linux_dsm_epyc7002/include
Chris Wilson a0e047156c drm/i915/gem: Make context persistence optional
Our existing behaviour is to allow contexts and their GPU requests to
persist past the point of closure until the requests are complete. This
allows clients to operate in a 'fire-and-forget' manner where they can
setup a rendering pipeline and hand it over to the display server and
immediately exit. As the rendering pipeline is kept alive until
completion, the display server (or other consumer) can use the results
in the future and present them to the user.

The compute model is a little different. They have little to no buffer
sharing between processes as their kernels tend to operate on a
continuous stream, feeding the results back to the client application.
These kernels operate for an indeterminate length of time, with many
clients wishing that the kernel was always running for as long as they
keep feeding in the data, i.e. acting like a DSP.

Not all clients want this persistent "desktop" behaviour and would prefer
that the contexts are cleaned up immediately upon closure. This ensures
that when clients are run without hangchecking (e.g. for compute kernels
of indeterminate runtime), any GPU hang or other unexpected workloads
are terminated with the process and does not continue to hog resources.

The default behaviour for new contexts is the legacy persistence mode,
as some desktop applications are dependent upon the existing behaviour.
New clients will have to opt in to immediate cleanup on context
closure. If the hangchecking modparam is disabled, so is persistent
context support -- all contexts will be terminated on closure.

We expect this behaviour change to be welcomed by compute users, who
have often been caught between a rock and a hard place. They disable
hangchecking to avoid their kernels being "unfairly" declared hung, but
have also experienced true hangs that the system was then unable to
clean up. Naturally, this leads to bug reports.

Testcase: igt/gem_ctx_persistence
Link: https://github.com/intel/compute-runtime/pull/228
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029202338.8841-1-chris@chris-wilson.co.uk
2019-10-29 21:02:52 +00:00
..
acpi
asm-generic Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
clocksource
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2019-09-27 19:37:27 -07:00
drm drm-misc-next for 5.5: 2019-10-11 09:30:53 +10:00
dt-bindings Main MIPS changes for v5.4: 2019-09-22 09:30:30 -07:00
keys
kvm
linux drm-misc-next for 5.5: 2019-10-11 09:30:53 +10:00
math-emu
media cec: add cec_adapter to cec_notifier_cec_adap_unregister() 2019-10-07 12:47:43 +02:00
misc
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2019-09-27 20:15:00 +02:00
pcmcia
ras
rdma RDMA subsystem updates for 5.4 2019-09-21 10:26:24 -07:00
scsi SCSI misc on 20190919 2019-09-21 10:50:15 -07:00
soc Char/Misc driver patches for 5.4-rc1 2019-09-18 11:14:31 -07:00
sound
target
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-05 08:50:15 -07:00
uapi drm/i915/gem: Make context persistence optional 2019-10-29 21:02:52 +00:00
vdso
video
xen xen: fixes and cleanups for 5.4-rc2 2019-10-04 11:13:09 -07:00
Kbuild - New Drivers 2019-09-23 19:37:49 -07:00