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[Bug 1543165] Re: kernel: update kernel configuration

 

** Changed in: linux (Ubuntu)
     Assignee: Canonical Kernel Team (canonical-kernel-team) => Andy Whitcroft (apw)

** Changed in: linux (Ubuntu)
    Milestone: None => ubuntu-16.02

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https://bugs.launchpad.net/bugs/1543165

Title:
  kernel: update kernel configuration

Status in linux package in Ubuntu:
  Confirmed

Bug description:
  == Comment: #0 - Hendrik Brueckner <brueckner@xxxxxxxxxx> - 2016-02-08 09:41:49 ==
  The below mentioned kernel configuration options are still not yet integrated into the Ubuntu kernel. In addition to the discussions on the skipper mailing list, hereby the bugzilla / launchpad to integrate and update the kernel configuration.

  > Short explaination for all requested changes:                                                                                                           
  >                                                                                                                                                         
  > CONFIG_NUMA (and all related config options):                                                                                                           
  > s390 gained fake NUMA support with kernel version 4.3. Performance                                                                                      
  > measurements did show that this helps for very large machines (lot's of                                                                                 
  > memory), and also doesn't hurt for small machines.  Therfore the config                                                                                 
  > option should be enabled.                                                                                                                               
  >                                                                                                                                                         
  > CONFIG_PREEMPT_NONE:                                                                                                                                    
  > We only have performance numbers for non-preemptible kernels. While kernel                                                                              
  > preemption generally should work from a functional point of view on s390,                                                                               
  > we do not have numbers about the performance costs. Nor do we have any                                                                                  
  > production systems running with kernel preemption enabled currently.                                                                                    
  > Therefore let's please switch to PREEMPT_NONE which has proven to work.                                                                                 
  >                                                                                                                                                         
  > CONFIG_SCSI_SCAN_ASYNC:                                                                                                                                 
  > Hendrik already requested to disable this config option.                                                                                                
  >                                                                                                                                                         
  > CONFIG_REGMAP,                                                                                                                                          
  > CONFIG_NET_VENDOR_EMULEX,                                                                                                                               
  > CONFIG_BE2NET,                                                                                                                                          
  > CONFIG_BE2NET_VXLAN,                                                                                                                                    
  > CONFIG_NET_VENDOR_SYNOPSYS,                                                                                                                             
  > CONFIG_NVMEM:                                                                                                                                           
  > Looks like all of these crept in with the kernel update to 4.3. None of                                                                                 
  > these are relevant to s390 and can be disabled.                                                                                                         

  An updated config patch to the kernel version above will be added

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