Commit 73a11c96 authored Oct 15, 2020 by David Hildenbrand Committed by Linus Torvalds Oct 16, 2020

mm/memory_hotplug: inline __offline_pages() into offline_pages()



Patch series "mm/memory_hotplug: online_pages()/offline_pages() cleanups", v2.

These are a bunch of cleanups for online_pages()/offline_pages() and
related code, mostly getting rid of memory hole handling that is no longer
necessary.  There is only a single walk_system_ram_range() call left in
offline_pages(), to make sure we don't have any memory holes.  I had some
of these patches lying around for a longer time but didn't have time to
polish them.

In addition, the last patch marks all pageblocks of memory to get onlined
MIGRATE_ISOLATE, so pages that have just been exposed to the buddy cannot
get allocated before onlining is complete.  Once heavy lifting is done,
the pageblocks are set to MIGRATE_MOVABLE, such that allocations are
possible.

I played with DIMMs and virtio-mem on x86-64 and didn't spot any
surprises.  I verified that the numer of isolated pageblocks is correctly
handled when onlining/offlining.

This patch (of 10):

There is only a single user, offline_pages(). Let's inline, to make
it look more similar to online_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>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
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@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Link: https://lkml.kernel.org/r/20200819175957.28465-1-david@redhat.com
Link: https://lkml.kernel.org/r/20200819175957.28465-2-david@redhat.com


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

parent c9682d10

mm/memory_hotplug.c

+5 −11

Original line number	Diff line number	Diff line
		@@ -1484,11 +1484,10 @@ static int count_system_ram_pages_cb(unsigned long start_pfn,
		return 0;
		}

		static int __ref __offline_pages(unsigned long start_pfn,
		unsigned long end_pfn)
		int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
		{
		unsigned long pfn, nr_pages = 0;
		unsigned long offlined_pages = 0;
		const unsigned long end_pfn = start_pfn + nr_pages;
		unsigned long pfn, system_ram_pages = 0, offlined_pages = 0;
		int ret, node, nr_isolate_pageblock;
		unsigned long flags;
		struct zone *zone;
		@@ -1505,9 +1504,9 @@ static int __ref __offline_pages(unsigned long start_pfn,
		* memory holes PG_reserved, don't need pfn_valid() checks, and can
		* avoid using walk_system_ram_range() later.
		*/
		walk_system_ram_range(start_pfn, end_pfn - start_pfn, &nr_pages,
		walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages,
		count_system_ram_pages_cb);
		if (nr_pages != end_pfn - start_pfn) {
		if (system_ram_pages != nr_pages) {
		ret = -EINVAL;
		reason = "memory holes";
		goto failed_removal;
		@@ -1656,11 +1655,6 @@ failed_removal:
		return ret;
		}

		int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
		{
		return __offline_pages(start_pfn, start_pfn + nr_pages);
		}

		static int check_memblock_offlined_cb(struct memory_block mem, void arg)
		{
		int ret = !is_memblock_offlined(mem);

Admin message