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 05F9FC4332F for ; Fri, 10 Nov 2023 18:57:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230134AbjKJS5Z (ORCPT ); Fri, 10 Nov 2023 13:57:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229824AbjKJS5L (ORCPT ); Fri, 10 Nov 2023 13:57:11 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ECF5357AA for ; Fri, 10 Nov 2023 10:19:28 -0800 (PST) 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=ZMzOaie4lywyOPf2qJYwfQniWHJ785xzMVX7+oeUO70=; b=V1/+fRC4D72zEHzXEcZAduUdd1 pb1y7v9rAMDlrrgMItIiW3TYe9rOF8vvJFo/g5sdeXUlNJEftP9ynKZ5JXZ14nEhvlI9z48e/IYRz NtP/pR30g/6aZwFqEzDhQPMiZwmMCTRlNB5nlaIGvh8A+Sj/JgD64+DkAzCPm7UnFP2Ict7r2gLf+ pw15c6cCj5FUGBPRNcCaSJZEoL7pnNYgjSra9nNPzvhghugr/9u6e0xkyuXApbXois2WzbrViiuUn mQ+pjwy81BB9gCPf5ADmwHiv1BW86pB3tnV9RQPWrV/e/4CBQ+l+QZccPF7OXRtE4uu77H8AtI0zk Nht54HBw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1r1W69-00EtFN-4N; Fri, 10 Nov 2023 18:19:17 +0000 Date: Fri, 10 Nov 2023 18:19:17 +0000 From: Matthew Wilcox To: Kefeng Wang Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Hildenbrand , Gregory Price Subject: Re: [PATCH v2 3/7] fs/proc/page: respect folio head-page flag placement Message-ID: References: <20231110033324.2455523-1-wangkefeng.wang@huawei.com> <20231110033324.2455523-4-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231110033324.2455523-4-wangkefeng.wang@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 10, 2023 at 11:33:20AM +0800, Kefeng Wang wrote: > kpageflags reads page-flags directly from the page, even when the > respective flag is only updated on the headpage of a folio. > > Since most flags are stored in head flags, make k = folio->flags, > and add new p = page->flags used for per-page flags. You'd do better to steal Greg's commit message. > Originally-from: Gregory Price > Suggested-by: Matthew Wilcox > Signed-off-by: Kefeng Wang > @@ -202,7 +202,7 @@ u64 stable_page_flags(struct page *page) > u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); > > #ifdef CONFIG_MEMORY_FAILURE > - u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); > + u |= kpf_copy_bit(p, KPF_HWPOISON, PG_hwpoison); This is correct. > @@ -211,13 +211,13 @@ u64 stable_page_flags(struct page *page) > > u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); > u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk); > - u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private); > - u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); > - u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); > + u |= kpf_copy_bit(p, KPF_PRIVATE, PG_private); > + u |= kpf_copy_bit(p, KPF_PRIVATE_2, PG_private_2); > + u |= kpf_copy_bit(p, KPF_OWNER_PRIVATE, PG_owner_priv_1); This is not. PG_private is not, I believe, set on tail pages. Ditto the other two. If you know differently ... ? > #ifdef CONFIG_ARCH_USES_PG_ARCH_X > - u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); > - u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3); > + u |= kpf_copy_bit(p, KPF_ARCH_2, PG_arch_2); > + u |= kpf_copy_bit(p, KPF_ARCH_3, PG_arch_3); > #endif I also don't think this is correct, but there are many uses of PG_arch* and I may have missed something.