From a98ec863fdedf4940447f32ceda7d937bebd06a2 Mon Sep 17 00:00:00 2001 From: Audra Mitchell Date: Mon, 1 Dec 2025 13:18:48 -0500 Subject: lib/test_vmalloc.c: minor fixes to test_vmalloc.c 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. Link: https://lkml.kernel.org/r/20251201181848.1216197-1-audra@redhat.com Signed-off-by: Audra Mitchell Reviewed-by: Andrew Morton Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Rafael Aquini Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: "Uladzislau Rezki (Sony)" Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/test_vmalloc.sh | 31 +++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) (limited to 'tools') 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." } -- cgit v1.2.3