Re: [PATCH] Simple memory hot-add for ia64.

[Yasunori Goto <y-goto@jp.fujitsu.com>]

> On Fri, 2006-01-06 at 11:50 +0900, Yasunori Goto wrote:
> > Fortunately, 2.6.15 includes memory hot-add function for i386 and ppc.
> > So, I made a patch for ia64.
> > This doesn't make new pgdat. All of new memory will belong to
> > node 0 by this patch. But this is simplest first step and best start for
> > future work.
> 
> It does look quite simple.  Nice work.
> 
> > +#ifdef CONFIG_MEMORY_HOTPLUG
> > +void online_page(struct page *page)
> > +{
> > +	ClearPageReserved(page);
> > +	set_page_count(page, 1);
> > +	__free_page(page);
> > +	totalram_pages++;
> > +	num_physpages++;
> > +}
> 
> You're the first one to get one of these in for an alternate
> architecture.  We'll need to keep an eye out so that one of these
> doesn't pop up on each of the 64-bit arches with no highmem as we add
> support.  But, this should be just fine for now. 
> 
> > +int add_memory(u64 start, u64 size)
> > +{
> > +	pg_data_t *pgdat;
> > +	struct zone *zone;
> > +	unsigned long start_pfn = start >> PAGE_SHIFT;
> > +	unsigned long nr_pages = size >> PAGE_SHIFT;
> > +	int ret;
> > +
> > +	pgdat = NODE_DATA(0);
> > +
> > +	zone = pgdat->node_zones + ZONE_NORMAL;
> > +	ret = __add_pages(zone, start_pfn, nr_pages);
> > +
> > +	if (ret)
> > +		printk("%s: Problem encountered in __add_pages() as ret=%d\n", __func__,  ret);
> 
> For some reason, I thought we were officially supposed to use
> __FUNCTION__ for stuff like this.  However, I am usually lazy in my
> debugging patches and use __func__.  I'm a bad example.

I didn't know it. Thanks!

> This also looks a bit past 80 columns.

Ok. This is newer one. :-)

Bye.

------------------

Fortunately, 2.6.15 includes memory hot-add function for i386 and ppc.
So, I made a patch for ia64.
This doesn't make new pgdat. All of new memory will belong to
node 0 by this patch. But this is simplest first step and best start for
future work.

I tested on my Tiger4. Please apply.

(This patch doesn't use ZONE_EASY_RECLAIM yet, because its zone will be useful
 for just hot-remove.)

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>


Index: new_feature_patch/arch/ia64/mm/init.c
===================================================================
--- new_feature_patch.orig/arch/ia64/mm/init.c	2006-01-07 10:58:27.000000000 +0900
+++ new_feature_patch/arch/ia64/mm/init.c	2006-01-07 10:59:52.000000000 +0900
@@ -635,3 +635,39 @@ mem_init (void)
 	ia32_mem_init();
 #endif
 }
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+void online_page(struct page *page)
+{
+	ClearPageReserved(page);
+	set_page_count(page, 1);
+	__free_page(page);
+	totalram_pages++;
+	num_physpages++;
+}
+
+int add_memory(u64 start, u64 size)
+{
+	pg_data_t *pgdat;
+	struct zone *zone;
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	int ret;
+
+	pgdat = NODE_DATA(0);
+
+	zone = pgdat->node_zones + ZONE_NORMAL;
+	ret = __add_pages(zone, start_pfn, nr_pages);
+
+	if (ret)
+		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
+		       __FUNCTION__,  ret);
+
+	return ret;
+}
+
+int remove_memory(u64 start, u64 size)
+{
+	return -EINVAL;
+}
+#endif

-- 
Yasunori Goto 


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