Commit 2ce13640 authored Jul 06, 2017 by Michal Hocko Committed by Linus Torvalds Jul 06, 2017

mm: __first_valid_page skip over offline pages

__first_valid_page skips over invalid pfns in the range but it might
still stumble over offline pages.  At least start_isolate_page_range
will mark those set_migratetype_isolate.  This doesn't represent any
immediate AFAICS because alloc_contig_range will fail to isolate those
pages but it relies on not fully initialized page which will become a
problem later when we stop associating offline pages to zones.  Use
pfn_to_online_page to handle this.

This is more a preparatory patch than a fix.

Link: http://lkml.kernel.org/r/20170515085827.16474-10-mhocko@kernel.org


Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Tobias Regnery <tobias.regnery@gmail.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent ccbe1e4d

mm/page_isolation.c

+18 −8

Original line number	Diff line number	Diff line
		@@ -138,12 +138,18 @@ static inline struct page *
		__first_valid_page(unsigned long pfn, unsigned long nr_pages)
		{
		int i;
		for (i = 0; i < nr_pages; i++)
		if (pfn_valid_within(pfn + i))
		break;
		if (unlikely(i == nr_pages))

		for (i = 0; i < nr_pages; i++) {
		struct page *page;

		if (!pfn_valid_within(pfn + i))
		continue;
		page = pfn_to_online_page(pfn + i);
		if (!page)
		continue;
		return page;
		}
		return NULL;
		return pfn_to_page(pfn + i);
		}

		/*
		@@ -184,8 +190,12 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
		undo:
		for (pfn = start_pfn;
		pfn < undo_pfn;
		pfn += pageblock_nr_pages)
		unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
		pfn += pageblock_nr_pages) {
		struct page *page = pfn_to_online_page(pfn);
		if (!page)
		continue;
		unset_migratetype_isolate(page, migratetype);
		}

		return -EBUSY;
		}

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