1. 31 Jul, 2020 1 commit
    • Vaibhav Jain's avatar
      powerpc/papr_scm: Fetch nvdimm performance stats from PHYP · 2d02bf83
      Vaibhav Jain authored
      Update papr_scm.c to query dimm performance statistics from PHYP via
      H_SCM_PERFORMANCE_STATS hcall and export them to user-space as PAPR
      specific NVDIMM attribute 'perf_stats' in sysfs. The patch also
      provide a sysfs ABI documentation for the stats being reported and
      their meanings.
      
      During NVDIMM probe time in papr_scm_nvdimm_init() a special variant
      of H_SCM_PERFORMANCE_STATS hcall is issued to check if collection of
      performance statistics is supported or not. If successful then a PHYP
      returns a maximum possible buffer length needed to read all
      performance stats. This returned value is stored in a per-nvdimm
      attribute 'stat_buffer_len'.
      
      The layout of request buffer for reading NVDIMM performance stats from
      PHYP is defined in 'struct papr_scm_perf_stats' and 'struct
      papr_scm_perf_stat'. These structs are used in newly introduced
      drc_pmem_query_stats() that issues the H_SCM_PERFORMANCE_STATS hcall.
      
      The sysfs access function perf_stats_show() uses value
      'stat_buffer_len' to allocate a buffer large enough to hold all
      possible NVDIMM performance stats and passes it to
      drc_pmem_query_stats() to populate. Finally statistics reported in the
      buffer are formatted into the sysfs access function output buffer.
      Signed-off-by: default avatarVaibhav Jain <vaibhav@linux.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200731064153.182203-2-vaibhav@linux.ibm.com
      2d02bf83
  2. 30 Jul, 2020 13 commits
  3. 29 Jul, 2020 26 commits