When running test_kmod.sh the following shows up
# sysctl cannot stat /proc/sys/net/core/bpf_jit_enable No such file or directory
cannot: stat_/proc/sys/net/core/bpf_jit_enable #
# sysctl cannot stat /proc/sys/net/core/bpf_jit_harden No such file or directory
cannot: stat_/proc/sys/net/core/bpf_jit_harden #
Rework to enable CONFIG_BPF_JIT to solve "No such file or directory"
Signed-off-by: Anders Roxell <anders.roxell(a)linaro.org>
---
tools/testing/selftests/bpf/config | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index f7a0744db31e..5dc109f4c097 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -34,3 +34,4 @@ CONFIG_NET_MPLS_GSO=m
CONFIG_MPLS_ROUTING=m
CONFIG_MPLS_IPTUNNEL=m
CONFIG_IPV6_SIT=m
+CONFIG_BPF_JIT=y
--
2.20.1
## TL;DR
This revision addresses comments from Stephen and Bjorn Helgaas. Most
changes are pretty minor stuff that doesn't affect the API in anyway.
One significant change, however, is that I added support for freeing
kunit_resource managed resources before the test case is finished via
kunit_resource_destroy(). Additionally, Bjorn pointed out that I broke
KUnit on certain configurations (like the default one for x86, whoops).
Based on Stephen's feedback on the previous change, I think we are
pretty close. I am not expecting any significant changes from here on
out.
## Background
This patch set proposes KUnit, a lightweight unit testing and mocking
framework for the Linux kernel.
Unlike Autotest and kselftest, KUnit is a true unit testing framework;
it does not require installing the kernel on a test machine or in a VM
(however, KUnit still allows you to run tests on test machines or in VMs
if you want[1]) and does not require tests to be written in userspace
running on a host kernel. Additionally, KUnit is fast: From invocation
to completion KUnit can run several dozen tests in about a second.
Currently, the entire KUnit test suite for KUnit runs in under a second
from the initial invocation (build time excluded).
KUnit is heavily inspired by JUnit, Python's unittest.mock, and
Googletest/Googlemock for C++. KUnit provides facilities for defining
unit test cases, grouping related test cases into test suites, providing
common infrastructure for running tests, mocking, spying, and much more.
### What's so special about unit testing?
A unit test is supposed to test a single unit of code in isolation,
hence the name. There should be no dependencies outside the control of
the test; this means no external dependencies, which makes tests orders
of magnitudes faster. Likewise, since there are no external dependencies,
there are no hoops to jump through to run the tests. Additionally, this
makes unit tests deterministic: a failing unit test always indicates a
problem. Finally, because unit tests necessarily have finer granularity,
they are able to test all code paths easily solving the classic problem
of difficulty in exercising error handling code.
### Is KUnit trying to replace other testing frameworks for the kernel?
No. Most existing tests for the Linux kernel are end-to-end tests, which
have their place. A well tested system has lots of unit tests, a
reasonable number of integration tests, and some end-to-end tests. KUnit
is just trying to address the unit test space which is currently not
being addressed.
### More information on KUnit
There is a bunch of documentation near the end of this patch set that
describes how to use KUnit and best practices for writing unit tests.
For convenience I am hosting the compiled docs here[2].
Additionally for convenience, I have applied these patches to a
branch[3]. The repo may be cloned with:
git clone https://kunit.googlesource.com/linux
This patchset is on the kunit/rfc/v5.3/v13 branch.
## Changes Since Last Version
- Added support for freeing kunit_resources (KUnit managed resources)
via kunit_resource_destroy() as suggested by Stephen.
- Promoted WARN() after __noreturn function to BUG() in
"[PATCH v13 09/18] kunit: test: add support for test abort" as
suggested by Stephen.
- Dropped concept of death test since I am not actually using it yet as
pointed out by Stephen.
