From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D05F2367B6A; Mon, 8 Jun 2026 17:50:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780941060; cv=none; b=gIXBQynZIKYfbyUeczOXMV3N4SKW/gqTCAND3G0eDspFX6A2u4re3RFNU9N39t4FiKUaJfxkPhqaq0pyGw3IWe/7fxUlePHtBk+16fOofLHP21a+R+02Z8yisI9tZYFNEZ5UByFzeYPf4vi6KmtOCOe9n48UhlwdvUl2+v+4UrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780941060; c=relaxed/simple; bh=U9wyANSYdY3qQUTOynYoX6e0eez4BXm5RkIg4Fl2PEI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=p7YzH6pG6wsGdLtfo9MmWFG9eryLu5sAsAPVC37QtCnE28INY83MiKFNLtu7gfeUtBj4uufL0yYRyNZGo9I2rEkR3jt7TTKD2mAGtU8rQiRoHSc7iPpj5ZDjOUmwDSe2RvSD3V/FD7vDj5bE/gZU39AmVFasd7qRUAF5qyLHAEY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FqXdrUY7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FqXdrUY7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D24281F00893; Mon, 8 Jun 2026 17:50:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780941059; bh=aHDkkZM0LDnjg910cSwEzql9JdvUeeXv0ZHTIK7GDLE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FqXdrUY7MnZgXjGyS34UzEp+k9mBFwy1XPyfvBzqH9M5+Rrj97WZggA524whLavtU fex1sh7aoVw9IMLuHbqG0bK53P45PgKGPHUWWGnuSTW9bgc0GPSFWZWjJ5vXQvYnm6 jK3z3oPOO/9d8708nmY88nJxhryP72whFMVt1KqHlIeWHOf9gOvgtu09nP9cF9fTIK NZvYXB/YeKY2j/gbsgK46F08vVHhDMqb/hdaRrs1gnoNECKz8Y7N866XxI2YSKkbTY G82BRdrb2Nid29WdnkhJpE0VI5yr5LASvGW6ohHaH4bsJi3Jr2Wv2m4U+XIdkZsAwh GkNZa8J2v58QQ== Date: Mon, 8 Jun 2026 18:50:46 +0100 From: Lorenzo Stoakes To: Gregory Price Cc: "Vlastimil Babka (SUSE)" , "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, "David Hildenbrand (Arm)" , Jason Wang , Xuan Zhuo , Eugenio =?utf-8?B?UMOpcmV6?= , Muchun Song , Oscar Salvador , Andrew Morton , "Liam R. Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Hugh Dickins , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , virtualization@lists.linux.dev, linux-mm@kvack.org, Andrea Arcangeli Subject: Re: [PATCH v10 00/37] mm/virtio: skip redundant zeroing of host-zeroed pages Message-ID: References: <8d5d2fa3-a60c-4d04-b3bf-7a8fe89cb1a0@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Jun 08, 2026 at 11:45:18AM -0400, Gregory Price wrote: > On Mon, Jun 08, 2026 at 01:13:42PM +0200, Vlastimil Babka (SUSE) wrote: > > On 6/8/26 13:02, Vlastimil Babka (SUSE) wrote: > > > On 6/8/26 10:33, Michael S. Tsirkin wrote: > > >> Further, on architectures with aliasing caches, upstream with init_on_alloc > > > > > > It seems those are niche architectures so we can ignore that part for perf > > > purposes; the other reason why user_alloc_needs_zeroing() would be true is > > > booting with init_on_alloc. > > > > OK I misread how user_alloc_needs_zeroing() works wrt init_on_alloc, as it's > > negated. But you're changing that anyway to skip that user zeroing, right? > > > > " > > This series eliminates that double-zeroing by moving the zeroing > > into the post_alloc_hook + propagating the "host > > already zeroed this page" information through the buddy allocator. > > " > > > > So relying on "everything in buddy is zeroed" would still work I'd think. > > > > This regresses for anything that previously didn't zero on free or > alloc, which is most kernel allocations. > > I think the scope of this set has increased too much based on early > feedback to fix the userland-initiated allocations piece along with the > balloon/reporting/double-zero piece. That's making all of this > difficult to continue following. Yeah I feel this is 3, 4 or 5 series put together, and there's a lot to discuss in each :) so it's pretty difficult to work with them all put together. These need to be deferred/separated. > > ~Gregory Thanks, Lorenzo