lkml.org 
[lkml]   [2013]   [May]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v6 0/8] kdump, vmcore: support mmap() on /proc/vmcore
On 05/15/2013 02:05 AM, HATAYAMA Daisuke wrote:
> Currently, read to /proc/vmcore is done by read_oldmem() that uses
> ioremap/iounmap per a single page. For example, if memory is 1GB,
> ioremap/iounmap is called (1GB / 4KB)-times, that is, 262144
> times. This causes big performance degradation.

read_oldmem() is fundamentally broken and unsafe. It needs to be
unified with the plain /dev/mem code and any missing functionality fixed
instead of "let's just do a whole new driver".

-hpa




\
 
 \ /
  Last update: 2013-05-17 02:21    [W:1.293 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site