delayacct: add delay min to record delay peak

Delay accounting can now calculate the average delay of processes, detect
the overall system load, and also record the 'delay max' to identify
potential abnormal delays.  However, 'delay min' can help us identify
another useful delay peak.  By comparing the difference between 'delay
max' and 'delay min', we can understand the optimization space for
latency, providing a reference for the optimization of latency
performance.

Use case
=========
bash-4.4# ./getdelays -d -t 242
print delayacct stats ON
TGID    242
CPU         count     real total  virtual total    delay total  delay average      delay max      delay min
               39      156000000      156576579        2111069          0.054ms     0.212296ms     0.031307ms
IO          count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
SWAP        count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
RECLAIM     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
THRASHING   count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
COMPACT     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
WPCOPY      count    delay total  delay average      delay max      delay min
              156       11215873          0.072ms     0.207403ms     0.033913ms
IRQ         count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms

Link: https://lkml.kernel.org/r/20241220173105906EOdsPhzjMLYNJJBqgz1ga@zte.com.cn


Co-developed-by: Wang Yong <wang.yong12@zte.com.cn>
Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
Co-developed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Co-developed-by: Kun Jiang <jiang.kun2@zte.com.cn>
Signed-off-by: Kun Jiang <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: tuqiang <tu.qiang35@zte.com.cn>
Cc: ye xingchen <ye.xingchen@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>