On 2015/11/4 16:23, liuchangsheng wrote: > After the user config CONFIG_MOVABLE_NODE, > When the memory is hot added, should_add_memory_movable() return 0 > because all zones including ZONE_MOVABLE are empty, > so the memory that was hot added will be assigned to ZONE_NORMAL, > and we need using the udev rules to online the memory automatically: > SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", > ATTR{state}="online_movable" > The memory block onlined by udev must be adjacent to ZONE_MOVABLE. > The events of memory section are notified to udev asynchronously, Hi Yasuaki, If udev onlines memory in descending order, like 3->2->1->0, it will success, but we notifiy to udev in ascending order, like 0->1->2->3, so the udev rules cannot online memory as movable, right? > so it can not ensure that the memory block onlined by udev is > adjacent to ZONE_MOVABLE.So it can't ensure memory online always success. > But we want the whole node to be added to ZONE_MOVABLE by default. > > So we change should_add_memory_movable(): if the user config > CONFIG_MOVABLE_NODE and movable_node kernel option > and the ZONE_NORMAL is empty or the pfn of the hot-added memory > is after the end of the ZONE_NORMAL it will always return 1 > and then the whole node will be added to ZONE_MOVABLE by default. > If we want the node to be assigned to ZONE_NORMAL, > we can do it as follows: > "echo online_kernel > /sys/devices/system/memory/memoryXXX/state" > The order should like 0->1->2->3, right? 3->2->1->0 will be failed. > Signed-off-by: liuchangsheng <liuchangsheng@xxxxxxxxxx> > Signed-off-by: Xiaofeng Yan <yanxiaofeng@xxxxxxxxxx> > Tested-by: Dongdong Fan <fandd@xxxxxxxxxx> > Reviewed-by: <yasu.isimatu@xxxxxxxxx> > Cc: Wang Nan <wangnan0@xxxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxx> > Cc: Yinghai Lu <yinghai@xxxxxxxxxx> > Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx> > Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> > Cc: Toshi Kani <toshi.kani@xxxxxx> > Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx> > --- > mm/memory_hotplug.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index aa992e2..8617b9f 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1201,6 +1201,9 @@ static int check_hotplug_memory_range(u64 start, u64 size) > /* > * If movable zone has already been setup, newly added memory should be check. > * If its address is higher than movable zone, it should be added as movable. > + * And if system boots up with movable_node and config CONFIG_MOVABLE_NOD and > + * added memory does not overlap the zone before MOVABLE_ZONE, > + * the memory is added as movable. > * Without this check, movable zone may overlap with other zone. > */ > static int should_add_memory_movable(int nid, u64 start, u64 size) > @@ -1208,6 +1211,10 @@ static int should_add_memory_movable(int nid, u64 start, u64 size) > unsigned long start_pfn = start >> PAGE_SHIFT; > pg_data_t *pgdat = NODE_DATA(nid); > struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE; > + struct zone *pre_zone = pgdat->node_zones + (ZONE_MOVABLE - 1); > + > + if (movable_node_is_enabled() && (zone_end_pfn(pre_zone) <= start_pfn)) > + return 1; > Looks good to me. How about add some comment in mm/Kconfig? Thanks, Xishi Qiu > if (zone_is_empty(movable_zone)) > return 0; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>