Re: [PATCH i-g-t v6 3/9] tests/intel/xe_madvise: Add dontneed-before-mmap subtest

["Yadav, Arvind" <arvind.yadav@intel.com>]

On 06-04-2026 16:00, Sharma, Nishit wrote:
>
> On 4/6/2026 3:23 PM, Sharma, Nishit wrote:
>>
>> On 3/25/2026 6:14 PM, Arvind Yadav wrote:
>>> This test validates that mmap() fails with -EBUSY when attempting to
>>> map a BO marked DONTNEED. The mmap offset ioctl succeeds (it just
>>> returns the pre-allocated offset); the purgeable check happens in
>>> xe_gem_object_mmap() at mmap() time.
>>>
>>>    - DONTNEED BOs: return -EBUSY (temporary purgeable state, BO still
>>>      has backing store but can be purged at any time)
>>>    - Purged BOs: return -EINVAL (permanent, backing store discarded)
>>>
>>> v4:
>>>    - Move unmap outside the block. (Pravalika)
>>>    - Added proper resource cleanup before calling igt_skip(). (Nishit)
>>>    - Added assertion for xe_bo_map. (Nishit)
>>>
>>> v5:
>>>    - Add kernel capability check *_FLAG_HAS_PURGING_SUPPORT for
>>>      purgeable support. (Jose)
>>>    - Drop memory pressure trigger path; mark DONTNEED directly and
>>>      assert -EBUSY from mmap offset ioctl; restore WILLNEED before
>>>      cleanup.
>>>
>>> v6:
>>>    - Support iGPU by using total system RAM as the pressure baseline
>>>      instead of VRAM size (which is 0 on iGPU).
>>>    - Raise overpressure from 25% to 50% of the baseline to ensure the
>>>      kernel shrinker is forced to reclaim on systems with large free 
>>> RAM.
>>>    - The DONTNEED enforcement point is mmap() itself, not the
>>>      DRM_IOCTL_XE_GEM_MMAP_OFFSET ioctl. Update the test to mark 
>>> DONTNEED
>>>      first, then verify DRM_IOCTL_XE_GEM_MMAP_OFFSET still succeeds, 
>>> and
>>>      finally verify that mmap() fails with -EBUSY
>>>
>>> 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 | 233 
>>> +++++++++++++++++++++++++++++++++++++++
>>>   tests/meson.build        |   1 +
>>>   2 files changed, 234 insertions(+)
>>>   create mode 100644 tests/intel/xe_madvise.c
>>>
>>> diff --git a/tests/intel/xe_madvise.c b/tests/intel/xe_madvise.c
>>> new file mode 100644
>>> index 000000000..de4a6e34c
>>> --- /dev/null
>>> +++ b/tests/intel/xe_madvise.c
>>> @@ -0,0 +1,233 @@
>>> +// SPDX-License-Identifier: MIT
>>> +/*
>>> + * Copyright © 2025 Intel Corporation
>>> + */
>>> +
>>> +/**
>>> + * TEST: Validate purgeable BO madvise functionality
>>> + * Category: Core
>>> + * Mega feature: General Core features
>>> + * Sub-category: Memory management tests
>>> + * Functionality: madvise, purgeable
>>> + */
>>> +
>>> +#include "igt.h"
>>> +#include "xe_drm.h"
>>> +
>>> +#include "xe/xe_ioctl.h"
>>> +#include "xe/xe_query.h"
>>> +
>>> +static bool xe_has_purgeable_support(int fd)
>>> +{
>>> +    struct drm_xe_query_config *config = xe_config(fd);
>>> +
>>> +    return config->info[DRM_XE_QUERY_CONFIG_FLAGS] &
>>> +        DRM_XE_QUERY_CONFIG_FLAG_HAS_PURGING_SUPPORT;
>>> +}
>>> +
>>> +/* Purgeable test constants */
>>> +#define PURGEABLE_ADDR        0x1a0000
>>> +#define PURGEABLE_BO_SIZE    4096
>>> +
>>> +/**
>>> + * trigger_memory_pressure - Fill VRAM/RAM + 50% to force purgeable 
>>> reclaim
>>> + * @fd: DRM file descriptor
>>> + * @vm: VM handle (unused, kept for API compatibility)
>>> + *
>>> + * Allocates BOs in a temporary VM until memory is overcommitted by 
>>> 50%,
>>> + * forcing the kernel to purge DONTNEED-marked BOs.
>>> + */
>>> +static void trigger_memory_pressure(int fd, uint32_t vm)
>>> +{
>>> +    uint64_t vram_size, mem_size, overpressure;
>>> +    const uint64_t chunk = 8ull << 20; /* 8 MiB */
>>> +    int max_objs, n = 0;
>>> +    uint32_t *handles;
>>> +    uint64_t total;
>>> +    void *p;
>>> +    uint32_t handle, temp_vm;
>>> +
>>> +    /* Use a separate VM so pressure BOs don't affect the test VM */
>>> +    temp_vm = xe_vm_create(fd, 0, 0);
>>> +
>>> +    vram_size = xe_visible_vram_size(fd, 0);
>>> +    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;
>>> +    }
>>> +
>>> +    /* Scale overpressure to 50% of memory, minimum 64MB */
>>> +    overpressure = mem_size / 2;
>>> +    if (overpressure < (64 << 20))
>>> +        overpressure = 64 << 20;
>>> +
>>> +    max_objs = (mem_size + overpressure) / chunk + 1;
>>> +    handles = malloc(max_objs * sizeof(*handles));
>>> +    igt_assert(handles);
>>> +
>>> +    total = 0;
>>> +    while (total < mem_size + overpressure && n < max_objs) {
>>> +        uint32_t err;
>>> +
>>> +        err = __xe_bo_create(fd, temp_vm, chunk,
>>> +                     vram_if_possible(fd, 0),
>>> + DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM,
>>> +                     NULL, &handle);
>>> +        if (err) /* Out of memory — sufficient pressure achieved */
>>> +            break;
>>> +
>>> +        handles[n++] = handle;
>>> +        total += chunk;
>>> +
>>> +        p = xe_bo_map(fd, handle, chunk);
>>> +        igt_assert(p != MAP_FAILED);
>>> +
>>> +        /* Fault in all pages so they actually consume memory */
>>> +        memset(p, 0xCD, chunk);
>>> +        munmap(p, chunk);
>>> +    }
>>> +
>>> +    /* Allow shrinker time to process pressure */
>>> +    usleep(100000);
>>> +
>>> +    for (int i = 0; i < n; i++)
>>> +        gem_close(fd, handles[i]);
>>> +
>>> +    free(handles);
>>> +
>>> +    xe_vm_destroy(fd, temp_vm);
>>> +}
>> This function is called from below function which is not part of this 
>> Patch-3/9. This must be removed and introduced in Patch-4/9.


