mm/memory_hotplug: optimize probe routine
When memory is hotplugged pages_correctly_reserved() is called to verify that the added memory is present, this routine traverses through every struct page and verifies that PageReserved() is set. This is a slow operation especially if a large amount of memory is added. Instead of checking every page, it is enough to simply check that the section is present, has mapping (struct page array is allocated), and the mapping is online. In addition, we should not excpect that probe routine sets flags in struct page, as the struct pages have not yet been initialized. The initialization should be done in __init_single_page(), the same as during boot. Link: http://lkml.kernel.org/r/20180215165920.8570-5-pasha.tatashin@oracle.com Signed-off-by:Pavel Tatashin <pasha.tatashin@oracle.com> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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