Bionic SRU request submitted:
https://lists.ubuntu.com/archives/kernel-team/2018-September/095678.html
** Description changed:
- == Comment: #0 - Michael Ranweiler <mranw...@us.ibm.com> - 2018-09-10
- 19:26:14 ==
+ == SRU Justification ==
+ Due to a recent change for powernv, now the total GPU memory is no longer
+ available. This impacts performance for any application/benchmark has a
+ large GPU memory utilization.
+
+ IBM is requesting mainlien commit 7acf50e4efa6 in Bionic, which reverts
+ mainline commit 4b5d62ca17a1.
+
+ == Fix ==
+ 7acf50e4efa6 ("Revert "powerpc/powernv: Increase memory block size to 1GB on
radix"")
+
+ == Regression Potential ==
+ Low. This is a revert that was also done upstream due to a regression.
+ Limited to powerpc.
+
+ == Test Case ==
+ A test kernel was built with this patch and tested by the original bug
reporter.
+ The bug reporter states the test kernel resolved the bug.
+
+
+
+
+
+ == Comment: #0 - Michael Ranweiler <mranw...@us.ibm.com> - 2018-09-10
19:26:14 ==
Due to a recent change for powernv, now the total GPU memory is no
longer available. This impacts performance for any application/benchmark
has a large GPU memory utilization.
- Previous amount of memory : 16128MiB
- Current amount of available memory : 15360MiB
+ Previous amount of memory : 16128MiB
+ Current amount of available memory : 15360MiB
- From Anton, describing the recent change.:
- powerpc/powernv: Increase memory block size to 1GB on radix
-
- Memory hot unplug on PowerNV radix hosts is broken. Our memory block
- size is 256MB but since we map the linear region with very large
- pages, each pte we tear down maps 1GB.
-
- A hot unplug of one 256MB memory block results in 768MB of memory
- getting unintentionally unmapped. At this point we are likely to oops.
-
- Fix this by increasing our memory block size to 1GB on PowerNV radix
- hosts.
-
- Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()")
+ From Anton, describing the recent change.:
+ powerpc/powernv: Increase memory block size to 1GB on radix
+ Memory hot unplug on PowerNV radix hosts is broken. Our memory block
+ size is 256MB but since we map the linear region with very large
+ pages, each pte we tear down maps 1GB.
+
+ A hot unplug of one 256MB memory block results in 768MB of memory
+ getting unintentionally unmapped. At this point we are likely to oops.
+
+ Fix this by increasing our memory block size to 1GB on PowerNV radix
+ hosts.
+
+ Fixes: 4b5d62ca17a1 ("powerpc/mm: add
+ radix__remove_section_mapping()")
This is fixed with:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7acf50e4efa6
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https://bugs.launchpad.net/bugs/1792102
Title:
Ubuntu18.04: GPU total memory is reduced
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