lkml.org 
[lkml]   [2008]   [Oct]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] rudimentary tracing for Classic RCU
KOSAKI Motohiro wrote:
> Hi Lai-san,
>
>>>> In this case, why not define it as:
>>>> static char buf[20*NR_CPUS + 100];
>>> Actually you should near never use NR_CPUS now but always num_possible_cpus()
>>> (or even num_online_cpus()) Using NR_CPUS can lead to extreme waste
>>> of memory on kernels which are compiled for 4096 CPUs for example.
>>>
>>> And with num_possible_cpus() kmalloc is needed.
>> I thought the default value of NR_CPUS is 32.
>
> it's pointless.
> Almost distribution use _very_ large NR_CPUS (likes 4096).
> So, We should concern large NR_CPUS.

Thanks.

So my advice is to use seq_file.

>
>
>> if NR_CPUS is too large, I think using seq_file is good idea,
>> and rcuclassic_trace_mutex is not need too.
>
>
>
>
>




\
 
 \ /
  Last update: 2008-10-09 09:33    [W:0.389 / U:0.296 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site