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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 CCC62C2B9F4 for ; Mon, 14 Jun 2021 11:33:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B846A613DF for ; Mon, 14 Jun 2021 11:33:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235701AbhFNLfy (ORCPT ); Mon, 14 Jun 2021 07:35:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235349AbhFNLVw (ORCPT ); Mon, 14 Jun 2021 07:21:52 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED381C0611C6 for ; Mon, 14 Jun 2021 04:16:24 -0700 (PDT) Date: Mon, 14 Jun 2021 13:16:19 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1623669381; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=++e4A/S400E85MA7JQbxrze69YWqU4ooV/kaCLvdV1M=; b=LrPKSkXilgXlJ80Tlo2vEln+cxsJ/bOVcQL9pwU4dfucv71qBhsKGEn6/kvL2TPJ/SJlrA 2bz3ynWqUuT8TYrRp4FNF3WySeWXE4fL7Z5Yp05grcyC+BJIkmEA+hkM3Nfkf+ddCDVMY2 MjEpGbLZ5Iir4mbVH4FOK/vyVca4vJf6yHyxhokjHm0j/R6B8jPSC5bxZTJ1piZIe6ku1f RtRmaUqkRdONvxV38zafFtjdw6QAwA8GgYJQXgz9TnNieTnSwN2VUGgFuEqDZa9Am5TAre MYeKV7DAmeHIx5b4HsC3Ueqtld+KPJyCYrVTbr3APyTu8X35cxqXjsZSYqH7OQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1623669381; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=++e4A/S400E85MA7JQbxrze69YWqU4ooV/kaCLvdV1M=; b=7t5RdSbKecVbT7rqp3zRhYOnZm2a/qTFJ9Y569zzdkoOCsTDGP2ZN065AYWGbOAOlmnT+a 1nBIEkCUO7ty+BAA== From: Sebastian Andrzej Siewior To: Vlastimil Babka Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Lameter , David Rientjes , Pekka Enberg , Joonsoo Kim , Thomas Gleixner , Mel Gorman , Jesper Dangaard Brouer , Peter Zijlstra , Jann Horn Subject: Re: [RFC v2 33/34] mm, slub: use migrate_disable() on PREEMPT_RT Message-ID: <20210614111619.l3ral7tt2wasvlb4@linutronix.de> References: <20210609113903.1421-1-vbabka@suse.cz> <20210609113903.1421-34-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-06-14 13:07:14 [+0200], Vlastimil Babka wrote: > > +#ifdef CONFIG_PREEMPT_RT > > +#define slub_get_cpu_ptr(var) get_cpu_ptr(var) > > +#define slub_put_cpu_ptr(var) put_cpu_ptr(var) > > After Mel's report and bisect pointing to this patch, I realized I got the > #ifdef wrong and it should be #ifnded So if you got the ifdef wrong (and kept everything as-is) then you tested the RT version on !RT. migrate_disable() behaves on !RT as on RT. As per changelog you don't use migrate_disable() unconditionally because it increases the overhead on !RT. I haven't looked at the series and I have just this tiny question: why did migrate_disable() crash for Mel on !RT and why do you expect that it does not happen on PREEMPT_RT? Sebastian