From: "Aneesh Kumar K.V" aneesh.kumar@linux.ibm.com
[ Upstream commit 75838a3290cd4ebbd1f567f310ba04b6ef017ce4 ]
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.kumar@linux.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20191024093542.29777-2-aneesh.kumar@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/mm/hash_utils_64.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index b1007e9a31ba7..11b41383e1672 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -296,7 +296,14 @@ 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;