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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 16886C43457 for ; Tue, 13 Oct 2020 23:53:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A2D5F206D5 for ; Tue, 13 Oct 2020 23:53:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="iBg5b81n" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2D5F206D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4C9F56B00F1; Tue, 13 Oct 2020 19:53:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 47C356B00F2; Tue, 13 Oct 2020 19:53:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 390AC6B00F3; Tue, 13 Oct 2020 19:53:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0134.hostedemail.com [216.40.44.134]) by kanga.kvack.org (Postfix) with ESMTP id 077376B00F1 for ; Tue, 13 Oct 2020 19:53:53 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 9B15E3625 for ; Tue, 13 Oct 2020 23:53:53 +0000 (UTC) X-FDA: 77368557546.01.crush40_27173b727207 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id 6FB9510045ECA for ; Tue, 13 Oct 2020 23:53:53 +0000 (UTC) X-HE-Tag: crush40_27173b727207 X-Filterd-Recvd-Size: 2807 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Oct 2020 23:53:53 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ED0ED208B3; Tue, 13 Oct 2020 23:53:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633232; bh=7z5RTuF6n2bqCTQ9mBG0OJMrs40XgLbxWHeH4B+Ttwg=; h=Date:From:To:Subject:In-Reply-To:From; b=iBg5b81nKJ9fCPZ37qSbW+0zkXK6gNHpbpXBm5pFfbkVz1sevoBJSVSH860nq6G5H gGQl3+yydciqDAOCHj+W8G4sJecuT3pm5IcE3A4lhXPtMeFgPWHslG1sIaakrZr2Uv Je2kpioaH/uyP7QYaV6oUxVib/JqD+1Xrxpd+8YM= Date: Tue, 13 Oct 2020 16:53:50 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, willy@infradead.org, ziy@nvidia.com Subject: [patch 100/181] mm: move PageDoubleMap bit Message-ID: <20201013235350.KlkfTUJYD%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: "Matthew Wilcox (Oracle)" Subject: mm: move PageDoubleMap bit Patch series "Fix PageDoubleMap". This is a purely theoretical problem for now as none of the filesystems which use PG_private_2 (ie PG_fscache) are being converted at this time, but it's confusing to leave it like this. This patch (of 2): PG_private_2 is defined as being PF_ANY (applicable to tail pages as well as regular & head pages). That means that the first tail page of a double-map page will appear to have Private2 set. Use the Workingset bit instead which is defined as PF_HEAD so any attempt to access the Workingset bit on a tail page will redirect to the head page's Workingset bit. Link: https://lkml.kernel.org/r/20200629151933.15671-1-willy@infradead.org Link: https://lkml.kernel.org/r/20200629151933.15671-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Zi Yan Signed-off-by: Andrew Morton --- include/linux/page-flags.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/page-flags.h~mm-move-pagedoublemap-bit +++ a/include/linux/page-flags.h @@ -167,7 +167,7 @@ enum pageflags { PG_slob_free = PG_private, /* Compound pages. Stored in first tail page's flags */ - PG_double_map = PG_private_2, + PG_double_map = PG_workingset, /* non-lru isolated movable page */ PG_isolated = PG_reclaim, _