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From:   David Hildenbrand <david@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     linux-mm@kvack.org, David Hildenbrand <david@redhat.com>,
        Segher Boessenkool <segher@kernel.crashing.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Oscar Salvador <osalvador@suse.de>,
        Michal Hocko <mhocko@kernel.org>, Baoquan He <bhe@redhat.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Wei Yang <richardw.yang@linux.intel.com>
Subject: [PATCH v2 2/2] mm/memory_hotplug: cleanup __add_pages()
Date:   Fri, 28 Feb 2020 10:58:19 +0100
Message-Id: <20200228095819.10750-3-david@redhat.com>
In-Reply-To: <20200228095819.10750-1-david@redhat.com>
References: <20200228095819.10750-1-david@redhat.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Let's drop the basically unused section stuff and simplify. The logic
now matches the logic in __remove_pages().

Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/memory_hotplug.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 8fe7e32dad48..1a00b5a37ef6 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -307,8 +307,9 @@ static int check_hotplug_memory_addressable(unsigned =
long pfn,
 int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages=
,
 		struct mhp_restrictions *restrictions)
 {
+	const unsigned long end_pfn =3D pfn + nr_pages;
+	unsigned long cur_nr_pages;
 	int err;
-	unsigned long nr, start_sec, end_sec;
 	struct vmem_altmap *altmap =3D restrictions->altmap;
=20
 	err =3D check_hotplug_memory_addressable(pfn, nr_pages);
@@ -331,18 +332,13 @@ int __ref __add_pages(int nid, unsigned long pfn, u=
nsigned long nr_pages,
 	if (err)
 		return err;
=20
-	start_sec =3D pfn_to_section_nr(pfn);
-	end_sec =3D pfn_to_section_nr(pfn + nr_pages - 1);
-	for (nr =3D start_sec; nr <=3D end_sec; nr++) {
-		unsigned long pfns;
-
-		pfns =3D min(nr_pages, PAGES_PER_SECTION
-				- (pfn & ~PAGE_SECTION_MASK));
-		err =3D sparse_add_section(nid, pfn, pfns, altmap);
+	for (; pfn < end_pfn; pfn +=3D cur_nr_pages) {
+		/* Select all remaining pages up to the next section boundary */
+		cur_nr_pages =3D min(end_pfn - pfn,
+				   SECTION_ALIGN_UP(pfn + 1) - pfn);
+		err =3D sparse_add_section(nid, pfn, cur_nr_pages, altmap);
 		if (err)
 			break;
-		pfn +=3D pfns;
-		nr_pages -=3D pfns;
 		cond_resched();
 	}
 	vmemmap_populate_print_last();
--=20
2.24.1