Remove `use core::ffi::c_void`, which shadows `kernel::ffi::c_void`
brought in via `use crate::prelude::*`, to maintain consistency and
centralize the abstraction.
Since `kernel::ffi::c_void` is a straightforward re-export of
`core::ffi::c_void`, both are functionally equivalent. However, using
`kernel::ffi::c_void` improves consistency across the kernel's Rust code
and provides a unified reference point in case the definition ever needs
to change, even if such a change is unlikely.
Reviewed-by: Benno Lossin <lossin(a)kernel.org>
Signed-off-by: Jesung Yang <y.j3ms.n(a)gmail.com>
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089/topic/x/near/52…
---
Changes in v3:
- Rebase on a3b2347343e0
- Remove the explicit import of `kernel::ffi::c_void`
- Reword the commit message accordingly
- Link to v2: https://lore.kernel.org/rust-for-linux/20250528155147.2793921-1-y.j3ms.n@gm…
Changes in v2:
- Add "Link" tag to the related discussion on Zulip
- Reword the commit message to clarify `kernel::ffi::c_void` is a re-export
- Link to v1: https://lore.kernel.org/rust-for-linux/20250526162429.1114862-1-y.j3ms.n@gm…
---
rust/kernel/kunit.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 4b8cdcb21e77..603330f247c7 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -7,7 +7,7 @@
//! Reference: <https://docs.kernel.org/dev-tools/kunit/index.html>
use crate::prelude::*;
-use core::{ffi::c_void, fmt};
+use core::fmt;
/// Prints a KUnit error-level message.
///
base-commit: a3b2347343e077e81d3c169f32c9b2cb1364f4cc
--
2.39.5
This series is built on top of the Fuad's v7 "mapping guest_memfd backed
memory at the host" [1].
With James's KVM userfault [2], it is possible to handle stage-2 faults
in guest_memfd in userspace. However, KVM itself also triggers faults
in guest_memfd in some cases, for example: PV interfaces like kvmclock,
PV EOI and page table walking code when fetching the MMIO instruction on
x86. It was agreed in the guest_memfd upstream call on 23 Jan 2025 [3]
that KVM would be accessing those pages via userspace page tables. In
order for such faults to be handled in userspace, guest_memfd needs to
support userfaultfd.
Changes since v2 [4]:
- James: Fix sgp type when calling shmem_get_folio_gfp
- James: Improved vm_ops->fault() error handling
- James: Add and make use of the can_userfault() VMA operation
- James: Add UFFD_FEATURE_MINOR_GUEST_MEMFD feature flag
- James: Fix typos and add more checks in the test
Nikita
[1] https://lore.kernel.org/kvm/20250318161823.4005529-1-tabba@google.com/T/
[2] https://lore.kernel.org/kvm/20250109204929.1106563-1-jthoughton@google.com/…
[3] https://docs.google.com/document/d/1M6766BzdY1Lhk7LiR5IqVR8B8mG3cr-cxTxOrAo…
[4] https://lore.kernel.org/kvm/20250402160721.97596-1-kalyazin@amazon.com/T/
Nikita Kalyazin (6):
mm: userfaultfd: generic continue for non hugetlbfs
mm: provide can_userfault vma operation
mm: userfaultfd: use can_userfault vma operation
KVM: guest_memfd: add support for userfaultfd minor
mm: userfaultfd: add UFFD_FEATURE_MINOR_GUEST_MEMFD
KVM: selftests: test userfaultfd minor for guest_memfd
fs/userfaultfd.c | 3 +-
include/linux/mm.h | 5 +
include/linux/mm_types.h | 4 +
include/linux/userfaultfd_k.h | 10 +-
include/uapi/linux/userfaultfd.h | 8 +-
mm/hugetlb.c | 9 +-
mm/shmem.c | 17 +++-
mm/userfaultfd.c | 47 ++++++---
.../testing/selftests/kvm/guest_memfd_test.c | 99 +++++++++++++++++++
virt/kvm/guest_memfd.c | 10 ++
10 files changed, 188 insertions(+), 24 deletions(-)
base-commit: 3cc51efc17a2c41a480eed36b31c1773936717e0
--
2.47.1
Fix the spelling error from "multible" to "multiple".
