title: Too many rcuob and rcuos are shown
body: <p>On my Linux server, Too many rcuob and rcuos process are shown.</p>
  
  <p>Execute a following command.</p>
  
  <pre><code>ps auxwwf | grep rcu
  </code></pre>
  
  <p>And shown below.</p>
  
  <pre><code>root          9  0.0  0.0      0     0 ?        S     5月30   0:00  \_ [rcuob/0]
  root         10  0.0  0.0      0     0 ?        S     5月30   0:00  \_ [rcuob/1]
  :
  :
  root        151  0.0  0.0      0     0 ?        S     5月30   0:00  \_ [rcuob/142]
  root        152  0.0  0.0      0     0 ?        S     5月30   0:00  \_ [rcuob/143]
  </code></pre>
  
  <p>and</p>
  
  <pre><code>root        154  0.0  0.0      0     0 ?        S     5月30   0:11  \_ [rcuos/0]
  root        155  0.0  0.0      0     0 ?        S     5月30   0:04  \_ [rcuos/1]
  :
  :
  root        296  0.0  0.0      0     0 ?        S     5月30   0:00  \_ [rcuos/142]
  root        297  0.0  0.0      0     0 ?        S     5月30   0:00  \_ [rcuos/143]
  </code></pre>
  
  <p>The server's CPU is "Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz"</p>
  
  <p>Total Memory is "32GB"</p>
  
  <p>and OS is"CentOS Linux release 7.2.1511 (Core)"</p>
  
  <p>I do not know what these are, and if they are the problem, please let me know the procedure to fix it.</p>