As noted by John Hubbard the original test relied on side effects of the
implementation of migrate_vma_setup() to detect if pages had been
swapped to disk or not. This is subject to change in future so
explicitly check for swap entries via pagemap instead. Fix a spelling
mistake while we're at it.
Signed-off-by: Alistair Popple <[email protected]>
Fixes: 5cc88e844e87 ("selftests/hmm-tests: add test for dirty bits")
---
tools/testing/selftests/vm/hmm-tests.c | 50 +++++++++++++++++++++++---
1 file changed, 46 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
index 70fdb49b59ed..b5f6a7dc1f12 100644
--- a/tools/testing/selftests/vm/hmm-tests.c
+++ b/tools/testing/selftests/vm/hmm-tests.c
@@ -1261,9 +1261,47 @@ static int destroy_cgroup(void)
return 0;
}
+static uint64_t get_pfn(int fd, uint64_t ptr)
+{
+ uint64_t pfn;
+ int ret;
+
+ ret = pread(fd, &pfn, sizeof(ptr),
+ (uint64_t) ptr / getpagesize() * sizeof(ptr));
+ if (ret != sizeof(ptr))
+ return 0;
+
+ return pfn;
+}
+
+#define PAGEMAP_SWAPPED (1ULL << 62)
+
+/* Returns true if at least one page in the range is on swap */
+static bool pages_swapped(void *ptr, unsigned long pages)
+{
+ uint64_t pfn;
+ int fd = open("/proc/self/pagemap", O_RDONLY);
+ unsigned long i;
+
+ if (fd < 0)
+ return false;
+
+ for (i = 0; i < pages; i++) {
+ pfn = get_pfn(fd, (uint64_t) ptr + i * getpagesize());
+
+ if (pfn & PAGEMAP_SWAPPED) {
+ close(fd);
+ return true;
+ }
+ }
+
+ close(fd);
+ return false;
+}
+
/*
* Try and migrate a dirty page that has previously been swapped to disk. This
- * checks that we don't loose dirty bits.
+ * checks that we don't lose dirty bits.
*/
TEST_F(hmm, migrate_dirty_page)
{
@@ -1300,6 +1338,10 @@ TEST_F(hmm, migrate_dirty_page)
ASSERT_FALSE(write_cgroup_param(cgroup, "memory.reclaim", 1UL<<30));
+ /* Make sure at least some pages got paged to disk. */
+ if (!pages_swapped(buffer->ptr, npages))
+ SKIP(return, "Pages weren't swapped when they should have been");
+
/* Fault pages back in from swap as clean pages */
for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
tmp += ptr[i];
@@ -1309,10 +1351,10 @@ TEST_F(hmm, migrate_dirty_page)
ptr[i] = i;
/*
- * Attempt to migrate memory to device, which should fail because
- * hopefully some pages are backed by swap storage.
+ * Attempt to migrate memory to device. This might fail if some pages
+ * are/were backed by swap but that's ok.
*/
- ASSERT_TRUE(hmm_migrate_sys_to_dev(self->fd, buffer, npages));
+ hmm_migrate_sys_to_dev(self->fd, buffer, npages);
ASSERT_FALSE(write_cgroup_param(cgroup, "memory.reclaim", 1UL<<30));
--
2.35.1
On 13.9.2022 8.22, Alistair Popple wrote:
> As noted by John Hubbard the original test relied on side effects of the
> implementation of migrate_vma_setup() to detect if pages had been
> swapped to disk or not. This is subject to change in future so
> explicitly check for swap entries via pagemap instead. Fix a spelling
> mistake while we're at it.
>
> Signed-off-by: Alistair Popple <[email protected]>
> Fixes: 5cc88e844e87 ("selftests/hmm-tests: add test for dirty bits")
> ---
> tools/testing/selftests/vm/hmm-tests.c | 50 +++++++++++++++++++++++---
> 1 file changed, 46 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
> index 70fdb49b59ed..b5f6a7dc1f12 100644
> --- a/tools/testing/selftests/vm/hmm-tests.c
> +++ b/tools/testing/selftests/vm/hmm-tests.c
> @@ -1261,9 +1261,47 @@ static int destroy_cgroup(void)
> return 0;
> }
>
> +static uint64_t get_pfn(int fd, uint64_t ptr)
> +{
> + uint64_t pfn;
> + int ret;
> +
> + ret = pread(fd, &pfn, sizeof(ptr),
> + (uint64_t) ptr / getpagesize() * sizeof(ptr));
> + if (ret != sizeof(ptr))
> + return 0;
> +
> + return pfn;
> +}
> +
> +#define PAGEMAP_SWAPPED (1ULL << 62)
> +
> +/* Returns true if at least one page in the range is on swap */
> +static bool pages_swapped(void *ptr, unsigned long pages)
> +{
> + uint64_t pfn;
> + int fd = open("/proc/self/pagemap", O_RDONLY);
> + unsigned long i;
> +
> + if (fd < 0)
> + return false;
> +
> + for (i = 0; i < pages; i++) {
> + pfn = get_pfn(fd, (uint64_t) ptr + i * getpagesize());
> +
> + if (pfn & PAGEMAP_SWAPPED) {
> + close(fd);
> + return true;
> + }
> + }
> +
> + close(fd);
> + return false;
> +}
> +
> /*
> * Try and migrate a dirty page that has previously been swapped to disk. This
> - * checks that we don't loose dirty bits.
