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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61303C46475 for ; Thu, 25 Oct 2018 15:07:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2821D20848 for ; Thu, 25 Oct 2018 15:07:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2821D20848 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727761AbeJYXkx (ORCPT ); Thu, 25 Oct 2018 19:40:53 -0400 Received: from mx2.suse.de ([195.135.220.15]:56600 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727502AbeJYXkx (ORCPT ); Thu, 25 Oct 2018 19:40:53 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 542E6AD72; Thu, 25 Oct 2018 15:07:41 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 11253DABAA; Thu, 25 Oct 2018 17:07:30 +0200 (CEST) Date: Thu, 25 Oct 2018 17:07:29 +0200 From: David Sterba To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Jiri Kosina Subject: Re: [PATCH AUTOSEL 4.4 08/65] btrfs: cleaner_kthread() doesn't need explicit freeze Message-ID: <20181025150729.GD16290@suse.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Sasha Levin , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Jiri Kosina References: <20181025141705.213937-1-sashal@kernel.org> <20181025141705.213937-8-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181025141705.213937-8-sashal@kernel.org> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 25, 2018 at 10:16:08AM -0400, Sasha Levin wrote: > From: Jiri Kosina > > [ Upstream commit 838fe1887765f4cc679febea60d87d2a06bd300e ] > > cleaner_kthread() is not marked freezable, and therefore calling > try_to_freeze() in its context is a pointless no-op. > > In addition to that, as has been clearly demonstrated by 80ad623edd2d > ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"), it's perfectly > valid / legal for cleaner_kthread() to stay scheduled out in an arbitrary > place during suspend (in that particular example that was waiting for > reading of extent pages), so there is no need to leave any traces of > freezer in this kthread. > > Fixes: 80ad623edd2d ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()") > Fixes: 696249132158 ("btrfs: clear PF_NOFREEZE in cleaner_kthread()") > Signed-off-by: Jiri Kosina > Signed-off-by: David Sterba > Signed-off-by: Sasha Levin IIRC it was some preparatory work for livepatching. I did a quick check if this is safe for 4.4 and would say yes, but the patch does not fix anything so IMO this does not need to go to stable.