From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> [ 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@xxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20191024093542.29777-2-aneesh.kumar@xxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 bd666287c5eda..de1d8cdd29915 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -289,7 +289,14 @@ 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; -- 2.20.1
