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SubjectRe: [PATCH v5 3/6] mm/cma: populate ZONE_CMA
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On 09/22/2016 08:50 AM, Joonsoo Kim wrote:
> On Thu, Sep 22, 2016 at 02:45:46PM +0900, Joonsoo Kim wrote:
>> >
>> > > /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
>> > > void __init init_cma_reserved_pageblock(struct page *page)
>> > > {
>> > > unsigned i = pageblock_nr_pages;
>> > >+ unsigned long pfn = page_to_pfn(page);
>> > > struct page *p = page;
>> > >+ int nid = page_to_nid(page);
>> > >+
>> > >+ /*
>> > >+ * ZONE_CMA will steal present pages from other zones by changing
>> > >+ * page links so page_zone() is changed. Before that,
>> > >+ * we need to adjust previous zone's page count first.
>> > >+ */
>> > >+ adjust_present_page_count(page, -pageblock_nr_pages);
>> > >
>> > > do {
>> > > __ClearPageReserved(p);
>> > > set_page_count(p, 0);
>> > >- } while (++p, --i);
>> > >+
>> > >+ /* Steal pages from other zones */
>> > >+ set_page_links(p, ZONE_CMA, nid, pfn);
>> > >+ } while (++p, ++pfn, --i);
>> > >+
>> > >+ adjust_present_page_count(page, pageblock_nr_pages);
>> >
>> > This seems to assign pages to ZONE_CMA on the proper node, which is
>> > good. But then ZONE_CMA on multiple nodes will have unnecessary
>> > holes in the spanned pages, as each will contain only a subset.
>>
>> True, I will fix it and respin the series.
>
> I now realize that it's too late to send full series for next
> merge window. I will send full series after next merge window is closed.

I think there might still be rc8 thus another week.

> Anyway, I'd like to confirm that following incremental patch will solve
> your concern.

Yeah that should work, as long as single cma areas don't include multiple nodes?

> Thanks.
>
>
> ------>8--------------
> mm/cma.c | 25 ++++++++++++++++---------
> 1 file changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/mm/cma.c b/mm/cma.c
> index d69bdf7..8375554 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -146,22 +146,29 @@ static int __init cma_init_reserved_areas(void)
> {
> int i;
> struct zone *zone;
> - unsigned long start_pfn = UINT_MAX, end_pfn = 0;
> + pg_data_t *pgdat;
>
> if (!cma_area_count)
> return 0;
>
> - for (i = 0; i < cma_area_count; i++) {
> - if (start_pfn > cma_areas[i].base_pfn)
> - start_pfn = cma_areas[i].base_pfn;
> - if (end_pfn < cma_areas[i].base_pfn + cma_areas[i].count)
> - end_pfn = cma_areas[i].base_pfn + cma_areas[i].count;
> - }
> + for_each_online_pgdat(pgdat) {
> + unsigned long start_pfn = UINT_MAX, end_pfn = 0;
>
> - for_each_zone(zone) {
> - if (!is_zone_cma(zone))
> + for (i = 0; i < cma_area_count; i++) {
> + if (page_to_nid(pfn_to_page(cma_areas[i].base_pfn)) !=

We have pfn_to_nid() (although the implementation is just like this).

> + pgdat->node_id)
> + continue;
> +
> + start_pfn = min(start_pfn, cma_areas[i].base_pfn);
> + end_pfn = max(end_pfn, cma_areas[i].base_pfn +
> + cma_areas[i].count);
> + }
> +
> + if (!end_pfn)
> continue;
>
> + zone = &pgdat->node_zones[ZONE_CMA];
> +
> /* ZONE_CMA doesn't need to exceed CMA region */
> zone->zone_start_pfn = max(zone->zone_start_pfn, start_pfn);
> zone->spanned_pages = min(zone_end_pfn(zone), end_pfn) -
>

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