Commit ab00ddd8 authored by Feng Tang's avatar Feng Tang Committed by Andrew Morton
Browse files

selftests/mm: compaction_test: support platform with huge mount of memory 

When running mm selftest to verify mm patches, 'compaction_test' case
failed on an x86 server with 1TB memory.  And the root cause is that it
has too much free memory than what the test supports.

The test case tries to allocate 100000 huge pages, which is about 200 GB
for that x86 server, and when it succeeds, it expects it's large than 1/3
of 80% of the free memory in system.  This logic only works for platform
with 750 GB ( 200 / (1/3) / 80% ) or less free memory, and may raise false
alarm for others.

Fix it by changing the fixed page number to self-adjustable number
according to the real number of free memory.

Link: https://lkml.kernel.org/r/20250423103645.2758-1-feng.tang@linux.alibaba.com


Fixes: bd67d5c1 ("Test compaction of mlocked memory")
Signed-off-by: default avatarFeng Tang <feng.tang@linux.alibaba.com>
Acked-by: default avatarDev Jain <dev.jain@arm.com>
Reviewed-by: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: default avatarBaolin Wang <baolin.wang@inux.alibaba.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Sri Jayaramappa <sjayaram@akamai.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a47694ec

tools/testing/selftests/mm/compaction_test.c

+14 −5
Original line number Diff line number Diff line
@@ -90,6 +90,8 @@ int check_compaction(unsigned long mem_free, unsigned long hugepage_size, 
	int compaction_index = 0;

	char nr_hugepages[20] = {0};

	char init_nr_hugepages[24] = {0};

	char target_nr_hugepages[24] = {0};

	int slen;



	snprintf(init_nr_hugepages, sizeof(init_nr_hugepages),

		 "%lu", initial_nr_hugepages);
@@ -106,11 +108,18 @@ int check_compaction(unsigned long mem_free, unsigned long hugepage_size, 
		goto out;

	}



	/* Request a large number of huge pages. The Kernel will allocate

	   as much as it can */

	if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) {

		ksft_print_msg("Failed to write 100000 to /proc/sys/vm/nr_hugepages: %s\n",

			       strerror(errno));

	/*

	 * Request huge pages for about half of the free memory. The Kernel

	 * will allocate as much as it can, and we expect it will get at least 1/3

	 */

	nr_hugepages_ul = mem_free / hugepage_size / 2;

	snprintf(target_nr_hugepages, sizeof(target_nr_hugepages),

		 "%lu", nr_hugepages_ul);



	slen = strlen(target_nr_hugepages);

	if (write(fd, target_nr_hugepages, slen) != slen) {

		ksft_print_msg("Failed to write %lu to /proc/sys/vm/nr_hugepages: %s\n",

			       nr_hugepages_ul, strerror(errno));

		goto close_fd;

	}