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 0EC52EF06E2 for ; Sun, 8 Feb 2026 10:23:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 233316B0089; Sun, 8 Feb 2026 05:23:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1B6936B0092; Sun, 8 Feb 2026 05:23:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0B8E26B0093; Sun, 8 Feb 2026 05:23:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id EEB426B0089 for ; Sun, 8 Feb 2026 05:23:05 -0500 (EST) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 802C414054A for ; Sun, 8 Feb 2026 10:23:05 +0000 (UTC) X-FDA: 84420901530.10.0134782 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf14.hostedemail.com (Postfix) with ESMTP id E9A67100005 for ; Sun, 8 Feb 2026 10:23:03 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=hFIlpYuV; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf14.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770546183; 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=S9EksYV9/lRgzN5hUhPRpNXuRskPBsHzGvJwBmB1B2A=; b=mHqulqnOUBivzyWe0Mc026tdRFoO+Vy59dF8mBcsg/lan77dA6HGYTcNJvBLM3ZlQ2Q7dd zdRMKN3rpXkCFU9dr4J28fergMgFcsaR1kDXAwJ4BDGertIitReSAWbAaotF/jNT9DtT0n VkYkxKNs2XQ+pPp9F/VDnscbbwQLDuE= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1770546183; a=rsa-sha256; cv=none; b=wIsxH6gPwl0SRxXaku99+8SKrlUSuDUMZxc836B30A7PtO00vcgDdjRV39jCWfrItkWC0G t+4/CjbnosuulFK6GZfGEHSxl8k6ZQhSxS8fNBK4dcQ+aowzeUp07IMTYxRGlnqEgoBkjx NXyF6rU1IyHKdm96mGGcADAarLazXf4= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=hFIlpYuV; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf14.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 4DCDE60054; Sun, 8 Feb 2026 10:23:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 001AFC4CEF7; Sun, 8 Feb 2026 10:22:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770546183; bh=X40rdyS6Y6fl2CRiDiW77eJoxxt8y+6p1hMAAnDEfLU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hFIlpYuV5D2Emx0Q2sDypBVW+AhWi8fSuO40+NXrjL28KqRmx6A6QX5FXeeOTE2lp 6vMssip5iI0KL66gFswfQfau4ZitOqeDjeJPa5ij89+dq4dttWgDU68XSnzlha4G9f LTAWMWKeN1Z54We7+CPufJwweWX/BWwB+W/BOGIgIDkmowaq+fRqHccfv5EgbnMUUr IEeSng43gd7rVXZgTs/6sXTfjTo0xIdTvGOXB2DRzi2krxzvdH8dqRYbYcOmrYKZu0 JiSwbNAXpr6U01oLDpnksOIAJDuhD6t0mXS6fR4uz+MuX72J1xltL3Z2pLZXcGmATE /Uj7w4dxYwc2w== Date: Sun, 8 Feb 2026 12:22:52 +0200 From: Mike Rapoport To: Peter Xu Cc: linux-mm@kvack.org, Andrea Arcangeli , Andrew Morton , Axel Rasmussen , Baolin Wang , David Hildenbrand , Hugh Dickins , James Houghton , "Liam R. Howlett" , Lorenzo Stoakes , Michal Hocko , Muchun Song , Nikita Kalyazin , Oscar Salvador , Paolo Bonzini , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH RFC 09/17] userfaultfd: introduce vm_uffd_ops->alloc_folio() Message-ID: References: <20260127192936.1250096-1-rppt@kernel.org> <20260127192936.1250096-10-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: E9A67100005 X-Stat-Signature: kadur418hpgztgsxaq8uofghequeiqja X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1770546183-807860 X-HE-Meta: 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 EiZJF+Vr YmekL6gL73hUawQMLl9xiu2RWeahaRJ/QdIAVoNfxuuPhTOchc2YKOHEa3iw0IcrupprbpXAIQk1jBtzh6eOy1ZSXoZ5O3kVtwaksuXsZcqWWrx/VR/Sqe8Q+4JDnGQ0DhWGX0RMtB6mm4ij3YT0ZDPQtan8MPBxVbGv8y1CMWaHsDWr1npVkdOaQhmnQWNZuqkkU/oWPeHgeJ6mmsVP0VGnMM0OBs+RqkLaXFaHObQiu+ILiRKIsUt3GmBr5RK0+As/KhQBF0LtdckogDGF3c3DtLFMkzpSEsS2TGG88WNBo44Y= 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, Feb 02, 2026 at 05:13:20PM -0500, Peter Xu wrote: > On Tue, Jan 27, 2026 at 09:29:28PM +0200, Mike Rapoport wrote: > > [...] > > > -static int mfill_atomic_pte_zeroed_folio(pmd_t *dst_pmd, > > - struct vm_area_struct *dst_vma, > > - unsigned long dst_addr) > > +static int mfill_atomic_pte_copy(struct mfill_state *state) > > { > > - struct folio *folio; > > - int ret = -ENOMEM; > > - > > - folio = vma_alloc_zeroed_movable_folio(dst_vma, dst_addr); > > - if (!folio) > > - return ret; > > - > > - if (mem_cgroup_charge(folio, dst_vma->vm_mm, GFP_KERNEL)) > > - goto out_put; > > + const struct vm_uffd_ops *ops = vma_uffd_ops(state->vma); > > > > - /* > > - * The memory barrier inside __folio_mark_uptodate makes sure that > > - * zeroing out the folio become visible before mapping the page > > - * using set_pte_at(). See do_anonymous_page(). > > - */ > > - __folio_mark_uptodate(folio); > > + return __mfill_atomic_pte(state, ops); > > +} > > > > - ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr, > > - &folio->page, true, 0); > > - if (ret) > > - goto out_put; > > +static int mfill_atomic_pte_zeroed_folio(struct mfill_state *state) > > +{ > > + const struct vm_uffd_ops *ops = vma_uffd_ops(state->vma); > > > > - return 0; > > -out_put: > > - folio_put(folio); > > - return ret; > > + return __mfill_atomic_pte(state, ops); > > } > > > > static int mfill_atomic_pte_zeropage(struct mfill_state *state) > > @@ -542,7 +546,7 @@ static int mfill_atomic_pte_zeropage(struct mfill_state *state) > > int ret; > > > > if (mm_forbids_zeropage(dst_vma->vm_mm)) > > - return mfill_atomic_pte_zeroed_folio(dst_pmd, dst_vma, dst_addr); > > + return mfill_atomic_pte_zeroed_folio(state); > > After this patch, mfill_atomic_pte_zeroed_folio() should be 100% the same > impl with mfill_atomic_pte_copy(), so IIUC we can drop it. It will be slightly different after the next patch to emphasize that copying into MAP_PRIVATE actually creates anonymous memory. > > _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), > > dst_vma->vm_page_prot)); > > -- > > 2.51.0 > > > > -- > Peter Xu > -- Sincerely yours, Mike.