From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 84917305E28; Thu, 10 Sep 2026 14:38:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789051094; cv=none; b=HSxPPpxtO4S+YZhoxmFa2mOwLE67TQfBK0fPx7qPVS8VzIAcRKvQ4K0xon49k+UqhTVh/pnWFwmTNN0myjOxtbfxU/eity7HGzv9JAU6CdwnDsajimWqh9IcS8cacEaUin4ufshkL8q82I5Yi37YCCovNTT/ncaDnJBIig3uR+Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789051094; c=relaxed/simple; bh=579RDGAe/WRL3OlaVw3qhRslyCTWudTRZekqpzQAT/E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=o0TqHnDjXn5NWQw91GiBeqFz0Ux6mEKfsGE4bdkqJWV63+qzuHtReU4TkG09y2Y7l7e8+4+Fqq3uoIWm6GtMubLPo1Gn7nhndRRPsp7uieVUxMSGSaIqRNZUWmM1GxAcKXiAkf/xO5oEpWiT8+FYEcwyreGyB3S1QzIzJm+rWR8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=I5pFoW74; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="I5pFoW74" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5071B1F000FF; Thu, 10 Sep 2026 14:38:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789051093; bh=MK4zUJB9+wzOo/C/BizaklPC9wZpzdasI2Hvs/7YAKY=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=I5pFoW746SSPNXz9o8Gr2kFBOSCOW/xePk4xTDfyqFgvoAmf0tODgEET0eRkncke9 XZfiCBHYBPe3zMjtgMElX9WcKhEFwpWObpy1cDNNXfZ82Q10+JbzOCJjnJSyAnK53x 7vuGYjH/35JsI1+OK1y/muHGz9/onzcxiv9oEU+nc6hi8+rY0ajtvZgR1zgS1lrdUl MYlX5KHgZuMvcheoJuo7cNLrgBsMOqearr46U9pUJlt6Hu0phy1p2dpwJ5CUSI15fd AtCXxUto9Jhl3wqLtR0RwSlAn2asx1Z4EZT3Es7V9UREdrzYdWck5ixnGT2gsty54b uZsXfs+QijvtQ== Date: Thu, 10 Sep 2026 15:38:03 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , Brendan Jackman , Johannes Weiner , Zi Yan , Oscar Salvador , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Jan Kiszka , Kieran Bingham , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-cxl@vger.kernel.org, driver-core@lists.linux.dev, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 02/12] mm/sparse: refactor sparse_sections_init() Message-ID: References: <20260909-b4-sparsemem_cleanups-v1-0-008fc8d579fe@kernel.org> <20260909-b4-sparsemem_cleanups-v1-2-008fc8d579fe@kernel.org> <44f7ce5c-b75c-4c44-9202-1d2d3a1de965@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <44f7ce5c-b75c-4c44-9202-1d2d3a1de965@kernel.org> On Thu, Sep 10, 2026 at 04:30:43PM +0200, David Hildenbrand (Arm) wrote: > On 9/10/26 15:29, Lorenzo Stoakes (ARM) wrote: > > On Wed, Sep 09, 2026 at 03:32:55PM +0200, David Hildenbrand (Arm) wrote: > >> memory_present() really identifies+prepares all early sections so the > >> initialization in sparse_init() can properly iterating them to > >> initialize metadata. > >> > >> Let's just inline memory_present() into sparse_sections_init() and > >> cleaning up the code a bit while at it: make it clear that we are operating > >> on pfns. > >> > >> Note that we call set_section_nid() now only if the section > >> was not already created earlier. Now, there is no more inconsistency > >> between what we (temporarily) store in ms->section_mem_map and what > >> we store in our section->nid array. > >> > >> Signed-off-by: David Hildenbrand (Arm) > > > > In general please keep move/refactor steps separate. It makes it harder to > > review when two things are going on at one time. > > > > But I guess in this case the diff wouldn't be that different. > > Yeah, I actually want back and forth here and decided to keep it simple. Yeah, this one's a bit of a blurry line but I think fine as it is! > > > > > Anyway seems reasonable so: > > > > Acked-by: Lorenzo Stoakes (ARM) > > Thanks! > > > > >> --- > >> mm/sparse.c | 41 +++++++++++++++++------------------------ > >> 1 file changed, 17 insertions(+), 24 deletions(-) > >> > >> diff --git a/mm/sparse.c b/mm/sparse.c > >> index 6a6d258862904..36e3d854febc5 100644 > >> --- a/mm/sparse.c > >> +++ b/mm/sparse.c > >> @@ -179,22 +179,27 @@ static inline unsigned long first_present_section_nr(void) > >> return next_present_section_nr(-1); > >> } > >> > >> -/* Record a memory area against a node. */ > >> -static void __init memory_present(int nid, unsigned long start, unsigned long end) > >> +void __init sparse_sections_init(void) > >> { > >> - unsigned long pfn; > >> + unsigned long pfn, start_pfn, end_pfn; > >> + int i, nid; > >> + > >> + sparse_extreme_init(); > >> > >> - start &= PAGE_SECTION_MASK; > >> - mminit_validate_memmodel_limits(&start, &end); > >> - for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) { > >> - unsigned long section_nr = pfn_to_section_nr(pfn); > >> - struct mem_section *ms; > >> + for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { > >> + start_pfn &= PAGE_SECTION_MASK; > >> + mminit_validate_memmodel_limits(&start_pfn, &end_pfn); > >> > >> - sparse_index_init(section_nr, nid); > >> - set_section_nid(section_nr, nid); > >> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { > >> + unsigned long section_nr = pfn_to_section_nr(pfn); > >> + struct mem_section *ms; > >> > >> - ms = __nr_to_section(section_nr); > >> - if (!ms->section_mem_map) { > >> + sparse_index_init(section_nr, nid); > >> + ms = __nr_to_section(section_nr); > >> + if (ms->section_mem_map) > >> + continue; > >> + > >> + set_section_nid(section_nr, nid); > > > > So the main change seems to be calling set_section_nid() only if > > !ms->section_mem_map (and obv. calculating ms earlier), as described in the > > commit msg. > > Yes! I also played with having that in a standalone patch but judged that it's > not really worth it. I can move it to a separate patch if you think it would be > better! No need, not really a big diff delta and you call it out in the commit msg! > > -- > Cheers, > > David -- Cheers, Lorenzo