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d="scan'208";a="203705569" Received: from dhhellew-desk2.ger.corp.intel.com (HELO fedora) ([10.245.244.93]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Dec 2025 08:21:45 -0800 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= To: intel-xe@lists.freedesktop.org Cc: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Matthew Brost , Himal Prasad Ghimiray , dri-devel@lists.freedesktop.org, apopple@nvidia.com, airlied@gmail.com, Simona Vetter , felix.kuehling@amd.com, =?UTF-8?q?Christian=20K=C3=B6nig?= , dakr@kernel.org, "Mrozek, Michal" , Joonas Lahtinen Subject: [PATCH v5 04/24] drm/pagemap, drm/xe: Add refcounting to struct drm_pagemap Date: Thu, 18 Dec 2025 17:20:41 +0100 Message-ID: <20251218162101.605379-5-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251218162101.605379-1-thomas.hellstrom@linux.intel.com> References: <20251218162101.605379-1-thomas.hellstrom@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" With the end goal of being able to free unused pagemaps and allocate them on demand, add a refcount to struct drm_pagemap, remove the xe embedded drm_pagemap, allocating and freeing it explicitly. v2: - Make the drm_pagemap pointer in drm_gpusvm_pages reference-counted. v3: - Call drm_pagemap_get() before drm_pagemap_put() in drm_gpusvm_pages (Himal Prasad Ghimiray) Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost #v1 Reviewed-by: Himal Prasad Ghimiray --- drivers/gpu/drm/drm_gpusvm.c | 3 ++ drivers/gpu/drm/drm_pagemap.c | 51 ++++++++++++++++++++++++++++++ drivers/gpu/drm/xe/xe_svm.c | 26 ++++++++++----- drivers/gpu/drm/xe/xe_vram_types.h | 2 +- include/drm/drm_pagemap.h | 36 +++++++++++++++++++++ 5 files changed, 109 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c index 39c8c50401dd..4c7474a331bc 100644 --- a/drivers/gpu/drm/drm_gpusvm.c +++ b/drivers/gpu/drm/drm_gpusvm.c @@ -1038,6 +1038,7 @@ static void __drm_gpusvm_unmap_pages(struct drm_gpusvm *gpusvm, flags.has_dma_mapping = false; WRITE_ONCE(svm_pages->flags.__flags, flags.__flags); + drm_pagemap_put(svm_pages->dpagemap); svm_pages->dpagemap = NULL; } } @@ -1434,6 +1435,8 @@ int drm_gpusvm_get_pages(struct drm_gpusvm *gpusvm, if (pagemap) { flags.has_devmem_pages = true; + drm_pagemap_get(dpagemap); + drm_pagemap_put(svm_pages->dpagemap); svm_pages->dpagemap = dpagemap; } diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c index ac3832f85190..87648a498a31 100644 --- a/drivers/gpu/drm/drm_pagemap.c +++ b/drivers/gpu/drm/drm_pagemap.c @@ -543,6 +543,57 @@ static int drm_pagemap_migrate_populate_ram_pfn(struct vm_area_struct *vas, return -ENOMEM; } +static void drm_pagemap_release(struct kref *ref) +{ + struct drm_pagemap *dpagemap = container_of(ref, typeof(*dpagemap), ref); + + kfree(dpagemap); +} + +/** + * drm_pagemap_create() - Create a struct drm_pagemap. + * @dev: Pointer to a struct device providing the device-private memory. + * @pagemap: Pointer to a pre-setup struct dev_pagemap providing the struct pages. + * @ops: Pointer to the struct drm_pagemap_ops. + * + * Allocate and initialize a struct drm_pagemap. + * + * Return: A refcounted pointer to a struct drm_pagemap on success. + * Error pointer on error. + */ +struct drm_pagemap * +drm_pagemap_create(struct device *dev, + struct dev_pagemap *pagemap, + const struct drm_pagemap_ops *ops) +{ + struct drm_pagemap *dpagemap = kzalloc(sizeof(*dpagemap), GFP_KERNEL); + + if (!dpagemap) + return ERR_PTR(-ENOMEM); + + kref_init(&dpagemap->ref); + dpagemap->dev = dev; + dpagemap->ops = ops; + dpagemap->pagemap = pagemap; + + return dpagemap; +} +EXPORT_SYMBOL(drm_pagemap_create); + +/** + * drm_pagemap_put() - Put a struct drm_pagemap reference + * @dpagemap: Pointer to a struct drm_pagemap object. + * + * Puts a struct drm_pagemap reference and frees the drm_pagemap object + * if the refount reaches zero. + */ +void drm_pagemap_put(struct drm_pagemap *dpagemap) +{ + if (likely(dpagemap)) + kref_put(&dpagemap->ref, drm_pagemap_release); +} +EXPORT_SYMBOL(drm_pagemap_put); + /** * drm_pagemap_evict_to_ram() - Evict GPU SVM range to RAM * @devmem_allocation: Pointer to the device memory allocation diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c index b806a1fce188..b72d523a4416 