Noted.

>>> +
>>> +static jmp_buf jmp;
>>> +
>>> +__noreturn static void sigtrap(int sig)
>>> +{
>>> +    siglongjmp(jmp, sig);
>>> +}
>>> +
>>> +/**
>>> + * purgeable_mark_and_verify_purged - Mark DONTNEED, pressure, 
>>> check purged
>>> + * @fd: DRM file descriptor
>>> + * @vm: VM handle
>>> + * @addr: Virtual address of the BO
>>> + * @size: Size of the BO
>>> + *
>>> + * Returns true if the BO was purged under memory pressure.
>>> + */
>>> +static bool purgeable_mark_and_verify_purged(int fd, uint32_t vm, 
>>> uint64_t addr, size_t size)
>>> +{
>>> +    uint32_t retained;
>>> +
>>> +    /* Mark as DONTNEED */
>>> +    retained = xe_vm_madvise_purgeable(fd, vm, addr, size,
>>> +                       DRM_XE_VMA_PURGEABLE_STATE_DONTNEED);
>>> +    if (retained != 1)
>>> +        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;
>>> +}
>> This function is introduced in test_dontneed_after_mmap() in 
>> Patch-4/9. Remove this and introduced in Patch-4/9.
> Correction here, this function is called from subtest 
> test_purged_mmap_blocked(fd); which is in Patch-4/9. Please move these 
> functions in Patch-4/9


Noted.

