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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AA259CD6E52 for ; Sun, 31 May 2026 19:29:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qu2+WTwuJ2gVSCxV3OmrdSWwWtogPX4uTQ5dajqvUVA=; b=BAPPwqTWlpraZtlA71zq0EAaC9 Aj4lsDG4gIGlChE0ROhM71p7JyE1LK3lEbBuqR65g3VQuS9vUKJAG+5TkE1BktpO7EnmLhyaHtqg1 6N/bOMteUDZYmTzLUe7kWjnlN2/h9nRFUaLULyTJQjL2RpJ9BQa1ZIN60vyZrTCGcuZ9Hb3X4gbvO IImrv/hj3L12uz564/Agx3hezlawXKyPy4vfGJpaHgmcwUiznN1814LYv+f+Xcwb9DRahuezZvk2C OeKjxM5beMzwK9ZrnTPpggpcxHa42sjXBk34a+aiNSrerGceo49ar8vLhLxloe5J9i0BEXc1tMm8J l7naOhFQ==; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260531_122925_125485_CB3D333D X-CRM114-Status: GOOD ( 11.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 5/27/26 09:34, Kevin Brodsky wrote: > On 26/05/2026 14:31, David Hildenbrand (Arm) wrote: >> On 5/26/26 13:54, Kevin Brodsky wrote: >>> 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); >> That code pattern is wrong. >> >> folio_test_pgtable() shouldn't exist. >> >> In the future, something is either a pgtable or a folio, not both. >> >> So check the type against the page, not the folio. > > In other words use PageTable(page) instead? Interestingly I can see a > few calls to folio_test_pgtable() across the kernel but none to > PageTable(), maybe just an antipattern then? The ctor/dtor also use > __folio_{set,clear}_pgtable(). We started running into the wrong direction, and now have to undo all the wrong things we already did :) In the current design Willy has in mind, doing a page_folio() will later return NULL if it's not actually a folio. -- Cheers, David