Commits · 6341eb6f39bb76018676dc85e01596bf32a592f6 · Kirill Smelkov / linux

24 Sep, 2021 10 commits

drm/i915/selftests: exercise shmem_writeback with THP · 6341eb6f

Matthew Auld authored Sep 21, 2021

In commit:

commit 1e6decf3
Author: Hugh Dickins <hughd@google.com>
Date:   Thu Sep 2 14:54:43 2021 -0700

    shmem: shmem_writepage() split unlikely i915 THP

it looks THP + shmem_writeback was an unexpected combination, and ends up
hitting some BUG_ON, but it also looks like that is now fixed.

While the IGTs did eventually hit this(although not during pre-merge it
seems), it's likely worthwhile adding some explicit coverage for this
scenario in the shrink_thp selftest.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/4166Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210921142116.3807946-1-matthew.auld@intel.com

6341eb6f

drm/i915/request: fix early tracepoints · be988eae

Matthew Auld authored Sep 21, 2021

Currently we blow up in trace_dma_fence_init, when calling into
get_driver_name or get_timeline_name, since both the engine and context
might be NULL(or contain some garbage address) in the case of newly
allocated slab objects via the request ctor. Note that we also use
SLAB_TYPESAFE_BY_RCU here, which allows requests to be immediately
freed, but delay freeing the underlying page by an RCU grace period.
With this scheme requests can be re-allocated, at the same time as they
are also being read by some lockless RCU lookup mechanism.

In the ctor case, which is only called for new slab objects(i.e allocate
new page and call the ctor for each object) it's safe to reset the
context/engine prior to calling into dma_fence_init, since we can be
certain that no one is doing an RCU lookup which might depend on peeking
at the engine/context, like in active_engine(), since the object can't
yet be externally visible.

In the recycled case(which might also be externally visible) the request
refcount always transitions from 0->1 after we set the context/engine
etc, which should ensure it's valid to dereference the engine for
example, when doing an RCU list-walk, so long as we can also increment
the refcount first. If the refcount is already zero, then the request is
considered complete/released.  If it's non-zero, then the request might
be in the process of being re-allocated, or potentially still in flight,
however after successfully incrementing the refcount, it's possible to
carefully inspect the request state, to determine if the request is
still what we were looking for. Note that all externally visible
requests returned to the cache must have zero refcount.

One possible fix then is to move dma_fence_init out from the request
ctor. Originally this was how it was done, but it was moved in:

commit 855e39e6
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Feb 3 09:41:48 2020 +0000

    drm/i915: Initialise basic fence before acquiring seqno

where it looks like intel_timeline_get_seqno() relied on some of the
rq->fence state, but that is no longer the case since:

commit 12ca695d
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date:   Tue Mar 23 16:49:50 2021 +0100

    drm/i915: Do not share hwsp across contexts any more, v8.

intel_timeline_get_seqno() could also be cleaned up slightly by dropping
the request argument.

Moving dma_fence_init back out of the ctor, should ensure we have enough
of the request initialised in case of trace_dma_fence_init.
Functionally this should be the same, and is effectively what we were
already open coding before, except now we also assign the fence->lock
and fence->ops, but since these are invariant for recycled
requests(which might be externally visible), and will therefore already
hold the same value, it shouldn't matter.

An alternative fix, since we don't yet have a fully initialised request
when in the ctor, is just setting the context/engine as NULL, but this
does require adding some extra handling in get_driver_name etc.

v2(Daniel):
  - Try to make the commit message less confusing

Fixes: 855e39e6 ("drm/i915: Initialise basic fence before acquiring seqno")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Michael Mason <michael.w.mason@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210921134202.3803151-1-matthew.auld@intel.com

be988eae

drm/i915: Reduce the number of objects subject to memcpy recover · a259cc14

Thomas Hellström authored Sep 22, 2021

We really only need memcpy restore for objects that affect the
operability of the migrate context. That is, primarily the page-table
objects of the migrate VM.

Add an object flag, I915_BO_ALLOC_PM_EARLY for objects that need early
restores using memcpy and a way to assign LMEM page-table object flags
to be used by the vms.

Restore objects without this flag with the gpu blitter and only objects
carrying the flag using TTM memcpy.

