From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8DD88606A31A for ; Wed, 28 Oct 2026 13:04:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=uq6tqtvM; dkim=fail reason="signature verification failed" (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=NhoVazCk DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=BkoJ6VhezW37LSJ5ZWZfxvgZBW5DS5sPcqish+qr+kI=; b=uq6tqtvM59fl4BRJNyGQjd2dhv r054zukDErp4MeSdPLhsn5Kn3TD750P7wdvmHYPg2cE7wFcJsrygMRaChQlcAtl1yFsRDelwUgqSZ /K4y8XzfG8gsW6r03AcGi622s1ex1yrfedV5bWh7wH46sAhynOR2mM0IdxA5ypX5qyYX+9E15SlAA FKDXTUm/dmO9mPZmUXfe4TkjDm+1TvpFmXSLTNa/JbgWSihKFpd9obXm/7LwfuDFUCulaV0drYMla 0mJ/IEHMdLJDnCQk0AEmh59NpusSiDeuqkmpMAiaRcuJpOIV/nRrD+GmAd7fgS245Wt4pmpye7diw mmgXhcLg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xM3Kn-000000070aq-0YjB; Wed, 28 Oct 2026 13:04:53 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xM3Kl-000000070aT-48w3 for linux-riscv@lists.infradead.org; Wed, 28 Oct 2026 13:04:52 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id BB21160120; Wed, 28 Oct 2026 13:04:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1D551F01825; Wed, 28 Oct 2026 13:04:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793192689; bh=OG80Mz0mVm49EyuyKHOkJqtYHLMvKooWxYEt+ri6Okc=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=NhoVazCkHOBZd/Zh8WtWlntaIO9ino1lTyefSK8Dzb4X7rZBNS7fhkNVtdGcP7Vdb cGNbg6lFcEZvFjT9yMlCTwP0SqOF9qq5NhXW5cvhPl0xIwEr/6L1LkNZ/uQXf4aKoi clPXr9aGTTc3EyDb+CotvlY11YlESdSO1VdrbdyIfTAyysBgktMbUkrEUpSh9IMlcM ftZdaz6ql75fiVG+RctbuKjhXW5zisfa9P6A7RWIlUDFmg1y4qEYh9gGrGcv24aiMY RQJ+Uor7BCdHWg/Ja0NxSTpMLPcpXq6FVL+09fkmcCDKK41pgGMTScRqAMVA7WiXTd C1UvOifI78Avg== Received: from phl-compute-11.internal (phl-compute-11.internal [10.202.2.51]) by mailfauth.ams.internal (Postfix) with ESMTP id 72805198003A; Wed, 28 Oct 2026 09:04:41 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-11.internal (MEProxy); Wed, 28 Oct 2026 09:04:46 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTFg4m4oPEAUf0wKUWw/Iv3SvfDuV2dwoufosxi56rG8rE3yzXkDOL9mHtdMD5t3xb TNtQvdWPVpliQZzMEq2j9Gt/Qeqa/rF77vTyxnTf5UOLPNJ2zUCh17VsnOcEYbxGgk6pd/ jnrFGdaKttqtWNKjNbixKC92UE8SCbRpRx0WxGiIqSl0J0ICk0JQhy9Sr/LMCk3/IVcW/o bCjLH09OVr/VQlaboh+GTF0eV9P0WsRQ0NN8dvTtbJ5CULwJ3YspX58BzjPnKc4esZY0AE vCO/2EXsD9kJV70LTbLoWjGuNnwDImFpXgd/qrFbj8lz7uaYEYKynkoZbbntZlYoJ2cVe9 /+rhqV/xdrC6ND9aiGvuSZn+fk+lMFKBk+CwBAGjoY66y4uTs5oqVkdwtiVpN3jnfufyiw mbFGB54MLhrD1QUgxn90nVffgd8oQRT4PZ2d0Cv8SF1Gpgx6GZU5qUwdlixKbbdcCnstPy C4OiiGs/7AHNy17plPHaquUuUuXG0T7RKsstw38S2VOjByMTyHT12LhV9xiy9nSaBbtkzo eBHrVxgrtsC+JoLewb5t0X58mNTZctuMyI/X+JJS417uckswZSke7odEKVKiXLKSFCGJgN lxiRKVDKgquvVnW9gYMK5Q2ompqZeG5/mSl+cviBwf32c/V8SUzaJThtISOA X-ME-Proxy: Feedback-ID: i10464835:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 28 Oct 2026 09:04:39 -0400 (EDT) Date: Wed, 28 Oct 2026 13:04:38 +0000 From: Kiryl Shutsemau To: Muchun Song Cc: "David Hildenbrand (Arm)" , Peter Zijlstra , Andrew Morton , Matthew Wilcox , Usama Arif , Frank van der Linden , Oscar Salvador , Mike Rapoport , Vlastimil Babka , Lorenzo Stoakes , Zi Yan , Baoquan He , Michal Hocko , Johannes Weiner , Jonathan Corbet , Huacai Chen , WANG Xuerui , Palmer Dabbelt , Paul Walmsley , Albert Ou , Alexandre Ghiti , kernel-team@meta.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, Dave Hansen , Andy Lutomirski Subject: Re: [PATCHv7 13/18] mm: Drop fake head checks Message-ID: References: <20261027110028.GH2668564@noisy.programming.kicks-ass.net> <070DDE5C-2183-4A8B-AC2D-891CAE15E581@linux.dev> <4A32F5E6-977D-4720-8723-B19AFBC08FCF@linux.dev> <7cb3dd91-f518-49b6-b311-9ec807b3c63b@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <7cb3dd91-f518-49b6-b311-9ec807b3c63b@linux.dev> X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Oct 28, 2026 at 10:38:22AM +0800, Muchun Song wrote: > > Bootmem folios optimized in early boot get their tails mapped writable > > and write protected later. Drop the write protect step. > > For bootmem folios, I don't think the RO mapping should be removed, > because we are in the initialization stage of struct page. > No one should touch those pages at this point; otherwise, they could > encounter uninitialized struct page as well. This assumes no race > exists during early boot. > > Since such a problem does not exist during the boot stage, why should > we give up the protection that RO provides? Agreed. Nothing does a lockless get on bootmem folios before hugetlb takes them, so they can stay RO. I will keep the pre-HVO write-protect and post the patch. -- Kiryl Shutsemau / Kirill A. Shutemov _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv