From patchwork Fri Mar 4 07:06:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Byungchul Park X-Patchwork-Id: 12768587 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B431C433EF for ; Fri, 4 Mar 2022 07:07:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E87AB8D0007; Fri, 4 Mar 2022 02:07:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DE3B58D0008; Fri, 4 Mar 2022 02:07:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E7B58D0001; Fri, 4 Mar 2022 02:07:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0091.hostedemail.com [216.40.44.91]) by kanga.kvack.org (Postfix) with ESMTP id D90398D0007 for ; Fri, 4 Mar 2022 02:07:10 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 71703181B7E35 for ; Fri, 4 Mar 2022 07:07:10 +0000 (UTC) X-FDA: 79205822220.29.F8C95F9 Received: from lgeamrelo11.lge.com (lgeamrelo12.lge.com [156.147.23.52]) by imf16.hostedemail.com (Postfix) with ESMTP id 9C26F180003 for ; Fri, 4 Mar 2022 07:07:08 +0000 (UTC) Received: from unknown (HELO lgemrelse6q.lge.com) (156.147.1.121) by 156.147.23.52 with ESMTP; 4 Mar 2022 16:07:06 +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; 4 Mar 2022 16:07:06 +0900 X-Original-SENDERIP: 10.177.244.38 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park To: torvalds@linux-foundation.org Cc: damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, chris@chris-wilson.co.uk, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, bfields@fieldses.org, 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, jack@suse.com, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, airlied@linux.ie, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com Subject: [PATCH v4 04/24] dept: Add a API for skipping dependency check temporarily Date: Fri, 4 Mar 2022 16:06:23 +0900 Message-Id: <1646377603-19730-5-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1646377603-19730-1-git-send-email-byungchul.park@lge.com> References: <1646377603-19730-1-git-send-email-byungchul.park@lge.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 9C26F180003 X-Stat-Signature: yh4w137qh81b8jfgyga847rz5bs6gfjt Authentication-Results: imf16.hostedemail.com; dkim=none; spf=pass (imf16.hostedemail.com: domain of byungchul.park@lge.com designates 156.147.23.52 as permitted sender) smtp.mailfrom=byungchul.park@lge.com; dmarc=none X-Rspam-User: X-HE-Tag: 1646377628-115824 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Dept would skip check for dmaps marked by dept_map_nocheck() permanently. However, sometimes it needs to skip check for some dmaps temporarily and back to normal, for instance, lock acquisition with a nest lock. Lock usage check with regard to nest lock could be performed by Lockdep, however, dependency check is not necessary for that case. So prepared for it by adding two new APIs, dept_skip() and dept_unskip_if_skipped(). Signed-off-by: Byungchul Park --- include/linux/dept.h | 9 +++++++++ include/linux/dept_sdt.h | 2 +- include/linux/lockdep.h | 4 +++- kernel/dependency/dept.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 62 insertions(+), 2 deletions(-) diff --git a/include/linux/dept.h b/include/linux/dept.h index c3fb3cf..c0bbb8e 100644 --- a/include/linux/dept.h +++ b/include/linux/dept.h @@ -352,6 +352,11 @@ struct dept_map { unsigned int wgen; /* + * for skipping dependency check temporarily + */ + atomic_t skip_cnt; + + /* * whether this map should be going to be checked or not */ bool nocheck; @@ -444,6 +449,8 @@ struct dept_task { extern void dept_ask_event(struct dept_map *m); extern void dept_event(struct dept_map *m, unsigned long e_f, unsigned long ip, const char *e_fn); extern void dept_ecxt_exit(struct dept_map *m, unsigned long ip); +extern void dept_skip(struct dept_map *m); +extern bool dept_unskip_if_skipped(struct dept_map *m); /* * for users who want to manage external keys @@ -475,6 +482,8 @@ struct dept_task { #define dept_ask_event(m) do { } while (0) #define dept_event(m, e_f, ip, e_fn) do { (void)(e_fn); } while (0) #define dept_ecxt_exit(m, ip) do { } while (0) +#define dept_skip(m) do { } while (0) +#define dept_unskip_if_skipped(m) (false) #define dept_key_init(k) do { (void)(k); } while (0) #define dept_key_destroy(k) do { (void)(k); } while (0) #endif diff --git a/include/linux/dept_sdt.h b/include/linux/dept_sdt.h index 375c4c3..e9d558d 100644 --- a/include/linux/dept_sdt.h +++ b/include/linux/dept_sdt.h @@ -13,7 +13,7 @@ #include #ifdef CONFIG_DEPT -#define DEPT_SDT_MAP_INIT(dname) { .name = #dname } +#define DEPT_SDT_MAP_INIT(dname) { .name = #dname, .skip_cnt = ATOMIC_INIT(0) } /* * SDT(Single-event Dependency Tracker) APIs diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index c56f6b6..c1a56fe 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -488,7 +488,9 @@ enum xhlock_context_t { */ #define STATIC_DEPT_MAP_INIT(_name, _key) .dmap = { \ .name = (_name), \ - .keys = NULL }, + .keys = NULL, \ + .skip_cnt = ATOMIC_INIT(0), \ + }, #else #define STATIC_DEPT_MAP_INIT(_name, _key) #endif diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c index ec3f131..3f22c5b 100644 --- a/kernel/dependency/dept.c +++ b/kernel/dependency/dept.c @@ -1943,6 +1943,7 @@ void dept_map_init(struct dept_map *m, struct dept_key *k, int sub, m->name = n; m->wgen = 0U; m->nocheck = false; + atomic_set(&m->skip_cnt, 0); exit: dept_exit(flags); } @@ -1963,6 +1964,7 @@ void dept_map_reinit(struct dept_map *m) clean_classes_cache(&m->keys_local); m->wgen = 0U; + atomic_set(&m->skip_cnt, 0); dept_exit(flags); } @@ -2346,6 +2348,53 @@ void dept_ecxt_exit(struct dept_map *m, unsigned long ip) } EXPORT_SYMBOL_GPL(dept_ecxt_exit); +void dept_skip(struct dept_map *m) +{ + struct dept_task *dt = dept_task(); + unsigned long flags; + + if (READ_ONCE(dept_stop) || dt->recursive) + return; + + if (m->nocheck) + return; + + flags = dept_enter(); + + atomic_inc(&m->skip_cnt); + + dept_exit(flags); +} +EXPORT_SYMBOL_GPL(dept_skip); + +/* + * Return true if successfully unskip, otherwise false. + */ +bool dept_unskip_if_skipped(struct dept_map *m) +{ + struct dept_task *dt = dept_task(); + unsigned long flags; + bool ret = false; + + if (READ_ONCE(dept_stop) || dt->recursive) + return false; + + if (m->nocheck) + return false; + + flags = dept_enter(); + + if (!atomic_read(&m->skip_cnt)) + goto exit; + + atomic_dec(&m->skip_cnt); + ret = true; +exit: + dept_exit(flags); + return ret; +} +EXPORT_SYMBOL_GPL(dept_unskip_if_skipped); + void dept_task_exit(struct task_struct *t) { struct dept_task *dt = &t->dept_task;