include/uapi/linux/restrictedmem.h | 1 + mm/restrictedmem.c | 27 ++++++++++++------- .../restrictedmem_hugepage_test.c | 25 +++++++++++++++++ 3 files changed, 43 insertions(+), 10 deletions(-)
Hello,
This patchset builds upon the memfd_restricted() system call that has
been discussed in the ‘KVM: mm: fd-based approach for supporting KVM’
patch series, at
https://lore.kernel.org/lkml/20221202061347.1070246-1-chao.p.peng@linux.intel.com/T/#m7e944d7892afdd1d62a03a287bd488c56e377b0c
The tree can be found at:
https://github.com/googleprodkernel/linux-cc/tree/restrictedmem-rmfd-hugepage
Following the RFC to provide mount for memfd_restricted() syscall at
https://lore.kernel.org/lkml/cover.1676507663.git.ackerleytng@google.com/T/#u,
this patchset adds the RMFD_HUGEPAGE flag to the memfd_restricted()
syscall, which will hint the kernel to use Transparent HugePages to
back restrictedmem pages.
This supplements the interface proposed earlier, which requires the
creation of a tmpfs mount to be passed to memfd_restricted(), with a
more direct per-file hint.
Dependencies:
+ Sean’s iteration of the ‘KVM: mm: fd-based approach for supporting
KVM’ patch series at
https://github.com/sean-jc/linux/tree/x86/upm_base_support
+ Proposed fix for restrictedmem_getattr() as mentioned on the mailing
list at
https://lore.kernel.org/lkml/diqzzga0fv96.fsf@ackerleytng-cloudtop-sg.c.googlers.com/
+ Hugh’s patch:
https://lore.kernel.org/lkml/c140f56a-1aa3-f7ae-b7d1-93da7d5a3572@google.com/,
which provides functionality in shmem that reads the VM_HUGEPAGE
flag in key functions shmem_is_huge() and shmem_get_inode()
Future work/TODOs:
+ man page for the memfd_restricted() syscall
+ Support for per file NUMA binding hints
Ackerley Tng (2):
mm: restrictedmem: Add flag as THP allocation hint for
memfd_restricted() syscall
selftests: restrictedmem: Add selftest for RMFD_HUGEPAGE
include/uapi/linux/restrictedmem.h | 1 +
mm/restrictedmem.c | 27 ++++++++++++-------
.../restrictedmem_hugepage_test.c | 25 +++++++++++++++++
3 files changed, 43 insertions(+), 10 deletions(-)
--
2.39.2.637.g21b0678d19-goog
On Sat, Feb 18, 2023 at 12:43:00AM +0000, Ackerley Tng wrote: > Hello, > > This patchset builds upon the memfd_restricted() system call that has > been discussed in the ‘KVM: mm: fd-based approach for supporting KVM’ > patch series, at > https://lore.kernel.org/lkml/20221202061347.1070246-1-chao.p.peng@linux.intel.com/T/#m7e944d7892afdd1d62a03a287bd488c56e377b0c > > The tree can be found at: > https://github.com/googleprodkernel/linux-cc/tree/restrictedmem-rmfd-hugepage > > Following the RFC to provide mount for memfd_restricted() syscall at > https://lore.kernel.org/lkml/cover.1676507663.git.ackerleytng@google.com/T/#u, > this patchset adds the RMFD_HUGEPAGE flag to the memfd_restricted() > syscall, which will hint the kernel to use Transparent HugePages to > back restrictedmem pages. > > This supplements the interface proposed earlier, which requires the > creation of a tmpfs mount to be passed to memfd_restricted(), with a > more direct per-file hint. > > Dependencies: > > + Sean’s iteration of the ‘KVM: mm: fd-based approach for supporting > KVM’ patch series at > https://github.com/sean-jc/linux/tree/x86/upm_base_support > + Proposed fix for restrictedmem_getattr() as mentioned on the mailing > list at > https://lore.kernel.org/lkml/diqzzga0fv96.fsf@ackerleytng-cloudtop-sg.c.googlers.com/ > + Hugh’s patch: > https://lore.kernel.org/lkml/c140f56a-1aa3-f7ae-b7d1-93da7d5a3572@google.com/, > which