- Replaced usage of warn_slowpath_fmt with WARN in kunit_do_assertion
since warn_slowpath_fmt is not available on some build configurations,
as pointed out by Bjorn.
- Lots of other minor changes suggested by Stephen.
[1] https://google.github.io/kunit-docs/third_party/kernel/docs/usage.html#kuni…
[2] https://google.github.io/kunit-docs/third_party/kernel/docs/
[3] https://kunit.googlesource.com/linux/+/kunit/rfc/v5.3/v13
--
2.23.0.rc1.153.gdeed80330f-goog
Problem:
Currently tasks attempting to allocate more hugetlb memory than is available get
a failure at mmap/shmget time. This is thanks to Hugetlbfs Reservations [1].
However, if a task attempts to allocate hugetlb memory only more than its
hugetlb_cgroup limit allows, the kernel will allow the mmap/shmget call,
but will SIGBUS the task when it attempts to fault the memory in.
We have developers interested in using hugetlb_cgroups, and they have expressed
dissatisfaction regarding this behavior. We'd like to improve this
behavior such that tasks violating the hugetlb_cgroup limits get an error on
mmap/shmget time, rather than getting SIGBUS'd when they try to fault
the excess memory in.
The underlying problem is that today's hugetlb_cgroup accounting happens
at hugetlb memory *fault* time, rather than at *reservation* time.
Thus, enforcing the hugetlb_cgroup limit only happens at fault time, and
the offending task gets SIGBUS'd.
Proposed Solution:
A new page counter named hugetlb.xMB.reservation_[limit|usage]_in_bytes. This
counter has slightly different semantics than
hugetlb.xMB.[limit|usage]_in_bytes:
- While usage_in_bytes tracks all *faulted* hugetlb memory,
reservation_usage_in_bytes tracks all *reserved* hugetlb memory.
- If a task attempts to reserve more memory than limit_in_bytes allows,
the kernel will allow it to do so. But if a task attempts to reserve
more memory than reservation_limit_in_bytes, the kernel will fail this
reservation.
This proposal is implemented in this patch, with tests to verify
functionality and show the usage.
Alternatives considered:
1. A new cgroup, instead of only a new page_counter attached to
the existing hugetlb_cgroup. Adding a new cgroup seemed like a lot of code
duplication with hugetlb_cgroup. Keeping hugetlb related page counters under
hugetlb_cgroup seemed cleaner as well.
2. Instead of adding a new counter, we considered adding a sysctl that modifies
the behavior of hugetlb.xMB.[limit|usage]_in_bytes, to do accounting at
reservation time rather than fault time. Adding a new page_counter seems
better as userspace could, if it wants, choose to enforce different cgroups
differently: one via limit_in_bytes, and another via
reservation_limit_in_bytes. This could be very useful if you're
transitioning how hugetlb memory is partitioned on your system one
cgroup at a time, for example. Also, someone may find usage for both
limit_in_bytes and reservation_limit_in_bytes concurrently, and this
approach gives them the option to do so.
Caveats:
1. This support is implemented for cgroups-v1. I have not tried
hugetlb_cgroups with cgroups v2, and AFAICT it's not supported yet.
This is largely because we use cgroups-v1 for now. If required, I
can add hugetlb_cgroup support to cgroups v2 in this patch or
a follow up.
2. Most complicated bit of this patch I believe is: where to store the
pointer to the hugetlb_cgroup to uncharge at unreservation time?
Normally the cgroup pointers hang off the struct page. But, with
hugetlb_cgroup reservations, one task can reserve a specific page and another
task may fault it in (I believe), so storing the pointer in struct
page is not appropriate. Proposed approach here is to store the pointer in
the resv_map. See patch for details.
Signed-off-by: Mina Almasry <almasrymina(a)google.com>
[1]: https://www.kernel.org/doc/html/latest/vm/hugetlbfs_reserv.html
Changes in v2:
- Split the patch into a 5 patch series.
- Fixed patch subject.