> + * checks that we don't lose dirty bits.
> */
> TEST_F(hmm, migrate_dirty_page)
> {
> @@ -1300,6 +1338,10 @@ TEST_F(hmm, migrate_dirty_page)
>
> ASSERT_FALSE(write_cgroup_param(cgroup, "memory.reclaim", 1UL<<30));
>
> + /* Make sure at least some pages got paged to disk. */
> + if (!pages_swapped(buffer->ptr, npages))
> + SKIP(return, "Pages weren't swapped when they should have been");
> +
> /* Fault pages back in from swap as clean pages */
> for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
> tmp += ptr[i];
> @@ -1309,10 +1351,10 @@ TEST_F(hmm, migrate_dirty_page)
> ptr[i] = i;
>
> /*
> - * Attempt to migrate memory to device, which should fail because
> - * hopefully some pages are backed by swap storage.
> + * Attempt to migrate memory to device. This might fail if some pages
> + * are/were backed by swap but that's ok.
> */
> - ASSERT_TRUE(hmm_migrate_sys_to_dev(self->fd, buffer, npages));
> + hmm_migrate_sys_to_dev(self->fd, buffer, npages);
>
> ASSERT_FALSE(write_cgroup_param(cgroup, "memory.reclaim", 1UL<<30));
>
Reviewed-by: Mika Penttilä <[email protected]>
David Hildenbrand <[email protected]> writes:
> On 13.09.22 07:22, Alistair Popple wrote:
>> As noted by John Hubbard the original test relied on side effects of the
>> implementation of migrate_vma_setup() to detect if pages had been
>> swapped to disk or not. This is subject to change in future so
>> explicitly check for swap entries via pagemap instead. Fix a spelling
>> mistake while we're at it.
>> Signed-off-by: Alistair Popple <[email protected]>
>> Fixes: 5cc88e844e87 ("selftests/hmm-tests: add test for dirty bits")
>> ---
>> tools/testing/selftests/vm/hmm-tests.c | 50 +++++++++++++++++++++++---
>> 1 file changed, 46 insertions(+), 4 deletions(-)
>> diff --git a/tools/testing/selftests/vm/hmm-tests.c
>> b/tools/testing/selftests/vm/hmm-tests.c
>> index 70fdb49b59ed..b5f6a7dc1f12 100644
>> --- a/tools/testing/selftests/vm/hmm-tests.c
>> +++ b/tools/testing/selftests/vm/hmm-tests.c
>> @@ -1261,9 +1261,47 @@ static int destroy_cgroup(void)
>> return 0;
>> }
>> +static uint64_t get_pfn(int fd, uint64_t ptr)
>> +{
>> + uint64_t pfn;
>> + int ret;
>> +
>> + ret = pread(fd, &pfn, sizeof(ptr),
>> + (uint64_t) ptr / getpagesize() * sizeof(ptr));
>> + if (ret != sizeof(ptr))
>> + return 0;
>> +
>> + return pfn;
>> +}
>> +
>> +#define PAGEMAP_SWAPPED (1ULL << 62)
>> +
>> +/* Returns true if at least one page in the range is on swap */
>> +static bool pages_swapped(void *ptr, unsigned long pages)
>> +{
>> + uint64_t pfn;
>> + int fd = open("/proc/self/pagemap", O_RDONLY);
>> + unsigned long i;
>> +
>> + if (fd < 0)
>> + return false;
>> +
>> + for (i = 0; i < pages; i++) {
>> + pfn = get_pfn(fd, (uint64_t) ptr + i * getpagesize());
>> +
>> + if (pfn & PAGEMAP_SWAPPED) {
>> + close(fd);
>> + return true;
>> + }
>
> We do have pagemap_get_entry() in vm_util.c to query the pagemap entry.
Thanks. I'd missed that, although `grep pagemap
tools/testing/selftests/vm` suggests I'm not the first to follow a
tradition of open-coding this :-)
But there's no need to perpetuate that tradition, so will redo this to
use vm_util.c instead.
> Can you further, add pagemap_is_swapped() to vm_util.c?
>
> I'll be also needing that (including a variant for testing a range) in anon COW
> tests.
On 13.09.22 07:22, Alistair Popple wrote:
> As noted by John Hubbard the original test relied on side effects of the
> implementation of migrate_vma_setup() to detect if pages had been
> swapped to disk or not. This is subject to change in future so
> explicitly check for swap entries via pagemap instead. Fix a spelling
> mistake while we're at it.
