On 8/12/2016 4:19 PM, Tvrtko Ursulin wrote:
On 12/08/16 07:25, akash.goel@xxxxxxxxx wrote:From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> vmaps has a provision for controlling the page protection bits, with which we can use to control the mapping type, e.g. WB, WC, UC or even WT. To allow the caller to choose their mapping type, we add a parameter to i915_gem_object_pin_map - but we still only allow one vmap to be cached per object. If the object is currently not pinned, then we recreate the previous vmap with the new access type, but if it was pinned we report an error. This effectively limits the access via i915_gem_object_pin_map to a single mapping type for the lifetime of the object. Not usually a problem, but something to be aware of when setting up the object's vmap. We will want to vary the access type to enable WC mappings of ringbuffer and context objects on !llc platforms, as well as other objects where we need coherent access to the GPU's pages without going through the GTT v2: Remove the redundant braces around pin count check and fix the marker in documentation (Chris) v3: - Add a new enum for the vmalloc mapping type & pass that as an argument to i915_object_pin_map. (Tvrtko) - Use PAGE_MASK to extract or filter the mapping type info and remove a superfluous BUG_ON.(Tvrtko) v4: - Rename the enums and clean up the pin_map function. (Chris) Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Signed-off-by: Akash Goel <akash.goel@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_drv.h | 9 ++++- drivers/gpu/drm/i915/i915_gem.c | 58 +++++++++++++++++++++++------- drivers/gpu/drm/i915/i915_gem_dmabuf.c | 2 +- drivers/gpu/drm/i915/i915_guc_submission.c | 2 +- drivers/gpu/drm/i915/intel_lrc.c | 8 ++--- drivers/gpu/drm/i915/intel_ringbuffer.c | 2 +- 6 files changed, 60 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 4bd3790..6603812 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -834,6 +834,11 @@ enum i915_cache_level { I915_CACHE_WT, /* hsw:gt3e WriteThrough for scanouts */ }; +enum i915_map_type { + I915_MAP_WB = 0, + I915_MAP_WC, +}; + struct i915_ctx_hang_stats { /* This context had batch pending when hang was declared */ unsigned batch_pending; @@ -3150,6 +3155,7 @@ static inline void i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj) /** * i915_gem_object_pin_map - return a contiguous mapping of the entire object * @obj - the object to map into kernel address space + * @map_type - whether the vmalloc mapping should be using WC or WB pgprot_t * * Calls i915_gem_object_pin_pages() to prevent reaping of the object's * pages and then returns a contiguous mapping of the backing storage into @@ -3161,7 +3167,8 @@ static inline void i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj) * Returns the pointer through which to access the mapped object, or an * ERR_PTR() on error. */ -void *__must_check i915_gem_object_pin_map(struct drm_i915_gem_object *obj); +void *__must_check i915_gem_object_pin_map(struct drm_i915_gem_object *obj, + enum i915_map_type map_type); /** * i915_gem_object_unpin_map - releases an earlier mapping diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 03548db..7dabbc3f 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2077,10 +2077,11 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj) list_del(&obj->global_list); if (obj->mapping) { - if (is_vmalloc_addr(obj->mapping)) - vunmap(obj->mapping); + void *ptr = (void *)((uintptr_t)obj->mapping & PAGE_MASK); + if (is_vmalloc_addr(ptr)) + vunmap(ptr); else - kunmap(kmap_to_page(obj->mapping)); + kunmap(kmap_to_page(ptr)); obj->mapping = NULL; } @@ -2253,7 +2254,8 @@ i915_gem_object_get_pages(struct drm_i915_gem_object *obj) } /* The 'mapping' part of i915_gem_object_pin_map() below */ -static void *i915_gem_object_map(const struct drm_i915_gem_object *obj) +static void *i915_gem_object_map(const struct drm_i915_gem_object *obj, + enum i915_map_type type) { unsigned long n_pages = obj->base.size >> PAGE_SHIFT; struct sg_table *sgt = obj->pages; @@ -2263,9 +2265,10 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj) struct page **pages = stack_pages; unsigned long i = 0; void *addr; + bool use_wc = (type == I915_MAP_WC); /* A single page can always be kmapped */ - if (n_pages == 1) + if (n_pages == 1 && !use_wc) return kmap(sg_page(sgt->sgl)); if (n_pages > ARRAY_SIZE(stack_pages)) { @@ -2281,7 +2284,8 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj) /* Check that we have the expected number of pages */ GEM_BUG_ON(i != n_pages); - addr = vmap(pages, n_pages, 0, PAGE_KERNEL); + addr = vmap(pages, n_pages, VM_NO_GUARD,Unreleated and unmentioned change to no guard page. Best to remove IMHO. Can keep the RB in that case.
Though its not called out, sorry for that, but isn't it better to avoid using the guard page, which will save 4KB of vmalloc virtual space (which is scarce) for every mapping created by Driver.
