lkml.org 
[lkml]   [2009]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: What can OpenVZ do?
From
Date
On Wed, 2009-02-18 at 19:16 +0100, Ingo Molnar wrote:
> Nothing motivates more than app designers complaining about the
> one-way flag.
>
> Furthermore, it's _far_ easier to make a one-way flag SMP-safe.
> We just set it and that's it. When we unset it, what do we about
> SMP races with other threads in the same MM installing another
> non-linear vma, etc.

After looking at this for file descriptors, I have to really agree with
Ingo on this one, at least as far as the flag is concerned. I want to
propose one teeny change, though: I think the flag should be
per-resource.

We should have one flag in mm_struct, one in files_struct, etc... The
task_is_checkpointable() function can just query task->mm, task->files,
etc... This gives us nice behavior at clone() *and* fork that just
works.

I'll do this for files_struct and see how it comes out so you can take a
peek.

-- Dave



\
 
 \ /
  Last update: 2009-02-18 22:29    [W:0.145 / U:1.336 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site