linux-kernel - [PATCH v5 1/2] mm/sparse.c: Use kvmalloc/kvfree to alloc/free memmap for the classic sparse

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Date:   Mon, 16 Mar 2020 20:54:50 +0800
From:   Baoquan He <bhe@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-mm@...ck.org, mhocko@...e.com, akpm@...ux-foundation.org,
        david@...hat.com, willy@...radead.org, richard.weiyang@...il.com,
        vbabka@...e.cz
Subject: [PATCH v5 1/2] mm/sparse.c: Use kvmalloc/kvfree to alloc/free memmap
 for the classic sparse

This change makes populate_section_memmap()/depopulate_section_memmap
much simpler.

Suggested-by: Michal Hocko <mhocko@...nel.org>
Signed-off-by: Baoquan He <bhe@...hat.com>
Reviewed-by: David Hildenbrand <david@...hat.com>
Acked-by: Michal Hocko <mhocko@...e.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@...il.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 mm/sparse.c | 27 +++------------------------
 1 file changed, 3 insertions(+), 24 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index e747a238a860..3fa407d7f70a 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -719,35 +719,14 @@ static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
 struct page * __meminit populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
-	struct page *page, *ret;
-	unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
-
-	page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
-	if (page)
-		goto got_map_page;
-
-	ret = vmalloc(memmap_size);
-	if (ret)
-		goto got_map_ptr;
-
-	return NULL;
-got_map_page:
-	ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
-got_map_ptr:
-
-	return ret;
+	return kvmalloc(array_size(sizeof(struct page),
+				   PAGES_PER_SECTION), GFP_KERNEL);
 }
 
 static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
 		struct vmem_altmap *altmap)
 {
-	struct page *memmap = pfn_to_page(pfn);
-
-	if (is_vmalloc_addr(memmap))
-		vfree(memmap);
-	else
-		free_pages((unsigned long)memmap,
-			   get_order(sizeof(struct page) * PAGES_PER_SECTION));
+	kvfree(pfn_to_page(pfn));
 }
 
 static void free_map_bootmem(struct page *memmap)
-- 
2.17.2