From nobody Tue Sep 16 02:28:12 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 9451DC61DB3 for ; Mon, 9 Jan 2023 04:08:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236649AbjAIEID (ORCPT ); Sun, 8 Jan 2023 23:08:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236703AbjAIEEb (ORCPT ); Sun, 8 Jan 2023 23:04:31 -0500 Received: from lgeamrelo11.lge.com (lgeamrelo11.lge.com [156.147.23.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 237AE11C39 for ; Sun, 8 Jan 2023 20:03:55 -0800 (PST) Received: from unknown (HELO lgemrelse6q.lge.com) (156.147.1.121) by 156.147.23.51 with ESMTP; 9 Jan 2023 12:33:54 +0900 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: byungchul.park@lge.com Received: from unknown (HELO localhost.localdomain) (10.177.244.38) by 156.147.1.121 with ESMTP; 9 Jan 2023 12:33:54 +0900 X-Original-SENDERIP: 10.177.244.38 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park To: linux-kernel@vger.kernel.org Cc: torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, paolo.valente@linaro.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, 42.hyeyoo@gmail.com, chris.p.wilson@intel.com, gwan-gyeong.mun@intel.com Subject: [PATCH RFC v7 23/23] dept: Record the latest one out of consecutive waits of the same class Date: Mon, 9 Jan 2023 12:33:51 +0900 Message-Id: <1673235231-30302-24-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1673235231-30302-1-git-send-email-byungchul.park@lge.com> References: <1673235231-30302-1-git-send-email-byungchul.park@lge.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The current code records all the waits for later use to track relation between waits and events in each context. However, since the same class is handled the same way, it'd be okay to record only one on behalf of the others if they all have the same class. Even though it's the ideal to search the whole history buffer for that, since it'd cost too high, alternatively, let's keep the latest one at least when the same class'ed waits consecutively appear. Signed-off-by: Byungchul Park --- kernel/dependency/dept.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c index cd25995..9cd37b4 100644 --- a/kernel/dependency/dept.c +++ b/kernel/dependency/dept.c @@ -1521,9 +1521,28 @@ static inline struct dept_wait_hist *new_hist(void) return wh; } =20 +static inline struct dept_wait_hist *last_hist(void) +{ + int pos_n =3D hist_pos_next(); + struct dept_wait_hist *wh_n =3D hist(pos_n); + + /* + * This is the first try. + */ + if (!pos_n && !wh_n->wait) + return NULL; + + return hist(pos_n + DEPT_MAX_WAIT_HIST - 1); +} + static void add_hist(struct dept_wait *w, unsigned int wg, unsigned int ct= xt_id) { - struct dept_wait_hist *wh =3D new_hist(); + struct dept_wait_hist *wh; + + wh =3D last_hist(); + + if (!wh || wh->wait->class !=3D w->class || wh->ctxt_id !=3D ctxt_id) + wh =3D new_hist(); =20 if (likely(wh->wait)) put_wait(wh->wait); --=20 1.9.1