2021-07-01 16:06:32

by Christian Borntraeger

Subject: [PATCH] KVM: selftests: do not require 64GB in set_memory_region_test

Unless the user sets overcommit_memory or has plenty of swap, the latest
changes to the testcase will result in ENOMEM failures for hosts with
less than 64GB RAM. As we do not use much of the allocated memory, we
can use MAP_NORESERVE to avoid this error.

Cc: Zenghui Yu <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Fixes: 309505dd5685 ("KVM: selftests: Fix mapping length truncation in m{,un}map()")
Signed-off-by: Christian Borntraeger <[email protected]>
---
tools/testing/selftests/kvm/set_memory_region_test.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
index d8812f27648c..d31f54ac4e98 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -377,7 +377,8 @@ static void test_add_max_memory_regions(void)
(max_mem_slots - 1), MEM_REGION_SIZE >> 10);

mem = mmap(NULL, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment,
- PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
mem_aligned = (void *)(((size_t) mem + alignment - 1) & ~(alignment - 1));

--
2.31.1

2021-07-02 06:51:00

by Zenghui Yu

Subject: Re: [PATCH] KVM: selftests: do not require 64GB in set_memory_region_test

On 2021/7/2 0:04, Christian Borntraeger wrote:
> Unless the user sets overcommit_memory or has plenty of swap, the latest
> changes to the testcase will result in ENOMEM failures for hosts with
> less than 64GB RAM. As we do not use much of the allocated memory, we
> can use MAP_NORESERVE to avoid this error.

Had a go on arm64:

Tested-by: Zenghui Yu <[email protected]>

Thanks,
Zenghui