On Fedora 31, starting a 'mock' build alters /proc/$pid/cgroup,
probably due to usage of systemd-nspawn.

Before:
$ cat /proc/self/cgroup
0::/user.slice/user-1000.slice/...

After:
$ cat /proc/self/cgroup
1:name=systemd:/
0::/user.slice/user-1000.slice/...

The cgroupv2 code mishandles that first line in the second case, which
causes VM startup to fail with: Unable to read from
'/sys/fs/cgroup/machine/cgroup.controllers': No such file or directory

The kernel docs[1] say that the cgroupv2 path will always start with
'0::', which in the code here controllers="". Only set the v2 placement
path when we see that cgroup file entry.

[1] https://www.kernel.org/doc/html/v5.3/admin-guide/cgroup-v2.html#processes

https://bugzilla.redhat.com/show_bug.cgi?id=1751120Reviewed-by: NPavel Hrdina <phrdina@redhat.com>
Signed-off-by: NCole Robinson <crobinso@redhat.com>

When we set cpu.max period we need to parse the cpu.max file first as
it contains both quota and period values separated by space.  When only
a single number is written to that file it will set quota.  However,
in order to change period we need to write both values.

The code was prepared for that but mistakenly used new line to end the
string with the first value.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1749227Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

Introduced by commit <c854e0bd> that
tried to fix an issue where we would fail to parse values from files.

We cannot change the original pointer that is going to be used by
VIR_AUTOFREE.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1747440Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>

If the first value in cpu.max is "max" return from function.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1741837Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>

Our virStrToLong* helpers converts string to integers where it wraps
strtol standard function.  After the conversion happens and there are
some remaining invalid characters our helpers will fail if the second
argument is NULL.

We need to pass pointer to string in cases where there are multiple
values in a single file.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1741825Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>

In cgroups v2 when a new group is created by default no controller is
enabled so the detection code will not detect any controllers.

When enabling the controllers we should also store them for the group.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>

When creating new group for cgroups v2 the we cannot check
cgroups.controllers for that cgroup because the directory is created
later.  In that case we should check cgroups.subtree_control of parent
group to get list of controllers enabled for child cgroups.

In order to achieve that we will prefer the parent group if it exists,
the current group will be used only for root group.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>

Because of a systemd delegation policy [1] we should not write to any
cgroups files owned by systemd which in case of cgroups v2 includes
'cgroups.subtree_control'.

systemd will enable controllers automatically for us to have them
available for VM cgroups.

[1] <https://github.com/systemd/systemd/blob/master/docs/CGROUP_DELEGATION.md>
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

This reverts commit 7bca1c9b.

As it turns out it's not a good idea on systemd hosts.  The root
cgroup can have all controllers enabled but they don't have to be
enabled for sub-cgroups.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

When detecting available controllers on host we can be limited by list
of controllers from qemu.conf file.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

Currently CPU controller cannot be enabled if there is any real-time
task running and is assigned to non-root cgroup which is the case on
several distributions with graphical environment.

Instead of erroring out treat it as the controller is not available.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

In order to skip controllers that we are not able to activate we need
to return different return value so the caller can decide what to do.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

It might happen that we are not able to enable CPU controller so we
can enable it for thread sub-cgroups only if it's available in parent
cgroup.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

The assumption that CPU controller would be always enabled is wrong, we
should use any available controller to create a new sub-cgroup.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

This affects only cgroups v2 where enabled controllers are not based on
available mount points but on the list provided in cgroup.controllers
file.  However, moving it will fill in placement as well, so it needs
to be freed together with mount point if we don't need that controller.

Before this patch we were assuming that all controllers available in
root cgroup where available in all other sub-cgroups which was wrong.

In order to fix it we need to move the cgroup controllers detection
after cgroup placement was prepared in order to build correct path for
cgroup.controllers file.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

In cgroups v2 we don't have to detect available controllers every single
time if we are creating a new cgroup based on parent cgroup.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

In kernel 4.12 there was introduced new BFQ scheduler and in kernel
5.0 the old CFQ scheduler was removed.  This has an implication on
the cgroups file names.

If the CFQ controller is enabled we use one file:

    io.weight

The new BFQ controller expose one file with different name:

    io.bfq.weight

Except for different name they have different syntax.

io.weight:

    default $val
    major:minor $val

io.bfq.weight:

    $val

The difference is that BFQ doesn't support per-device weight.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

If we need to get a path of specific file and we need to check its
existence before we use it then we can reuse that path to get value
for specific device.  This way we will not build the path again in
virCgroupGetValueForBlkDev.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Standardize on putting the _LAST enum value on the second line
of VIR_ENUM_IMPL invocations. Later patches that add string labels
to VIR_ENUM_IMPL will push most of these to the second line anyways,
so this saves some noise.
Signed-off-by: NCole Robinson <crobinso@redhat.com>

This reverts commit a5e16020.

Getting rid of unistd.h from our headers will require more work than
just fixing the broken mingw build. Revert it until I have a more
complete proposal.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

util/virutil.h bogously included unistd.h. Drop it and replace it by
including it directly where needed.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

'viralloc.h' does not provide any type or macro which would be necessary
in headers. Prevent leakage of the inclusion.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

When we create cgroup for qemu threads we need to enable cpuset
controller in order to use it.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Cgroups v2 don't have memory_migrate interface and the migration is
enabled by default.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Instead of repetitive:
  s ? s : ""
use NULLSTR_EMPTY.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NAndrea Bolognani <abologna@redhat.com>

Missing semicolon at the end of macros can confuse some analyzers
(like cppcheck <filename>), and we have a mix of semicolon and
non-semicolon usage through the code. Let's standardize on using
a semicolon for VIR_ENUM_IMPL calls.

Move the verify() statement to the end of the macro and drop
the semicolon, so the compiler will require callers to add a
semicolon.

While we are touching these call sites, standardize on putting
the closing parenth on its own line, as discussed here:
https://www.redhat.com/archives/libvir-list/2019-January/msg00750.htmlReviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NCole Robinson <crobinso@redhat.com>

Require that all headers are guarded by a symbol named

  LIBVIRT_$FILENAME

where $FILENAME is the uppercased filename, with all characters
outside a-z changed into '_'.

Note we do not use a leading __ because that is technically a
namespace reserved for the toolchain.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

When libvirt is reconnecting to running domain that uses cgroup v2
the QEMU process reports cgroup for the emulator directory because the
main thread is in that cgroup.  We need to remove the "/emulator" part
in order to match with the root cgroup directory name for that domain.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

The rewrite to support cgroup v2 missed this function.  In cgroup v2
we have different files to track tasks.

We would fail to remove cgroup on non-systemd OSes if there is any
extra process assigned to guest cgroup because we would not kill any
process form the guest cgroup.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Commit 901d2b9c introduced virCgroupGetMemoryStat and replaced
the LXC virLXCCgroupGetMemStat logic in commit e634c7cd. However,
in doing so the replacement wasn't exact as the LXC logic used
getline() to process the cgroup controller data, while the new
virCgroupGetMemoryStat used "memory.stat" manual buffer read/
processing which neglected to forward through @line in order
to read each line in the output.

To fix that, we should be sure to carry forward the @line value
for each line read updating it beyond that current @newLine value
once we've calculated the values that we want.
Signed-off-by: NPeter Chubb <peter.chubb@data61.csiro.au>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

In order to set CPU cfs period using cgroup v2 'cpu.max' interface
we need to load the current value of CPU cfs quota first because
format of 'cpu.max' interface is '$quota $period' and in order to
change 'period' we need to write 'quota' as well.  Writing only one
number changes only 'quota'.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>