Re: [RFC][PATCH][EXPERIMENTAL] Make kernel threads nonfreezable by default

[Pavel Machek <pavel@ucw.cz>]

Hi!

> Index: linux-2.6.22-rc3/Documentation/power/kernel_threads.txt
> ===================================================================
> --- linux-2.6.22-rc3.orig/Documentation/power/kernel_threads.txt
> +++ linux-2.6.22-rc3/Documentation/power/kernel_threads.txt
> @@ -1,13 +1,22 @@
> -KERNEL THREADS
> +The Freezer and Kernel Threads
>  
> -
> -Freezer
> -
> -Upon entering a suspended state the system will freeze all
> -tasks. This is done by delivering pseudosignals. This affects
> -kernel threads, too. To successfully freeze a kernel thread
> -the thread has to check for the pseudosignal and enter the
> -refrigerator. Code to do this looks like this:
> +Before entering a system-wide suspend state as well as before creating a
> +hibernation snapshot image the system will freeze all tasks, which is done
> +by delivering fake signals.  This affects kernel threads too, but they won't be
> +frozen unless they declare that they want to.  For this purpose

Well... and unless thread that does disk writes or DMA _wants_ to, you
have nice disk corruption... It should be pointed out that it is not
voluntary for those types of threads.
									Pavel
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