Move the Device-related types to libcontainer/devices, so that
the package can be used in isolation. Aliases have been created
in libcontainer/configs for backward compatibility.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Move the functionality of opening a cgroup file into a separate
function, OpenFile, which, similar to ReadFile and WriteFile,
use separate dir and file arguments.
Change ReadFile and WriteFile to rely on OpenFile, and use lower-level
read and write instead of ones from ioutil.
It changes the semantics of WriteFile a bit -- it no longer uses
O_CREAT flag. This is good for real cgroup as there is no need to try
creating the files in there, but can potentially break WriteFile users
-- previously, EPERM error was returned for non-existing files, and
now it's ENOENT.
This also breaks the fs/fs2 unit tests since they write to pseudo-cgroup
files inside a test directory (not to a real cgroup fs), and now
fscommon.WriteFile do not create or truncate files, so we have to add a
variable that is set by the unit tests.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
While at it,
- change some functions to not be methods of CpusetCgroup as
they don't use any members;
- simplify isEmpty.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
fscommon.WriteFile is added specifically to work with cgroup files,
and the error it returns does not need to be wrapped.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The names of these templates overlapped with some local
variables, which made reading the code somewhat confusing.
Changing them to a const, given that these were not updated anywere.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
When paths are set, we only need to place the PID into proper
cgroups, and we do know all the paths already.
Both fs/d.path() and systemd/v1/getSubsystemPath() parse
/proc/self/mountinfo, and the only reason they are used
here is to check whether the subsystem is available.
Use a much simpler/faster check instead.
Frankly, I am not sure why the check is needed at all. Maybe it should
be dropped.
Also, for fs driver, since d is no longer used in this code path,
move its initialization to after it.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
All the test cases are doing the same checks, only input differs,
so we can unify those using a test data table.
While at it:
- use t.Fatalf where it makes sense (no further checks are possible);
- remove the "XXX" comments as we won't get rid of cgroup Name/Parent.
PS I tried using t.Parallel() as well but it did not result in any
noticeable speedup, so I dropped it for simplicity.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
...by checking the default path first.
Quick benchmark shows it's about 5x faster on an idle system, and the
gain should be much more on a system doing mounts etc.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In manager.Apply() method, a path to each subsystem is obtained by
calling d.path(sys.Name()), and the sys.Apply() is called that does
the same call to d.path() again.
d.path() is an expensive call, so rather than to call it twice, let's
reuse the result.
This results the number of times we parse mountinfo during container
start from 62 to 34 on my setup.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Instead of iterating over m.paths, iterate over subsystems and look up
the path for each. This is faster since a map lookup is faster than
iterating over the names in Get. A quick benchmark shows that the new
way is 2.5x faster than the old one.
Note though that this is not done to make things faster, as savings are
negligible, but to make things simpler by removing some code.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Half of controllers' GetStats just return nil, and most of the others
ignore ENOENT on files, so it will be cheaper to not check that the
path exists in the main GetStats method, offloading that to the
controllers.
Drop PathExists check from GetStats, add it to those controllers'
GetStats where it was missing.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
RemovePaths() deletes elements from the paths map for paths that has
been successfully removed.
Although, it does not empty the map itself (which is needed that AFAIK
Go garbage collector does not shrink the map), but all its callers do.
Move this operation from callers to RemovePaths.
No functional change, except the old map should be garbage collected now.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The result of cgroupv1.FindCgroupMountpoint() call (which is relatively
expensive) is only used in case raw.innerPath is absolute, so it only
makes sense to call it in that case.
This drastically reduces the number of calls to FindCgroupMountpoint
during container start (from 116 to 62 in my setup).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In here, defer looks like an overkill, since the code is very simple and
we already have an error path.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Iterating over the list of subsystems and comparing their names to get an
instance of fs.cgroupFreezer is useless and a waste of time, since it is
a shallow type (i.e. does not have any data/state) and we can create an
instance in place.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The kubelet uses libct/cgroups code to set up cgroups. It creates a
parent cgroup (kubepods) to put the containers into.
The problem (for cgroupv2 that uses eBPF for device configuration) is
the hard requirement to have devices cgroup configured results in
leaking an eBPF program upon every kubelet restart. program. If kubelet
is restarted 64+ times, the cgroup can't be configured anymore.
Work around this by adding a SkipDevices flag to Resources.
A check was added so that if SkipDevices is set, such a "container"
can't be started (to make sure it is only used for non-containers).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This function is cgroupv1-specific, is only used once, and its name
is very close to the name of another function, FindCgroupMountpoint.
Inline it into the (only) caller.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This fixes a few cases of accessing m.paths map directly without holding
the mutex lock.
Fixes: 9087f2e82
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Since commit 714c91e9f7, method GetPaths() should only be used
for saving container state. For other uses, we have a new method,
Path(), which is cleaner.
Fix GetPaths() usage introduced by recent commits 859a780d6f and 9087f2e82.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
When we use cgroup with systemd driver, the cgroup path will be auto removed
by systemd when all processes exited. So we should check cgroup path exists
when we access the cgroup path, for example in `kill/ps`, or else we will
got an error.
Signed-off-by: lifubang <lifubang@acmcoder.com>
Commit 4e65e0e90a added a check for cpu shares. Apparently, the
kernel allows to set a value higher than max or lower than min without
an error, but the value read back is always within the limits.
The check (which was later moved out to a separate CheckCpushares()
function) is always performed after setting the cpu shares, so let's
move it to the very place where it is set.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Commit 18ebc51b3cc3 "Reset Swap when memory is set to unlimited (-1)"
added handling of the case when a user updates the container limits
to set memory to unlimited (-1) but do not set any other limits.
Apparently, in this case, if swap limit was previously set, kernel fails
to set memory.limit_in_bytes to -1 if memory.memsw.limit_in_bytes is
not set to -1.
What the above commit fails to handle correctly is the request when
Memory is set to -1 and MemorySwap is set to some specific limit N
(where N > 0). In this case, the value of N is silently discarded
and MemorySwap is set to -1 instead.
This is wrong thing to do, as the limit set, even if incorrectly,
should not be ignored.
Fix this by only assigning MemorySwap == -1 in case it was not
explicitly set.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The function GetClosestMountpointAncestor is not very efficient,
does not really belong to cgroup package, and is only used once
(from fs/cpuset.go).
Remove it, replacing with the implementation based on moby/sys/mountinfo
parser.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Piotr Wagner