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 A3FC9CCF9F8 for ; Mon, 3 Nov 2025 16:03:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0FB238E008B; Mon, 3 Nov 2025 11:03:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0AC118E0057; Mon, 3 Nov 2025 11:03:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EB52A8E008B; Mon, 3 Nov 2025 11:03:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id DA0BA8E0057 for ; Mon, 3 Nov 2025 11:03:55 -0500 (EST) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A363112ACEE for ; Mon, 3 Nov 2025 16:03:55 +0000 (UTC) X-FDA: 84069766830.02.D3FBA46 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf03.hostedemail.com (Postfix) with ESMTP id C3F702001B for ; Mon, 3 Nov 2025 16:03:52 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="ERy/tB+e"; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762185833; 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=lAB1nRPhZgw2D2F/txfufevKSsNDcd09VLHZkiGFvSY=; b=cKLufkDg63FM4khkIEaikBFalN7S63Kuhs+tvIRL8+sPkcNb83Ta8QoFLzKlQ8cAF7PBHY 2mQCpOL055zOt5pA286T72dYUslzmgqdaXEGFIxq6VmjMfA47/oOp1NLds6uhzEavKtrEm wr3yIS/Uazvn6cqoPTRmsAkE1dLVafg= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="ERy/tB+e"; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762185833; a=rsa-sha256; cv=none; b=ZtopA8uOiLFhMwiny0UENPbD7XAO0f0DBp3tvIgZxwfW5LTPhqICTc0Y0CFKs3qkwamHk4 ktxQcOEkz6hPNoYkA1n7i9QHW43avAFXeshxf9EFj9lHqvs4e0fyc0YxoUUi8E9uGhCLbl fRtyM4Hu8EQy9evl0qa3p7bALJVrv7s= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762185831; h=from:from: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:autocrypt:autocrypt; bh=lAB1nRPhZgw2D2F/txfufevKSsNDcd09VLHZkiGFvSY=; b=ERy/tB+ehZto1IpdDRbiQl00jssLP7gyHWstsZKqt+ljYZbFZNciSW6++nCbhTFi2MiDft NlqifGfj7MiJvAG+UMTHqdPFLo5AfO++z2NP49AwVyIVWet/odHc15SCit5SWmvkfLPaQg tIxBKeB2PlX9vGY/DlViI4UN7weqXtI= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-226-bVLB6bNHMSauhsdWD0H9Tw-1; Mon, 03 Nov 2025 11:03:47 -0500 X-MC-Unique: bVLB6bNHMSauhsdWD0H9Tw-1 X-Mimecast-MFC-AGG-ID: bVLB6bNHMSauhsdWD0H9Tw_1762185826 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-47717c2737bso17705175e9.2 for ; Mon, 03 Nov 2025 08:03:46 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762185825; x=1762790625; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=lAB1nRPhZgw2D2F/txfufevKSsNDcd09VLHZkiGFvSY=; b=muWD+A3DE8hHvLkL+2w7HYDiJksryMY6Kh5WMTKwZlkScLyU4/jM/tNEOi/Q7V9UFG CXMIF9blXqZTd4cCfFF+ZrUr1iEGjHlQjFIr7d+UJ6T7AW5P/OCLEk5pgCotgxJmx/Q/ 2+xz1r0OgGMAuMXTWJYYyJlvQo0X2Ltfl4VvUPHzKJTywxOdj68Mh2Q+Mdx+CENFRu+g rRgX4ZWNGJ4okdnLFAzI87UWfouk0A02UB6gcflnvN/Kk0G70aH6Ja/InLbuCGdNaCVg G5kORS7D2ELQFOp6xYnovywI2t2+oBLXslYTjrCa42sGeq00skJZHDKHoRMcW6dRgkOx MOSQ== X-Forwarded-Encrypted: i=1; AJvYcCV9INGzA8x954IiKKaY2SLere1VlTfQHilee0mwsqIEEI1O/qoSkdwDKYmiAeyjk7XpaqdrnATJew==@kvack.org X-Gm-Message-State: AOJu0Ywn8WzLYSrFE7X2ZYXeSFoultxMW5rNLwCmaS4hGJZfB7NWHN1Z 9hmaZSHLiXe/FSld2vrvGHF99kw4Zg/C9rxQSFEoWRPB3ZO9cLVqU8Uijcv66pG43fJdu0r7NZ5 jDjt3+811hgVFa6nAD1yNYH/r35uT8p1b81G5qB97LjoXzNEPhqpo X-Gm-Gg: ASbGncvSZTvW6IwE3sZN/8g5ZV6MxjLzhjcLbueX09Z0auOsLPvydbAeWTX+egnrd5r 4Y1RtvvzVIX6Los6bwIccZwQWdR7jOrCZtL/wPpU8E0XMA9oCEyq82/m+boBWP/Ez1gGWYBiM6l 8j4tAOrKPSU+nOAIWnPch7JE6aLCeZ03A4Dxn/Xx7p3pmjYI9BxWtwsp8PiRHi+J0dCDzgwxuXo DFkCjAZA9QspBcuyfrgFQhugJ4wbCktA2CZD27KbR368Vq7k/V72J717X+r+VWy0BEvgnq9MsS0 