forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 1
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge branches 'topic/fix/asoc', 'topic/fix/hda', 'topic/fix/misc' an…
…d 'topic/pci-ioremap-bar' into for-linus
- Loading branch information
Showing
1,054 changed files
with
46,654 additions
and
20,692 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
|
@@ -66,6 +66,7 @@ Kenneth W Chen <[email protected]> | |
Koushik <[email protected]> | ||
Leonid I Ananiev <[email protected]> | ||
Linas Vepstas <[email protected]> | ||
Mark Brown <[email protected]> | ||
Matthieu CASTET <[email protected]> | ||
Michael Buesch <[email protected]> | ||
Michael Buesch <[email protected]> | ||
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
|
@@ -1653,14 +1653,14 @@ S: Chapel Hill, North Carolina 27514-4818 | |
S: USA | ||
|
||
N: Dave Jones | ||
E: davej@codemonkey.org.uk | ||
E: davej@redhat.com | ||
W: http://www.codemonkey.org.uk | ||
D: x86 errata/setup maintenance. | ||
D: AGPGART driver. | ||
D: Assorted VIA x86 support. | ||
D: 2.5 AGPGART overhaul. | ||
D: CPUFREQ maintenance. | ||
D: Backport/Forwardport merge monkey. | ||
D: Various Janitor work. | ||
S: United Kingdom | ||
D: Fedora kernel maintainence. | ||
D: Misc/Other. | ||
S: 314 Littleton Rd, Westford, MA 01886, USA | ||
|
||
N: Martin Josfsson | ||
E: [email protected] | ||
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
File renamed without changes.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,99 @@ | ||
The cgroup freezer is useful to batch job management system which start | ||
and stop sets of tasks in order to schedule the resources of a machine | ||
according to the desires of a system administrator. This sort of program | ||
is often used on HPC clusters to schedule access to the cluster as a | ||
whole. The cgroup freezer uses cgroups to describe the set of tasks to | ||
be started/stopped by the batch job management system. It also provides | ||
a means to start and stop the tasks composing the job. | ||
|
||
The cgroup freezer will also be useful for checkpointing running groups | ||
of tasks. The freezer allows the checkpoint code to obtain a consistent | ||
image of the tasks by attempting to force the tasks in a cgroup into a | ||
quiescent state. Once the tasks are quiescent another task can | ||
walk /proc or invoke a kernel interface to gather information about the | ||
quiesced tasks. Checkpointed tasks can be restarted later should a | ||
recoverable error occur. This also allows the checkpointed tasks to be | ||
migrated between nodes in a cluster by copying the gathered information | ||
to another node and restarting the tasks there. | ||
|
||
Sequences of SIGSTOP and SIGCONT are not always sufficient for stopping | ||
and resuming tasks in userspace. Both of these signals are observable | ||
from within the tasks we wish to freeze. While SIGSTOP cannot be caught, | ||
blocked, or ignored it can be seen by waiting or ptracing parent tasks. | ||
SIGCONT is especially unsuitable since it can be caught by the task. Any | ||
programs designed to watch for SIGSTOP and SIGCONT could be broken by | ||
attempting to use SIGSTOP and SIGCONT to stop and resume tasks. We can | ||
demonstrate this problem using nested bash shells: | ||
|
||
$ echo $$ | ||
16644 | ||
$ bash | ||
$ echo $$ | ||
16690 | ||
|
||
From a second, unrelated bash shell: | ||
$ kill -SIGSTOP 16690 | ||
$ kill -SIGCONT 16990 | ||
|
||
<at this point 16990 exits and causes 16644 to exit too> | ||
|
||
This happens because bash can observe both signals and choose how it | ||
responds to them. | ||
|
||
Another example of a program which catches and responds to these | ||
signals is gdb. In fact any program designed to use ptrace is likely to | ||
have a problem with this method of stopping and resuming tasks. | ||
|
||
In contrast, the cgroup freezer uses the kernel freezer code to | ||
prevent the freeze/unfreeze cycle from becoming visible to the tasks | ||
being frozen. This allows the bash example above and gdb to run as | ||
expected. | ||
|
||
The freezer subsystem in the container filesystem defines a file named | ||
freezer.state. Writing "FROZEN" to the state file will freeze all tasks in the | ||
cgroup. Subsequently writing "THAWED" will unfreeze the tasks in the cgroup. | ||
Reading will return the current state. | ||
|
||
* Examples of usage : | ||
|
||
# mkdir /containers/freezer | ||
# mount -t cgroup -ofreezer freezer /containers | ||
# mkdir /containers/0 | ||
# echo $some_pid > /containers/0/tasks | ||
|
||
to get status of the freezer subsystem : | ||
|
||
# cat /containers/0/freezer.state | ||
THAWED | ||
|
||
to freeze all tasks in the container : | ||
|
||
# echo FROZEN > /containers/0/freezer.state | ||
# cat /containers/0/freezer.state | ||
FREEZING | ||
# cat /containers/0/freezer.state | ||
FROZEN | ||
|
||
to unfreeze all tasks in the container : | ||
|
||
# echo THAWED > /containers/0/freezer.state | ||
# cat /containers/0/freezer.state | ||
THAWED | ||
|
||
This is the basic mechanism which should do the right thing for user space task | ||
in a simple scenario. | ||
|
||
It's important to note that freezing can be incomplete. In that case we return | ||
EBUSY. This means that some tasks in the cgroup are busy doing something that | ||
prevents us from completely freezing the cgroup at this time. After EBUSY, | ||
the cgroup will remain partially frozen -- reflected by freezer.state reporting | ||
"FREEZING" when read. The state will remain "FREEZING" until one of these | ||
things happens: | ||
|
||
1) Userspace cancels the freezing operation by writing "THAWED" to | ||
the freezer.state file | ||
2) Userspace retries the freezing operation by writing "FROZEN" to | ||
the freezer.state file (writing "FREEZING" is not legal | ||
and returns EIO) | ||
3) The tasks that blocked the cgroup from entering the "FROZEN" | ||
state disappear from the cgroup's set of tasks. |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.