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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B73BC2D0D1 for ; Mon, 24 Jun 2024 19:26:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 746876B0083; Mon, 24 Jun 2024 15:26:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6CF426B00E9; Mon, 24 Jun 2024 15:26:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 547FC6B00F9; Mon, 24 Jun 2024 15:26:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 300CA6B0083 for ; Mon, 24 Jun 2024 15:26:58 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A524BA3643 for ; Mon, 24 Jun 2024 19:26:57 +0000 (UTC) X-FDA: 82266764874.30.AE95205 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf18.hostedemail.com (Postfix) with ESMTP id 0AE261C0004 for ; Mon, 24 Jun 2024 19:26:54 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=O5Z1R62R; dmarc=none; spf=none (imf18.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1719257204; a=rsa-sha256; cv=none; b=EZPl9m9J3pI1xbt/RlCVnh3dUDWU2/6vSxQofQeH2G8vAxOBIt1z9LOpkkhSJY+JeHHxEn AqHJ9Mezn4GAICnXUD+LDQGycroffZBOLyEOKPMyHenamOFzo5lkN+NliqXGrjs3n5aprl A4lIJY3vqRjWHO+VkcH4AdAYQecuM28= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=O5Z1R62R; dmarc=none; spf=none (imf18.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1719257204; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=2ze4lo7T22dkN683PR4LGCHaCsLSG6Pgxy5Fyl8OuRo=; b=U7eEIxU2c0xaHK5sFHoBU9xEfIeX21U2w1DjhPJ37HSX7Kjok/Sjb55wHSHHBlTAiJ40cN DOE7dQ5f2ClQ2Kmiot6N2JzZw3u1O6bXb6WmeRjEUNEn4rFXJn9Vct8DCr26c9dUt8wHSv oGYIFxZwN90HJkxDlhWwZ9IUKyXEo5I= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=2ze4lo7T22dkN683PR4LGCHaCsLSG6Pgxy5Fyl8OuRo=; b=O5Z1R62RnZnqiIOsEyR5avK426 puj1m8I7kYzzPBFXfUyZZeikV/zaWA4UI5r1FCq79Fc0N/1G3t6YHmGYdzomqxXr28TjjsIzhRKpv YQX3XFWVJIp6tZKXO/E52rUyTprf6/TqyadRDfanXwOa/TNyQjBj4H89ZT62ZbzhRkkUJoNAR2UF8 Vr9hq1DnRl99Mh2a0uwAfQ2+F4TJSgzqTtccGctvZ26zfdf7tZJmYT0F7fkBXvL5T7V+nnK+n1m/k x6EEgPBCznF3LKa9ca5Hpn669DR6d3liQGDOwC0R0sgC8lArkssAyQzcN+o/A4ax3yjkesn7EhZSu sICN1jbw==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1sLpKx-0000000AN1L-2GDk; Mon, 24 Jun 2024 19:26:47 +0000 Date: Mon, 24 Jun 2024 20:26:47 +0100 From: Matthew Wilcox To: Yosry Ahmed Cc: kernel test robot , Usama Arif , oe-lkp@lists.linux.dev, lkp@intel.com, Linux Memory Management List , Andrew Morton , Chengming Zhou , Nhat Pham , David Hildenbrand , "Huang, Ying" , Hugh Dickins , Johannes Weiner , Shakeel Butt , Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [linux-next:master] [mm] 0fa2857d23: WARNING:at_mm/page_alloc.c:#__alloc_pages_noprof Message-ID: References: <202406241651.963e3e78-oliver.sang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Queue-Id: 0AE261C0004 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: hmucsiury3dhfbow4rms8k9axt5r4qka X-HE-Tag: 1719257214-419631 X-HE-Meta: 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 cAJSgmLg h47jKZP8Jv+FjukyXotjN+FiniEOY0RUNfMiMwbExEmKJULu9ZNMONdJuBQPas1qwdTpX/AIQ4QsmajbiA0cfMDwgnZBdet2GjEpjNJHDE9WXDJkCcGT1YHpyT8hPTiuZmbrVIShK252thArcYq+LeK8oJbbaCiGT0LbnAhZWp6AZeANGXd0De4JdMzaVeeYy3D9jMwvZnifQUL7vNnLXIIm/PCF1Wct26f5Qo823UodarKmTGKWObAlUi3YZRh6UlY8xMPGBK0ZN8xl/CW0ICJC6FvrRPDbVm6yh2zbggcVdWudrTSvmr0D3spnDmSBGAEGtNEz1YMC1qqS2ClrvZyyX6Q== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jun 24, 2024 at 11:57:45AM -0700, Yosry Ahmed wrote: > On Mon, Jun 24, 2024 at 11:56 AM Matthew Wilcox wrote: > > > > On Mon, Jun 24, 2024 at 11:53:30AM -0700, Yosry Ahmed wrote: > > > After a page is swapped out during reclaim, __remove_mapping() will > > > call __delete_from_swap_cache() to replace the swap cache entry with a > > > shadow entry (which is an xa_value). > > > > Special entries are disjoint from shadow entries. Shadow entries have > > the last two bits as 01 or 11 (are congruent to 1 or 3 modulo 4). > > Special entries have values below 4096 which end in 10 (are congruent > > to 2 modulo 4). > > You are implying that we would no longer have a shadow entry for such > zero folios, because we will be storing a special entry instead. > Right? umm ... maybe I have a misunderstanding here. I'm saying that there wouldn't be a _swap_ entry here because the folio wouldn't be stored anywhere on the swap device. But there could be a _shadow_ entry. Although if the page is full of zeroes, it was probably never referenced and doesn't really need a shadow entry.