Hi Alistair,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on s390/features]
[also build test ERROR on kselftest/next linus/master v5.12-rc2 next-20210309]
[cannot apply to hnaz-linux-mm/master]
[If your patch is applied to the wrong git tree, kindly drop us a note
Some NVIDIA GPUs do not support direct atomic access to system memory
via PCIe. Instead this must be emulated by granting the GPU exclusive
access to the memory. This is achieved by replacing CPU page table
entries with special swap entries that fault on userspace access.
The driver then grants
Call mmu_interval_notifier_insert() as part of nouveau_range_fault().
This doesn't introduce any functional change but makes it easier for a
subsequent patch to alter the behaviour of nouveau_range_fault() to
support GPU atomic operations.
Signed-off-by: Alistair Popple
---
On Tue, Mar 09, 2021 at 11:14:58PM +1100, Alistair Popple wrote:
> -static inline struct page *migration_entry_to_page(swp_entry_t entry)
> -{
> - struct page *p = pfn_to_page(swp_offset(entry));
> - /*
> - * Any use of migration entries may only occur while the
> - *
Adds some selftests for exclusive device memory.
Signed-off-by: Alistair Popple
Acked-by: Jason Gunthorpe
Tested-by: Ralph Campbell
Reviewed-by: Ralph Campbell
---
lib/test_hmm.c | 126 +-
lib/test_hmm_uapi.h| 2 +
Some devices require exclusive write access to shared virtual
memory (SVM) ranges to perform atomic operations on that memory. This
requires CPU page tables to be updated to deny access whilst atomic
operations are occurring.
In order to do this introduce a new swap entry
type
Migration is currently implemented as a mode of operation for
try_to_unmap_one() generally specified by passing the TTU_MIGRATION flag
or in the case of splitting a huge anonymous page TTU_SPLIT_FREEZE.
However it does not have much in common with the rest of the unmap
functionality of
The behaviour of try_to_unmap_one() is difficult to follow because it
performs different operations based on a fairly large set of flags used
in different combinations.
TTU_MUNLOCK is one such flag. However it is exclusively used by
try_to_munlock() which specifies no other flags. Therefore
Both migration and device private pages use special swap entries that
are manipluated by a range of inline functions. The arguments to these
are somewhat inconsitent so rework them to remove flag type arguments
and to make the arguments similar for both read and write entry
creation.
Remove the migration and device private entry_to_page() and
entry_to_pfn() inline functions and instead open code them directly.
This results in shorter code which is easier to understand.
Signed-off-by: Alistair Popple
Reviewed-by: Ralph Campbell
---
v4:
* Added pfn_swap_entry_to_page()
*
This is the fifth version of a series to add support to Nouveau for atomic
memory operations on OpenCL shared virtual memory (SVM) regions.
The main changes since v4 are a rebase onto v5.12-rc2, the removal of
check_device_exclusive_range() and the addition of MMU_NOTIFY_EXCLUSIVE
which makes the
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