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 65A4DC433ED for ; Mon, 10 May 2021 13:38:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 33E3161421 for ; Mon, 10 May 2021 13:38:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239371AbhEJNeF (ORCPT ); Mon, 10 May 2021 09:34:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237544AbhEJM3E (ORCPT ); Mon, 10 May 2021 08:29:04 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0002C061347; Mon, 10 May 2021 05:22:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=2Yh4qogtudzmfgkcxgXTiGLEV+AsfBbQiX5QEdiz68g=; b=RhGQgJvpVQjX+m22dblFpLtGY0 54cH/JGOx89AD/JHvuX3Fh/OvaeNjEsvFnT6DUIC3JBD7NjD1U9uyUnEEqqVZns3OkhG4P2yYJKyE g76rb1GuEqhB0tQiNs5YCZyG3m8+iZbdsJKEQvAxiydlTmjK3YRYc1hyEPt1z/eFuc80IvZPgcRzR DrOFtKGn3AL/VuhqFiut9GgBzugrJ03Rp5BCbpRRexNFgtmnyY0Bhr9XZK41VZAvs2GBHF63KL1Mh 20OuRPQfzWzyF+5R9Dk0gxmGNBWr5hhc/wqPqk9auqLQ3ItxI9JUlVfSQy4Bw3itPRm8TwPr7km0J pOaPxJSg==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lg4ss-00676P-Vk; Mon, 10 May 2021 12:20:02 +0000 Date: Mon, 10 May 2021 13:19:38 +0100 From: Matthew Wilcox To: "Rantala, Tommi T. (Nokia - FI/Espoo)" Cc: "hch@lst.de" , "linux-fsdevel@vger.kernel.org" , "rdna@fb.com" , "linux-kernel@vger.kernel.org" , "viro@zeniv.linux.org.uk" Subject: Re: cat /proc/sys/kernel/tainted => page allocation failure: order:6 Message-ID: References: <04735c17a20f6edd3c97374323ba2dc15e7fd624.camel@nokia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <04735c17a20f6edd3c97374323ba2dc15e7fd624.camel@nokia.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, May 10, 2021 at 11:12:21AM +0000, Rantala, Tommi T. (Nokia - FI/Espoo) wrote: > Hello, > > Why is order 6 allocation required for "cat /proc/sys/kernel/tainted" ...? > I'm seeing (occasional) failures in one VM (with 65d uptime): > > [5674989.634561] cat: page allocation failure: order:6, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null),cpuset=user.slice,mems_allowed=0 > [5674989.645432] CPU: 0 PID: 2717524 Comm: cat Not tainted 5.10.19-200.fc33.x86_64 #1 The underlying problem is that 'cat' is asking to do a 128kB read (!) so we allocate 256kB (!) of contiguous (!) memory. This is already mostly fixed upstream. Please upgrade your kernel.