Replace the struct_mutex requirement for pinning the i915_vma with the
local vm->mutex instead. Note that the vm->mutex is tainted by the
shrinker (we require unbinding from inside fs-reclaim) and so we cannot
allocate while holding that mutex. Instead we have to preallocate
workers to do allocate and apply the PTE updates after we have we
reserved their slot in the drm_mm (using fences to order the PTE writes
with the GPU work and with later unbind).
In adding the asynchronous vma binding, one subtle requirement is to
avoid coupling the binding fence into the backing object->resv. That is
the asynchronous binding only applies to the vma timeline itself and not
to the pages as that is a more global timeline (the binding of one vma
does not need to be ordered with another vma, nor does the implicit GEM
fencing depend on a vma, only on writes to the backing store). Keeping
the vma binding distinct from the backing store timelines is verified by
a number of async gem_exec_fence and gem_exec_schedule tests. The way we
do this is quite simple, we keep the fence for the vma binding separate
and only wait on it as required, and never add it to the obj->resv
itself.
Another consequence in reducing the locking around the vma is the
destruction of the vma is no longer globally serialised by struct_mutex.
A natural solution would be to add a kref to i915_vma, but that requires
decoupling the reference cycles, possibly by introducing a new
i915_mm_pages object that is own by both obj->mm and vma->pages.
However, we have not taken that route due to the overshadowing lmem/ttm
discussions, and instead play a series of complicated games with
trylocks to (hopefully) ensure that only one destruction path is called!
v2: Add some commentary, and some helpers to reduce patch churn.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-4-chris@chris-wilson.co.uk
Everything about the file is about display, and mostly about types
related to display. Move under display/ as intel_display_types.h to
reflect the facts.
There's still plenty to clean up, but start off with moving the file
where it logically belongs and naming according to contents.
v2: fix the include guard name in the renamed file
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190806113933.11799-1-jani.nikula@intel.com
If we map an object as readonly into the GTT, we know that the GPU
cannot have written to it and so the object is not dirty and we don't
need to flush the writes back to the system.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190709081718.27843-1-chris@chris-wilson.co.uk
set_page_dirty says:
For pages with a mapping this should be done under the page lock
for the benefit of asynchronous memory errors who prefer a
consistent dirty state. This rule can be broken in some special
cases, but should be better not to.
Under those rules, it is only safe for us to use the plain set_page_dirty
calls for shmemfs/anonymous memory. Userptr may be used with real
mappings and so needs to use the locked version (set_page_dirty_lock).
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203317
Fixes: 5cc9ed4b9a ("drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl")
References: 6dcc693bc5 ("ext4: warn when page is dirtied without buffers")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190708140327.26825-1-chris@chris-wilson.co.uk
As we have dropped the final reference to the object, we do not need to
wait until after the rcu grace period to drop its pages. We still require
struct_mutex to completely unbind the object to release the pages, so we
still need a free-worker to manage that from process context. By
scheduling the release of pages before waiting for the rcu should mean
that we are not trapping those pages from beyond the reach of the
shrinker.
v2: Pass along the request to skip if the vma is busy to the underlying
unbind routine, to avoid checking the reservation underneath the
i915->mm.obj_lock which may be used from inside irq context.
v3: Flip the bit for unbinding while active, for later convenience.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111035
Fixes: a93615f900 ("drm/i915: Throw away the active object retirement complexity")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190703091726.11690-6-chris@chris-wilson.co.uk
Out scatterlist utility routines can be pulled out of i915_gem.h for a
bit more decluttering.
v2: Push I915_GTT_PAGE_SIZE out of i915_scatterlist itself and into the
caller.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528092956.14910-9-chris@chris-wilson.co.uk
