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 3B389C79F82 for ; Tue, 8 Sep 2026 15:16:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 291BC6B0099; Tue, 8 Sep 2026 11:16:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 242B36B009B; Tue, 8 Sep 2026 11:16:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 131066B009D; Tue, 8 Sep 2026 11:16:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id DBE966B0099 for ; Tue, 8 Sep 2026 11:16:36 -0400 (EDT) Received: from smtpin18.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 669EBA074D for ; Tue, 8 Sep 2026 15:16:36 +0000 (UTC) X-FDA: 85190946792.18.AE16EEB Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf06.hostedemail.com (Postfix) with ESMTP id 90315180017 for ; Tue, 8 Sep 2026 15:16:34 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=none; spf=pass (imf06.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788880594; b=PvOhx/nGP+LqJ7MhD+B4HNQdqbGZO6ahkFJJepils22rDbrlqRtYkcvA9PCcEZ+Ds4wKd9 CKa8nWpwPNofvfbDczCnMY+AV2AlKhaUZTJ92s9enK4FlZvAFaUYq+mFRN86pGa1d1kIuY uFrK5iZ/MyPa/bSUTDSr+e5X1G/0KeM= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=none; spf=pass (imf06.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788880594; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8yHLq3RvqtdNHUaXQ1bxGbj1cSsC+//PVXrbKsrfw1I=; b=KvV6gCQ/smTfb5IgtQAxHB283hl+CXr1rG63Qm2+f9x6PVq3CkHZixLNUzQCdToWXkI4n/ PCNJ27Eh66rWNZjayXbGKEYMdDTZBWuL149dMOSdlJE1mo2g/evfDFuna5ZznDAccWSWcO /GgWpmlvXcuM3Cy2ctUjFh8VS8UHOXs= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 67B3542E3B; Tue, 8 Sep 2026 15:16:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2F2B1F00A3A; Tue, 8 Sep 2026 15:16:24 +0000 (UTC) Message-ID: Date: Tue, 8 Sep 2026 17:16:20 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 03/14] xen/grant-table: stop setting PG_private on pages for grant mapping To: Zi Yan , "Matthew Wilcox (Oracle)" , Andrew Morton , Muchun Song , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Gregory Price , Ying Huang , Alistair Popple , Johannes Weiner , Qi Zheng , Shakeel Butt , Kairui Song Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , xen-devel@lists.xenproject.org References: <20260907-remove-pg_private-v3-0-6ae22f9d9272@nvidia.com> <20260907-remove-pg_private-v3-3-6ae22f9d9272@nvidia.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260907-remove-pg_private-v3-3-6ae22f9d9272@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 90315180017 X-Stat-Signature: ws41xtcwa7ndpgq9tmnnykrpr63g6xdb X-HE-Tag: 1788880594-347017 X-HE-Meta: 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 mSOK5UqL cHA5r3QGSJ3D/0FMhot4whp1eVqFB/QidmzWVA1xvBShiXTFQZJopCaF/VwC/DhCFNkkNY08d1Pnb2eKP1WAOXW3eX7tMD0JtCZnh/xSriFJn2Cmu5GeHbfAueyKQusUpcuTQsepz/LyVwSOHeIGkhlq23OSaHvU/dmELPpoaj0WNUAfNG7bYUUuUV1axjplU4pqn/WBkGmyPLEMeWlLgKUVcB2ZwfOV4VvIr6EIkH0rbWB5OnYgNljAyIkl6YTyTkdFkdnucLQ2AxvwbUf2AyR/T5di4dEQ4oVf0RXnt6JmRaC/U3wxqolemr6SO8ne8MEq9PTeDxVqs7dONy73G6GQNp3s6H8esQCu4We6OI5lpXqpezQDEMX6BIDEnQfvCtstg8rCLY8MPg3k= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/8/26 04:56, Zi Yan wrote: > gnttab_alloc_pages() stores xen_page_foreign in page->private. On 32-bit, a > pointer to an allocated xen_page_foreign is stored; on 64-bit, > xen_page_foreign is stored inline. Checking page->private != NULL is enough > to tell whether a xen_page_foreign needs to be freed on 32-bit and > page->private is zeroed unconditionally on 64-bit. > > It prepares for a future commit that remove PG_private. > > No functional change intended. > > Assisted-by: Claude:claude-opus-4-8 > Assisted-by: Codex:gpt-5 > Signed-off-by: Zi Yan > To: Juergen Gross > To: Stefano Stabellini > Cc: Oleksandr Tyshchenko > Cc: xen-devel@lists.xenproject.org > Cc: linux-kernel@vger.kernel.org > --- > drivers/xen/balloon.c | 5 +++++ > drivers/xen/grant-table.c | 11 +++++------ > 2 files changed, 10 insertions(+), 6 deletions(-) > > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > index e7f74ea7cd5eb..fdb18348cfdfe 100644 > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -182,6 +182,11 @@ static struct page *balloon_retrieve(bool require_lowmem) > > __ClearPageOffline(page); > dec_node_page_state(page, NR_BALLOON_PAGES); > + /* > + * clear page->private before giving it out, since it might be used to > + * store xen_page_foreign info. > + */ > + set_page_private(page, 0); Who would have set it to != 0 in the first place? e.g., gnttab_free_pages() resets it to 0 now before calling xen_free_unpopulated_pages(). -- Cheers, David