Updating the commit message would be fine to mention about this ?. Best regards Akash
+ use_wc ? pgprot_writecombine(PAGE_KERNEL_IO) : PAGE_KERNEL); if (pages != stack_pages) drm_free_large(pages); @@ -2290,11 +2294,16 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj) } /* get, pin, and map the pages of the object into kernel space */ -void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj) +void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj, + enum i915_map_type type) { + enum i915_map_type has_type; + bool pinned; + void *ptr; int ret; lockdep_assert_held(&obj->base.dev->struct_mutex); + GEM_BUG_ON((obj->ops->flags & I915_GEM_OBJECT_HAS_STRUCT_PAGE) == 0); ret = i915_gem_object_get_pages(obj); if (ret) @@ -2302,15 +2311,38 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj) i915_gem_object_pin_pages(obj); - if (!obj->mapping) { - obj->mapping = i915_gem_object_map(obj); - if (!obj->mapping) { - i915_gem_object_unpin_pages(obj); - return ERR_PTR(-ENOMEM); + pinned = obj->pages_pin_count > 1; + ptr = (void *)((uintptr_t)obj->mapping & PAGE_MASK); + has_type = (uintptr_t)obj->mapping & ~PAGE_MASK; + + if (ptr && has_type != type) { + if (pinned) { + ret = -EBUSY; + goto err; + } + + if (is_vmalloc_addr(ptr)) + vunmap(ptr); + else + kunmap(kmap_to_page(ptr)); + ptr = obj->mapping = NULL; + } + + if (!ptr) { + ptr = i915_gem_object_map(obj, type); + if (!ptr) { + ret = -ENOMEM; + goto err; } + + obj->mapping = (void *)((uintptr_t)ptr | type); } - return obj->mapping; + return ptr; + +err: + i915_gem_object_unpin_pages(obj); + return ERR_PTR(ret); } static void diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c index c60a8d5b..10265bb 100644 --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c @@ -119,7 +119,7 @@ static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf) if (ret) return ERR_PTR(ret); - addr = i915_gem_object_pin_map(obj); + addr = i915_gem_object_pin_map(obj, I915_MAP_WB); mutex_unlock(&dev->struct_mutex); return addr; diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index 041cf68..1d58d36 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -1178,7 +1178,7 @@ static int guc_create_log_extras(struct intel_guc *guc) if (!guc->log.buf_addr) { /* Create a vmalloc mapping of log buffer pages */ - vaddr = i915_gem_object_pin_map(guc->log.obj); + vaddr = i915_gem_object_pin_map(guc->log.obj, I915_MAP_WB); if (IS_ERR(vaddr)) { ret = PTR_ERR(vaddr); DRM_ERROR("Couldn't map log buffer pages %d\n", ret); diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index c7f4b64..c24ac39 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -780,7 +780,7 @@ static int intel_lr_context_pin(struct i915_gem_context *ctx, if (ret) goto err; - vaddr = i915_gem_object_pin_map(ce->state); + vaddr = i915_gem_object_pin_map(ce->state, I915_MAP_WB); if (IS_ERR(vaddr)) { ret = PTR_ERR(vaddr); goto unpin_ctx_obj; @@ -1755,7 +1755,7 @@ lrc_setup_hws(struct intel_engine_cs *engine, /* The HWSP is part of the default context object in LRC mode. */ engine->status_page.gfx_addr = i915_gem_obj_ggtt_offset(dctx_obj) + LRC_PPHWSP_PN * PAGE_SIZE; - hws = i915_gem_object_pin_map(dctx_obj); + hws = i915_gem_object_pin_map(dctx_obj, I915_MAP_WB); if (IS_ERR(hws)) return PTR_ERR(hws); engine->status_page.page_addr = hws + LRC_PPHWSP_PN * PAGE_SIZE; @@ -1968,7 +1968,7 @@ populate_lr_context(struct i915_gem_context *ctx, return ret; } - vaddr = i915_gem_object_pin_map(ctx_obj); + vaddr = i915_gem_object_pin_map(ctx_obj, I915_MAP_WB); if (IS_ERR(vaddr)) { ret = PTR_ERR(vaddr); DRM_DEBUG_DRIVER("Could not map object pages! (%d)\n", ret); @@ -2189,7 +2189,7 @@ void intel_lr_context_reset(struct drm_i915_private *dev_priv, if (!ctx_obj) continue; - vaddr = i915_gem_object_pin_map(ctx_obj); + vaddr = i915_gem_object_pin_map(ctx_obj, I915_MAP_WB); if (WARN_ON(IS_ERR(vaddr))) continue; diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index e8fa26c..69ec5da 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -1951,7 +1951,7 @@ int intel_ring_pin(struct intel_ring *ring) if (ret) goto err_unpin; - addr = i915_gem_object_pin_map(obj); + addr = i915_gem_object_pin_map(obj, I915_MAP_WB); if (IS_ERR(addr)) { ret = PTR_ERR(addr); goto err_unpin;Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Regards, Tvrtko
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