Re: [ndctl PATCH] ndctl, list: display the 'map' location in listings

[Dan Williams <dan.j.williams@intel.com>]

On Tue, May 29, 2018 at 11:52 AM, Verma, Vishal L
<vishal.l.verma@intel.com> wrote:
> On Mon, 2018-05-28 at 11:04 -0700, Dan Williams wrote:
>> On Fri, May 25, 2018 at 3:36 PM Vishal Verma <vishal.l.verma@intel.com>
>> wrote:
>>
>> > For 'fsdax' and 'devdax' namespaces, a 'map' location may be specified
>> > for page structures storage. This can be 'mem', for system RAM, or
>> > 'dev'
>> > for using pmem as the backing storage. Once set, there was no way of
>> > telling using ndctl, which of the two locations a namespace was
>> > configured for. Add this in util_namespace_to_json so that all
>> > namespace listings contain the map location.
>> > Reported-by: "Yigal Korman" <yigal.korman@netapp.com>
>> > Cc: Dan Williams <dan.j.williams@intel.com>
>> > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
>> > ---
>> >   util/json.c | 18 ++++++++++++++++++
>> >   1 file changed, 18 insertions(+)
>> > diff --git a/util/json.c b/util/json.c
>> > index c606e1c..17dd90c 100644
>> > --- a/util/json.c
>> > +++ b/util/json.c
>> > @@ -667,11 +667,17 @@ struct json_object *util_namespace_to_json(struct
>>
>> ndctl_namespace *ndns,
>> >   {
>> >          struct json_object *jndns = json_object_new_object();
>> >          struct json_object *jobj, *jbbs = NULL;
>> > +       const char *locations[] = {
>> > +               [NDCTL_PFN_LOC_NONE] = "none",
>> > +               [NDCTL_PFN_LOC_RAM] = "mem",
>> > +               [NDCTL_PFN_LOC_PMEM] = "dev",
>> > +       };
>> >          unsigned long long size = ULLONG_MAX;
>> >          unsigned int sector_size = UINT_MAX;
>> >          enum ndctl_namespace_mode mode;
>> >          const char *bdev = NULL, *name;
>> >          unsigned int bb_count = 0;
>> > +       enum ndctl_pfn_loc loc;
>> >          struct ndctl_btt *btt;
>> >          struct ndctl_pfn *pfn;
>> >          struct ndctl_dax *dax;
>> > @@ -749,6 +755,12 @@ struct json_object *util_namespace_to_json(struct
>>
>> ndctl_namespace *ndns,
>> >                  jobj = util_raw_uuid(ndns);
>> >                  if (jobj)
>> >                          json_object_object_add(jndns, "raw_uuid",
>> > jobj);
>> > +               loc = ndctl_pfn_get_location(pfn);
>> > +               jobj = json_object_new_string(locations[loc]);
>> > +               if (!jobj)
>> > +                       goto err;
>> > +               if (jobj)
>> > +                       json_object_object_add(jndns, "map", jobj);
>> >                  bdev = ndctl_pfn_get_block_device(pfn);
>> >          } else if (dax) {
>> >                  struct daxctl_region *dax_region;
>> > @@ -763,6 +775,12 @@ struct json_object *util_namespace_to_json(struct
>>
>> ndctl_namespace *ndns,
>> >                  jobj = util_raw_uuid(ndns);
>> >                  if (jobj)
>> >                          json_object_object_add(jndns, "raw_uuid",
>> > jobj);
>> > +               loc = ndctl_dax_get_location(dax);
>> > +               jobj = json_object_new_string(locations[loc]);
>> > +               if (!jobj)
>> > +                       goto err;
>> > +               if (jobj)
>> > +                       json_object_object_add(jndns, "map", jobj);
>> >                  if ((flags & UTIL_JSON_DAX) && dax_region) {
>> >                          jobj = util_daxctl_region_to_json(dax_region,
>>
>> NULL,
>> >                                          flags);
>>
>> There appears to be one case missing in this:
>>
>>          case NDCTL_NS_MODE_MEMORY:
>>                  if (pfn) /* dynamic memory mode */
>>                          size = ndctl_pfn_get_size(pfn);
>>                  else /* native/static memory mode */
>>                          size = ndctl_namespace_get_size(ndns);
>>                  jobj = json_object_new_string("fsdax");
>>                  break;
>>
>> In the "/* native/static memory mode */" configuration we should emit a
>> 'map:"mem"' indication.
>
> Ah good catch. Is this for legacy/labelless namespaces that have been
> configured into fsdax mode?

This is strictly for memmap=ss!nn and legacy-e820 defined namespaces
where the assumption is that they are small and never need to have the
map allocated anywhere else but System RAM.
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