On Tue, 2026-10-27 at 15:49 -0700, Matthew Brost wrote:
> Servicing a page fault validates the VMA's backing store and binds
> it,
> making the BO part of the VM's active working set, but unlike exec it
> never moves anything on the TTM LRU. In fault mode, where a VM may
> run
> for a long time without a single exec, the BOs the GPU actually
> touches
> therefore drift towards the LRU head and are picked by eviction and
> by
> the shrinker ahead of genuinely cold BOs.
>
> Bump the BO's LRU on a successful page fault.
>
> Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel
> GPUs")
> Signed-off-by: Matthew Brost <[email protected]>
Found the newer version:
Reviewed-by: Thomas Hellström <[email protected]>
> ---
> drivers/gpu/drm/xe/xe_pagefault.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_pagefault.c
> b/drivers/gpu/drm/xe/xe_pagefault.c
> index 5247321c805e..6828f81df50e 100644
> --- a/drivers/gpu/drm/xe/xe_pagefault.c
> +++ b/drivers/gpu/drm/xe/xe_pagefault.c
> @@ -201,6 +201,8 @@ static int xe_pagefault_handle_vma(struct xe_gt
> *gt, struct xe_vma *vma,
> xe_validation_ctx_init(&ctx, &vm->xe->val, &exec,
> (struct xe_val_flags) {});
> drm_exec_until_all_locked(&exec) {
> + struct xe_bo *bo = xe_vma_bo(vma);
> +
> err = xe_pagefault_begin(&exec, vma, tile-
> >mem.vram,
> needs_vram == 1);
> drm_exec_retry_on_contention(&exec);
> @@ -221,6 +223,11 @@ static int xe_pagefault_handle_vma(struct xe_gt
> *gt, struct xe_vma *vma,
> xe_pagefault_set_error(pf,
> XE_PAGEFAULT_ERROR_VMA_REBIND);
> break;
> }
> +
> + if (bo) {
> + scoped_guard(spinlock, &vm->xe-
> >ttm.lru_lock)
> + ttm_bo_move_to_lru_tail(&bo-
> >ttm);
> + }
> }
> xe_validation_ctx_fini(&ctx);
> } while (err == -EAGAIN);
