On 11/04/2014 02:31 PM, Chris Wilson wrote:
Running __mmu_notifier_register() is surprisingly expensive, so let's
not do that unless we have to.
Affects some program startup or what? What is the cost? I would add some
notes in the commit for future reference.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
intel/intel_bufmgr_gem.c | 114 +++++++++++++++++++++++++++--------------------
1 file changed, 65 insertions(+), 49 deletions(-)
diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index f2f4fea..addf413 100644
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -935,6 +935,70 @@ drm_intel_gem_bo_alloc_userptr(drm_intel_bufmgr *bufmgr,
return &bo_gem->bo;
}
+static bool
+has_userptr(drm_intel_bufmgr_gem *bufmgr_gem)
+{
+ int ret;
+ void *ptr;
+ long pgsz;
+ struct drm_i915_gem_userptr userptr;
+ struct drm_gem_close close_bo;
+
+ pgsz = sysconf(_SC_PAGESIZE);
+ assert(pgsz > 0);
+
+ ret = posix_memalign(&ptr, pgsz, pgsz);
+ if (ret) {
+ DBG("Failed to get a page (%ld) for userptr detection!\n",
+ pgsz);
+ return false;
+ }
+
+ memset(&userptr, 0, sizeof(userptr));
+ userptr.user_ptr = (__u64)(unsigned long)ptr;
+ userptr.user_size = pgsz;
+
+retry:
+ ret = drmIoctl(bufmgr_gem->fd, DRM_IOCTL_I915_GEM_USERPTR, &userptr);
+ if (ret) {
+ if (errno == ENODEV && userptr.flags == 0) {
+ userptr.flags = I915_USERPTR_UNSYNCHRONIZED;
+ goto retry;
+ }
+ free(ptr);
+ return false;
+ }
+
+ close_bo.handle = userptr.handle;
+ ret = drmIoctl(bufmgr_gem->fd, DRM_IOCTL_GEM_CLOSE, &close_bo);
+ free(ptr);
+ if (ret) {
+ fprintf(stderr, "Failed to release test userptr object! (%d) "
+ "i915 kernel driver may not be sane!\n", errno);
+ return false;
+ }
+
+ return true;
+}
+
+static drm_intel_bo *
+check_bo_alloc_userptr(drm_intel_bufmgr *bufmgr,
+ const char *name,
+ void *addr,
+ uint32_t tiling_mode,
+ uint32_t stride,
+ unsigned long size,
+ unsigned long flags)
+{
+ if (has_userptr((drm_intel_bufmgr_gem *)bufmgr))
+ bufmgr->bo_alloc_userptr = drm_intel_bo_alloc_userptr;
I wouldn't have spotted this - so retroactively compile tested I assume?
Otherwise,
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Regards,
Tvrtko
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