Now that we use this function for ringbuffers and other "small" objects, it's worth avoiding an extra kmalloc()/kfree() cycle if the page array is small enough to put on the stack. Here we've chosen an arbitrary cutoff of 32 (4k) pages, which is big enough for a ringbuffer (4 pages) or a context image (currently up to 22 pages).
Signed-off-by: Dave Gordon <[email protected]> Cc: Tvrtko Ursulin <[email protected]> Cc: Alex Dai <[email protected]> Cc: Chris Wilson <[email protected]> --- drivers/gpu/drm/i915/i915_gem.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 14942cf..effb69b 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2422,6 +2422,7 @@ void *i915_gem_object_vmap_range(struct drm_i915_gem_object *obj, unsigned int npages) { struct sg_page_iter sg_iter; + struct page *mypages[32]; struct page **pages; void *addr; int i; @@ -2431,10 +2432,16 @@ void *i915_gem_object_vmap_range(struct drm_i915_gem_object *obj, return NULL; } - pages = drm_malloc_ab(npages, sizeof(*pages)); - if (pages == NULL) { - DRM_DEBUG_DRIVER("Failed to get space for pages\n"); - return NULL; + if (npages <= ARRAY_SIZE(mypages)) + pages = mypages; + else { + pages = kmalloc(npages*sizeof(*pages), GFP_TEMPORARY | __GFP_NOWARN); + if (pages == NULL) + pages = drm_malloc_ab(npages, sizeof(*pages)); + if (pages == NULL) { + DRM_DEBUG_DRIVER("Failed to get space for pages\n"); + return NULL; + } } i = 0; @@ -2447,7 +2454,8 @@ void *i915_gem_object_vmap_range(struct drm_i915_gem_object *obj, addr = vmap(pages, npages, 0, PAGE_KERNEL); if (addr == NULL) DRM_DEBUG_DRIVER("Failed to vmap pages\n"); - drm_free_large(pages); + if (pages != mypages) + drm_free_large(pages); return addr; } -- 1.9.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
