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 48D76C4338F for ; Tue, 17 Aug 2021 09:34:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C82A60184 for ; Tue, 17 Aug 2021 09:34:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235872AbhHQJev (ORCPT ); Tue, 17 Aug 2021 05:34:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234593AbhHQJeo (ORCPT ); Tue, 17 Aug 2021 05:34:44 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FDC6C061764 for ; Tue, 17 Aug 2021 02:34:12 -0700 (PDT) Date: Tue, 17 Aug 2021 11:34:08 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1629192849; 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=IZ6fACXUc9apVwlz8xHJ8mN1EdefFeUDadYvHeqk1X4=; b=3s8hAMQiMxa0vuIbKYwmkRIGf5kGXAurxh8BLI70WIR9mypWnYmZkIB/13g+wBQDJbJLmH PQyQF5ETYv+GrOHioyMtiadHUKVFELfNY0HCkz1GKFpQXWBb6a2BHiMzAXun2SJyCSwZ+n uA+jbQ+TpfovebZqJfOQ4qyhpbBEt2rWb/HY16Jui4OhgSfGDzpTJjsuVgQKNUnY0EzjZ5 0hQflpoZYWg/be0Hue5mF19r63WQKEhh7fnkUM0GZwjpuV1ohB7IV5lVN6ps94PemKnV9i E9f5krH4zdz4jC52TfcnBiyi0Y0IwToD1rop0g2qQwuEDV99uCdaktcDB9Dtvg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1629192849; 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=IZ6fACXUc9apVwlz8xHJ8mN1EdefFeUDadYvHeqk1X4=; b=bIGH2L88+AIsWN+iUd3kfGlZWpIcGLdQNkfOtDLmSa5eYpElsoU8Q4iTmGYdJJayifC69g vAWEvEJW849aIxCw== From: Sebastian Andrzej Siewior To: Vlastimil Babka Cc: Sven Eckelmann , akpm@linux-foundation.org, brouer@redhat.com, cl@linux.com, efault@gmx.de, iamjoonsoo.kim@lge.com, jannh@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mgorman@techsingularity.net, penberg@kernel.org, rientjes@google.com, tglx@linutronix.de, Stephen Rothwell , Peter Zijlstra Subject: Re: [PATCH v4 35/35] mm, slub: convert kmem_cpu_slab protection to local_lock Message-ID: <20210817093408.zanfoybsbnrdnav7@linutronix.de> References: <2666777.vCjUEy5FO1@sven-desktop> <7329198a-2a4e-ebc2-abf8-f7f38f00d5e1@suse.cz> <20210817091224.nqnrro34cyb67chj@linutronix.de> <3da13f0a-2720-a38c-33a7-744668013390@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <3da13f0a-2720-a38c-33a7-744668013390@suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-08-17 11:31:56 [+0200], Vlastimil Babka wrote: > On 8/17/21 11:12 AM, Sebastian Andrzej Siewior wrote: > > On 2021-08-17 10:37:48 [+0200], Vlastimil Babka wrote: > >> OK reproduced. Thanks, will investigate. > > > > With the local_lock at the top, the needed alignment gets broken for dbl > > cmpxchg. > > Right. I wondered why the checks in __pcpu_double_call_return_bool > didn't trigger. They are VM_BUG_ON() so they did trigger after enabling > DEBUG_VM. Without the right debugging enabled | typedef struct { | #ifdef CONFIG_DEBUG_LOCK_ALLOC | struct lockdep_map dep_map; | struct task_struct *owner; | #endif | } local_lock_t; the struct is just empty. Sebastian