On Thu 20-08-15 16:14:34, Michal Hocko wrote: > On Thu 20-08-15 13:43:21, Vlastimil Babka wrote: > > Perform the same debug checks in alloc_pages_node() as are done in > > __alloc_pages_node(), by making the former function a wrapper of the latter > > one. > > > > In addition to better diagnostics in DEBUG_VM builds for situations which > > have been already fatal (e.g. out-of-bounds node id), there are two visible > > changes for potential existing buggy callers of alloc_pages_node(): > > > > - calling alloc_pages_node() with any negative nid (e.g. due to arithmetic > > overflow) was treated as passing NUMA_NO_NODE and fallback to local node was > > applied. This will now be fatal. > > OK, this is sensible > > > - calling alloc_pages_node() with an offline node will now be checked for > > DEBUG_VM builds. Since it's not fatal if the node has been previously online, > > and this patch may expose some existing buggy callers, change the VM_BUG_ON > > in __alloc_pages_node() to VM_WARN_ON. > > Yes, bugging on just because we race with memory hotplug or use > stale node number is not appropriate because the fallback is > straightforward. A warning should help to identify and fix those place. > > > > > Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> > > Acked-by: David Rientjes <rientjes@xxxxxxxxxx> > > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > Acked-by: Christoph Lameter <cl@xxxxxxxxx> Forgot to add Acked-by: Michal Hocko <mhocko@xxxxxxxx> -- Michal Hocko SUSE Labs -- 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>