iocost_monitor: Always use strings for json values

mainline inclusion
from mainline-5.4-rc1
commit e742bd5cb55ec0be48c5e7b356393a708e7f73c9
category: feature
bugzilla: 38688
CVE: NA

---------------------------

Json has limited accuracy for numbers and can silently truncate 64bit
values, which can be extremely confusing.  Let's consistently use
string encapsulated values for json output.

While at it, convert an unnecesary f-string to str().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

tools/cgroup/iocost_monitor.py

@@ -111,14 +111,14 @@ class IocStat:
 
     def dict(self, now):
         return { 'device'               : devname,
-                 'timestamp'            : now,
-                 'enabled'              : self.enabled,
-                 'running'              : self.running,
-                 'period_ms'            : self.period_ms,
-                 'period_at'            : self.period_at,
-                 'period_vtime_at'      : self.vperiod_at,
-                 'busy_level'           : self.busy_level,
-                 'vrate_pct'            : self.vrate_pct, }
+                 'timestamp'            : str(now),
+                 'enabled'              : str(int(self.enabled)),
+                 'running'              : str(int(self.running)),
+                 'period_ms'            : str(self.period_ms),
+                 'period_at'            : str(self.period_at),
+                 'period_vtime_at'      : str(self.vperiod_at),
+                 'busy_level'           : str(self.busy_level),
+                 'vrate_pct'            : str(self.vrate_pct), }
 
     def table_preamble_str(self):
         state = ('RUN' if self.running else 'IDLE') if self.enabled else 'OFF'
@@ -171,19 +171,19 @@ class IocgStat:
 
     def dict(self, now, path):
         out = { 'cgroup'                : path,
-                'timestamp'             : now,
-                'is_active'             : self.is_active,
-                'weight'                : self.weight,
-                'weight_active'         : self.active,
-                'weight_inuse'          : self.inuse,
-                'hweight_active_pct'    : self.hwa_pct,
-                'hweight_inuse_pct'     : self.hwi_pct,
-                'inflight_pct'          : self.inflight_pct,
-                'use_delay'             : self.use_delay,
-                'delay_ms'              : self.delay_ms,
-                'usage_pct'             : self.usage }
+                'timestamp'             : str(now),
+                'is_active'             : str(int(self.is_active)),
+                'weight'                : str(self.weight),
+                'weight_active'         : str(self.active),
+                'weight_inuse'          : str(self.inuse),
+                'hweight_active_pct'    : str(self.hwa_pct),
+                'hweight_inuse_pct'     : str(self.hwi_pct),
+                'inflight_pct'          : str(self.inflight_pct),
+                'use_delay'             : str(self.use_delay),
+                'delay_ms'              : str(self.delay_ms),
+                'usage_pct'             : str(self.usage) }
         for i in range(len(self.usages)):
-            out[f'usage_pct_{i}'] = f'{self.usages[i]}'
+            out[f'usage_pct_{i}'] = str(self.usages[i])
         return out
 
     def table_row_str(self, path):