+ mm-sparse-vmemmap-refactor-core-of-vmemmap_populate_basepages-to-helper.patch added to -mm tree

* + mm-sparse-vmemmap-refactor-core-of-vmemmap_populate_basepages-to-helper.patch added to -mm tree
@ 2022-03-04  0:45 Andrew Morton
  0 siblings, 0 replies; 3+ messages in thread
From: Andrew Morton @ 2022-03-04  0:45 UTC (permalink / raw)
  To: mm-commits, willy, vishal.l.verma, songmuchun, mike.kravetz, jgg,
	jane.chu, hch, dan.j.williams, corbet, joao.m.martins, akpm


The patch titled
     Subject: mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper
has been added to the -mm tree.  Its filename is
     mm-sparse-vmemmap-refactor-core-of-vmemmap_populate_basepages-to-helper.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-sparse-vmemmap-refactor-core-of-vmemmap_populate_basepages-to-helper.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-sparse-vmemmap-refactor-core-of-vmemmap_populate_basepages-to-helper.patch

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------------------------------------------------------
From: Joao Martins <joao.m.martins@oracle.com>
Subject: mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper

In preparation for describing a memmap with compound pages, move the
actual pte population logic into a separate function
vmemmap_populate_address() and have a new helper vmemmap_populate_range()
walk through all base pages it needs to populate.

While doing that, change the helper to use a pte_t* as return value,
rather than an hardcoded errno of 0 or -ENOMEM.

Link: https://lkml.kernel.org/r/20220303213252.28593-3-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/sparse-vmemmap.c |   53 ++++++++++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 17 deletions(-)

--- a/mm/sparse-vmemmap.c~mm-sparse-vmemmap-refactor-core-of-vmemmap_populate_basepages-to-helper
+++ a/mm/sparse-vmemmap.c
@@ -608,38 +608,57 @@ pgd_t * __meminit vmemmap_pgd_populate(u
 	return pgd;
 }
 
-int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
-					 int node, struct vmem_altmap *altmap)
+static pte_t * __meminit vmemmap_populate_address(unsigned long addr, int node,
+					      struct vmem_altmap *altmap)
 {
-	unsigned long addr = start;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 
+	pgd = vmemmap_pgd_populate(addr, node);
+	if (!pgd)
+		return NULL;
+	p4d = vmemmap_p4d_populate(pgd, addr, node);
+	if (!p4d)
+		return NULL;
+	pud = vmemmap_pud_populate(p4d, addr, node);
+	if (!pud)
+		return NULL;
+	pmd = vmemmap_pmd_populate(pud, addr, node);
+	if (!pmd)
+		return NULL;
+	pte = vmemmap_pte_populate(pmd, addr, node, altmap);
+	if (!pte)
+		return NULL;
+	vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
+
+	return pte;
+}
+
+static int __meminit vmemmap_populate_range(unsigned long start,
+					    unsigned long end, int node,
+					    struct vmem_altmap *altmap)
+{
+	unsigned long addr = start;
+	pte_t *pte;
+
 	for (; addr < end; addr += PAGE_SIZE) {
-		pgd = vmemmap_pgd_populate(addr, node);
-		if (!pgd)
-			return -ENOMEM;
-		p4d = vmemmap_p4d_populate(pgd, addr, node);
-		if (!p4d)
-			return -ENOMEM;
-		pud = vmemmap_pud_populate(p4d, addr, node);
-		if (!pud)
-			return -ENOMEM;
-		pmd = vmemmap_pmd_populate(pud, addr, node);
-		if (!pmd)
-			return -ENOMEM;
-		pte = vmemmap_pte_populate(pmd, addr, node, altmap);
+		pte = vmemmap_populate_address(addr, node, altmap);
 		if (!pte)
 			return -ENOMEM;
-		vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
 	}
 
 	return 0;
 }
 
+int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
+					 int node, struct vmem_altmap *altmap)
+{
+	return vmemmap_populate_range(start, end, node, altmap);
+}
+
 struct page * __meminit __populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
 		struct dev_pagemap *pgmap)
_

Patches currently in -mm which might be from joao.m.martins@oracle.com are

mm-sparse-vmemmap-add-a-pgmap-argument-to-section-activation.patch
mm-sparse-vmemmap-refactor-core-of-vmemmap_populate_basepages-to-helper.patch
mm-hugetlb_vmemmap-move-comment-block-to-documentation-vm.patch
mm-sparse-vmemmap-improve-memory-savings-for-compound-devmaps.patch
mm-page_alloc-reuse-tail-struct-pages-for-compound-devmaps.patch


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