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 <david.s.gordon@xxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Alex Dai <yu.dai@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
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
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