• Naoya Horiguchi's avatar
    mm: memory-hotplug: enable memory hotplug to handle hugepage · c8721bbb
    Naoya Horiguchi authored
    Until now we can't offline memory blocks which contain hugepages because a
    hugepage is considered as an unmovable page.  But now with this patch
    series, a hugepage has become movable, so by using hugepage migration we
    can offline such memory blocks.
    What's different from other users of hugepage migration is that we need to
    decompose all the hugepages inside the target memory block into free buddy
    pages after hugepage migration, because otherwise free hugepages remaining
    in the memory block intervene the memory offlining.  For this reason we
    introduce new functions dissolve_free_huge_page() and
    Other than that, what this patch does is straightforwardly to add hugepage
    migration code, that is, adding hugepage code to the functions which scan
    over pfn and collect hugepages to be migrated, and adding a hugepage
    allocation function to alloc_migrate_target().
    As for larger hugepages (1GB for x86_64), it's not easy to do hotremove
    over them because it's larger than memory block.  So we now simply leave
    it to fail as it is.
    [yongjun_wei@trendmicro.com.cn: remove duplicated include]
    Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Acked-by: default avatarAndi Kleen <ak@linux.intel.com>
    Cc: Hillf Danton <dhillf@gmail.com>
    Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Cc: Michal Hocko <mhocko@suse.cz>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
    Signed-off-by: default avatarWei Yongjun <yongjun_wei@trendmicro.com.cn>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>