| Message ID | 20230621155025.370672-1-tsahu@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 46e66dab8565f742374e9cc4ff7d35f344d774e2 |
| Headers | show |
| Series | [v3] dax/kmem: Pass valid argument to memory_group_register_static | expand |
Hi, This is just a gentle reminder, If any other information is needed. Tarun Sahu <tsahu@linux.ibm.com> writes: > memory_group_register_static takes maximum number of pages as the argument > while dev_dax_kmem_probe passes total_len (in bytes) as the argument. > > IIUC, I don't see any crash/panic impact as such. As, > memory_group_register_static just set the max_pages limit which is used in > auto_movable_zone_for_pfn to determine the zone. > > which might cause these condition to behave differently, > > This will be true always so jump will happen to kernel_zone > ... > if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) > goto kernel_zone; > > ... > kernel_zone: > return default_kernel_zone_for_pfn(nid, pfn, nr_pages); > > Here, In below, zone_intersects compare range will be larger as nr_pages > will be higher (derived from total_len passed in dev_dax_kmem_probe). > > ... > static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, > unsigned long nr_pages) > { > struct pglist_data *pgdat = NODE_DATA(nid); > int zid; > > for (zid = 0; zid < ZONE_NORMAL; zid++) { > struct zone *zone = &pgdat->node_zones[zid]; > > if (zone_intersects(zone, start_pfn, nr_pages)) > return zone; > } > > return &pgdat->node_zones[ZONE_NORMAL]; > } > > Incorrect zone will be returned here, which in later time might cause bigger > problem. > > Fixes: eedf634aac3b ("dax/kmem: use a single static memory group for a single probed unit") > Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com> > Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> > --- > V3<-V2 > 1. Removed skip characters. > > V2<-V1 > 1. Added more details to commit message > > > drivers/dax/kmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c > index 7b36db6f1cbd..898ca9505754 100644 > --- a/drivers/dax/kmem.c > +++ b/drivers/dax/kmem.c > @@ -99,7 +99,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) > if (!data->res_name) > goto err_res_name; > > - rc = memory_group_register_static(numa_node, total_len); > + rc = memory_group_register_static(numa_node, PFN_UP(total_len)); > if (rc < 0) > goto err_reg_mgid; > data->mgid = rc; > -- > 2.31.1 ~Tarun
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index 7b36db6f1cbd..898ca9505754 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -99,7 +99,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) if (!data->res_name) goto err_res_name; - rc = memory_group_register_static(numa_node, total_len); + rc = memory_group_register_static(numa_node, PFN_UP(total_len)); if (rc < 0) goto err_reg_mgid; data->mgid = rc;
memory_group_register_static takes maximum number of pages as the argument while dev_dax_kmem_probe passes total_len (in bytes) as the argument. IIUC, I don't see any crash/panic impact as such. As, memory_group_register_static just set the max_pages limit which is used in auto_movable_zone_for_pfn to determine the zone. which might cause these condition to behave differently, This will be true always so jump will happen to kernel_zone ... if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) goto kernel_zone; ... kernel_zone: return default_kernel_zone_for_pfn(nid, pfn, nr_pages); Here, In below, zone_intersects compare range will be larger as nr_pages will be higher (derived from total_len passed in dev_dax_kmem_probe). ... static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, unsigned long nr_pages) { struct pglist_data *pgdat = NODE_DATA(nid); int zid; for (zid = 0; zid < ZONE_NORMAL; zid++) { struct zone *zone = &pgdat->node_zones[zid]; if (zone_intersects(zone, start_pfn, nr_pages)) return zone; } return &pgdat->node_zones[ZONE_NORMAL]; } Incorrect zone will be returned here, which in later time might cause bigger problem. Fixes: eedf634aac3b ("dax/kmem: use a single static memory group for a single probed unit") Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com> Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> --- V3<-V2 1. Removed skip characters. V2<-V1 1. Added more details to commit message drivers/dax/kmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)