Re: [PATCH v4 31/33] drm/xe: Add modparam for SVM notifier size

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On Wed, 2025-01-29 at 11:52 -0800, Matthew Brost wrote:
> Useful to experiment with notifier size and how it affects
> performance.
> 
> v3:
>  - Pull missing changes including in following patch (Thomas)
> 
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>

Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

> ---
>  drivers/gpu/drm/xe/xe_module.c | 4 ++++
>  drivers/gpu/drm/xe/xe_module.h | 1 +
>  drivers/gpu/drm/xe/xe_svm.c    | 4 +++-
>  3 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_module.c
> b/drivers/gpu/drm/xe/xe_module.c
> index 0f2c20e9204a..2126e99ede01 100644
> --- a/drivers/gpu/drm/xe/xe_module.c
> +++ b/drivers/gpu/drm/xe/xe_module.c
> @@ -25,9 +25,13 @@ struct xe_modparam xe_modparam = {
>  	.max_vfs = IS_ENABLED(CONFIG_DRM_XE_DEBUG) ? ~0 : 0,
>  #endif
>  	.wedged_mode = 1,
> +	.svm_notifier_size = 512,
>  	/* the rest are 0 by default */
>  };
>  
> +module_param_named(svm_notifier_size, xe_modparam.svm_notifier_size,
> uint, 0600);
> +MODULE_PARM_DESC(svm_notifier_size, "Set the svm notifier size(in
> MiB), must be pow2");
> +
>  module_param_named_unsafe(force_execlist,
> xe_modparam.force_execlist, bool, 0444);
>  MODULE_PARM_DESC(force_execlist, "Force Execlist submission");
>  
> diff --git a/drivers/gpu/drm/xe/xe_module.h
> b/drivers/gpu/drm/xe/xe_module.h
> index 161a5e6f717f..5a3bfea8b7b4 100644
> --- a/drivers/gpu/drm/xe/xe_module.h
> +++ b/drivers/gpu/drm/xe/xe_module.h
> @@ -22,6 +22,7 @@ struct xe_modparam {
>  	unsigned int max_vfs;
>  #endif
>  	int wedged_mode;
> +	u32 svm_notifier_size;
>  };
>  
>  extern struct xe_modparam xe_modparam;
> diff --git a/drivers/gpu/drm/xe/xe_svm.c
> b/drivers/gpu/drm/xe/xe_svm.c
> index 0df924ca8ed1..f291b2eb2073 100644
> --- a/drivers/gpu/drm/xe/xe_svm.c
> +++ b/drivers/gpu/drm/xe/xe_svm.c
> @@ -6,6 +6,7 @@
>  #include "xe_bo.h"
>  #include "xe_gt_tlb_invalidation.h"
>  #include "xe_migrate.h"
> +#include "xe_module.h"
>  #include "xe_pt.h"
>  #include "xe_svm.h"
>  #include "xe_ttm_vram_mgr.h"
> @@ -596,7 +597,8 @@ int xe_svm_init(struct xe_vm *vm)
>  
>  	err = drm_gpusvm_init(&vm->svm.gpusvm, "Xe SVM", &vm->xe-
> >drm,
>  			      current->mm, xe_svm_devm_owner(vm-
> >xe), 0,
> -			      vm->size, SZ_512M, &gpusvm_ops,
> fault_chunk_sizes,
> +			      vm->size,
> xe_modparam.svm_notifier_size * SZ_1M,
> +			      &gpusvm_ops, fault_chunk_sizes,
>  			      ARRAY_SIZE(fault_chunk_sizes));
>  	if (err)
>  		return err;