On 2016/12/15 14:18, Xishi Qiu wrote:

On 2016/12/14 20:16, Maciej Bielski wrote:

quoted

 
-#ifdef CONFIG_MEMORY_HOTREMOVE
-int arch_remove_memory(u64 start, u64 size)
-{
-	unsigned long start_pfn = start >> PAGE_SHIFT;
-	unsigned long nr_pages = size >> PAGE_SHIFT;
-	struct zone *zone;
-	int ret;
+		SetPageReserved(pfn_to_page(pfn));
+	}

Hi Maciej,

Why we need to set reserved here?
I think the new pages are already reserved in __add_zone() -> memmap_init_zone(), right?

Hi Maciej,

The reason is as follows, right?

It's because that in memmap_init_zone() -> early_pfn_valid(), the new page is still
invalid, so we need to init it after memblock_clear_nomap()

So why not use __init_single_page() and set_pageblock_migratetype()?

Thanks,
Xishi Qiu