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 735813E63AE for ; Wed, 15 Apr 2026 17:03:15 +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=1776272595; cv=none; b=LkUNS8rXeegkEeA8IsBG0lcjrGKwtgWXyBDIfPlaC4bpNhcue1A77440IqR45vDc3JGbcjfF5J6MGtCkBkGqR6XjmSdhMBw/NSSoC2t0H6GWxJ+h9Vahs59TxSIeIqrj05J/FjTpJzdjXat6GztTX8b6PqbGDiv5hcTGW7/pyls= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776272595; c=relaxed/simple; bh=mTAGT4DOoB+Ql7bFiOXRTX+ODnCO2UkCTVqe5r/JaGY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Mw+iRBvfQgTRx2wfrilgXkx35ULvUz4KLKRSsPV/f/sXQ1GPhJeytWtQ0oGGQ+jhtiBxkBNY3WvV7aeYftqW3fkWSQHUjAJWvkpUBSkO1TvfvtlndZovLXvQqp/fvnOzb0T3SSSfSmnx0Z1BGFVxmJN5VifBEqVsATHnOdcV7+E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L06wAtHS; 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="L06wAtHS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A83C4C19424; Wed, 15 Apr 2026 17:03:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776272594; bh=mTAGT4DOoB+Ql7bFiOXRTX+ODnCO2UkCTVqe5r/JaGY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=L06wAtHSsRMa8OvFoMaXwNH+1eYa2W/v97alLbMISAOhCVynQoCeVmWJ5ZTbJM2MU QP7uytxhoWHErO3ob8f61vSccJltnPjAWtlZt4lsROLQKwiy6NhoQ5oVgulzUN2XE7 Uo3FI5DmnXnfiqIlq8mgXKJj1rnTTcT/r34LozkpmiTLGt7Qjx1MyAk6v8ee1n+Rpk 74o3/NiC27Orm8AO8F1joPLIciZG77gcb4LXn7GyeQNAW8nrMjUVV+grPXZ+Huzp/Z RmjoqCkMBFE6XBtZkfqKwxw5eGbivNgTzlGo0+AdBKR6c4ga/EKSAl1llk+H4Pev8Q 9k3GwIuIRnuKA== Date: Wed, 15 Apr 2026 20:03:06 +0300 From: Mike Rapoport To: Muchun Song Cc: Andrew Morton , David Hildenbrand , Muchun Song , Oscar Salvador , Michael Ellerman , Madhavan Srinivasan , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Nicholas Piggin , Christophe Leroy , aneesh.kumar@linux.ibm.com, joao.m.martins@oracle.com, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 6/6] mm/mm_init: Fix pageblock migratetype for ZONE_DEVICE compound pages Message-ID: References: <20260415111412.1003526-1-songmuchun@bytedance.com> <20260415111412.1003526-7-songmuchun@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260415111412.1003526-7-songmuchun@bytedance.com> Hi Muchun, On Wed, Apr 15, 2026 at 07:14:12PM +0800, Muchun Song wrote: > The memmap_init_zone_device() function only initializes the migratetype > of the first pageblock of a compound page. If the compound page size > exceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks), > subsequent pageblocks in the compound page remain uninitialized. > > Move the migratetype initialization out of __init_zone_device_page() > and into a separate pageblock_migratetype_init_range() function. This > iterates over the entire PFN range of the memory, ensuring that all > pageblocks are correctly initialized. > > Fixes: c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages") > Signed-off-by: Muchun Song > --- > mm/mm_init.c | 42 +++++++++++++++++++++++++++--------------- > 1 file changed, 27 insertions(+), 15 deletions(-) > > diff --git a/mm/mm_init.c b/mm/mm_init.c > index f9f8e1af921c..30528c4206c1 100644 > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -674,6 +674,19 @@ static inline void fixup_hashdist(void) > static inline void fixup_hashdist(void) {} > #endif /* CONFIG_NUMA */ > > +static __meminit void pageblock_migratetype_init_range(unsigned long pfn, > + unsigned long nr_pages, > + int migratetype) > +{ > + unsigned long end = pfn + nr_pages; > + > + for (pfn = pageblock_align(pfn); pfn < end; pfn += pageblock_nr_pages) { > + init_pageblock_migratetype(pfn_to_page(pfn), migratetype, false); > + if (IS_ALIGNED(pfn, PAGES_PER_SECTION)) > + cond_resched(); > + } > +} > + > /* > * Initialize a reserved page unconditionally, finding its zone first. > */ > @@ -1011,21 +1024,6 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, > page_folio(page)->pgmap = pgmap; > page->zone_device_data = NULL; > > - /* > - * Mark the block movable so that blocks are reserved for > - * movable at startup. This will force kernel allocations > - * to reserve their blocks rather than leaking throughout > - * the address space during boot when many long-lived > - * kernel allocations are made. > - * > - * Please note that MEMINIT_HOTPLUG path doesn't clear memmap > - * because this is done early in section_activate() > - */ > - if (pageblock_aligned(pfn)) { > - init_pageblock_migratetype(page, MIGRATE_MOVABLE, false); > - cond_resched(); > - } > - > /* > * ZONE_DEVICE pages other than MEMORY_TYPE_GENERIC are released > * directly to the driver page allocator which will set the page count > @@ -1122,6 +1120,8 @@ void __ref memmap_init_zone_device(struct zone *zone, > > __init_zone_device_page(page, pfn, zone_idx, nid, pgmap); > > + cond_resched(); > + I don't think we want cond_resched() for every page here too, even it's a compound page :) Otherwise Reviewed-by: Mike Rapoport (Microsoft) > if (pfns_per_compound == 1) > continue; > > @@ -1129,6 +1129,18 @@ void __ref memmap_init_zone_device(struct zone *zone, > compound_nr_pages(altmap, pgmap)); > } > > + /* > + * Mark the block movable so that blocks are reserved for > + * movable at startup. This will force kernel allocations > + * to reserve their blocks rather than leaking throughout > + * the address space during boot when many long-lived > + * kernel allocations are made. > + * > + * Please note that MEMINIT_HOTPLUG path doesn't clear memmap > + * because this is done early in section_activate() > + */ > + pageblock_migratetype_init_range(start_pfn, nr_pages, MIGRATE_MOVABLE); > + > pr_debug("%s initialised %lu pages in %ums\n", __func__, > nr_pages, jiffies_to_msecs(jiffies - start)); > } > -- > 2.20.1 > -- Sincerely yours, Mike.