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 F2EACFD0659 for ; Wed, 11 Mar 2026 08:29:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 388276B0099; Wed, 11 Mar 2026 04:29:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 33FC06B009D; Wed, 11 Mar 2026 04:29:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 237EB6B009E; Wed, 11 Mar 2026 04:29:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id EF7CC6B0099 for ; Wed, 11 Mar 2026 04:29:05 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 88D921A062A for ; Wed, 11 Mar 2026 08:29:05 +0000 (UTC) X-FDA: 84533107050.21.B529B21 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf23.hostedemail.com (Postfix) with ESMTP id A8F1C14000D for ; Wed, 11 Mar 2026 08:29:03 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=utVavD96; spf=pass (imf23.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=1773217743; 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:dkim-signature; bh=iTqYii1hI2e00krqbtsX9LEsDy2UgfEWXTijiExHbW0=; b=rNBusE3tTUOa5jzreZoGZUZz9FJiF8sudEv8fZzXznn2nWdaKl6CU7Ui5QVhX59wXjagE2 oHC9YSviUXl+v8OQaSZVS7oOnh9p0UsWOoYATHwtwm/qLFzlKmLhuzLQd+6Swr8IiE1PnJ Bd9Ejq3APeP+aO2GbqyD6m6SKm7gUds= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=utVavD96; spf=pass (imf23.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; s=arc-20220608; d=hostedemail.com; t=1773217743; a=rsa-sha256; cv=none; b=mRkHjDFvMDX2fGIqybgf0NNWDPHBYIkU6cjLyWz5GMYZANMqemB4a5cbkhPal5q6VWOA5w mZefSsl0jY/ND71qv1UTqnrOuv9w5ZfAzvclomuOM9roNFPb1bOZXNNYb6F1GS/goaus3I BaA1gJ1Q59VGMov37FYKCVUGhunOPYg= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id A3FF143FE5; Wed, 11 Mar 2026 08:29:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C4C3C4CEF7; Wed, 11 Mar 2026 08:28:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773217742; bh=GE6B9Axf2iqOgQ6Zt2ej9Oufrn3oudVjXjL2vTIfmAQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=utVavD961L/MIxHcghlNRfP+qmyZvTz3tZkkai8biCLxovJiwSfi721dAan4WAerP qQU5S4O+so1CV/l13lXL1pBvxe6Xcb8kk+l/bBNkxM6Og8LAf+De6dljLV/bYd9vPF RnkVuR2LJMC1aO8Mmf8ZYzGG89DCjYYyg3JerSgXRXHIS9MEy5aP+0VPOJEnsfhJP/ cAHnLbI4JCoH8Po1okfUE05z/3RGXHVkg9UE9OHdr7DaaCoUol+/nBwm0m7BwYmG4l DzBEoPXPx1/wX7BQYXu4AinRZizyRYhr3BiDVj3GhukhaNvYNRYVgru+HF9UqoHZIa O0mPmtOaDieiw== Message-ID: <5e5e0169-5197-4626-b91b-af4c13520805@kernel.org> Date: Wed, 11 Mar 2026 09:28:47 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 09/16] mm/memory: convert details->even_cows into details->skip_cows To: "Lorenzo Stoakes (Oracle)" Cc: linux-kernel@vger.kernel.org, "linux-mm @ kvack . org" , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , David Rientjes , Shakeel Butt , "Matthew Wilcox (Oracle)" , Alice Ryhl , Madhavan Srinivasan , Michael Ellerman , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Jarkko Sakkinen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Greg Kroah-Hartman , =?UTF-8?Q?Arve_Hj=C3=B8nnev=C3=A5g?= , Todd Kjos , Christian Brauner , Carlos Llamas , Ian Abbott , H Hartley Sweeten , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Jason Gunthorpe , Leon Romanovsky , Dimitri Sivanich , Arnd Bergmann , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Andy Lutomirski , Vincenzo Frascino , Eric Dumazet , Neal Cardwell , "David S. Miller" , David Ahern , Jakub Kicinski , Paolo Abeni , Miguel Ojeda , linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-sgx@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, rust-for-linux@vger.kernel.org, x86@kernel.org