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SubjectRe: [PATCH 1/7] mm/sparse.c: Introduce new function fill_subsection_map()
On Mon, Feb 10, 2020 at 07:05:56AM +0800, Wei Yang wrote:
>On Sun, Feb 09, 2020 at 06:48:20PM +0800, Baoquan He wrote:
>>Wrap the codes filling subsection map in section_activate() into
>>fill_subsection_map(), this makes section_activate() cleaner and
>>easier to follow.
>>
>
>This looks a preparation for #ifdef the code for VMEMMAP, then why not take
>the usage handling into this function too?
>

Oops, you are right. My mistake.

>>Signed-off-by: Baoquan He <bhe@redhat.com>
>>---
>> mm/sparse.c | 45 ++++++++++++++++++++++++++++++++++-----------
>> 1 file changed, 34 insertions(+), 11 deletions(-)
>>
>>diff --git a/mm/sparse.c b/mm/sparse.c
>>index c184b69460b7..9ad741ccbeb6 100644
>>--- a/mm/sparse.c
>>+++ b/mm/sparse.c
>>@@ -788,24 +788,28 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
>> depopulate_section_memmap(pfn, nr_pages, altmap);
>> }
>>
>>-static struct page * __meminit section_activate(int nid, unsigned long pfn,
>>- unsigned long nr_pages, struct vmem_altmap *altmap)
>>+/**
>>+ * fill_subsection_map - fill subsection map of a memory region
>>+ * @pfn - start pfn of the memory range
>>+ * @nr_pages - number of pfns to add in the region
>>+ *
>>+ * This clears the related subsection map inside one section, and only
>
>s/clears/fills/ ?
>
>>+ * intended for hotplug.
>>+ *
>>+ * Return:
>>+ * * 0 - On success.
>>+ * * -EINVAL - Invalid memory region.
>>+ * * -EEXIST - Subsection map has been set.
>>+ */
>>+static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
>> {
>>- DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
>> struct mem_section *ms = __pfn_to_section(pfn);
>>- struct mem_section_usage *usage = NULL;
>>+ DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
>> unsigned long *subsection_map;
>>- struct page *memmap;
>> int rc = 0;
>>
>> subsection_mask_set(map, pfn, nr_pages);
>>
>>- if (!ms->usage) {
>>- usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
>>- if (!usage)
>>- return ERR_PTR(-ENOMEM);
>>- ms->usage = usage;
>>- }
>> subsection_map = &ms->usage->subsection_map[0];
>>
>> if (bitmap_empty(map, SUBSECTIONS_PER_SECTION))
>>@@ -816,6 +820,25 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,
>> bitmap_or(subsection_map, map, subsection_map,
>> SUBSECTIONS_PER_SECTION);
>>
>>+ return rc;
>>+}
>>+
>>+static struct page * __meminit section_activate(int nid, unsigned long pfn,
>>+ unsigned long nr_pages, struct vmem_altmap *altmap)
>>+{
>>+ struct mem_section *ms = __pfn_to_section(pfn);
>>+ struct mem_section_usage *usage = NULL;
>>+ struct page *memmap;
>>+ int rc = 0;
>>+
>>+ if (!ms->usage) {
>>+ usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
>>+ if (!usage)
>>+ return ERR_PTR(-ENOMEM);
>>+ ms->usage = usage;
>>+ }
>>+
>>+ rc = fill_subsection_map(pfn, nr_pages);
>> if (rc) {
>> if (usage)
>> ms->usage = NULL;
>>--
>>2.17.2
>
>--
>Wei Yang
>Help you, Help me

--
Wei Yang
Help you, Help me

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