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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71E07C61D92 for ; Tue, 21 Nov 2023 15:48:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234505AbjKUPsD (ORCPT ); Tue, 21 Nov 2023 10:48:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230509AbjKUPsC (ORCPT ); Tue, 21 Nov 2023 10:48:02 -0500 Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10C0999 for ; Tue, 21 Nov 2023 07:47:58 -0800 (PST) Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1700581676; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zVdBdlkIsnH6I2p3E5sm8f7fpOQeckAW/foyxumZ7OY=; b=rvCdEZdneqNOUqfvNgM8d99zC5r7Hm7vbnpqQFZJWCW0yCRnq4Mebspr9XdHZ8UY5+giaE HTGgWBHAIqQCryqFsD7hJeOB7HWW9cZr4dJMhVVMAI/Lns9q20GyA8hbbwYm4nWX/hWBGk 0AMg52MLYLOzj2rDPE0PqBd2xWyR3Zk= Date: Tue, 21 Nov 2023 23:47:26 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v5 6/9] slub: Delay freezing of partial slabs Content-Language: en-US To: Mark Brown Cc: vbabka@suse.cz, cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chengming Zhou References: <20231102032330.1036151-1-chengming.zhou@linux.dev> <20231102032330.1036151-7-chengming.zhou@linux.dev> <4f3bc1bd-ea87-465d-b58a-0ed57b15187b@sirena.org.uk> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/11/21 09:29, Mark Brown wrote: > On Tue, Nov 21, 2023 at 08:58:40AM +0800, Chengming Zhou wrote: >> On 2023/11/21 02:49, Mark Brown wrote: >>> On Thu, Nov 02, 2023 at 03:23:27AM +0000, chengming.zhou@linux.dev wrote: > >>> When we see problems we see RCU stalls while logging in, for example: > >>> [ 46.453323] rcu: INFO: rcu_sched detected stalls on CPUs/tasks: >>> [ 46.459361] rcu: 3-...0: (1 GPs behind) idle=def4/1/0x40000000 softirq=1304/1304 fqs=951 >>> [ 46.467669] rcu: (detected by 0, t=2103 jiffies, g=1161, q=499 ncpus=4) >>> [ 46.474472] Sending NMI from CPU 0 to CPUs 3: > >> IIUC, here should print the backtrace of CPU 3, right? It looks like CPU 3 is the cause, >> but we couldn't see what it's doing from the log. > > AIUI yes, but it looks like we've just completely lost the CPU - there's > more attempts to talk to it visible in the log: > >>> A full log for that run can be seen at: >>> >>> https://validation.linaro.org/scheduler/job/4017095 > > but none of them appear to cause CPU 3 to respond. Note that 32 bit ARM > is just using a regular IPI rather than something that's actually a NMI > so this isn't hugely out of the ordinary, I'd guess it's stuck with > interrupts masked. Ah yes, there is no NMI on ARM, so CPU 3 maybe running somewhere with interrupts disabled. I searched the full log, but still haven't a clue. And there is no any WARNING or BUG related to SLUB in the log. I wonder how to reproduce it locally with a Qemu VM since I don't have the ARM machine. Thanks!