If the hypervisor returned H_PTEG_FULL for H_ENTER hcall, retry a hash page
table
insert by removing a random entry from the group.
After some runtime, it is very well possible to find all the 8 hash page table
entry slot in the hpte group used for mapping. Don't fail a bolted entry insert
in that case. With Storage class memory a user can find this error easily since
a namespace enable/disable is equivalent to memory add/remove.
This results in failures as reported below:
$ ndctl create-namespace -r region1 -t pmem -m devdax -a 65536 -s 100M
libndctl: ndctl_dax_enable: dax1.3: failed to enable
Error: namespace1.2: failed to enable
failed to create namespace: No such device or address
In kernel log we find the details as below:
Unable to create mapping for hot added memory
0xc000042006000000..0xc00004200d000000: -1
dax_pmem: probe of dax1.3 failed with error -14
This indicates that we failed to create a bolted hash table entry for direct-map
address backing the namespace.
We also observe failures such that not all namespaces will be enabled with
ndctl enable-namespace all command.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
Changes from v1:
* update commit message
arch/powerpc/mm/book3s64/hash_utils.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c
b/arch/powerpc/mm/book3s64/hash_utils.c
index 6c123760164e..6e5a769ebcb8 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -294,7 +294,14 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long
vend,
ret = mmu_hash_ops.hpte_insert(hpteg, vpn, paddr, tprot,
HPTE_V_BOLTED, psize, psize,
ssize);
-
+ if (ret == -1) {
+ /* Try to remove a non bolted entry */
+ ret = mmu_hash_ops.hpte_remove(hpteg);
+ if (ret != -1)
+ ret = mmu_hash_ops.hpte_insert(hpteg, vpn,
paddr, tprot,
+ HPTE_V_BOLTED,
psize, psize,
+ ssize);
+ }
if (ret < 0)
break;
--
2.21.0