Signed-off-by: Ankit Chauhan <ankitchauhan2065(a)gmail.com>
---
tools/testing/selftests/ptrace/peeksiginfo.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/ptrace/peeksiginfo.c b/tools/testing/selftests/ptrace/peeksiginfo.c
index a6884f66dc01..2f345d11e4b8 100644
--- a/tools/testing/selftests/ptrace/peeksiginfo.c
+++ b/tools/testing/selftests/ptrace/peeksiginfo.c
@@ -199,7 +199,7 @@ int main(int argc, char *argv[])
/*
* Dump signal from the process-wide queue.
- * The number of signals is not multible to the buffer size
+ * The number of signals is not multiple to the buffer size
*/
if (check_direct_path(child, 1, 3))
goto out;
--
2.34.1
This series is a follow-up to [1], which adds mTHP support to khugepaged.
mTHP khugepaged support is a "loose" dependency for the sysfs/sysctl
configs to make sense. Without it global="defer" and mTHP="inherit" case
is "undefined" behavior.
We've seen cases were customers switching from RHEL7 to RHEL8 see a
significant increase in the memory footprint for the same workloads.
Through our investigations we found that a large contributing factor to
the increase in RSS was an increase in THP usage.
For workloads like MySQL, or when using allocators like jemalloc, it is
often recommended to set /transparent_hugepages/enabled=never. This is
in part due to performance degradations and increased memory waste.
This series introduces enabled=defer, this setting acts as a middle
ground between always and madvise. If the mapping is MADV_HUGEPAGE, the
page fault handler will act normally, making a hugepage if possible. If
the allocation is not MADV_HUGEPAGE, then the page fault handler will
default to the base size allocation. The caveat is that khugepaged can
still operate on pages that are not MADV_HUGEPAGE.
This allows for three things... one, applications specifically designed to
use hugepages will get them, and two, applications that don't use
hugepages can still benefit from them without aggressively inserting
THPs at every possible chance. This curbs the memory waste, and defers
the use of hugepages to khugepaged. Khugepaged can then scan the memory
for eligible collapsing. Lastly there is the added benefit for those who
want THPs but experience higher latency PFs. Now you can get base page
performance at the PF handler and Hugepage performance for those mappings
after they collapse.
Admins may want to lower max_ptes_none, if not, khugepaged may
aggressively collapse single allocations into hugepages.
TESTING:
- Built for x86_64, aarch64, ppc64le, and s390x
- selftests mm
- In [1] I provided a script [2] that has multiple access patterns
- lots of general use.
- redis testing. This test was my original case for the defer mode. What I
was able to prove was that THP=always leads to increased max_latency
cases; hence why it is recommended to disable THPs for redis servers.
However with 'defer' we dont have the max_latency spikes and can still
get the system to utilize THPs. I further tested this with the mTHP
defer setting and found that redis (and probably other jmalloc users)
can utilize THPs via defer (+mTHP defer) without a large latency
penalty and some potential gains. I uploaded some mmtest results
here[3] which compares:
stock+thp=never
stock+(m)thp=always
khugepaged-mthp + defer (max_ptes_none=64)
The results show that (m)THPs can cause some throughput regression in
some cases, but also has gains in other cases. The mTHP+defer results
have more gains and less losses over the (m)THP=always case.
V6 Changes:
- nits
- rebased dependent series and added review tags
V5 Changes:
- rebased dependent series
- added reviewed-by tag on 2/4
V4 Changes:
- Minor Documentation fixes
- rebased the dependent series [1] onto mm-unstable
commit 0e68b850b1d3 ("vmalloc: use atomic_long_add_return_relaxed()")
V3 Changes:
- Combined the documentation commits into one, and moved a section to the
khugepaged mthp patchset
V2 Changes:
- base changes on mTHP khugepaged support
- Fix selftests parsing issue
- add mTHP defer option
- add mTHP defer Documentation
[1] - https://lore.kernel.org/all/20250515032226.128900-1-npache@redhat.com/
[2] - https://gitlab.com/npache/khugepaged_mthp_test
[3] - https://people.redhat.com/npache/mthp_khugepaged_defer/testoutput2/output.h…
Nico Pache (4):
mm: defer THP insertion to khugepaged
mm: document (m)THP defer usage
khugepaged: add defer option to mTHP options
selftests: mm: add defer to thp setting parser
Documentation/admin-guide/mm/transhuge.rst | 31 +++++++---
include/linux/huge_mm.h | 18 +++++-
mm/huge_memory.c | 69 +++++++++++++++++++---
mm/khugepaged.c | 8 +--
tools/testing/selftests/mm/thp_settings.c | 1 +
tools/testing/selftests/mm/thp_settings.h | 1 +
6 files changed, 106 insertions(+), 22 deletions(-)
--
2.49.0
Nolibc is useful for selftests as the test programs can be very small,
and compiled with just a kernel crosscompiler, without userspace support.
