Commits
Aneesh Kumar K.V committed faa6d21153f
powerpc/nvdimm: use H_SCM_QUERY hcall on H_OVERLAP error Right now we force an unbind of SCM memory at drcindex on H_OVERLAP error. This really slows down operations like kexec where we get the H_OVERLAP error because we don't go through a full hypervisor re init. H_OVERLAP error for a H_SCM_BIND_MEM hcall indicates that SCM memory at drc index is already bound. Since we don't specify a logical memory address for bind hcall, we can use the H_SCM_QUERY hcall to query the already bound logical address. Boot time difference with and without patch is: [ 5.583617] IOMMU table initialized, virtual merging enabled [ 5.603041] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Retrying bind after unbinding [ 301.514221] papr_scm ibm,persistent-memory:ibm,pmemory@44108001: Retrying bind after unbinding [ 340.057238] hv-24x7: read 1530 catalog entries, created 537 event attrs (0 failures), 275 descs after fix [ 5.101572] IOMMU table initialized, virtual merging enabled [ 5.116984] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Querying SCM details [ 5.117223] papr_scm ibm,persistent-memory:ibm,pmemory@44108001: Querying SCM details [ 5.120530] hv-24x7: read 1530 catalog entries, created 537 event attrs (0 failures), 275 descs 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/20190903123452.28620-2-aneesh.kumar@linux.ibm.com