From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794261618; b=CaPucE8in61dPXg6/TdPd7EoUhH3j1/RYVfTnuITZvp1Exw4xUJJZZol24yXPkqVt4Mp g/Jya8ZF9n6Zq/OMah+DTqwX+x7ZDutQUW+LNyruEWj5BijPNMETDYnsC5rm7E0OXCEky yDphCmCKsZmkt7ZlCi37XDJEWZMhTXi00s+PmKbZSR68SJGZJs0Wx2Ft9AEeKeGXL5hvl Jzhbt05+SReXjkH7cYLg+gT55RvVpkp8aDNPDNNs2NTnRr2BEab4TSBrGZvXY+5oKa9Xo jkwGNjiPL+GogMnU8DXsoP9dfJTukBsm9F93EmLCcm3CuOoFTQmQHCIIvW1gT+HtpEg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794261618; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:Content-Language:Autocrypt:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=+uUNFNsJ/y/TsHe5tSEE2ggVSbT2u5FUwgZN1VUTMzo=; b=Hxdw661Zx98gMQcR78CPsgb5vG8GTqawJORtjh0DYSvIj4IhXYlfhuGziIGTMEAMd6Og BEMq5UMuXpgQvZtTGCU9a/d4uzqjwJ9zslcITwlwnb60OFf1K5svluDI5Rq+HdBgOsTKH WWjGvPCuPd0vg/YOnVK7F8h59wYwxWa4BLGsZtz80aOBtQb8xGNydidSkFmHcAJTzmyx6 nlBGurYK+3TLqJ2M8O3YDoLVHhMi43bhyWMhU5lGk57wbCRDXRaEZqeWvsQEjR38THAD/ j4QVIjTIJVvbwNO+xOGbdNh/RusO13T6ONUAPnQNtzT0Twel5GypS9ndDt0KbS3Ztmg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=kAxaUji6; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1C7D606A321 for ; Mon, 9 Nov 2026 22:00:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=kAxaUji6 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6216E1F0089F; Mon, 9 Nov 2026 22:00:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794261617; bh=+uUNFNsJ/y/TsHe5tSEE2ggVSbT2u5FUwgZN1VUTMzo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=kAxaUji6k2KW8rfSAvXJhJiuO/EZX60VCydj5QPGZtcNUy06hAoNW9MKWzQpV/4uY 142BRjiWbeltdP+9LWvBZfp5X6D9yTvRt07tXHpQJQcdUSLNrdfPrpSOMbUAEzgqTJ HpoHuTXP9QBCPx6WtPB9860DKqnLXKCenm87BaDg/78/XEw1a1CZdxAudNjGgcTC0q a5a+b5trvcOnvtXTOE6cSO7RlzSheWSRnx8xcpPWyP7WaNq+puxs1zaPHfh94lUUPA vzgZD0i0Ir0h7TMIxXspZ4uUgVnKKFn5jCj1KLtemmJsQDjBdqPd4VXe2ZInUO7b9F xPh8W3FLuSQIA== Message-ID: Date: Mon, 9 Nov 2026 23:00:06 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/memory: drop PROCESS_PAGES_NON_PREEMPT_BATCH To: Shivank Garg , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Ankur Arora , Pedro Falcato , Peter Zijlstra , Borislav Petkov , Bharata B Rao , Hrushikesh Salunke , K Prateek Nayak Cc: x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20261109-clear-pages-batch-v3-1-6693efe18dff@amd.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: <20261109-clear-pages-batch-v3-1-6693efe18dff@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/9/26 20:15, Shivank Garg wrote: > clear_contig_highpages() clears the whole range at once under > preemptible models. Otherwise it clears PROCESS_PAGES_NON_PREEMPT_BATCH > pages at a time, with a cond_resched() in between. The batch is 32MB if > the architecture defines clear_pages(), and one page otherwise. > > Since commit 7dadeaa6e851 ("sched: Further restrict the preemption > modes"), architectures that support lazy preemption only offer the > full, lazy and RT preemption models, also with PREEMPT_DYNAMIC. x86 is > one of them, and it is the only architecture that defines > clear_pages(). So the 32MB batch is never used: whenever > clear_contig_highpages() runs under a cooperative model, the batch is > one page. > > Make that explicit. Clear the whole range when CONFIG_PREEMPTION is > set, and one page at a time with cond_resched() in between otherwise. > Drop PROCESS_PAGES_NON_PREEMPT_BATCH, which has no other users. > > PREEMPT_DYNAMIC kernels also have CONFIG_PREEMPTION set, and > cond_resched() does nothing on any of these kernels. So a build-time > CONFIG_PREEMPTION check is enough, and preempt_model_preemptible() is > not needed. > > No functional change intended. > > Suggested-by: David Hildenbrand > Reviewed-by: Pedro Falcato > Signed-off-by: Shivank Garg > --- > Thanks, I'll wait a bit for more review before applying. Reviewed-by: David Hildenbrand (Arm) -- Cheers, David