From mboxrd@z Thu Jan 1 00:00:00 1970 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 06F49EE49AE for ; Mon, 21 Aug 2023 04:40:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233059AbjHUEkz (ORCPT ); Mon, 21 Aug 2023 00:40:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233056AbjHUEky (ORCPT ); Mon, 21 Aug 2023 00:40:54 -0400 Received: from invmail4.hynix.com (exvmail4.hynix.com [166.125.252.92]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 93114A8; Sun, 20 Aug 2023 21:40:48 -0700 (PDT) X-AuditID: a67dfc5b-d6dff70000001748-09-64e2eacf1ef5 Date: Mon, 21 Aug 2023 13:37:44 +0900 From: Byungchul Park To: Matthew Wilcox Cc: linux-kernel@vger.kernel.org, kernel_team@skhynix.com, 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, 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, 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, max.byungchul.park@gmail.com, boqun.feng@gmail.com, longman@redhat.com, hdanton@sina.com, her0gyugyu@gmail.com Subject: Re: [RESEND PATCH v10 08/25] dept: Apply sdt_might_sleep_{start,end}() to PG_{locked,writeback} wait Message-ID: <20230821043744.GA73328@system.software.com> References: <20230821034637.34630-1-byungchul@sk.com> <20230821034637.34630-9-byungchul@sk.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA02SbUxTZxTH8zz3lWrnpZP4SBenXcgWFpwyDCebMUu2yE0WExM1cfoBm/Vm NFIgrYD4FphFWxAGmtJZiULB2mDV7YKuY+AYRKCSSafMdYhEauNAeUmY7caKZXTEzC8nv5yX X/4fDk+pFphkXp93QDLmaXM1rIJWTC13pg0+Deo2XPe+D7WnNkD4uYWG+mseFvxXLyPwtJVh mLiVBb9FJhFEfx6kwG7zI2gce0hBW+8ogk73lyzcC70GQ+EZFny2ShaON11j4Zdn8xhG6k5j uCxvg4EaJ4auuT9osE+wcM5+HC+WcQxzrhYOXKUpEHQ7OJgf2wi+0fsMdA6/C2fPj7DQ0emj odcbxHCvvZ6FUc8CAwO9/TT4a6sYuDLtZOFZxEWBKzzDwd2uBgzfmBdFJ/6MMdBX1YXhRPO3 GIZ+/wHBTcsjDLLnPgs94UkMrbKNgn8u3UIQrJ7ioPzUHAfnyqoRVJbX0TD4oo8B88gmiP5d z370gdgzOUOJ5tZisTPSQIu3nUT83vGQE803hzmxQS4UW92pYlPHBBYbZ8OMKLdYWVGePc2J FVNDWJy+c4cT+7+O0mJoyI63q/coNuukXH2RZHxvyz5FzsIZF1NgW3bQed2PS9E4X4ESeCJk kMrwc/olB0K1KM60kEKuTv/4H7PC2yQQmKMqEM+vFN4hk23p8TYl9CvIV/WH4vy6kE8CNXVU nJUCEIttnK1ACl4lVCJir75BLw0Sie9siF46TiWB2ASOOylBTS7F+DgmLEZ4IhfHN5KEt0jX jT4c1xChJ4E0mcu4pZiryU/uAF2DBMcrVscrVsf/1gZEtSCVPq/IoNXnZqzPKcnTH1z/eb5B Rotv6To6v9eLZv07upHAI81y5b43gjoVoy0ylRi6EeEpzUql+q8xnUqp05Yckoz52cbCXMnU jdQ8rVmlTI8U61TCF9oD0n5JKpCML6eYT0guRUmqgoHD9geJR5PhceRu7aO6C+FW7yp5RVm3 J5M9aazaneXZuoJe3Uzah73R8pD5Y3U0p3nti2NPvmvM2Gk1RT/b2dG+69O9+z/MzvzVkJh2 clZT8klqtu7YRV12e6HVYjlyxprmc1ulp6pYeWwQ39785o6ZlPTMNVnrmpJco1sMGtqUo92Y ShlN2n8BhnS87JIDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA02Sa0yTZxTH9zzvlY7qS4f6BlxiuhiVecPM5MTLLlmmT1w0274s3iKNfZXG