Commit ea15153c authored Oct 15, 2020 by David Hildenbrand Committed by Linus Torvalds Oct 16, 2020

mm/memory_hotplug: drop nr_isolate_pageblock in offline_pages()



We make sure that we cannot have any memory holes right at the beginning
of offline_pages() and we only support to online/offline full sections.
Both, sections and pageblocks are a power of two in size, and sections
always span full pageblocks.

We can directly calculate the number of isolated pageblocks from nr_pages.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal 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/20200819175957.28465-6-david@redhat.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 257bea71

mm/memory_hotplug.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -1471,10 +1471,10 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
		{
		const unsigned long end_pfn = start_pfn + nr_pages;
		unsigned long pfn, system_ram_pages = 0;
		int ret, node, nr_isolate_pageblock;
		unsigned long flags;
		struct zone *zone;
		struct memory_notify arg;
		int ret, node;
		char *reason;

		/* We can only offline full sections (e.g., SECTION_IS_ONLINE) */
		@@ -1518,7 +1518,6 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
		reason = "failure to isolate range";
		goto failed_removal;
		}
		nr_isolate_pageblock = ret;

		arg.start_pfn = start_pfn;
		arg.nr_pages = nr_pages;
		@@ -1596,7 +1595,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
		* pageblocks zone counter here.
		*/
		spin_lock_irqsave(&zone->lock, flags);
		zone->nr_isolate_pageblock -= nr_isolate_pageblock;
		zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages;
		spin_unlock_irqrestore(&zone->lock, flags);

		/* removal success */

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