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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8A992CCFA13 for ; Mon, 10 Nov 2025 14:03:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C86708E0008; Mon, 10 Nov 2025 09:03:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C5E578E0002; Mon, 10 Nov 2025 09:03:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B9B2F8E0008; Mon, 10 Nov 2025 09:03:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id A8D1F8E0002 for ; Mon, 10 Nov 2025 09:03:58 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 4BD6BC0DCC for ; Mon, 10 Nov 2025 14:03:58 +0000 (UTC) X-FDA: 84094866156.20.C9B5571 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf28.hostedemail.com (Postfix) with ESMTP id 4905FC001A for ; Mon, 10 Nov 2025 14:03:56 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=APBOPyKN; dmarc=pass (policy=none) header.from=infradead.org; spf=none (imf28.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=1762783436; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=wTntukXdaVFjnftz5WTTeF+x0iVhUlIwTUQPH67TnYI=; b=p/QLwmvJace2cpDO+6MDbCKOuIvlVBHTPnNsxAXAkXJxIeYLTo/a7Yv+26e98Ms2fRwSxP 7CnAg4HKWIK9u8pl8ilcuzyhqooXx7W11tyStk2b0cUUzdXV6aY3uWd1m7BNSZC/b43ltI DUX3dJD/VZ/Tyihgpdjp53bGAPyBjXc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762783436; a=rsa-sha256; cv=none; b=6kagJCty9RmlCp7ZXMehaejs6jwQHqHflnY3Pdgx0XuI2PsjkPLxpLGPk46FeUW2UdZZF7 rraFmKGerKs/ClN5FJrONcbhMW3TIEeOz0znYIUg76tICXPqtWnkO+E/l6SNHh3Hwp5tEa hrHGJZdVwARTgvjByGYvGIFJh6pD4hQ= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=APBOPyKN; dmarc=pass (policy=none) header.from=infradead.org; spf=none (imf28.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org 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=wTntukXdaVFjnftz5WTTeF+x0iVhUlIwTUQPH67TnYI=; b=APBOPyKNe6JNBjwvNL5ANy0RHS 6FNALoWP8USB0oxkWef8vyXGcUJ8QSiW6uIkCWiB/EIfRyqrImuDNRpbA9wWzVBdmn68foHJ1kDIh JLGqmtmQNQJEA9SXC9s2V5O14WEQyyPZaE19sGkWZYxsTx1WR5ZLU07/9gMwST/Zlo87g67UQMqQA HpbrFRnKHlhUxREbF+vv5DVk/ZNxmOF4QMCzG7IYGXk7CX/SZRGXr9miHifFgv2Gxkdf/JW7juAZk /reX6S9bZHznt9sJo3+2btv63m8oA7k86Bqwlg0JYGbVworWUEN3A3Nd0KlZLMiFOmTG5Wl+yIZoy tUGoVX8w==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vISUh-0000000GkmP-35kQ; Mon, 10 Nov 2025 14:03:43 +0000 Date: Mon, 10 Nov 2025 14:03:43 +0000 From: Matthew Wilcox To: "David Hildenbrand (Red Hat)" Cc: Shivank Garg , Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Zach O'Keefe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Branden Moore Subject: Re: [PATCH 1/2] mm/khugepaged: do synchronous writeback for MADV_COLLAPSE Message-ID: References: <20251110113254.77822-1-shivankg@amd.com> <9b622374-778a-4459-aca9-4eb406a58516@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9b622374-778a-4459-aca9-4eb406a58516@gmail.com> X-Stat-Signature: skni6xmz6o8zoipgup3yyr6s11t4xebi X-Rspam-User: X-Rspamd-Queue-Id: 4905FC001A X-Rspamd-Server: rspam10 X-HE-Tag: 1762783436-863031 X-HE-Meta: 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 023yD+kz pcu0jPYV7miOFLSNMx2BwRmuYfo9JMGaX6+0dSF6O/oBPkmyUTd0u9Olt6rcguEO1NWd4nMkXANw5Cm7IWXRVnn7HE63+EPJZH40CXzDQAf9gRKTk2siLz8LAp8JI3RN3qtSKq0nByEjOcewHgnt0/vCUfkrWG6uqObwboo6IY7Bs/+Wqg4PIYfYenxwQZ9Fxq7N+DJEbXnOqa+uS00ss+I7rfthfHzHtzk6qfjR7m28zhKIFWTYjYTPH9orOyE2cSpQ0++n7fK3q9IU2oOORhgoxetaSQC0VUiADR7h92xGjXQ4= 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, Nov 10, 2025 at 03:00:32PM +0100, David Hildenbrand (Red Hat) wrote: > On 10.11.25 14:47, Matthew Wilcox wrote: > > On Mon, Nov 10, 2025 at 11:32:53AM +0000, Shivank Garg wrote: > > > When MADV_COLLAPSE is called on file-backed mappings (e.g., executable > > > text sections), the pages may still be dirty from recent writes. The > > > > That explanation derails my brain entirely. Text isn't writable! How > > can the pages be dirty and file-backed text? > > Files are writable :) Well, if you're root ... -rwxr-xr-x 1 root root 158632 Jun 4 11:14 /bin/ls