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drm/i915: Allow compaction upto SWIOTLB max segment size

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commit 1625e7e549 ("drm/i915: make compact dma scatter lists creation
work with SWIOTLB backend") took a heavy handed approach to undo the
scatterlist compaction in the face of SWIOTLB. (The compaction hit a bug
whereby we tried to pass a segment larger than SWIOTLB could handle.) We
can be a little more intelligent and try compacting the scatterlist up
to the maximum SWIOTLB segment size (when using SWIOTLB).

v2: Tidy sg_mark_end() and cpp

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
CC: Imre Deak <imre.deak@intel.com>
CC: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161011082021.14606-2-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2016-10-11 09:20:21 +01:00
parent 465350d0db
commit 871dfbd67d
1 changed files with 18 additions and 12 deletions
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30
drivers/gpu/drm/i915/i915_gem.c
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@ -2208,6 +2208,15 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
return 0;
}
static unsigned long swiotlb_max_size(void)
{
#if IS_ENABLED(CONFIG_SWIOTLB)
return rounddown(swiotlb_nr_tbl() << IO_TLB_SHIFT, PAGE_SIZE);
#else
return 0;
#endif
}
static int
i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
{
@ -2219,6 +2228,7 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
struct sgt_iter sgt_iter;
struct page *page;
unsigned long last_pfn = 0; /* suppress gcc warning */
unsigned long max_segment;
int ret;
gfp_t gfp;
@ -2229,6 +2239,10 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
BUG_ON(obj->base.read_domains & I915_GEM_GPU_DOMAINS);
BUG_ON(obj->base.write_domain & I915_GEM_GPU_DOMAINS);
max_segment = swiotlb_max_size();
if (!max_segment)
max_segment = obj->base.size;
st = kmalloc(sizeof(*st), GFP_KERNEL);
if (st == NULL)
return -ENOMEM;
@ -2270,15 +2284,9 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
goto err_pages;
}
}
#ifdef CONFIG_SWIOTLB
if (swiotlb_nr_tbl()) {
st->nents++;
sg_set_page(sg, page, PAGE_SIZE, 0);
sg = sg_next(sg);
continue;
}
#endif
if (!i || page_to_pfn(page) != last_pfn + 1) {
if (!i ||
sg->length >= max_segment ||
page_to_pfn(page) != last_pfn + 1) {
if (i)
sg = sg_next(sg);
st->nents++;
@ -2291,9 +2299,7 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
/* Check that the i965g/gm workaround works. */
WARN_ON((gfp & __GFP_DMA32) && (last_pfn >= 0x00100000UL));
}
#ifdef CONFIG_SWIOTLB
if (!swiotlb_nr_tbl())
#endif
if (sg) /* loop terminated early; short sg table */
sg_mark_end(sg);
obj->pages = st;