Re: [patch 128/197] freezer: add try_to_freeze calls to all kernelthreads

From: Stefan Richter
Date: Wed May 09 2007 - 09:21:59 EST


Gautham R Shenoy wrote:
> freezer_exempt() as of now does what its name says. I.e, exempt the
> thread from all kinds of freeze chills.
>
> But with more subsystems using the process freezer, the exemption needs
> to be event specific. There may be threads which should not be frozen
> for say kprobes, should be frozen for cpu-hotplug. This selective
> freezing is not yet available. But it will be soon...

Thanks for the (necessary!) clarification.
Let me point out that the usual process would be to replace

freezer_exempt(current);
for (;;) {
...;
by
freezer_exempt_for_io(current);
for (;;) {
try_to_freeze();
...;

when or after freezer_exempt_for_io was implemented.

But as it was submitted now, we are temporarily left with

freezer_exempt(current);
for (;;) {
try_to_freeze(); /* useless irritating no-op */
...;

without any benefit. (And this explanatory comment ^^^ wasn't even
added; we only have the git log as explanation.)

As subsystem maintainer I have to trust now that "soon" actually means
"soon" and not "RSN"; otherwise my responsibility would be to send a NAK.
--
Stefan Richter
-=====-=-=== -=-= -=--=
http://arcgraph.de/sr/
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