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 306ACCD37AC for ; Sun, 17 May 2026 12:03:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4AFFB6B0005; Sun, 17 May 2026 08:03:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 487806B0088; Sun, 17 May 2026 08:03:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39D756B008C; Sun, 17 May 2026 08:03:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 28D006B0005 for ; Sun, 17 May 2026 08:03:52 -0400 (EDT) Received: from smtpin09.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id B9C0C402F4 for ; Sun, 17 May 2026 12:03:51 +0000 (UTC) X-FDA: 84776777862.09.D4B4F58 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) by imf22.hostedemail.com (Postfix) with ESMTP id C4A6EC0006 for ; Sun, 17 May 2026 12:03:49 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=XayuKuYk; spf=pass (imf22.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1779019430; 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=uzAHTZq9a1jN0cBlc3SNJJ0CnrHRNLBC13c5Nsix0sU=; b=wbMszK+jVVDBQiubhlld3GOaOx6rDi0otbTfdivLdGsDzz+4sQst1gDXa0ypVt34FbFqWS LdpMHa3c7keFLmcAsQKXkBtKA2zm0V6etyHa2NffLRIirGUT4qPnSKDpNzr0MVPI1LXonY qal3xEvynUgcbowcpjy/A48xDYlGrNE= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=XayuKuYk; spf=pass (imf22.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1779019430; a=rsa-sha256; cv=none; b=SSa2MpqnBTwNd+mER8RqB0zQPhb/ig+bvJzSmf0dOUi9cpQ4bLAVJwQn4ox0aix+kILa6C ZoBFW8tlFhD5slRgQdyB7b2Oh2qLd2AIObtzGTmWw2VvXSLYEw5YyVPFTzkppo3k902oqN cJljXAVHDwvYCuummK4AG+SNe0YjgMs= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1779019427; 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; bh=uzAHTZq9a1jN0cBlc3SNJJ0CnrHRNLBC13c5Nsix0sU=; b=XayuKuYkB18z5SlEgwurM6lOcrv/JPfJnlh1pVfuLc3lc0W7WAnCsugfqZ1qH4rEG3qso7 UP26Cljvrr66pZICIUqzgrrZIxqBMF07YN0Uknwrzdn+S9CsKRLsf/105e+d6+wf6fiyB5 FoTIArGY7IQ0lZwFUPg/51VboDuwLzk= From: Lance Yang To: luizcap@redhat.com, david@kernel.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, baolin.wang@linux.alibaba.com, ziy@nvidia.com, lance.yang@linux.dev, corbet@lwn.net, tsbogend@alpha.franken.de, maddy@linux.ibm.com, mpe@ellerman.id.au, agordeev@linux.ibm.com, gerald.schaefer@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, x86@kernel.org, dave.hansen@linux.intel.com, djbw@kernel.org, vishal.l.verma@intel.com, dave.jiang@intel.com, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com Subject: Re: [PATCH v4 2/9] mm: introduce pgtable_has_pmd_leaves() Date: Sun, 17 May 2026 20:03:28 +0800 Message-Id: <20260517120328.63143-1-lance.yang@linux.dev> In-Reply-To: <8d365dfa-98e0-478b-ba6b-377c939865d4@redhat.com> References: <8d365dfa-98e0-478b-ba6b-377c939865d4@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: C4A6EC0006 X-Rspamd-Server: rspam06 X-Stat-Signature: iiqcbh9iowxfsuxuowrpdq899c4oqeuu X-HE-Tag: 1779019429-219569 X-HE-Meta: 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 ZfNmBxr5 n+jPIX1v9whCJgFB31KUjMdWdeFbFGH5+eAufvQD7hz87LHVn5zIGIRmoSIsvlEy4N5q0qVoC6aEbTepcUqmqzk/syXBKjZ7WNGr1xU/RRkIeBhBdalPBRSAnH/SaUL4/EqEyLnkdJ5h1RnqN/kZRKGs792TgP8h9XaecoYP7j/olGCuhAiW/5X9wVTkRnxXNjW/6zVt52FjbakioS6mmNj4mWglAxnPiPFynVpOar5EKL9JdvAydaj7SxChk9UvVRN8p Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, May 13, 2026 at 09:52:05PM -0400, Luiz Capitulino wrote: [...] >>> >>> #if !defined(MAX_POSSIBLE_PHYSMEM_BITS) && !defined(CONFIG_64BIT) >>> diff --git a/init/main.c b/init/main.c >>> index 96f93bb06c49..eea7c5bdddf7 100644 >>> --- a/init/main.c >>> +++ b/init/main.c >>> @@ -1053,6 +1053,7 @@ void start_kernel(void) >>> print_kernel_cmdline(saved_command_line); >>> /* parameters may set static keys */ >>> parse_early_param(); >>> + init_arch_has_pmd_leaves(); >> >> Can't we do this a bit later from some mm code? >> >> This feels like something that can just go somewhere into mm_core_init()? Indeed. If nobody needs pgtable_has_pmd_leaves() that early, it is cleaner to put it in MM init code :) >Yes, this can be done. My intent in calling it as early as possible was >to allow callers to use the API from __setup() handlers if needed, but >since we don't have this case in the code today we can put it in >mm_core_init() for now. > >> There, we should probably call this something like XXX_init(), and prepare it >> from detecting support for PUD leaves as well. >> >> Maybe just >> >> pgtable_init() ? > >What about pgtable_api_init()? I'm afraid that pgtable_init() might be >confused with code doing real page table initialization. Or what about pgtable_leaf_support_init()? It says what this init is for, setting up the cached leaf-support check. Today that only means PMD leaves, but the name still works if we add PUD leaves later :) Cheers, Lance