Thanks,
Arvind

>>> +
>>> +/**
>>> + * purgeable_setup_simple_bo - Setup VM and bind a single BO
>>> + * @fd: DRM file descriptor
>>> + * @vm: Output VM handle
>>> + * @bo: Output BO handle
>>> + * @addr: Virtual address to bind at
>>> + * @size: Size of the BO
>>> + * @use_scratch: Whether to use scratch page flag
>>> + *
>>> + * Helper to create VM, BO, and bind it at the specified address.
>>> + */
>>> +static void purgeable_setup_simple_bo(int fd, uint32_t *vm, 
>>> uint32_t *bo,
>>> +                      uint64_t addr, size_t size, bool use_scratch)
>>> +{
>>> +    struct drm_xe_sync sync = {
>>> +        .type = DRM_XE_SYNC_TYPE_USER_FENCE,
>>> +        .flags = DRM_XE_SYNC_FLAG_SIGNAL,
>>> +        .timeline_value = 1,
>>> +    };
>>> +    uint64_t sync_val = 0;
>>> +
>>> +    *vm = xe_vm_create(fd, use_scratch ? 
>>> DRM_XE_VM_CREATE_FLAG_SCRATCH_PAGE : 0, 0);
>>> +    *bo = xe_bo_create(fd, *vm, size, vram_if_possible(fd, 0),
>>> +               DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM);
>>> +
>>> +    sync.addr = to_user_pointer(&sync_val);
>>> +    xe_vm_bind_async(fd, *vm, 0, *bo, 0, addr, size, &sync, 1);
>>> +    xe_wait_ufence(fd, &sync_val, 1, 0, NSEC_PER_SEC);
>>> +}
>>> +
>>> +/**
>>> + * SUBTEST: dontneed-before-mmap
>>> + * Description: Mark BO as DONTNEED before mmap, verify mmap() 
>>> fails with -EBUSY
>>> + * Test category: functionality test
>>> + */
>>> +static void test_dontneed_before_mmap(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 = {};
>>> +    uint32_t retained;
>>> +    void *ptr;
>>> +
>>> +    purgeable_setup_simple_bo(fd, &vm, &bo, addr, bo_size, false);
>>> +
>>> +    /* Mark BO as DONTNEED - new mmap operations must be blocked */
>>> +    retained = xe_vm_madvise_purgeable(fd, vm, addr, bo_size,
>>> +                       DRM_XE_VMA_PURGEABLE_STATE_DONTNEED);
>>> +    igt_assert_eq(retained, 1);
>>> +
>>> +    /* Ioctl succeeds even for DONTNEED BO; blocking happens at 
>>> mmap() time. */
>>> +    mmo.handle = bo;
>>> +    igt_assert_eq(igt_ioctl(fd, DRM_IOCTL_XE_GEM_MMAP_OFFSET, 
>>> &mmo), 0);
>>> +
>>> +    /* mmap() on a DONTNEED BO must fail with EBUSY. */
>>> +    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, EBUSY);
>>> +
>>> +    /* Restore to WILLNEED before cleanup */
>>> +    xe_vm_madvise_purgeable(fd, vm, addr, bo_size,
>>> +                DRM_XE_VMA_PURGEABLE_STATE_WILLNEED);
>>> +
>>> +    gem_close(fd, bo);
>>> +    xe_vm_destroy(fd, vm);
>>> +}
>>> +
>>> +int igt_main()
>>> +{
>>> +    struct drm_xe_engine_class_instance *hwe;
>>> +    int fd;
>>> +
>>> +    igt_fixture() {
>>> +        fd = drm_open_driver(DRIVER_XE);
>>> +        xe_device_get(fd);
>>> +        igt_require_f(xe_has_purgeable_support(fd),
>>> +                  "Kernel does not support purgeable buffer 
>>> objects\n");
>>> +    }
>>> +
>>> +    igt_subtest("dontneed-before-mmap")
>>> +        xe_for_each_engine(fd, hwe) {
>>> +            test_dontneed_before_mmap(fd);
>>> +            break;
>>> +        }
>>> +
>>> +    igt_fixture() {
>>> +        xe_device_put(fd);
>>> +        drm_close_driver(fd);
>>> +    }
>>> +}
>>> diff --git a/tests/meson.build b/tests/meson.build
>>> index cecb4a8ae..a6370b685 100644
>>> --- a/tests/meson.build
>>> +++ b/tests/meson.build
>>> @@ -314,6 +314,7 @@ intel_xe_progs = [
>>>       'xe_huc_copy',
>>>       'xe_intel_bb',
>>>       'xe_live_ktest',
>>> +    'xe_madvise',
>>>       'xe_media_fill',
>>>       'xe_mmap',
>>>           'xe_module_load',