AqZVEBINSm2Qm6CUQkWD1RUCKFrQ4LTagFw6olQh2hlA2zRCtYIyC3YgjM4s88vJL+d/fifn w+EphZeJ4zWpByRdqkqrZGW0bMvanGXdL3zqlb/5Y6CkYCWE3ubSUNlQz4L7ch2C+qajGAJt G+HxWBDBxL1uCswmN4Lz3n4KmtoHEDhqjrHQ458FvaERFlymfBZyLjSw8ODlJIa+slMY6uyb oavYisEZHqTBHGDhjDkHz5QhDGFbLQe27IXgq7FwMOlNBNfAIwZaz7oYcDz5EirO9bFwy+Gi ob3Zh6Hn90oWBuqnGehq76TBXVLIwKVhKwsvx2wU2EIjHDx0VmG4YpjZZvxrioGOQicG48Wr GHr/vIngdu4zDPb6Ryy0hoIYGu0mCv6ubkPgK3rFwfGCMAdnjhYhyD9eRkP3+w4GDH2rYeJd JfvtWtIaHKGIoTGDOMaqaPKHVSQ3LP0cMdx+wpEq+0HSWJNALtwKYHJ+NMQQe+0JlthHT3Ek 71UvJsP373Oks3yCJv5eM/5p/jbZOrWk1aRLuhVfJ8mSp0/bmP2mTw9Zr7lxNhri81AULwpf iR5/CYowLSwULw/f+ZdZYZHo8YSpPMTzscJiMdi0KtKmhE6ZeLIyK8KfCWmip7iMirBcADHX NMTmIRmvEPKRaC66Tn8IYkRXhZ/+ICeInqkAjuykhHixeoqPYNTMCc/tGZGJOcIXovN6By5G cstHsuUj2fK/XIWoWhSrSU1PUWm0q5fr9yVnpmoOLd+dlmJHM49nOzxZ0oze9mxsQQKPlNHy pPk+tYJRpeszU1qQyFPKWHn8uFetkKtVmVmSLm2X7qBW0regeJ5WzpNv+lVKUgh7VQekfZK0 X9L9l2I+Ki4bFW6PCWjftyZ6v/9l9pK42J8rjtyZNj60ij9QBaUvvpsoX7rmRuZOxY6x7NHB Je+efeL+PDh7gWf9+CqT87F7q/DNyd13l5ZmvfnxQWlGc8OGuW0xr/d4jTv5dZsdmxJed8Fe W13AHDaoPesHo/sHNuwoP5afcU89q7q6jzydvBg9fsKopPXJqsQESqdX/QMZ9r0hdAMAAA== X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Aug 21, 2023 at 05:09:44AM +0100, Matthew Wilcox wrote: > On Mon, Aug 21, 2023 at 12:46:20PM +0900, Byungchul Park wrote: > > @@ -1219,6 +1220,9 @@ static inline bool folio_trylock_flag(struct folio *folio, int bit_nr, > > /* How many times do we accept lock stealing from under a waiter? */ > > int sysctl_page_lock_unfairness = 5; > > > > +static struct dept_map __maybe_unused PG_locked_map = DEPT_MAP_INITIALIZER(PG_locked_map, NULL); > > +static struct dept_map __maybe_unused PG_writeback_map = DEPT_MAP_INITIALIZER(PG_writeback_map, NULL); > > Hmm, why are these "maybe unused"? *digs*. Ah. Because > sdt_might_sleep_start() becomes a no-op macro if DEPT is disabled. > > OK, the right way to handle this is > > #ifdef CONFIG_DEPT > #define DEPT_MAP(name) static struct dept_map name = \ > DEPT_MAP_INITIALIZER(name, NULL) > #else > #define DEPT_MAP(name) /* */ > #endif > > And now DEPT takes up no space if disabled. Currently: #if !defined(CONFIG_DEPT) struct dept_map { }; #endif So I think it doesn't take space at all. Do you think I still need to introduce e.g. DEPT_MAP()? Then I will. Thank you! Byungchul > /* */; is a somewhat unusual thing to see, but since this must work at > top level, we can't use "do { } while (0)" like we usually do. Given > where else this is likely to be used, i don't think it's going to be > a problem ...