drm/i915: Introduce & use new lightweight SGL iterators
The existing for_each_sg_page() iterator is somewhat heavyweight, and is
limiting i915 driver performance in a few benchmarks. So here we
introduce somewhat lighter weight iterators, primarily for use with GEM
objects or other case where we need only deal with whole aligned pages.
Unlike the old iterator, the new iterators use an internal state
structure which is not intended to be accessed by the caller; instead
each takes as a parameter an output variable which is set before each
iteration. This makes them particularly simple to use :)
One of the new iterators provides the caller with the DMA address of
each page in turn; the other provides the 'struct page' pointer required
by many memory management operations.
Various uses of for_each_sg_page() are then converted to the new macros.
v2: Force inlining of the sg_iter constructor and make the union
anonymous.
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1463741647-15666-4-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index fd3be2b..3251dec 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2165,7 +2165,8 @@
static void
i915_gem_object_put_pages_gtt(struct drm_i915_gem_object *obj)
{
- struct sg_page_iter sg_iter;
+ struct sgt_iter sgt_iter;
+ struct page *page;
int ret;
BUG_ON(obj->madv == __I915_MADV_PURGED);
@@ -2187,9 +2188,7 @@
if (obj->madv == I915_MADV_DONTNEED)
obj->dirty = 0;
- for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
- struct page *page = sg_page_iter_page(&sg_iter);
-
+ for_each_sgt_page(page, sgt_iter, obj->pages) {
if (obj->dirty)
set_page_dirty(page);
@@ -2246,7 +2245,7 @@
struct address_space *mapping;
struct sg_table *st;
struct scatterlist *sg;
- struct sg_page_iter sg_iter;
+ struct sgt_iter sgt_iter;
struct page *page;
unsigned long last_pfn = 0; /* suppress gcc warning */
int ret;
@@ -2343,8 +2342,8 @@
err_pages:
sg_mark_end(sg);
- for_each_sg_page(st->sgl, &sg_iter, st->nents, 0)
- put_page(sg_page_iter_page(&sg_iter));
+ for_each_sgt_page(page, sgt_iter, st)
+ put_page(page);
sg_free_table(st);
kfree(st);
@@ -2403,7 +2402,8 @@
{
unsigned long n_pages = obj->base.size >> PAGE_SHIFT;
struct sg_table *sgt = obj->pages;
- struct sg_page_iter sg_iter;
+ struct sgt_iter sgt_iter;
+ struct page *page;
struct page *stack_pages[32];
struct page **pages = stack_pages;
unsigned long i = 0;
@@ -2420,8 +2420,8 @@
return NULL;
}
- for_each_sg_page(sgt->sgl, &sg_iter, sgt->nents, 0)
- pages[i++] = sg_page_iter_page(&sg_iter);
+ for_each_sgt_page(page, sgt_iter, sgt)
+ pages[i++] = page;
/* Check that we have the expected number of pages */
GEM_BUG_ON(i != n_pages);