linux/include
Thomas Hellström 01e0cfc994 drm/xe: Use write-back caching mode for system memory on DGFX
The caching mode for buffer objects with VRAM as a possible
placement was forced to write-combined, regardless of placement.

However, write-combined system memory is expensive to allocate and
even though it is pooled, the pool is expensive to shrink, since
it involves global CPU TLB flushes.

Moreover write-combined system memory from TTM is only reliably
available on x86 and DGFX doesn't have an x86 restriction.

So regardless of the cpu caching mode selected for a bo,
internally use write-back caching mode for system memory on DGFX.

Coherency is maintained, but user-space clients may perceive a
difference in cpu access speeds.

v2:
- Update RB- and Ack tags.
- Rephrase wording in xe_drm.h (Matt Roper)
v3:
- Really rephrase wording.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Fixes: 622f709ca6 ("drm/xe/uapi: Add support for CPU caching mode")
Cc: Pallavi Mishra <pallavi.mishra@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Effie Yu <effie.yu@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Jose Souza <jose.souza@intel.com>
Cc: Michal Mrozek <michal.mrozek@intel.com>
Cc: <stable@vger.kernel.org> # v6.8+
Acked-by: Matthew Auld <matthew.auld@intel.com>
Acked-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Fixes: 622f709ca6 ("drm/xe/uapi: Add support for CPU caching mode")
Acked-by: Michal Mrozek <michal.mrozek@intel.com>
Acked-by: Effie Yu <effie.yu@intel.com> #On chat
Link: https://patchwork.freedesktop.org/patch/msgid/20240705132828.27714-1-thomas.hellstrom@linux.intel.com
2024-07-06 11:05:46 +02:00
..
acpi The usual shower of singleton fixes and minor series all over MM, 2024-05-19 09:21:03 -07:00
asm-generic asm-generic cleanups for 6.10 2024-05-20 15:18:34 -07:00
clocksource
crypto This push fixes a bug in the new ecc P521 code as well as a buggy 2024-05-20 08:47:54 -07:00
drm Merge drm/drm-next into drm-xe-next 2024-06-26 18:22:52 -04:00
dt-bindings - Core Frameworks 2024-05-22 10:49:54 -07:00
keys Hi, 2024-05-13 10:40:15 -07:00
kunit kunit: Print last test location on fault 2024-05-06 14:22:02 -06:00
kvm Merge branch kvm-arm64/misc-6.10 into kvmarm-master/next 2024-05-08 16:41:50 +01:00
linux Merge drm/drm-next into drm-xe-next 2024-06-26 18:22:52 -04:00
math-emu
media
memory
misc
net rtnetlink: make the "split" NLM_DONE handling generic 2024-06-05 12:34:54 +01:00
pcmcia
ras tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
rdma The usual shower of singleton fixes and minor series all over MM, 2024-05-19 09:21:03 -07:00
rv
scsi SCSI misc on 20240514 2024-05-14 18:25:53 -07:00
soc I'm actually surprised this time. There aren't any new Qualcomm SoC clk 2024-05-18 12:48:37 -07:00
sound Merge drm/drm-next into drm-intel-next 2024-06-19 11:38:31 +03:00
target
trace block-6.10-20240523 2024-05-23 13:44:47 -07:00
uapi drm/xe: Use write-back caching mode for system memory on DGFX 2024-07-06 11:05:46 +02:00
ufs
vdso
video
xen