/lTf1DP9WWV H5iXINSUW0dB57rg3MTW4mQnxqtXQMBWidwbBIrWXua4awmxZq9qLDfCQrCqK3P3wK uKb+G+s+SL95eFpdJuOuJMiT5S4CRPUVwuI/bAZipHgcHpNPnNf8KjGOw7iRv3DTw1 rjAKkU//Pz6RA== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , Jonathan Corbet , damon@lists.linux.dev, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH RESEND v2 2/2] Docs/admin-guide/mm/damon/usage: document damos_before_apply tracepoint Date: Wed, 13 Sep 2023 02:20:50 +0000 Message-Id: <20230913022050.2109-3-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230913022050.2109-1-sj@kernel.org> References: <20230913022050.2109-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Document damos_before_apply tracepoint on the usage document. Signed-off-by: SeongJae Park --- Documentation/admin-guide/mm/damon/usage.rst | 37 ++++++++++++++++---- 1 file changed, 30 insertions(+), 7 deletions(-) diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/a= dmin-guide/mm/damon/usage.rst index 282062b6f134..6272cd36590a 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -496,15 +496,24 @@ the files as above. Above is only for an example. =20 .. _tracepoint: =20 -Tracepoint for Monitoring Results -=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D +Tracepoints for Monitoring Results +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 Users can get the monitoring results via the :ref:`tried_regions -` or a tracepoint, ``damon:damon_aggregated``. -While the tried regions directory is useful for getting a snapshot, the -tracepoint is useful for getting a full record of the results. While the -monitoring is turned on, you could record the tracepoint events and show -results using tracepoint supporting tools like ``perf``. For example:: +`. The interface is useful for getting a +snapshot, but it could be inefficient for fully recording all the monitori= ng +results. For the purpose, two trace points, namely ``damon:damon_aggregat= ed`` +and ``damon:damos_before_apply``, are provided. ``damon:damon_aggregated`` +provides the whole monitoring results, while ``damon:damos_before_apply`` +provides the monitoring results for regions that each DAMON-based Operation +Scheme (:ref:`DAMOS `) is gonna be applied. Hence, +``damon:damos_before_apply`` is more useful for recording internal behavio= r of +DAMOS, or DAMOS target access +:ref:`pattern ` based query-like effici= ent +monitoring results recording. + +While the monitoring is turned on, you could record the tracepoint events = and +show results using tracepoint supporting tools like ``perf``. For example= :: =20 # echo on > monitor_on # perf record -e damon:damon_aggregated & @@ -527,6 +536,20 @@ counter). Finally the tenth field (``X``) shows the `= `age`` of the region (refer to :ref:`design ` for more details of the counter). =20 +If the event was ``damon:damos_beofre_apply``, the ``perf script`` output = would +be somewhat like below:: + + kdamond.0 47293 [000] 80801.060214: damon:damos_before_apply: ctx_idx= =3D0 scheme_idx=3D0 target_idx=3D0 nr_regions=3D11 121932607488-13512871116= 8: 0 136 + [...] + +Each line of the output represents each monitoring region that each DAMON-= based +Operation Scheme was about to be applied at the traced time. The first fi= ve +fields are as usual. It shows the index of the DAMON context (``ctx_idx= =3DX``) +of the scheme in the list of the contexts of the context's kdamond, the in= dex +of the scheme (``scheme_idx=3DX``) in the list of the schemes of the conte= xt, in +addition to the output of ``damon_aggregated`` tracepoint. + + .. _debugfs_interface: =20 debugfs Interface (DEPRECATED!) --=20 2.25.1