On Tue, 13 Dec 2016 15:29:49 -0500 Yasuaki Ishimatsu <yasu.isimatu@xxxxxxxxx> wrote: > online_{kernel|movable} is used to change the memory zone to > ZONE_{NORMAL|MOVABLE} and online the memory. > > To check that memory zone can be changed, zone_can_shift() is used. > Currently the function returns minus integer value, plus integer > value and 0. When the function returns minus or plus integer value, > it means that the memory zone can be changed to ZONE_{NORNAL|MOVABLE}. > > But when the function returns 0, there is 2 meanings. > > One of the meanings is that the memory zone does not need to be changed. > For example, when memory is in ZONE_NORMAL and onlined by online_kernel > the memory zone does not need to be changed. > > Another meaning is that the memory zone cannot be changed. When memory > is in ZONE_NORMAL and onlined by online_movable, the memory zone may > not be changed to ZONE_MOVALBE due to memory online limitation(see > Documentation/memory-hotplug.txt). In this case, memory must not be > onlined. > > The patch changes the return type of zone_can_shift() so that memory > is not onlined when memory zone cannot be changed. What are the user-visible runtime effects of this fix? Please always include this info when fixing bugs - it is required so that others can decide which kernel version(s) need the fix. Thanks. -- 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>