Commit a98ec863 authored by Audra Mitchell's avatar Audra Mitchell Committed by Andrew Morton
Browse files

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: default avatarAudra Mitchell <audra@redhat.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent bd4526e6

lib/test_vmalloc.c

+7 −4
Original line number Diff line number Diff line
@@ -58,6 +58,9 @@ __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.

 */
@@ -317,24 +320,24 @@ 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);

tools/testing/selftests/mm/test_vmalloc.sh

+28 −3
Original line number Diff line number Diff line
@@ -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."

}