linux_dsm_epyc7002/drivers
Chris Wilson edf4427b80 drm/i915: Fallback to using CPU relocations for large batch buffers
If the batch buffer is too large to fit into the aperture and we need a
GTT mapping for relocations, we currently fail. This only applies to a
subset of machines for a subset of environments, quite undesirable. We
can simply check after failing to insert the batch into the GTT as to
whether we only need a mappable binding for relocation and, if so, we can
revert to using a non-mappable binding and an alternate relocation
method. However, using relocate_entry_cpu() is excruciatingly slow for
large buffers on non-LLC as the entire buffer requires clflushing before
and after the relocation handling. Alternatively, we can implement a
third relocation method that only clflushes around the relocation entry.
This is still slower than updating through the GTT, so we prefer using
the GTT where possible, but is orders of magnitude faster as we
typically do not have to then clflush the entire buffer.

An alternative idea of using a temporary WC mapping of the backing store
is promising (it should be faster than using the GTT itself), but
requires fairly extensive arch/x86 support - along the lines of
kmap_atomic_prof_pfn() (which is not universally implemented even for
x86).

Testcase: igt/gem_exec_big #pnv,byt
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88392
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Add a WARN_ONCE for the impossible reloc case and explain in
a short comment why we want to avoid ping-pong.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-03-20 11:48:13 +01:00
..
accessibility
acpi
amba
android
ata
atm
auxdisplay
base
bcma
block
bluetooth
bus
cdrom
char
clk The clk fixes for 4.0-rc4 comprise three themes. First are the usual 2015-03-15 15:07:08 -07:00
clocksource
connector
coresight
cpufreq
cpuidle
crypto
dca
devfreq
dio
dma
dma-buf
edac
eisa
extcon
firewire
firmware
fmc
gpio
gpu drm/i915: Fallback to using CPU relocations for large batch buffers 2015-03-20 11:48:13 +01:00
hid
hsi
hv
hwmon
hwspinlock
i2c
ide
idle
iio
infiniband
input
iommu
ipack
irqchip Merge branch 'irqchip/urgent-gic' into irqchip/urgent 2015-03-15 01:41:26 +00:00
isdn
leds
lguest
macintosh
mailbox
mcb
md
media
memory
memstick
message
mfd
misc
mmc
mtd
net
nfc
ntb
nubus
of
oprofile
parisc
parport
pci
pcmcia
phy
pinctrl
platform
pnp
power
powercap
pps
ps3
ptp
pwm
rapidio
ras
regulator
remoteproc
reset
rpmsg
rtc
s390
sbus
scsi
sfi
sh
sn
soc
spi
spmi
ssb
staging
target
tc
thermal
thunderbolt
tty
uio
usb Merge branch 'gadget' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-03-13 10:55:32 -07:00
uwb
vfio
vhost
video
virt
virtio
vlynq
vme
w1
watchdog
xen
zorro
Kconfig
Makefile