The overcommit test uses sum_total, the sum (memory and swap) to test the overcommit settings.
This fixes two problems on 32-bit systems. The first is seen with a integer overflow can occur when calculating sum_total * 2, if the sum_total is larger than 2GB. The second is limited virtual address space (2-3GB) means the test can fail from address space exhaustion before overcommit has been tested.
Now the test runs correctly on low-memory 32-bit systems while avoiding both the overflow bug and virtual address space issues.
Signed-off-by: Ben Copeland ben.copeland@linaro.org Acked-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Petr Vorel pvorel@suse.cz --- .../kernel/mem/tunable/overcommit_memory.c | 33 +++++++++++++++---- 1 file changed, 27 insertions(+), 6 deletions(-)
diff --git a/testcases/kernel/mem/tunable/overcommit_memory.c b/testcases/kernel/mem/tunable/overcommit_memory.c index 9b2cb479d..7ff5a98d0 100644 --- a/testcases/kernel/mem/tunable/overcommit_memory.c +++ b/testcases/kernel/mem/tunable/overcommit_memory.c @@ -131,24 +131,45 @@ static void overcommit_memory_test(void) TST_SYS_CONF_LONG_SET(OVERCOMMIT_MEMORY, 2, 1);
update_mem_commit(); - alloc_and_check(commit_left * 2, EXPECT_FAIL); - alloc_and_check(commit_limit + total_batch_size, EXPECT_FAIL); + /* Skip tests that would overflow or exceed 32-bit address space */ + if (tst_kernel_bits() == 64 || (unsigned long)commit_left <= TST_GB / TST_KB) { + alloc_and_check(commit_left * 2, EXPECT_FAIL); + alloc_and_check(commit_limit + total_batch_size, EXPECT_FAIL); + } else { + tst_res(TCONF, "Skipping large allocation tests due to address space limits"); + } update_mem_commit(); - alloc_and_check(commit_left / 2, EXPECT_PASS); + if (tst_kernel_bits() == 64 || (unsigned long)commit_left <= TST_GB / TST_KB) { + alloc_and_check(commit_left / 2, EXPECT_PASS); + } else { + tst_res(TCONF, "Skipping commit_left/2 allocation test due to address space limits"); + }
/* start to test overcommit_memory=0 */ TST_SYS_CONF_LONG_SET(OVERCOMMIT_MEMORY, 0, 1);
update_mem(); alloc_and_check(free_total / 2, EXPECT_PASS); - alloc_and_check(sum_total * 2, EXPECT_FAIL); + /* Skip if sum_total * 2 would exceed address space. + * On 32-bit, skip when sum_total > ULONG_MAX/4 (~1GB). + * Most 32-bit systems with <=1GB RAM can map 2x that in 3GB vaddr space. + * Systems with 2GB+ RAM likely cannot fit allocations in vaddr space. */ + if (tst_kernel_bits() == 64 || (unsigned long)sum_total <= TST_GB / TST_KB) { + alloc_and_check(sum_total * 2, EXPECT_FAIL); + } else { + tst_res(TCONF, "Skipping large allocation test due to address space limits"); + }
/* start to test overcommit_memory=1 */ TST_SYS_CONF_LONG_SET(OVERCOMMIT_MEMORY, 1, 1);
alloc_and_check(sum_total / 2, EXPECT_PASS); - alloc_and_check(sum_total, EXPECT_PASS); - alloc_and_check(sum_total * 2, EXPECT_PASS); + if (tst_kernel_bits() == 64 || (unsigned long)sum_total <= TST_GB / TST_KB) { + alloc_and_check(sum_total, EXPECT_PASS); + alloc_and_check(sum_total * 2, EXPECT_PASS); + } else { + tst_res(TCONF, "Skipping large allocation tests due to address space limits"); + }
}