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authorAneesh Kumar K.V2019-10-24 15:05:41 +0530
committerMichael Ellerman2019-10-28 21:54:16 +1100
commit75838a3290cd4ebbd1f567f310ba04b6ef017ce4 (patch)
treee20039e7f4aaa19b7605c01deccb37aa8a0623e9
parent82ce028ad26dd075b06285ef61a854a564d910fb (diff)
powerpc/pseries: Don't fail hash page table insert for bolted mapping
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
-rw-r--r--arch/powerpc/mm/book3s64/hash_utils.c9
1 files changed, 8 insertions, 1 deletions
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;