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Commit bbc76be6 authored by Wen Congyang's avatar Wen Congyang Committed by Linus Torvalds
Browse files

memory-hotplug: remove redundant codes 



offlining memory blocks and checking whether memory blocks are offlined
are very similar.  This patch introduces a new function to remove
redundant codes.

Signed-off-by: default avatarWen Congyang <wency@cn.fujitsu.com>
Signed-off-by: default avatarTang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: default avatarKamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6677e3ea

mm/memory_hotplug.c

+82 −47
Original line number Diff line number Diff line
@@ -1380,20 +1380,26 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages) 
	return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);

}



int remove_memory(u64 start, u64 size)

/**

 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)

 * @start_pfn: start pfn of the memory range

 * @end_pfn: end pft of the memory range

 * @arg: argument passed to func

 * @func: callback for each memory section walked

 *

 * This function walks through all present mem sections in range

 * [start_pfn, end_pfn) and call func on each mem section.

 *

 * Returns the return value of func.

 */

static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,

		void *arg, int (*func)(struct memory_block *, void *))

{

	struct memory_block *mem = NULL;

	struct mem_section *section;

	unsigned long start_pfn, end_pfn;

	unsigned long pfn, section_nr;

	int ret;

	int return_on_error = 0;

	int retry = 0;



	start_pfn = PFN_DOWN(start);

	end_pfn = start_pfn + PFN_DOWN(size);



repeat:

	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {

		section_nr = pfn_to_section_nr(pfn);

		if (!present_section_nr(section_nr))
@@ -1410,22 +1416,76 @@ int remove_memory(u64 start, u64 size) 
		if (!mem)

			continue;



		ret = offline_memory_block(mem);

		ret = func(mem, arg);

		if (ret) {

			if (return_on_error) {

			kobject_put(&mem->dev.kobj);

			return ret;

			} else {

				retry = 1;

			}

		}

	}



	if (mem)

		kobject_put(&mem->dev.kobj);



	if (retry) {

		return_on_error = 1;

	return 0;

}



/**

 * offline_memory_block_cb - callback function for offlining memory block

 * @mem: the memory block to be offlined

 * @arg: buffer to hold error msg

 *

 * Always return 0, and put the error msg in arg if any.

 */

static int offline_memory_block_cb(struct memory_block *mem, void *arg)

{

	int *ret = arg;

	int error = offline_memory_block(mem);



	if (error != 0 && *ret == 0)

		*ret = error;



	return 0;

}



static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)

{

	int ret = !is_memblock_offlined(mem);



	if (unlikely(ret))

		pr_warn("removing memory fails, because memory "

			"[%#010llx-%#010llx] is onlined\n",

			PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),

			PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1);



	return ret;

}



int remove_memory(u64 start, u64 size)

{

	unsigned long start_pfn, end_pfn;

	int ret = 0;

	int retry = 1;



	start_pfn = PFN_DOWN(start);

	end_pfn = start_pfn + PFN_DOWN(size);



	/*

	 * When CONFIG_MEMCG is on, one memory block may be used by other

	 * blocks to store page cgroup when onlining pages. But we don't know

	 * in what order pages are onlined. So we iterate twice to offline

	 * memory:

	 * 1st iterate: offline every non primary memory block.

	 * 2nd iterate: offline primary (i.e. first added) memory block.

	 */

repeat:

	walk_memory_range(start_pfn, end_pfn, &ret,

			  offline_memory_block_cb);

	if (ret) {

		if (!retry)

			return ret;



		retry = 0;

		ret = 0;

		goto repeat;

	}
@@ -1443,38 +1503,13 @@ int remove_memory(u64 start, u64 size) 
	 * memory blocks are offlined.

	 */



	mem = NULL;

	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {

		section_nr = pfn_to_section_nr(pfn);

		if (!present_section_nr(section_nr))

			continue;



		section = __nr_to_section(section_nr);

		/* same memblock? */

		if (mem)

			if ((section_nr >= mem->start_section_nr) &&

			    (section_nr <= mem->end_section_nr))

				continue;



		mem = find_memory_block_hinted(section, mem);

		if (!mem)

			continue;



		ret = is_memblock_offlined(mem);

		if (!ret) {

			pr_warn("removing memory fails, because memory "

				"[%#010llx-%#010llx] is onlined\n",

				PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),

				PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1)) - 1);



			kobject_put(&mem->dev.kobj);

	ret = walk_memory_range(start_pfn, end_pfn, NULL,

				is_memblock_offlined_cb);

	if (ret) {

		unlock_memory_hotplug();

		return ret;

	}

	}



	if (mem)

		kobject_put(&mem->dev.kobj);

	unlock_memory_hotplug();



	return 0;