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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 528F3F9D0F6 for ; Tue, 14 Apr 2026 21:25:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 98E596B0088; Tue, 14 Apr 2026 17:25:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 93F776B0089; Tue, 14 Apr 2026 17:25:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 855D46B0092; Tue, 14 Apr 2026 17:25:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 716FB6B0088 for ; Tue, 14 Apr 2026 17:25:50 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 0279BB7014 for ; Tue, 14 Apr 2026 21:25:49 +0000 (UTC) X-FDA: 84658443660.26.B4D4AEB Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf14.hostedemail.com (Postfix) with ESMTP id 4C03C100015 for ; Tue, 14 Apr 2026 21:25:48 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=rbwiMaSd; spf=pass (imf14.hostedemail.com: domain of tglx@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=tglx@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776201948; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=oW246YAmOxlVG4uPvQVaSvCnMj5W7Vd9gYk0nyIHYB8=; b=67YXYujUED8UQ+WSvbGFu9/M9FQRMgtvQsDRcInRzYZewH9sTNb60bJ8jUfavgceMwuNwd l90DLmpbgHtOlnulVmqXkRwgmx53BtZ5VS/proTGi7nBq+fbnUibDtFOphKKgKGsfe2Ma/ awyHwg4ISMH4XX5wUxEzdDtaiGMc/G0= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=rbwiMaSd; spf=pass (imf14.hostedemail.com: domain of tglx@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=tglx@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776201948; a=rsa-sha256; cv=none; b=VgXOJmSGtpq6FQSS6oESOYx97Ma0OUfE4mbp7TIQ4Kmtfqg9tFLXLxOAY42gjS10VtlP3G dXItny/qZ3ejyqGhfF8CRZU1/Tfv7gcT/nl1ogMbeBL4//DZ54XLuY+d8ilk1Hix5CYt9B V5WshHEo0TLYyDmO8INvnz+docWzpDU= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 3A2EF442ED; Tue, 14 Apr 2026 21:25:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3471DC19425; Tue, 14 Apr 2026 21:25:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776201947; bh=7P7F7WGcbi2CGd41uCZAd0HNLhsC1TsYqmIPqKA6PoU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=rbwiMaSdhUF53StkQMJfEh0fMbLskeFVLCWnhMdfY3z54QSj4fBh65AsS1vLuLU+4 KgiZN8mRe0w7LQUfSeH5rUisEjLyGQhGOgPfxwNbiNj9HxgLBg5Wszcx0/hGp84bKF qCsCof+7C7NPbp3K7f0teEe0rAlfUE4486ArlgaOD0lTNQs85Rmg6nWCILPCFzY8P+ N304zWX9Va8hhExmbkycx0UdEGIWs27BS2mXRbfUCoXg/YvJurlwy2+WEtVfq4dMzN EOjqJdslad9D25iyRXrXMa9qC+Y5Qih+8yTThRZQ4CW62Vaz5kaFIE6c1aOjYQh8vd hKNe+sBCRDarQ== From: Thomas Gleixner To: Qiliang Yuan , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Anna-Maria Behnsen , Ingo Molnar , Tejun Heo , Andrew Morton , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Waiman Long , Chen Ridong , Michal =?utf-8?Q?Koutn=C3=BD?= , Jonathan Corbet , Shuah Khan , Shuah Khan Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Qiliang Yuan Subject: Re: [PATCH v2 02/12] sched/isolation: Introduce housekeeping notifier infrastructure In-Reply-To: <20260413-wujing-dhm-v2-2-06df21caba5d@gmail.com> References: <20260413-wujing-dhm-v2-0-06df21caba5d@gmail.com> <20260413-wujing-dhm-v2-2-06df21caba5d@gmail.com> Date: Tue, 14 Apr 2026 23:25:43 +0200 Message-ID: <87wly9dyjs.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 4C03C100015 X-Stat-Signature: awm3q6zstqa1j8dwytg5htp3sdrm8hzy X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1776201948-487492 X-HE-Meta: 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 wEML/ywn vf6jfxggWZKcaXEbJjaVCtzozkuwZ2HdBeKW93ntuftY6MzZ4uyzu41BG1ER8ukaJoyWtZlis+nn1YsRc72xzyXQ3xMBWcldvQvd+wrfSZFBmKZ0vtPHA1D4JX552mAGrvTyQmg6cKnohvSIsyuRlF5dczRnHJTVhZiBQb/NQ5yzG4h1Rj+c2OwfeQSeR4Sqmxx6YC9CBa7sEg/Jdn07wv+7vvuiO8jzQMpDhNz6zOvCfpNpFimrYE2WDZ7wRjaLhaVX0 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Apr 13 2026 at 15:43, Qiliang Yuan wrote: > > +int housekeeping_register_notifier(struct notifier_block *nb) > +{ > + return blocking_notifier_chain_register(&housekeeping_notifier_list, nb); > +} > +EXPORT_SYMBOL_GPL(housekeeping_register_notifier); > + > +int housekeeping_unregister_notifier(struct notifier_block *nb) > +{ > + return blocking_notifier_chain_unregister(&housekeeping_notifier_list, nb); > +} > +EXPORT_SYMBOL_GPL(housekeeping_unregister_notifier); As I said before, notifiers are a horrible interface especially for things where most callers are built-in. Especially providing proper ordering of the callbacks is a badly defined mechanism as demonstrated by the now eliminated CPU hotplug notifiers. > +int housekeeping_update_notify(enum hk_type type, const struct cpumask *new_mask) > +{ > + struct housekeeping_update update = { > + .type = type, > + .new_mask = new_mask, > + }; > + > + return blocking_notifier_call_chain(&housekeeping_notifier_list, HK_UPDATE_MASK, &update); > +} > +EXPORT_SYMBOL_GPL(housekeeping_update_notify); Why is this exported? Are random modules allowed to invoke this?