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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFC87CA0EEC for ; Tue, 12 Sep 2023 14:10:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 686F46B00FE; Tue, 12 Sep 2023 10:10:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 636E66B00FF; Tue, 12 Sep 2023 10:10:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4FE366B0100; Tue, 12 Sep 2023 10:10:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 3C7336B00FE for ; Tue, 12 Sep 2023 10:10:18 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 012AA80137 for ; Tue, 12 Sep 2023 14:10:17 +0000 (UTC) X-FDA: 81228130116.08.FB687D0 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf25.hostedemail.com (Postfix) with ESMTP id 9F46FA002A for ; Tue, 12 Sep 2023 14:10:15 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="q0IYV6V/"; dmarc=none; spf=none (imf25.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1694527815; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=1H8ls+IQkRjOoHBohtS89ylg9Re+cJdFS9AQQT8Ndhg=; b=APA9fMsSIaHuOx5NKjsL9r5zJe21ffEZ6RQjQHoQZBaxRfMqb9gWWIyOrrxXF01vo94/Tg poQ8bG8qTXDyAUHUZZg+G/OmS5ehvddirFq0LscGRiYsyYe9m909ZnC1bypAtCvJ6HZ2t5 6opGuWy8AYYulds8YrW7YeVTw+wsY8w= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="q0IYV6V/"; dmarc=none; spf=none (imf25.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1694527815; a=rsa-sha256; cv=none; b=BlVIqgRDUpW149tiR1NwHCb8Z7aIzH66BkGCOoLb7BCFJX2EoXJNh8rfqTeYHeERnwVdYM K6pbFWfR4X/gygRCKEmLrdTE3eeAWH9BOeNMb0apVlQw6/l2LZ4ih4De4/IMxRU5jPcgdS 2ZCYsxGpTKfSE+F2tG0tkzQBELZDPEQ= 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:To:From:Date:Sender:Reply-To:Cc: Content-Transfer-Encoding:Content-ID:Content-Description; bh=1H8ls+IQkRjOoHBohtS89ylg9Re+cJdFS9AQQT8Ndhg=; b=q0IYV6V/ayldHIS9jOHJgEblCA l0sDCPR7g5Kxq7OOYmWyXC9GIx8gQP9d42a/jxpZrr1T+kvOvU2XJFacUARSih9SEGoHSjJU+Pc6j KS3WngUvRlzMrudf2Aoy28JxpeIyMlnXOelIdmVEVSLuungSmw4Nrh0E/YMnf5lona7sYSxHq87yF 6xfa5G6QaSU+u7teIIdNjgu9UjHDfnApcbaS2cjToufYF4XsGyw088elsxEkm4q9Vghw4H3Ys0Hzw hNFP+xoau2giFfvRvE715f/C3qmTeWWd8gk9nRAgxM+qwWeKnyoPkal6WvEp9QGaJnfX2jGEkmk4t b0Q/U0fQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qg45e-007yYW-7T; Tue, 12 Sep 2023 14:10:06 +0000 Date: Tue, 12 Sep 2023 15:10:06 +0100 From: Matthew Wilcox To: "Liam R. Howlett" , "Paul E. McKenney" , Geert Uytterhoeven , Andrew Morton , maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Shanker Donthineni Subject: Re: [PATCH v2 1/2] maple_tree: Disable mas_wr_append() when other readers are possible Message-ID: References: <20230819004356.1454718-1-Liam.Howlett@oracle.com> <20230819004356.1454718-2-Liam.Howlett@oracle.com> <3f86d58e-7f36-c6b4-c43a-2a7bcffd3bd@linux-m68k.org> <20230906152325.dblzauybyoq5kd35@revolver> <20230906172954.oq4vogeuco25zam7@revolver> <495849d6-1dc6-4f38-bce7-23c50df3a99f@paulmck-laptop> <20230911235452.xhtnt7ply7ayr53x@revolver> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230911235452.xhtnt7ply7ayr53x@revolver> X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 9F46FA002A X-Stat-Signature: wwjzcx4ka7ki9bbpebgzfg13984bui7j X-HE-Tag: 1694527815-265140 X-HE-Meta: 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 GHV3g1Av l6OrlNDGBHoWH8kNSZq7Dg0RUDxvip/w7h6A2wQ4B5X2jJMP+sXyPsUt/U6i6CrVUjAPG7rDiWROXjCPm1m1zLZMRLiwGN5xdkr3EAAcp+FcH2/9lNrirH7bJLIgwI585DKUSqG0yDxfh+vlkZGPhli8b68IKr2xOuV2ByvIzDRUXq2xMVa7G9JPqGQ== 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: On Mon, Sep 11, 2023 at 07:54:52PM -0400, Liam R. Howlett wrote: > Taking the mutex lock in kernel/irq/manage.c __setup_irq() is calling a > cond_resched(). > > >From what Michael said [1] in this thread, since something has already > set TIF_NEED_RESCHED, it will eventually enable interrupts on us. > > I've traced this to running call_rcu() in kernel/rcu/tiny.c and > is_idle_task(current) is true, which means rcu runs: > /* force scheduling for rcu_qs() */ > resched_cpu(0); > > the task is set idle in sched_init() -> init_idle() and never changed, > afaict. Should calling init_idle() be deferred until after interrupts are all set up?