U1TG9KnJI8PO5KEypKJ1eZUqcD0R6r+9MqW3yz4xRurRWFUGARAAdXR/O76Dr41uQ6Qu0X9UDqb 51YCQu19/MfQ1f2tJ0mu4ySQdMBQQ5wsHxDTTsQ9wIukWoakBEZzoUphhHo2OIMunXp5vIcYf4R +4IDGhrahesSJfx8uzlfnaONgVoIw= X-Received: by 2002:a05:600d:831c:b0:477:542a:7ed1 with SMTP id 5b1f17b1804b1-477542a7ee4mr3984995e9.19.1762185825549; Mon, 03 Nov 2025 08:03:45 -0800 (PST) X-Google-Smtp-Source: AGHT+IE5tyJHb+sues0m+7ZNZilqyo2L9Cho1JQDhJMCuFOgAOZW6Lsc8SY3FhL38SgCM772181+5A== X-Received: by 2002:a05:600d:831c:b0:477:542a:7ed1 with SMTP id 5b1f17b1804b1-477542a7ee4mr3984625e9.19.1762185825048; Mon, 03 Nov 2025 08:03:45 -0800 (PST) Received: from ?IPV6:2003:d8:2f3f:4b00:ee13:8c22:5cc5:d169? (p200300d82f3f4b00ee138c225cc5d169.dip0.t-ipconnect.de. [2003:d8:2f3f:4b00:ee13:8c22:5cc5:d169]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4773c48daa0sm167032215e9.3.2025.11.03.08.03.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 Nov 2025 08:03:44 -0800 (PST) Message-ID: Date: Mon, 3 Nov 2025 17:03:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 08/12] arm64: mm: replace TIF_LAZY_MMU with in_lazy_mmu_mode() To: Kevin Brodsky , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , "David S. Miller" , David Woodhouse , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Ryan Roberts , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20251029100909.3381140-1-kevin.brodsky@arm.com> <20251029100909.3381140-9-kevin.brodsky@arm.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: <20251029100909.3381140-9-kevin.brodsky@arm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: EQA2HgPPnIp6yctTo-wcpgN-0uCbqMLYbV790-Z3ONA_1762185826 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C3F702001B X-Stat-Signature: fartskch7ypw53h73bax5o3yda4pcy9b X-Rspam-User: X-HE-Tag: 1762185832-881789 X-HE-Meta: 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 94nfQjb0 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 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 29.10.25 11:09, Kevin Brodsky wrote: > The generic lazy_mmu layer now tracks whether a task is in lazy MMU > mode. As a result we no longer need a TIF flag for that purpose - > let's use the new in_lazy_mmu_mode() helper instead. > > Signed-off-by: Kevin Brodsky > --- > arch/arm64/include/asm/pgtable.h | 16 +++------------- > arch/arm64/include/asm/thread_info.h | 3 +-- > 2 files changed, 4 insertions(+), 15 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 535435248923..61ca88f94551 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -62,30 +62,21 @@ static inline void emit_pte_barriers(void) > > static inline void queue_pte_barriers(void) > { > - unsigned long flags; > - > if (in_interrupt()) { > emit_pte_barriers(); > return; > } > > - flags = read_thread_flags(); > - > - if (flags & BIT(TIF_LAZY_MMU)) { > - /* Avoid the atomic op if already set. */ > - if (!(flags & BIT(TIF_LAZY_MMU_PENDING))) > - set_thread_flag(TIF_LAZY_MMU_PENDING); > - } else { > + if (in_lazy_mmu_mode()) > + test_and_set_thread_flag(TIF_LAZY_MMU_PENDING); You likely don't want a test_and_set here, which would do a test_and_set_bit() -- an atomic rmw. You only want to avoid the atomic write if already set. So keep the current /* Avoid the atomic op if already set. */ if (!(flags & BIT(TIF_LAZY_MMU_PENDING))) set_thread_flag(TIF_LAZY_MMU_PENDING); -- Cheers David