Re: [PATCH i-g-t v6 4/9] tests/intel/xe_madvise: Add purged-mmap-blocked subtest

Yadav, Arvind
2026-04-07T05:09:54Z

On 06-04-2026 18:04, Sharma, Nishit wrote:
>
> On 3/25/2026 6:14 PM, Arvind Yadav wrote:
>> Add a new purged-mmap-blocked subtest that triggers an actual purge
>> via memory pressure and verifies that mmap() fails with -EINVAL once
>> the BO backing store has been permanently discarded.
>>
>> The purgeable check moved from xe_gem_mmap_offset_ioctl()
>> into a new xe_gem_object_mmap() callback, so the blocking point is now
>> mmap() itself rather than the mmap offset ioctl:
>>
>>    - DRM_IOCTL_XE_GEM_MMAP_OFFSET: always succeeds regardless of
>>      purgeable state (just returns the pre-allocated offset)
>>    - mmap() on DONTNEED BO: fails with -EBUSY (temporary state)
>>    - mmap() on purged BO: fails with -EINVAL (permanent, no backing
>> store)
>>
>> v5:
>>    - Add purged-mmap-blocked subtest to verify mmap is blocked after
>>      BO backing store is permanently purged.
>>
>> v6:
>>    - DRM_IOCTL_XE_GEM_MMAP_OFFSET always succeeds; the purgeable check
>>      now happens in xe_gem_object_mmap() at mmap() time. For purged BOs,
>>      assert mmap() fails with -EINVAL.
>>
>> Cc: Nishit Sharma <nishit.sharma@intel.com>
>> Cc: Matthew Brost <matthew.brost@intel.com>
>> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
>> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
>> Cc: Pravalika Gurram <pravalika.gurram@intel.com>
>> Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
>> ---
>>   tests/intel/xe_madvise.c | 42 ++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 42 insertions(+)
>>
>> diff --git a/tests/intel/xe_madvise.c b/tests/intel/xe_madvise.c
>> index de4a6e34c..81e05b6d4 100644
>> --- a/tests/intel/xe_madvise.c
>> +++ b/tests/intel/xe_madvise.c
>> @@ -170,6 +170,42 @@ static void purgeable_setup_simple_bo(int fd,
>> uint32_t *vm, uint32_t *bo,
>>       xe_wait_ufence(fd, &sync_val, 1, 0, NSEC_PER_SEC);
>>   }
>>   +/**
>> + * SUBTEST: purged-mmap-blocked
>> + * Description: After BO is purged, verify mmap() fails with -EINVAL
>> + * Test category: functionality test
>> + */
>> +static void test_purged_mmap_blocked(int fd)
>> +{
>> +    uint32_t bo, vm;
>> +    uint64_t addr = PURGEABLE_ADDR;
>> +    size_t bo_size = PURGEABLE_BO_SIZE;
>> +    struct drm_xe_gem_mmap_offset mmo = {};
>> +    void *ptr;
>> +
>> +    purgeable_setup_simple_bo(fd, &vm, &bo, addr, bo_size, false);
>> +    if (!purgeable_mark_and_verify_purged(fd, vm, addr, bo_size)) {
>
> This function should be defined in this patch. Going through
> implementation available in Patch-3/9. In that below code used
>
>     vram_size = xe_visible_vram_size(fd, 0);
>
> What it returns in igfx platforms? Instead we can use
>
> /* Purgeable BO either in VRAM or SMEM */
> mem_size = xe_has_vram(pf_fd)?xe_visible_vram_size(fd,
> 0):igt_get_total_ram_mb() << 20;

Agreed — using xe_has_vram() is more explicit. Will switch to this.

> if (vram_size > 0) {
>                 /* dGPU: pressure VRAM to trigger purgeable reclaim */
>                 mem_size = vram_size;
>         } else {
>                 /*
>                  * iGPU: purgeable BOs reside in system memory. Use
> *total*
>                  * RAM (not just available) as the baseline so that we
> always
>                  * over-commit regardless of how much is already in use.
>                  */
>                 mem_size = igt_get_total_ram_mb() << 20;
>         }
>
>> +        gem_close(fd, bo);
>> +        xe_vm_destroy(fd, vm);
>> +        igt_skip("Unable to induce purge on this platform/config");
>> +    }
> static bool purgeable_mark_and_verify_purged(int fd, uint32_t vm,
> uint64_t addr, size_t size) --> this should be part of this patch
> {
>         uint32_t retained;
>
>         /* Mark as DONTNEED */
>         retained = xe_vm_madvise_purgeable(fd, vm, addr, size,
>  DRM_XE_VMA_PURGEABLE_STATE_DONTNEED);
>
>         if (retained != 1)
>
> So here if BO was purged after above call it'll return 0, so if (0 !=
> 1) will be true and it'll return false.

