drm/i915: Show vma allocator stack when in doubt

At the moment, gem_exec_gttfill fails with a sporadic EBUSY due to us
wanting to unbind a pinned batch. Let's dump who first bound that vma to
see if that helps us identify who still unexpectedly has it pinned.

v2: We cannot allocate inside the printer (as it may be on an fs-reclaim
path), so hope for the best and build the string on the stack
v3: stack depth of 16 routinely overflows a 512 character string, limit
it to 12 to avoid unsightly truncation.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180628132206.8329-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2018-06-28 14:22:06 +01:00
parent a24362ead9
commit 10195b1e44

View File

@ -21,7 +21,7 @@
* IN THE SOFTWARE.
*
*/
#include "i915_vma.h"
#include "i915_drv.h"
@ -30,6 +30,39 @@
#include <drm/drm_gem.h>
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && IS_ENABLED(CONFIG_DRM_DEBUG_MM)
#include <linux/stackdepot.h>
static void vma_print_allocator(struct i915_vma *vma, const char *reason)
{
unsigned long entries[12];
struct stack_trace trace = {
.entries = entries,
.max_entries = ARRAY_SIZE(entries),
};
char buf[512];
if (!vma->node.stack) {
DRM_DEBUG_DRIVER("vma.node [%08llx + %08llx] %s: unknown owner\n",
vma->node.start, vma->node.size, reason);
return;
}
depot_fetch_stack(vma->node.stack, &trace);
snprint_stack_trace(buf, sizeof(buf), &trace, 0);
DRM_DEBUG_DRIVER("vma.node [%08llx + %08llx] %s: inserted at %s\n",
vma->node.start, vma->node.size, reason, buf);
}
#else
static void vma_print_allocator(struct i915_vma *vma, const char *reason)
{
}
#endif
static void
i915_vma_retire(struct i915_gem_active *active, struct i915_request *rq)
{
@ -875,8 +908,10 @@ int i915_vma_unbind(struct i915_vma *vma)
}
GEM_BUG_ON(i915_vma_is_active(vma));
if (i915_vma_is_pinned(vma))
if (i915_vma_is_pinned(vma)) {
vma_print_allocator(vma, "is pinned");
return -EBUSY;
}
if (!drm_mm_node_allocated(&vma->node))
return 0;