If PAGE_SIZE is larger than 4k and if you have a system with a large number of CPUs, this test can require a very large amount of memory leading to oom-killer firing. Given the type of allocation, the kernel won't have anything to kill, causing the system to stall. Add a parameter to the test_vmalloc driver to represent the number of times a percpu object will be allocated. Calculate this in test_vmalloc.sh to be 90% of available memory or the current default of 35000, whichever is smaller.

Signed-off-by: Audra Mitchell audra@redhat.com --- lib/test_vmalloc.c | 11 +++++--- tools/testing/selftests/mm/test_vmalloc.sh | 31 +++++++++++++++++++--- 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c index 2815658ccc37..67e53cd6b619 100644 --- a/lib/test_vmalloc.c +++ b/lib/test_vmalloc.c @@ -57,6 +57,9 @@ __param(int, run_test_mask, 7, /* Add a new test case description here. */ );

+__param(int, nr_pcpu_objects, 35000, + "Number of pcpu objects to allocate for pcpu_alloc_test"); + /* * This is for synchronization of setup phase. */ @@ -292,24 +295,24 @@ pcpu_alloc_test(void) size_t size, align; int i;

- pcpu = vmalloc(sizeof(void __percpu *) * 35000); + pcpu = vmalloc(sizeof(void __percpu *) * nr_pcpu_objects); if (!pcpu) return -1;

- for (i = 0; i < 35000; i++) { + for (i = 0; i < nr_pcpu_objects; i++) { size = get_random_u32_inclusive(1, PAGE_SIZE / 4);

/* * Maximum PAGE_SIZE */ - align = 1 << get_random_u32_inclusive(1, 11); + align = 1 << get_random_u32_inclusive(1, PAGE_SHIFT - 1);

pcpu[i] = __alloc_percpu(size, align); if (!pcpu[i]) rv = -1; }

- for (i = 0; i < 35000; i++) + for (i = 0; i < nr_pcpu_objects; i++) free_percpu(pcpu[i]);

vfree(pcpu); diff --git a/tools/testing/selftests/mm/test_vmalloc.sh b/tools/testing/selftests/mm/test_vmalloc.sh index d39096723fca..b23d705bf570 100755 --- a/tools/testing/selftests/mm/test_vmalloc.sh +++ b/tools/testing/selftests/mm/test_vmalloc.sh @@ -13,6 +13,9 @@ TEST_NAME="vmalloc" DRIVER="test_${TEST_NAME}" NUM_CPUS=`grep -c ^processor /proc/cpuinfo`

+# Default number of times we allocate percpu objects: +NR_PCPU_OBJECTS=35000 + # 1 if fails exitcode=1

@@ -27,6 +30,8 @@ PERF_PARAM="sequential_test_order=1 test_repeat_count=3" SMOKE_PARAM="test_loop_count=10000 test_repeat_count=10" STRESS_PARAM="nr_threads=$NUM_CPUS test_repeat_count=20"

+PCPU_OBJ_PARAM="nr_pcpu_objects=$NR_PCPU_OBJECTS" + check_test_requirements() { uid=$(id -u) @@ -47,12 +52,30 @@ check_test_requirements() fi }

+check_memory_requirement() +{ + # The pcpu_alloc_test allocates nr_pcpu_objects per cpu. If the + # PAGE_SIZE is on the larger side it is easier to set a value + # that can cause oom events during testing. Since we are + # testing the functionality of vmalloc and not the oom-killer, + # calculate what is 90% of available memory and divide it by + # the number of online CPUs. + pages=$(($(getconf _AVPHYS_PAGES) * 90 / 100 / $NUM_CPUS)) + + if (($pages < $NR_PCPU_OBJECTS)); then + echo "Updated nr_pcpu_objects to 90% of available memory." + echo "nr_pcpu_objects is now set to: $pages." + PCPU_OBJ_PARAM="nr_pcpu_objects=$pages" + fi +} + run_performance_check() { echo "Run performance tests to evaluate how fast vmalloc allocation is." echo "It runs all test cases on one single CPU with sequential order."

- modprobe $DRIVER $PERF_PARAM > /dev/null 2>&1 + check_memory_requirement + modprobe $DRIVER $PERF_PARAM $PCPU_OBJ_PARAM > /dev/null 2>&1 echo "Done." echo "Check the kernel message buffer to see the summary." } @@ -63,7 +86,8 @@ run_stability_check() echo "available test cases are run by NUM_CPUS workers simultaneously." echo "It will take time, so be patient."

- modprobe $DRIVER $STRESS_PARAM > /dev/null 2>&1 + check_memory_requirement + modprobe $DRIVER $STRESS_PARAM $PCPU_OBJ_PARAM > /dev/null 2>&1 echo "Done." echo "Check the kernel ring buffer to see the summary." } @@ -74,7 +98,8 @@ run_smoke_check() echo "Please check $0 output how it can be used" echo "for deep performance analysis as well as stress testing."

- modprobe $DRIVER $SMOKE_PARAM > /dev/null 2>&1 + check_memory_requirement + modprobe $DRIVER $SMOKE_PARAM $PCPU_OBJ_PARAM > /dev/null 2>&1 echo "Done." echo "Check the kernel ring buffer to see the summary." }