provides functionality in shmem that reads the VM_HUGEPAGE > flag in key functions shmem_is_huge() and shmem_get_inode() Will Hugh's patch be merged into 6.3 ? I didn't find it in 6.2-rc8. IMHO this patch won't work without Hugh's patch, or at least need another way, e.g. HMEM_SB(inode->i_sb)->huge. > > Future work/TODOs: > + man page for the memfd_restricted() syscall > + Support for per file NUMA binding hints > > Ackerley Tng (2): > mm: restrictedmem: Add flag as THP allocation hint for > memfd_restricted() syscall > selftests: restrictedmem: Add selftest for RMFD_HUGEPAGE > > include/uapi/linux/restrictedmem.h | 1 + > mm/restrictedmem.c | 27 ++++++++++++------- > .../restrictedmem_hugepage_test.c | 25 +++++++++++++++++ > 3 files changed, 43 insertions(+), 10 deletions(-) > > -- > 2.39.2.637.g21b0678d19-goog >
Yuan Yao <yuan.yao@linux.intel.com> writes:
> On Sat, Feb 18, 2023 at 12:43:00AM +0000, Ackerley Tng wrote:
>> Hello,
>> This patchset builds upon the memfd_restricted() system call that has
>> been discussed in the ‘KVM: mm: fd-based approach for supporting KVM’
>> patch series, at
>> https://lore.kernel.org/lkml/20221202061347.1070246-1-chao.p.peng@linux.intel.com/T/#m7e944d7892afdd1d62a03a287bd488c56e377b0c
>> The tree can be found at:
>> https://github.com/googleprodkernel/linux-cc/tree/restrictedmem-rmfd-hugepage
>> Following the RFC to provide mount for memfd_restricted() syscall at
>> https://lore.kernel.org/lkml/cover.1676507663.git.ackerleytng@google.com/T/#u,
>> this patchset adds the RMFD_HUGEPAGE flag to the memfd_restricted()
>> syscall, which will hint the kernel to use Transparent HugePages to
>> back restrictedmem pages.
>> This supplements the interface proposed earlier, which requires the
>> creation of a tmpfs mount to be passed to memfd_restricted(), with a
>> more direct per-file hint.
>> Dependencies:
>> + Sean’s iteration of the ‘KVM: mm: fd-based approach for supporting
>> KVM’ patch series at
>> https://github.com/sean-jc/linux/tree/x86/upm_base_support
>> + Proposed fix for restrictedmem_getattr() as mentioned on the mailing
>> list at
>>
>> https://lore.kernel.org/lkml/diqzzga0fv96.fsf@ackerleytng-cloudtop-sg.c.googlers.com/
>> + Hugh’s patch:
>>
>> https://lore.kernel.org/lkml/c140f56a-1aa3-f7ae-b7d1-93da7d5a3572@google.com/,
>> which provides functionality in shmem that reads the VM_HUGEPAGE
>> flag in key functions shmem_is_huge() and shmem_get_inode()
> Will Hugh's patch be merged into 6.3 ? I didn't find it in 6.2-rc8.
> IMHO this patch won't work without Hugh's patch, or at least need
> another way, e.g. HMEM_SB(inode->i_sb)->huge.
Hugh's patch is still pending discussion and may not be merged so
soon. These patches will not work without Hugh's patch.
I would like to understand what the community thinks of the proposed
interface (RMFD_HUGEPAGE flag, passed to the memfd_restricted()
syscall). If this interface is favorably received, we can definitely
find another way for shmem to support this interface.
If I understand correctly, SHMEM_SB(inode->i_sb)->huge checks the state
of hugepage-ness for the superblock. Since the proposed interface will
only affect a single file, we will need something closer to
bool shmem_is_huge(struct vm_area_struct *vma, struct inode *inode,
pgoff_t index, bool shmem_huge_force)
{
...
if (SHMEM_I(inode)->flags & VM_HUGEPAGE)
return true;
...
}
from Hugh's patch.
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