You're right — if the BO is already purged when we mark DONTNEED
(retained == 0), the function incorrectly returns false, causing the
test to skip. Will fix to treat retained == 0 from DONTNEED as already
purged and return true.

>
>                 return false;
>
>         /* Trigger memory pressure */
>         trigger_memory_pressure(fd, vm);
>
>         /* Verify purged */
>         retained = xe_vm_madvise_purgeable(fd, vm, addr, size,
>  DRM_XE_VMA_PURGEABLE_STATE_WILLNEED);
>         return retained == 0;
>
> }
>
> static void test_purged_mmap_blocked(int fd)
> {
>         uint32_t bo, vm;
>         uint64_t addr = PURGEABLE_ADDR;
>         size_t bo_size = PURGEABLE_BO_SIZE;
>         struct drm_xe_gem_mmap_offset mmo = {};
>         void *ptr;
>
>         purgeable_setup_simple_bo(fd, &vm, &bo, addr, bo_size, false);
>         if (!purgeable_mark_and_verify_purged(fd, vm, addr, bo_size)) {
>
> Here if returned false from above which is basically if BO was purged
> retained  = 0 then skip is called which is not the intention

Noted,

Thanks,
Arvind

>         gem_close(fd, bo);
>                 xe_vm_destroy(fd, vm);
>                 igt_skip("Unable to induce purge on this
> platform/config");
>         }
>
>         /*
>          * Getting the mmap offset is always allowed regardless of
> purgeable
>          * state - the blocking happens at mmap() time
> (xe_gem_object_mmap).
>          * For a purged BO, mmap() must fail with -EINVAL (no backing
> store).
>          */
>         mmo.handle = bo;
>         igt_assert_eq(igt_ioctl(fd, DRM_IOCTL_XE_GEM_MMAP_OFFSET,
> &mmo), 0);
>
>         ptr = mmap(NULL, bo_size, PROT_READ | PROT_WRITE, MAP_SHARED,
> fd, mmo.offset);
>         igt_assert_eq_u64((uint64_t)ptr, (uint64_t)MAP_FAILED);
>         igt_assert_eq(errno, EINVAL);
>
>         gem_close(fd, bo);
>         xe_vm_destroy(fd, vm);
> }
>
>
>> +
>> +    /*
>> +     * Getting the mmap offset is always allowed regardless of
>> purgeable
>> +     * state - the blocking happens at mmap() time
>> (xe_gem_object_mmap).
>> +     * For a purged BO, mmap() must fail with -EINVAL (no backing
>> store).
>> +     */
>> +    mmo.handle = bo;
>> +    igt_assert_eq(igt_ioctl(fd, DRM_IOCTL_XE_GEM_MMAP_OFFSET, &mmo),
>> 0);
>> +
>> +    ptr = mmap(NULL, bo_size, PROT_READ | PROT_WRITE, MAP_SHARED,
>> fd, mmo.offset);
>> +    igt_assert_eq_u64((uint64_t)ptr, (uint64_t)MAP_FAILED);
>> +    igt_assert_eq(errno, EINVAL);
>> +
>> +    gem_close(fd, bo);
>> +    xe_vm_destroy(fd, vm);
>> +}
>> +
>>   /**
>>    * SUBTEST: dontneed-before-mmap
>>    * Description: Mark BO as DONTNEED before mmap, verify mmap()
>> fails with -EBUSY
>> @@ -226,6 +262,12 @@ int igt_main()
>>               break;
>>           }
>>   +    igt_subtest("purged-mmap-blocked")
>> +        xe_for_each_engine(fd, hwe) {
>> +            test_purged_mmap_blocked(fd);
>> +            break;
>> +        }
>> +
>>       igt_fixture() {
>>           xe_device_put(fd);
>>           drm_close_driver(fd);