Commit 2842f114 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
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[PATCH] catch valid mem range at onlining memory 



This patch allows hot-add memory which is not aligned to section.

Now, hot-added memory has to be aligned to section size.  Considering big
section sized archs, this is not useful.

When hot-added memory is registerd as iomem resoruce by iomem resource
patch, we can make use of that information to detect valid memory range.

Note: With this, not-aligned memory can be registerd. To allow hot-add
      memory with holes, we have to do more work around add_memory().
      (It doesn't allows add memory to already existing mem section.)

Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0a547039

include/linux/ioport.h

+3 −0
Original line number Diff line number Diff line
@@ -105,6 +105,9 @@ extern int allocate_resource(struct resource *root, struct resource *new, 
int adjust_resource(struct resource *res, unsigned long start,

		    unsigned long size);



/* get registered SYSTEM_RAM resources in specified area */

extern int find_next_system_ram(struct resource *res);



/* Convenience shorthand with allocation */

#define request_region(start,n,name)	__request_region(&ioport_resource, (start), (n), (name))

#define request_mem_region(start,n,name) __request_region(&iomem_resource, (start), (n), (name))

kernel/resource.c

+38 −0
Original line number Diff line number Diff line
@@ -232,6 +232,44 @@ int release_resource(struct resource *old) 


EXPORT_SYMBOL(release_resource);



#ifdef CONFIG_MEMORY_HOTPLUG

/*

 * Finds the lowest memory reosurce exists within [res->start.res->end)

 * the caller must specify res->start, res->end, res->flags.

 * If found, returns 0, res is overwritten, if not found, returns -1.

 */

int find_next_system_ram(struct resource *res)

{

	resource_size_t start, end;

	struct resource *p;



	BUG_ON(!res);



	start = res->start;

	end = res->end;



	read_lock(&resource_lock);

	for (p = iomem_resource.child; p ; p = p->sibling) {

		/* system ram is just marked as IORESOURCE_MEM */

		if (p->flags != res->flags)

			continue;

		if (p->start > end) {

			p = NULL;

			break;

		}

		if (p->start >= start)

			break;

	}

	read_unlock(&resource_lock);

	if (!p)

		return -1;

	/* copy data */

	res->start = p->start;

	res->end = p->end;

	return 0;

}

#endif



/*

 * Find empty slot in the resource tree given range and alignment.

 */

mm/memory_hotplug.c

+24 −4
Original line number Diff line number Diff line
@@ -127,6 +127,9 @@ int online_pages(unsigned long pfn, unsigned long nr_pages) 
	unsigned long i;

	unsigned long flags;

	unsigned long onlined_pages = 0;

	struct resource res;

	u64 section_end;

	unsigned long start_pfn;

	struct zone *zone;

	int need_zonelists_rebuild = 0;
@@ -149,11 +152,28 @@ int online_pages(unsigned long pfn, unsigned long nr_pages) 
	if (!populated_zone(zone))

		need_zonelists_rebuild = 1;



	res.start = (u64)pfn << PAGE_SHIFT;

	res.end = res.start + ((u64)nr_pages << PAGE_SHIFT) - 1;

	res.flags = IORESOURCE_MEM; /* we just need system ram */

	section_end = res.end;



	while (find_next_system_ram(&res) >= 0) {

		start_pfn = (unsigned long)(res.start >> PAGE_SHIFT);

		nr_pages = (unsigned long)

                           ((res.end + 1 - res.start) >> PAGE_SHIFT);



		if (PageReserved(pfn_to_page(start_pfn))) {

			/* this region's page is not onlined now */

			for (i = 0; i < nr_pages; i++) {

		struct page *page = pfn_to_page(pfn + i);

				struct page *page = pfn_to_page(start_pfn + i);

				online_page(page);

				onlined_pages++;

			}

		}



		res.start = res.end + 1;

		res.end = section_end;

	}

	zone->present_pages += onlined_pages;

	zone->zone_pgdat->node_present_pages += onlined_pages;

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