Commit 257bea71 authored by David Hildenbrand's avatar David Hildenbrand Committed by Linus Torvalds
Browse files

mm/page_alloc: simplify __offline_isolated_pages() 



offline_pages() is the only user.  __offline_isolated_pages() never gets
called with ranges that contain memory holes and we no longer care about
the return value.  Drop the return value handling and all pfn_valid()
checks.

Update the documentation.

Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Charan Teja Reddy <charante@codeaurora.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200819175957.28465-5-david@redhat.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0a1a9a00

include/linux/memory_hotplug.h

+2 −2
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ extern int online_pages(unsigned long pfn, unsigned long nr_pages, 
			int online_type, int nid);

extern struct zone *test_pages_in_a_zone(unsigned long start_pfn,

					 unsigned long end_pfn);

extern unsigned long __offline_isolated_pages(unsigned long start_pfn,

extern void __offline_isolated_pages(unsigned long start_pfn,

				     unsigned long end_pfn);



typedef void (*online_page_callback_t)(struct page *page, unsigned int order);

mm/page_alloc.c

+4 −23
Original line number Diff line number Diff line
@@ -8704,35 +8704,21 @@ void zone_pcp_reset(struct zone *zone) 


#ifdef CONFIG_MEMORY_HOTREMOVE

/*

 * All pages in the range must be in a single zone and isolated

 * before calling this.

 * All pages in the range must be in a single zone, must not contain holes,

 * must span full sections, and must be isolated before calling this function.

 */

unsigned long

__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)

void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)

{

	unsigned long pfn = start_pfn;

	struct page *page;

	struct zone *zone;

	unsigned int order;

	unsigned long pfn;

	unsigned long flags;

	unsigned long offlined_pages = 0;



	/* find the first valid pfn */

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

		if (pfn_valid(pfn))

			break;

	if (pfn == end_pfn)

		return offlined_pages;



	offline_mem_sections(pfn, end_pfn);

	zone = page_zone(pfn_to_page(pfn));

	spin_lock_irqsave(&zone->lock, flags);

	pfn = start_pfn;

	while (pfn < end_pfn) {

		if (!pfn_valid(pfn)) {

			pfn++;

			continue;

		}

		page = pfn_to_page(pfn);

		/*

		 * The HWPoisoned page may be not in buddy system, and
@@ -8740,7 +8726,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 
		 */

		if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {

			pfn++;

			offlined_pages++;

			continue;

		}

		/*
@@ -8751,20 +8736,16 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 
			BUG_ON(page_count(page));

			BUG_ON(PageBuddy(page));

			pfn++;

			offlined_pages++;

			continue;

		}



		BUG_ON(page_count(page));

		BUG_ON(!PageBuddy(page));

		order = page_order(page);

		offlined_pages += 1 << order;

		del_page_from_free_list(page, zone, order);

		pfn += (1 << order);

	}

	spin_unlock_irqrestore(&zone->lock, flags);



	return offlined_pages;

}

#endif

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