100644 --- a/drivers/gpu/drm/xe/xe_svm.c +++ b/drivers/gpu/drm/xe/xe_svm.c @@ -890,7 +890,7 @@ static int xe_drm_pagemap_populate_mm(struct drm_pagemap *dpagemap, struct mm_struct *mm, unsigned long timeslice_ms) { - struct xe_vram_region *vr = container_of(dpagemap, typeof(*vr), dpagemap); + struct xe_vram_region *vr = container_of(dpagemap->pagemap, typeof(*vr), pagemap); struct dma_fence *pre_migrate_fence = NULL; struct xe_device *xe = vr->xe; struct device *dev = xe->drm.dev; @@ -1414,7 +1414,7 @@ u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, u64 start, u64 end) static struct drm_pagemap *tile_local_pagemap(struct xe_tile *tile) { - return &tile->mem.vram->dpagemap; + return tile->mem.vram->dpagemap; } /** @@ -1524,6 +1524,15 @@ int xe_devm_add(struct xe_tile *tile, struct xe_vram_region *vr) return ret; } + vr->dpagemap = drm_pagemap_create(dev, &vr->pagemap, + &xe_drm_pagemap_ops); + if (IS_ERR(vr->dpagemap)) { + drm_err(&xe->drm, "Failed to create drm_pagemap tile %d memory: %pe\n", + tile->id, vr->dpagemap); + ret = PTR_ERR(vr->dpagemap); + goto out_no_dpagemap; + } + vr->pagemap.type = MEMORY_DEVICE_PRIVATE; vr->pagemap.range.start = res->start; vr->pagemap.range.end = res->end; @@ -1531,22 +1540,23 @@ int xe_devm_add(struct xe_tile *tile, struct xe_vram_region *vr) vr->pagemap.ops = drm_pagemap_pagemap_ops_get(); vr->pagemap.owner = xe_svm_devm_owner(xe); addr = devm_memremap_pages(dev, &vr->pagemap); - - vr->dpagemap.dev = dev; - vr->dpagemap.ops = &xe_drm_pagemap_ops; - if (IS_ERR(addr)) { - devm_release_mem_region(dev, res->start, resource_size(res)); ret = PTR_ERR(addr); drm_err(&xe->drm, "Failed to remap tile %d memory, errno %pe\n", tile->id, ERR_PTR(ret)); - return ret; + goto out_failed_memremap; } vr->hpa_base = res->start; drm_dbg(&xe->drm, "Added tile %d memory [%llx-%llx] to devm, remapped to %pr\n", tile->id, vr->io_start, vr->io_start + vr->usable_size, res); return 0; + +out_failed_memremap: + drm_pagemap_put(vr->dpagemap); +out_no_dpagemap: + devm_release_mem_region(dev, res->start, resource_size(res)); + return ret; } #else int xe_svm_alloc_vram(struct xe_tile *tile, diff --git a/drivers/gpu/drm/xe/xe_vram_types.h b/drivers/gpu/drm/xe/xe_vram_types.h index 83772dcbf1af..c0d2c5ee8c10 100644 --- a/drivers/gpu/drm/xe/xe_vram_types.h +++ b/drivers/gpu/drm/xe/xe_vram_types.h @@ -72,7 +72,7 @@ struct xe_vram_region { * @dpagemap: The struct drm_pagemap of the ZONE_DEVICE memory * pages of this tile. */ - struct drm_pagemap dpagemap; + struct drm_pagemap *dpagemap; /** * @hpa_base: base host physical address * diff --git a/include/drm/drm_pagemap.h b/include/drm/drm_pagemap.h index 70a7991f784f..093e7199c44b 100644 --- a/include/drm/drm_pagemap.h +++ b/include/drm/drm_pagemap.h @@ -130,11 +130,15 @@ struct drm_pagemap_ops { * struct drm_pagemap: Additional information for a struct dev_pagemap * used for device p2p handshaking. * @ops: The struct drm_pagemap_ops. + * @ref: Reference count. * @dev: The struct drevice owning the device-private memory. + * @pagemap: Pointer to the underlying dev_pagemap. */ struct drm_pagemap { const struct drm_pagemap_ops *ops; + struct kref ref; struct device *dev; + struct dev_pagemap *pagemap; }; struct drm_pagemap_devmem; @@ -209,6 +213,37 @@ struct drm_pagemap_devmem_ops { struct dma_fence *pre_migrate_fence); }; +struct drm_pagemap *drm_pagemap_create(struct device *dev, + struct dev_pagemap *pagemap, + const struct drm_pagemap_ops *ops); + +#if IS_ENABLED(CONFIG_DRM_GPUSVM) + +void drm_pagemap_put(struct drm_pagemap *dpagemap); + +#else + +static inline void drm_pagemap_put(struct drm_pagemap *dpagemap) +{ +} + +#endif /* IS_ENABLED(CONFIG_DRM_GPUSVM) */ + +/** + * drm_pagemap_get() - Obtain a reference on a struct drm_pagemap + * @dpagemap: Pointer to the struct drm_pagemap. + * + * Return: Pointer to the struct drm_pagemap. + */ +static inline struct drm_pagemap * +drm_pagemap_get(struct drm_pagemap *dpagemap) +{ + if (likely(dpagemap)) + kref_get(&dpagemap->ref); + + return dpagemap; +} + /** * struct drm_pagemap_devmem - Structure representing a GPU SVM device memory allocation * @@ -257,3 +292,4 @@ int drm_pagemap_populate_mm(struct drm_pagemap *dpagemap, unsigned long timeslice_ms); #endif + -- 2.51.1