Mina Almasry (5):
hugetlb_cgroup: Add hugetlb_cgroup reservation counter
hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations
hugetlb_cgroup: add reservation accounting for private mappings
hugetlb_cgroup: add accounting for shared mappings
hugetlb_cgroup: Add hugetlb_cgroup reservation tests
include/linux/hugetlb.h | 10 +-
include/linux/hugetlb_cgroup.h | 19 +-
mm/hugetlb.c | 256 ++++++++--
mm/hugetlb_cgroup.c | 153 +++++-
tools/testing/selftests/vm/.gitignore | 1 +
tools/testing/selftests/vm/Makefile | 4 +
.../selftests/vm/charge_reserved_hugetlb.sh | 438 ++++++++++++++++++
.../selftests/vm/write_hugetlb_memory.sh | 22 +
.../testing/selftests/vm/write_to_hugetlbfs.c | 252 ++++++++++
9 files changed, 1087 insertions(+), 68 deletions(-)
create mode 100755 tools/testing/selftests/vm/charge_reserved_hugetlb.sh
create mode 100644 tools/testing/selftests/vm/write_hugetlb_memory.sh
create mode 100644 tools/testing/selftests/vm/write_to_hugetlbfs.c
--
2.23.0.rc1.153.gdeed80330f-goog
When running tcp_fastopen_backup_key.sh the following issue was seen in
a busybox environment.
./tcp_fastopen_backup_key.sh: line 33: [: -ne: unary operator expected
Shellcheck showed the following issue.
$ shellcheck tools/testing/selftests/net/tcp_fastopen_backup_key.sh
In tools/testing/selftests/net/tcp_fastopen_backup_key.sh line 33:
if [ $val -ne 0 ]; then
^-- SC2086: Double quote to prevent globbing and word splitting.
Rework to do a string comparison instead.
Signed-off-by: Anders Roxell <anders.roxell(a)linaro.org>
---
tools/testing/selftests/net/tcp_fastopen_backup_key.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
index 41476399e184..f6e65674b83c 100755
--- a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
+++ b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
@@ -30,7 +30,7 @@ do_test() {
ip netns exec "${NETNS}" ./tcp_fastopen_backup_key "$1"
val=$(ip netns exec "${NETNS}" nstat -az | \
grep TcpExtTCPFastOpenPassiveFail | awk '{print $2}')
- if [ $val -ne 0 ]; then
+ if [ "$val" != 0 ]; then
echo "FAIL: TcpExtTCPFastOpenPassiveFail non-zero"
return 1
fi
--
2.20.1
When running tcp_fastopen_backup_key.sh the following issue was seen in
a busybox environment.
./tcp_fastopen_backup_key.sh: line 33: [: -ne: unary operator expected
Shellcheck showed the following issue.
$ shellcheck tools/testing/selftests/net/tcp_fastopen_backup_key.sh
In tools/testing/selftests/net/tcp_fastopen_backup_key.sh line 33:
if [ $val -ne 0 ]; then
^-- SC2086: Double quote to prevent globbing and word splitting.
Rework to add double quotes around the variable 'val' that shellcheck
recommends.
Signed-off-by: Anders Roxell <anders.roxell(a)linaro.org>
---
tools/testing/selftests/net/tcp_fastopen_backup_key.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
index 41476399e184..ba5ec3eb314e 100755
--- a/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
+++ b/tools/testing/selftests/net/tcp_fastopen_backup_key.sh
@@ -30,7 +30,7 @@ do_test() {
ip netns exec "${NETNS}" ./tcp_fastopen_backup_key "$1"
val=$(ip netns exec "${NETNS}" nstat -az | \
grep TcpExtTCPFastOpenPassiveFail | awk '{print $2}')
- if [ $val -ne 0 ]; then
+ if [ "$val" -ne 0 ]; then
echo "FAIL: TcpExtTCPFastOpenPassiveFail non-zero"
return 1
fi
--
2.20.1