From: Michal Hocko <mhocko@xxxxxxxx> Subject: mm, memory_hotplug: fix MMOP_ONLINE_KEEP behavior Heiko Carstens has noticed that the MMOP_ONLINE_KEEP is broken currently $ grep . memory3?/valid_zones memory34/valid_zones:Normal Movable memory35/valid_zones:Normal Movable memory36/valid_zones:Normal Movable memory37/valid_zones:Normal Movable $ echo online_movable > memory34/state $ grep . memory3?/valid_zones memory34/valid_zones:Movable memory35/valid_zones:Movable memory36/valid_zones:Movable memory37/valid_zones:Movable $ echo online > memory36/state $ grep . memory3?/valid_zones memory34/valid_zones:Movable memory36/valid_zones:Normal memory37/valid_zones:Movable so we have effectively punched a hole into the movable zone. The problem is that move_pfn_range() check for MMOP_ONLINE_KEEP is wrong. It only checks whether the given range is already part of the movable zone which is not the case here as only memory34 is in the zone. Fix this by using allow_online_pfn_range(..., MMOP_ONLINE_KERNEL) if that is false then we can be sure that movable onlining is the right thing to do. Fixes: "mm, memory_hotplug: do not associate hotadded memory to zones until online" Link: http://lkml.kernel.org/r/20170601083746.4924-2-mhocko@xxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Reported-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Tested-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory_hotplug.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff -puN mm/memory_hotplug.c~mm-memory_hotplug-fix-mmop_online_keep-behavior mm/memory_hotplug.c --- a/mm/memory_hotplug.c~mm-memory_hotplug-fix-mmop_online_keep-behavior +++ a/mm/memory_hotplug.c @@ -1115,11 +1115,12 @@ static struct zone * __meminit move_pfn_ if (online_type == MMOP_ONLINE_KEEP) { struct zone *movable_zone = &pgdat->node_zones[ZONE_MOVABLE]; /* - * MMOP_ONLINE_KEEP inherits the current zone which is - * ZONE_NORMAL by default but we might be within ZONE_MOVABLE - * already. + * MMOP_ONLINE_KEEP defaults to MMOP_ONLINE_KERNEL but use + * movable zone if that is not possible (e.g. we are within + * or past the existing movable zone) */ - if (zone_intersects(movable_zone, start_pfn, nr_pages)) + if (!allow_online_pfn_range(nid, start_pfn, nr_pages, + MMOP_ONLINE_KERNEL)) zone = movable_zone; } else if (online_type == MMOP_ONLINE_MOVABLE) { zone = &pgdat->node_zones[ZONE_MOVABLE]; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
