lkml.org 
[lkml]   [2012]   [Jan]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: + kmod-avoid-deadlock-by-recursive-kmod-call.patch added to -mm tree
On 01/29, Tejun Heo wrote:
>
> BTW, why does it have to be unbound_wq?

Perhaps we can use another system_wq, but afaics WQ_UNBOUND makes sense
in this case. I mean, there is no reason to bind this work to any CPU.
See also below.

> Is it expected consume large
> amount of CPU cycles?

Currently __call_usermodehelper() does kernel_thread(), this is almost
all. But it can block waiting for kernel_execve().

Not sure this really makes sense, but if we kill khelper_wq perhaps we
can simplify this code a bit. We can change __call_usermodehelper()

if (wait == UMH_WAIT_PROC)
- pid = kernel_thread(wait_for_helper, sub_info,
- CLONE_FS | CLONE_FILES | SIGCHLD);
+ wait_for_helper(...);
else

IOW, the worker thread itself can do the UMH_WAIT_PROC work. This makes
this work really "long running", but then we can kill sub_info->complete
and use flush_work().

Oleg.



\
 
 \ /
  Last update: 2012-01-30 14:13    [W:0.058 / U:1.260 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site