From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A8B103F54A0 for ; Tue, 26 May 2026 11:54:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779796457; cv=none; b=HDrXT4VO9mahrEQEVRnGHPtleTdBeBBSaCShlt2Pl3aDl1fwLQ9aTy4DgIlaqS+GP1xQfu9zodbSaAnxI8EQxj9neWIIRLEyONcjfkTIpaUmyeOFKmxBTNPD1VnLGmhDZU4Ev6FNZBakAvCyfXiWuZ6axHP42pzo7MVQBF9yOEw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779796457; c=relaxed/simple; bh=HhcY4TG/6pLCS5ZpzHLBZkS5pauDzOZDzxzLR0+SqjQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WcIHh1QKcL8pVExETsvK+BJFRPQ+0+6WK7mu7SPkl/EAaaIHvNQ7SJABJrNBjTc9T+ZTKIrjOupXBl166xWuYY8PmbhnTpnlBh6Tdvh9rSg5UnzmYlx4p45C5SfhKs4apGTT146a924meZEZu+geJmfXU9GpIsaE6elBdOVIBQY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=gLe2m3Yc; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="gLe2m3Yc" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 51C1E169C; Tue, 26 May 2026 04:54:02 -0700 (PDT) Received: from [10.43.20.71] (e126510-lin.lund.arm.com [10.43.20.71]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2F78B3F7D8; Tue, 26 May 2026 04:54:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1779796446; bh=HhcY4TG/6pLCS5ZpzHLBZkS5pauDzOZDzxzLR0+SqjQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=gLe2m3YcfahXbF6L9I64v0GrkoUwaoSfBtFJPZh1Es69i5BTm8ud5+HoppYSxqF8x xLrCWMqIkpVaBF4B1n5RlLbhQzwDaIwvIOQUNmMRZSZ37egc8hXFdCi7nuyyQJ/M52 IpRd39A1PTh7+YKNFNiYx9CT1/TsMBBprazNAgFk= Message-ID: <92450154-e1ab-46e4-b23d-eaa59c9cdd3b@arm.com> Date: Tue, 26 May 2026 13:54:00 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm64: mm: call pagetable dtor when freeing hot-removed page tables To: Vishal Moola , Catalin Marinas Cc: Andrew Morton , Alistair Popple , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, will@kernel.org, david@kernel.org References: <20260521032730.2104017-1-apopple@nvidia.com> <20260521153130.d7d5cd060f7522f894252333@linux-foundation.org> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 22/05/2026 11:36, Vishal Moola wrote: >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index 4c8959153ac4..9d42cbddce27 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1441,6 +1441,9 @@ static void free_hotplug_page_range(struct page *page, size_t size, >> >> static void free_hotplug_pgtable_page(struct page *page) >> { >> + if (folio_test_pgtable(page_folio(page))) > This should work. > >> + pagetable_dtor(page_ptdesc(page)); >> + >> free_hotplug_page_range(page, PAGE_SIZE, NULL); > In the case we presumably have a page table page (ptdesc) at this > point, we should really be freeing it with pagetable_free() as well. Agreed, I think this is the right thing to do, something like: if (folio_test_pgtable(page_folio(page))) pagetable_dtor_free(page_ptdesc(page)); else free_hotplug_page_range(page, PAGE_SIZE, NULL); Strangely enough x86 calls pagetable_free() in both cases. My series protecting page tables with pkeys has a patch [1] to get vmemmap to allocate page tables with pagetable_alloc(). The diff above will require pagetable_*_ctor() to be called as well, but I think that's the right thing to do anyway. That could be posted as a separate series, but I'm hesitant due to the lack of NUMA awareness in pagetable_alloc(). - Kevin [1] https://lore.kernel.org/all/20260526-kpkeys-v8-14-eaaacdacc67c@arm.com/ > Its not a big deal that we don't right now, but losing track of the > matching allocation/free sites will become a headache when separately > allocating from struct page. > >> }