lkml.org 
[lkml]   [2017]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC][PATCHv4 0/7] printk: introduce printing kernel threads
On (06/30/17 14:11), Petr Mladek wrote:
> > 2) can offload printing to other CPUs from vprintk_emit()
> > and avoid any of scheduler->timekeeping->etc. paths. which will
> > replace printk_deferred().
>
> I probably miss something. There is still called wake_up_process()
> in this patchset and we could not do this in some scheduler and
> timekeeping paths. Also we must not take the console_lock() in
> these paths because it calls wake_up_process() as well. But
> we want to flush few lines when possible.

yes. but we could call wake_up_process() on !this_cpu.
so we wouldn't take this_cpu ->rq lock and so on.

CPU1

vprintk_emit()
wake_up_process(printk_kthread on CPU2);

-ss

\
 
 \ /
  Last update: 2017-06-30 23:13    [W:0.124 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site