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 E8E3AEE49B0 for ; Mon, 21 Aug 2023 04:11:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232884AbjHUELK (ORCPT ); Mon, 21 Aug 2023 00:11:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232120AbjHUELI (ORCPT ); Mon, 21 Aug 2023 00:11:08 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D64BD11D; Sun, 20 Aug 2023 21:10:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=sTOdBFeZC0ZITAjiSCC8ryUnVRY9Lhk36Ip26KjeYr4=; b=ICymlCyLpaJ6lmuyoMFR5kttyw UBm9C082xuk3Z6hhwZEKWSF+ox3NgccEuO8Z/43fptOWwRZsWum/7FRoRaW1UQbyW1qJwMW+RtTE5 LuYT1pNyy0SaxkHsTTkacsbgLDntlcgS1wSJqQvwXrvlQeAEdAYSdM61NzEaEm48NI/eOnoim4ojj 8vV9ewOGSLgUh2r2vGs4nVL8ZJ4gZ46GXf8M9SfbYoQvZdxJbeNQKkzbyh3E1MLZutAHTaZUuOqIq 1S/Hr371deuhKGgzMbb+5HqLyRiiOPcO8oCTUXpithV1sUUXjoat+U6z6h/eBmQhpwA7bLdvom+us SUX4CjPw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qXwEa-0081su-Uu; Mon, 21 Aug 2023 04:09:45 +0000 Date: Mon, 21 Aug 2023 05:09:44 +0100 From: Matthew Wilcox To: Byungchul Park 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: 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: <20230821034637.34630-9-byungchul@sk.com> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org 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. /* */; 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 ...