This is the fourth iteration of the work previously posted here:
(v1) https://lists.freedesktop.org/archives/intel-gfx/2018-January/153156.html
(v2)
https://www.mail-archive.com/dri-devel@lists.freedesktop.org/msg208170.html
(v3) https://lists.freedesktop.org/archives/intel-gfx/2018-March/157928.html
The high level goal of this work is to allow non-cgroup-controller parts
of the kernel (e.g., device drivers) to register their own private
policy data for specific cgroups. That mechanism is then made use of in
the i915 graphics driver to allow GPU priority to be assigned according
to the cgroup membership of the owning process. Please see the v1 cover
letter linked above for a more in-depth explanation and justification.
v4 of this series brings large changes to the cgroup core half of the
series and moderate changes to the i915 side.
cgroup core changes:
* The cgroup private data interface and implementation has changed
again. The internal implementation is ida+radixtree based to allow
much faster lookups than the previous hashtable approach. Private
data is now registered and looked up via kref, which should allow
the same private data to be set on multiple cgroups at the same
time. The interface now looks like:
- cgroup_priv_getkey()
Obtain an integer key that will be used to store/lookup
cgroup private data. This only needs to be called once
at startup, driver init, etc.; after that the same key
is used to store private data against any cgroup
- cgroup_priv_destroykey(key)
Release a private data key and drop references to any
private data associated with the key on all cgroups. This
function is very heavy, but will generally only be called
by module-based users of the interface when the module is
unloaded.
- cgroup_priv_install(cgrp, key, ref)
Store private data for a cgroup under the given key and
increment the reference count.
- cgroup_priv_get(cgrp, key)
Take and return a reference to a cgroup's private data
associated with the given key.
- cgroup_priv_get_current(key)
Same as cgroup_priv_get, but operates on the current
task's cgroup.
- cgroup_priv_release(cgrp, key)
Remove private data from a cgroup and decrement its
reference count.
* Dropped the cgroup_permission() function. My i915 usage of this
functionality will take a different approach for determining access
control.
i915 cgroup-based priority changes:
* cgroup priority offset is now bounded such that (context+cgroup)
adjustments fall within the range [-0x7fffff,0x7fffff]. This
only takes 24 bits, leaving several effective priority bits for
future flags or bookkeeping.
* Display boost is added as a second cgroup parameter; each cgroup's
processes can get differing boosts if a display operation is waiting
on their completion. If we have non-overlapping cgroup priority
ranges, this allows a system administrator to decide whether
workloads from the lower priority cgroup(s) should still jump past
the workloads in some/all of the higher priority cgroups.
* Access control for cgroup settings has been changed. Instead of
following cgroup filesystem permissions, we now restrict the access
to either the DRM master or capable(CAP_SYS_RESOURCE).
Cc: Tejun Heo <t...@kernel.org>
Cc: Alexei Starovoitov <a...@fb.com>
Cc: Roman Gushchin <g...@fb.com>
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Matt Roper (8):
cgroup: Allow registration and lookup of cgroup private data (v2)
cgroup: Introduce task_get_dfl_cgroup() (v2)
cgroup: Introduce cgroup_priv_get_current
drm/i915: Adjust internal priority definitions
drm/i915: cgroup integration (v3)
drm/i915: Introduce 'priority offset' for GPU contexts (v3)
drm/i915: Introduce per-cgroup display boost setting
drm/i915: Add context priority & priority offset to debugfs (v2)
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/i915_cgroup.c | 205 +++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_debugfs.c | 3 +
drivers/gpu/drm/i915/i915_drv.c | 7 ++
drivers/gpu/drm/i915/i915_drv.h | 33 ++++-
drivers/gpu/drm/i915/i915_gem_context.c | 11 +-
drivers/gpu/drm/i915/i915_gem_context.h | 9 ++
drivers/gpu/drm/i915/i915_request.h | 18 ++-
drivers/gpu/drm/i915/intel_display.c | 5 +-
include/linux/cgroup-defs.h | 8 ++
include/linux/cgroup.h | 37 ++++++
include/uapi/drm/i915_drm.h | 14 +++
kernel/cgroup/cgroup.c | 208 +++++++++++++++++++++++++++++++-
13 files changed, 545 insertions(+), 14 deletions(-)
create mode 100644 drivers/gpu/drm/i915/i915_cgroup.c
--
2.14.3
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