>
> Signed-off-by: Alistair Popple <[email protected]>
> Fixes: 5cc88e844e87 ("selftests/hmm-tests: add test for dirty bits")
> ---
> tools/testing/selftests/vm/hmm-tests.c | 50 +++++++++++++++++++++++---
> 1 file changed, 46 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c
> index 70fdb49b59ed..b5f6a7dc1f12 100644
> --- a/tools/testing/selftests/vm/hmm-tests.c
> +++ b/tools/testing/selftests/vm/hmm-tests.c
> @@ -1261,9 +1261,47 @@ static int destroy_cgroup(void)
> return 0;
> }
>
> +static uint64_t get_pfn(int fd, uint64_t ptr)
> +{
> + uint64_t pfn;
> + int ret;
> +
> + ret = pread(fd, &pfn, sizeof(ptr),
> + (uint64_t) ptr / getpagesize() * sizeof(ptr));
> + if (ret != sizeof(ptr))
> + return 0;
> +
> + return pfn;
> +}
> +
> +#define PAGEMAP_SWAPPED (1ULL << 62)
> +
> +/* Returns true if at least one page in the range is on swap */
> +static bool pages_swapped(void *ptr, unsigned long pages)
> +{
> + uint64_t pfn;
> + int fd = open("/proc/self/pagemap", O_RDONLY);
> + unsigned long i;
> +
> + if (fd < 0)
> + return false;
> +
> + for (i = 0; i < pages; i++) {
> + pfn = get_pfn(fd, (uint64_t) ptr + i * getpagesize());
> +
> + if (pfn & PAGEMAP_SWAPPED) {
> + close(fd);
> + return true;
> + }
We do have pagemap_get_entry() in vm_util.c to query the pagemap entry.
Can you further, add pagemap_is_swapped() to vm_util.c?
I'll be also needing that (including a variant for testing a range) in
anon COW tests.
--
Thanks,
David / dhildenb
On 13.09.22 10:20, Alistair Popple wrote:
>
> David Hildenbrand <[email protected]> writes:
>
>> On 13.09.22 07:22, Alistair Popple wrote:
>>> As noted by John Hubbard the original test relied on side effects of the
>>> implementation of migrate_vma_setup() to detect if pages had been
>>> swapped to disk or not. This is subject to change in future so
>>> explicitly check for swap entries via pagemap instead. Fix a spelling
>>> mistake while we're at it.
>>> Signed-off-by: Alistair Popple <[email protected]>
>>> Fixes: 5cc88e844e87 ("selftests/hmm-tests: add test for dirty bits")
>>> ---
>>> tools/testing/selftests/vm/hmm-tests.c | 50 +++++++++++++++++++++++---
>>> 1 file changed, 46 insertions(+), 4 deletions(-)
>>> diff --git a/tools/testing/selftests/vm/hmm-tests.c
>>> b/tools/testing/selftests/vm/hmm-tests.c
>>> index 70fdb49b59ed..b5f6a7dc1f12 100644
>>> --- a/tools/testing/selftests/vm/hmm-tests.c
>>> +++ b/tools/testing/selftests/vm/hmm-tests.c
>>> @@ -1261,9 +1261,47 @@ static int destroy_cgroup(void)
>>> return 0;
>>> }
>>> +static uint64_t get_pfn(int fd, uint64_t ptr)
>>> +{
>>> + uint64_t pfn;
>>> + int ret;
>>> +
>>> + ret = pread(fd, &pfn, sizeof(ptr),
>>> + (uint64_t) ptr / getpagesize() * sizeof(ptr));
>>> + if (ret != sizeof(ptr))
>>> + return 0;
>>> +
>>> + return pfn;
>>> +}
>>> +
>>> +#define PAGEMAP_SWAPPED (1ULL << 62)
>>> +
>>> +/* Returns true if at least one page in the range is on swap */
>>> +static bool pages_swapped(void *ptr, unsigned long pages)
>>> +{
>>> + uint64_t pfn;
>>> + int fd = open("/proc/self/pagemap", O_RDONLY);
>>> + unsigned long i;
>>> +
>>> + if (fd < 0)
>>> + return false;
>>> +
>>> + for (i = 0; i < pages; i++) {
>>> + pfn = get_pfn(fd, (uint64_t) ptr + i * getpagesize());
>>> +
>>> + if (pfn & PAGEMAP_SWAPPED) {
>>> + close(fd);
>>> + return true;
>>> + }
>>
>> We do have pagemap_get_entry() in vm_util.c to query the pagemap entry.
>
> Thanks. I'd missed that, although `grep pagemap
> tools/testing/selftests/vm` suggests I'm not the first to follow a
> tradition of open-coding this :-)
>
> But there's no need to perpetuate that tradition, so will redo this to
> use vm_util.c instead.
Yeah, we just recently factored stuff out into there. I'll be factoring
out more in my upcoming tests from the madv_populate tests.
--
Thanks,
David / dhildenb