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[ 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>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.