References: <20260227200848.114019-1-david@kernel.org> <20260227200848.114019-10-david@kernel.org> <091ce280-9204-4b85-bf39-5e2a61e3d0ba@lucifer.local> 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: <091ce280-9204-4b85-bf39-5e2a61e3d0ba@lucifer.local> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: A8F1C14000D X-Rspamd-Server: rspam08 X-Stat-Signature: jfaew5z4ty4mq1hxnia68caggarjqop4 X-HE-Tag: 1773217743-139908 X-HE-Meta: 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 0JC9x6mO TGCGddccuVPoZBeGZuVXOiS/j2OzcQFHinGmWjvAVvDXNcsYey/qJjLPCW7qqj6rMXh09QBm2Z828+RLCFiXYwvSQHYXQRlSLUuTQ7JXLaCoyxHB4+oLS9kEfNQvLVdb+Dcl6WwOsyuH9NdD4G9kx+cq8Oi0khIyQr1CL/xYHgm9vLnMdRIOJy6xnC8X8eV3tUgiZO0zgx/AbK+uBf79FznoLAIMkvptIF9TJX1iAWU9hbwMmrcye4gKherc84iV9BJlZW9JYoLCT3wDlNuRbwrdioW3CUG5KEfpq4HJO0Msj0lnVhCot7ze7FQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >> >> zap_page_range_single_batched( >> diff --git a/mm/memory.c b/mm/memory.c >> index fdcd2abf29c2..7d7c24c6917c 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -1554,11 +1554,13 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) >> static inline bool should_zap_cows(struct zap_details *details) > > Not sure if you fix up later, but we should probably change this function to > should_skip_cows() to keep everything consistent, otherwise this is a bit weird > and confusing. should_skip_cows() is a bit misleading on its own IMHO, as we skip the "zap" context. Would have to be something like "should_skip_cows_when_zapping()", and I am not sure if that's really worth it. So I think we can leave it as is. Thanks! > >> { >> /* By default, zap all pages */ >> - if (!details || details->reclaim_pt) >> + if (!details) >> return true; >> >> + VM_WARN_ON_ONCE(details->skip_cows && details->reclaim_pt); >> + >> /* Or, we zap COWed pages only if the caller wants to */ >> - return details->even_cows; >> + return !details->skip_cows; >> } >> >> /* Decides whether we should zap this folio with the folio pointer specified */ >> @@ -2149,8 +2151,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct unmap_desc *unmap) >> struct mmu_notifier_range range; >> struct zap_details details = { >> .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, >> - /* Careful - we need to zap private pages too! */ >> - .even_cows = true, >> }; >> >> vma = unmap->first; >> @@ -4282,7 +4282,7 @@ void unmap_mapping_folio(struct folio *folio) >> first_index = folio->index; >> last_index = folio_next_index(folio) - 1; >> >> - details.even_cows = false; >> + details.skip_cows = true; >> details.single_folio = folio; >> details.zap_flags = ZAP_FLAG_DROP_MARKER; >> >> @@ -4312,7 +4312,7 @@ void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, >> pgoff_t first_index = start; >> pgoff_t last_index = start + nr - 1; >> >> - details.even_cows = even_cows; >> + details.skip_cows = !even_cows; > > Not sure if you clean up later, but seems sensible to cascade the change into > the local boolean here. There are too many unmap_mapping_range() users for me to want to change the external interface :) What I was thinking is that probably there should be two independent user-facing functions, instead of having this magical bool passed around Because I am sure, most users don't really know whether to set it to true or false ... But that's something for another cleanup. (I left the whole unmap_mapping_pages() interface etc alone in this series) -- Cheers, David