From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 066AA3AEF5D; Tue, 21 Apr 2026 14:15:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776780950; cv=none; b=QhBewimeVOWgkaoRqxTeixCzeERDQ5aM50iLN4rVgF95YbTxsLuQYcJx4/uKlcMRc4ReyjXlUeSrg7XIAu2OdonhhQdRFivakiZsQJrYrQrUrcX5Zxv3GmOZJJxCKEq/aAXdlbEEdMtW12Vfq4NUDWENc4hEfhi3nBvj7VAsY3Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776780950; c=relaxed/simple; bh=078Y92oKtVm6JEaZesj5rhwZKMHbAna64KrdSsEQIfs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=fmbfdhDxW5r9gr10WuDlwYSRBge3wQyzEre+okDblgfGExB9MePjaDdUyyrqOnixQfyZevDz1Em4PXeCPeVfBYAiMDz3h5ZdhRZ94nUbffq91gEufKvJLczS22IndcUCuKPGNnAzIZHh15vF6370jsjj0NRvOUPiXt0AC+u10X4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i9oQMpZI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="i9oQMpZI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 854CEC2BCB0; Tue, 21 Apr 2026 14:15:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776780949; bh=078Y92oKtVm6JEaZesj5rhwZKMHbAna64KrdSsEQIfs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=i9oQMpZIY1uhH0+44ae33445UDB7IEPaoe2usB9oftVTiBX8AcKxOtWv8uH66qByp XySy4CfY73X8OEb4xzEKEvLyvipLaEFw7NCEIlLzX/Y7EE8N5c5YePSRIGkvJFPR49 evHp/0KXRFY5FuLpU3yi0OwUYfKSh/fiPrAcn7LV4FpGV0u+i8BWXUUK/Mq+M7y+2s qozO7v8Lm/LBKkeNIqaS3JLEYCg0p3PpyERV+sXgIaLDIuZCNjNsTiSUeViGLhrBGO DSgnJWiHAdi3rHLNfo6jq3bI4a1Lt/AaAy1QHnF1TMBQcJYpT2s8I+eaS68VakM/Fq 8M3L04tqtNvcA== Message-ID: <3daccad8-cf08-4543-b9ec-b34711a4ed14@kernel.org> Date: Tue, 21 Apr 2026 16:15:44 +0200 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] mm: Make lazy MMU mode context-aware To: Alexander Gordeev , Kevin Brodsky , Andrew Morton , Gerald Schaefer , Heiko Carstens , Christian Borntraeger , Vasily Gorbik , Claudio Imbrenda Cc: linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <8809412aaed8a515fe2e149c822543d640060936.1776264097.git.agordeev@linux.ibm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit > +/** > + * lazy_mmu_mode_enable_for_pte_range() - Enable the lazy MMU mode with a speedup hint. > + * @mm: Address space the pages are mapped into. > + * @addr: Start address of the range. > + * @end: End address of the range. > + * @ptep: Page table pointer for the first entry. > + * > + * Enters a new lazy MMU mode section; if the mode was not already enabled, > + * enables it and calls arch_enter_lazy_mmu_mode_for_pte_range(). > + * > + * PTEs that fall within the specified range might observe update speedups. > + * The PTE range must belong to the specified memory space and not cross > + * a page table boundary. > + * > + * There are no requirements on the order or range completeness of PTE > + * updates for the specified range. > + * > + * Must be paired with a call to lazy_mmu_mode_disable(). > + * > + * Has no effect if called: > + * - While paused - see lazy_mmu_mode_pause() > + * - In interrupt context > + */ > +static inline void lazy_mmu_mode_enable_for_pte_range(struct mm_struct *mm, I'm still wondering about a better name for this. "enable_for" indeed sounds like it's only for that range. Maybe really something including a hint like you previously proposed lazy_mmu_mode_enable_with_ptes() lazy_mmu_mode_enable_with_pte_hints() I think lazy_mmu_mode_enable_with_ptes() is neat. Thoughts? In any case, on the general approach + semantics: Acked-by: David Hildenbrand (Arm) > + unsigned long addr, unsigned long end, pte_t *ptep) > +{ > + struct lazy_mmu_state *state = ¤t->lazy_mmu_state; > + > + if (in_interrupt() || state->pause_count > 0) > + return; > + > + VM_WARN_ON_ONCE(state->enable_count == U8_MAX); > + > + if (state->enable_count++ == 0) > + arch_enter_lazy_mmu_mode_for_pte_range(mm, addr, end, ptep); Okay, so the "hint" is ignored for nesting levels, that works. -- Cheers, David