Currently nolibc is only usable with kselftest.h, not the more
convenient to use kselftest_harness.h
This series provides this compatibility by removing the usage of problematic
libc features from the harness.
Based on nolibc/for-next.
The series is meant to be merged through the nolibc tree.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
---
Changes in v4:
- Drop patches for nolibc which where already applied
- Preserve signatures of test functions for tests making assumptions about them
drop 'selftests: harness: Always provide "self" and "variant"'
add 'selftests: harness: Add "variant" and "self" to test metadata'
adapt 'selftests: harness: Stop using setjmp()/longjmp()'
- Validate test function signatures in harness selftest
- Link to v3: https://lore.kernel.org/r/20250411-nolibc-kselftest-harness-v3-0-4d9c029589…
Changes in v3:
- Send patches to correct kselftest harness maintainers
- Move harness selftest to dedicated directory
- Add harness selftest to MAINTAINERS
- Integrate harness selftest cleanup with the selftest framework
- Consistently use "kselftest harness" in commit messages
- Properly propagate kselftest harness failure
- Link to v2: https://lore.kernel.org/r/20250407-nolibc-kselftest-harness-v2-0-f8812f76e9…
Changes in v2:
- Rebase unto v6.15-rc1
- Rename internal nolibc symbols
- Handle edge case of waitpid(INT_MIN) == ESRCH
- Fix arm configurations for final testing patch
- Clean up global getopt.h variable declarations
- Add Acks from Willy
- Link to v1: https://lore.kernel.org/r/20250304-nolibc-kselftest-harness-v1-0-adca7cd231…
---
Thomas Weißschuh (14):
selftests: harness: Add kselftest harness selftest
selftests: harness: Use C89 comment style
selftests: harness: Ignore unused variant argument warning
selftests: harness: Mark functions without prototypes static
selftests: harness: Remove inline qualifier for wrappers
selftests: harness: Remove dependency on libatomic
selftests: harness: Implement test timeouts through pidfd
selftests: harness: Don't set setup_completed for fixtureless tests
selftests: harness: Move teardown conditional into test metadata
selftests: harness: Add teardown callback to test metadata
selftests: harness: Add "variant" and "self" to test metadata
selftests: harness: Stop using setjmp()/longjmp()
selftests: harness: Guard includes on nolibc
HACK: selftests/nolibc: demonstrate usage of the kselftest harness
MAINTAINERS | 1 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/kselftest_harness.h | 175 +-
.../testing/selftests/kselftest_harness/.gitignore | 2 +
tools/testing/selftests/kselftest_harness/Makefile | 7 +
.../selftests/kselftest_harness/harness-selftest.c | 138 ++
.../kselftest_harness/harness-selftest.expected | 64 +
.../kselftest_harness/harness-selftest.sh | 13 +
tools/testing/selftests/nolibc/Makefile | 15 +-
tools/testing/selftests/nolibc/harness-selftest.c | 1 +
tools/testing/selftests/nolibc/nolibc-test.c | 1715 +-------------------
tools/testing/selftests/nolibc/run-tests.sh | 2 +-
12 files changed, 313 insertions(+), 1821 deletions(-)
---
base-commit: 2051d3b830c0889ae55e37e9e8ff0d43a4acd482
change-id: 20250130-nolibc-kselftest-harness-8b2c8cac43bf
Best regards,
--
Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
As titled, adding version file to kselftest installation dir, so the user
of the tarball can know which kernel version the tarball belongs to.
Signed-off-by: Tianyi Cui <1997cui(a)gmail.com>
---
tools/testing/selftests/Makefile | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index a0a6ba47d600..246e9863b45b 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -291,6 +291,12 @@ ifdef INSTALL_PATH
$(MAKE) -s --no-print-directory OUTPUT=$$BUILD_TARGET COLLECTION=$$TARGET \
-C $$TARGET emit_tests >> $(TEST_LIST); \
done;
+ @if git describe HEAD > /dev/null 2>&1; then \
+ git describe HEAD > $(INSTALL_PATH)/VERSION; \
+ printf "Version saved to $(INSTALL_PATH)/VERSION\n"; \
+ else \
+ printf "Unable to get version from git describe\n"; \
+ fi
else
$(error Error: set INSTALL_PATH to use install)
endif
--
2.47.1