From patchwork Mon Sep 11 04:59:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 13378773 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 015B6EE57DF for ; Mon, 11 Sep 2023 04:59:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233752AbjIKE7S (ORCPT ); Mon, 11 Sep 2023 00:59:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231517AbjIKE7R (ORCPT ); Mon, 11 Sep 2023 00:59:17 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BB6313E; Sun, 10 Sep 2023 21:59:13 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62D71C433CA; Mon, 11 Sep 2023 04:59:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694408352; bh=K9lgc7x4dZgenqq4OTRXq794HZJJ71R2FcZ9X3jYc3o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z8oSqJr6ToHgqtmreNWd7i9mI3hWW/YHUOWB3BBt6N5c0ltuTPl65Eol9sroTYQgj WrWC/T7TWJJHaaVIS/jtkfPPZM1JZ3fy2MGI5wwyNPS39axeVXnQZGMhcupjt4KDZH BbyG/QMXrLQkxsfkuODSQGBwws0vyt192WB3fWBWy8p35b96O8ER7MgOHQqGEBQWNV TRen1RmVJcLD8rijpg2VDGiceZgWPttWeAT5tYxITsP9Fu9i1+8f077aAgsmBbDVvp KzZ2Cscq1r/0XaINUrS+OlXnk6OWRUUaT64nZr9FwyHZmOTlHaAAp/WCuUh8LN3zBX 09mLr3nl0WOHA== 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 1/2] mm/damon/core: add a tracepoint for damos apply target regions Date: Mon, 11 Sep 2023 04:59:07 +0000 Message-Id: <20230911045908.97649-2-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230911045908.97649-1-sj@kernel.org> References: <20230911045908.97649-1-sj@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org 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 --- include/trace/events/damon.h | 37 ++++++++++++++++++++++++++++++++++++ mm/damon/core.c | 27 +++++++++++++++++++++++++- 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h index 0b8d13bde17a..9e7b39495b05 100644 --- a/include/trace/events/damon.h +++ b/include/trace/events/damon.h @@ -9,6 +9,43 @@ #include #include +TRACE_EVENT(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), + + TP_ARGS(context_idx, target_idx, scheme_idx, r, nr_regions), + + 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 = context_idx; + __entry->scheme_idx = scheme_idx; + __entry->target_idx = target_idx; + __entry->start = r->ar.start; + __entry->end = r->ar.end; + __entry->nr_accesses = r->nr_accesses; + __entry->age = r->age; + __entry->nr_regions = nr_regions; + ), + + TP_printk("ctx_idx=%u scheme_idx=%u target_idx=%lu nr_regions=%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, TP_PROTO(unsigned int target_id, struct damon_region *r, diff --git a/mm/damon/core.c b/mm/damon/core.c index ca631dd88b33..aa7fbcdf7310 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -950,6 +950,28 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t, struct timespec64 begin, end; unsigned long sz_applied = 0; int err = 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 = 0; + struct damos *siter; /* schemes iterator */ + unsigned int sidx = 0; + struct damon_target *titer; /* targets iterator */ + unsigned int tidx = 0; + + damon_for_each_scheme(siter, c) { + if (siter == s) + break; + sidx++; + } + damon_for_each_target(titer, c) { + if (titer == t) + break; + tidx++; + } if (c->ops.apply_scheme) { if (quota->esz && quota->charged_sz + sz > quota->esz) { @@ -964,8 +986,11 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t, ktime_get_coarse_ts64(&begin); if (c->callback.before_damos_apply) err = 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)); sz_applied = c->ops.apply_scheme(c, t, r, s); + } ktime_get_coarse_ts64(&end); quota->total_charged_ns += timespec64_to_ns(&end) - timespec64_to_ns(&begin);