Initially mark the migrate, gt, gtt and vgpu vms to use this flag, and
defer for a later audit which vms actually need it. Most importantly, user-
allocated vms with pinned page-table objects can be restored using the
blitter.

Performance-wise memcpy restore is probably as fast as gpu restore if not
faster, but using gpu restore will help tackling future restrictions in
mappable LMEM size.

v4:
- Don't mark the aliasing ppgtt page table flags for early resume, but
  rather the ggtt page table flags as intended. (Matthew Auld)
- The check for user buffer objects during early resume is pointless, since
  they are never marked I915_BO_ALLOC_PM_EARLY. (Matthew Auld)
v5:
- Mark GuC LMEM objects with I915_BO_ALLOC_PM_EARLY to have them restored
  before we fire up the migrate context.

Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-8-thomas.hellstrom@linux.intel.com

a259cc14

drm/i915: Don't back up pinned LMEM context images and rings during suspend · 0d8ee5ba

Thomas Hellström authored Sep 22, 2021

Pinned context images are now reset during resume. Don't back them up,
and assuming that rings can be assumed empty at suspend, don't back them
up either.

Introduce a new object flag, I915_BO_ALLOC_PM_VOLATILE meaning that an
object is allowed to lose its content on suspend.

v3:
- Slight documentation clarification (Matthew Auld)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-7-thomas.hellstrom@linux.intel.com

0d8ee5ba

drm/i915/gt: Register the migrate contexts with their engines · 3e42cc61

Thomas Hellström authored Sep 22, 2021

Pinned contexts, like the migrate contexts need reset after resume
since their context image may have been lost. Also the GuC needs to
register pinned contexts.

Add a list to struct intel_engine_cs where we add all pinned contexts on
creation, and traverse that list at resume time to reset the pinned
contexts.

This fixes the kms_pipe_crc_basic@suspend-read-crc-pipe-a selftest for now,
but proper LMEM backup / restore is needed for full suspend functionality.
However, note that even with full LMEM backup / restore it may be
desirable to keep the reset since backing up the migrate context images
must happen using memcpy() after the migrate context has become inactive,
and for performance- and other reasons we want to avoid memcpy() from
LMEM.

Also traverse the list at guc_init_lrc_mapping() calling
guc_kernel_context_pin() for the pinned contexts, like is already done
for the kernel context.

v2:
- Don't reset the contexts on each __engine_unpark() but rather at
  resume time (Chris Wilson).
v3:
- Reset contexts in the engine sanitize callback. (Chris Wilson)

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Brost Matthew <matthew.brost@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-6-thomas.hellstrom@linux.intel.com

3e42cc61

drm/i915 Implement LMEM backup and restore for suspend / resume · c56ce956

Thomas Hellström authored Sep 22, 2021

Just evict unpinned objects to system. For pinned LMEM objects,
make a backup system object and blit the contents to that.

Backup is performed in three steps,
1: Opportunistically evict evictable objects using the gpu blitter.
2: After gt idle, evict evictable objects using the gpu blitter. This will
be modified in an upcoming patch to backup pinned objects that are not used
by the blitter itself.
3: Backup remaining pinned objects using memcpy.

Also move uC suspend to after 2) to make sure we have a functional GuC
during 2) if using GuC submission.

v2:
- Major refactor to make sure gem_exec_suspend@hang-SX subtests work, and
suspend / resume works with a slightly modified GuC submission enabling
patch series.

v3:
- Fix a potential use-after-free (Matthew Auld)
- Use i915_gem_object_create_shmem() instead of
i915_gem_object_create_region (Matthew Auld)
- Minor simplifications (Matthew Auld)
- Fix up kerneldoc for i195_ttm_restore_region().
- Final lmem_suspend() call moved to i915_gem_backup_suspend from
i915_gem_suspend_late, since the latter gets called at driver unload
and we don't unnecessarily want to run it at that time.

v4:
- Interface change of ttm- & lmem suspend / resume functions to use
flags rather than bools. (Matthew Auld)
- Completely drop the i915_gem_backup_suspend change (Matthew Auld)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-5-thomas.hellstrom@linux.intel.com

c56ce956

drm/i915/gt: Increase suspend timeout · 81387fc4

Thomas Hellström authored Sep 22, 2021

With GuC submission on DG1, the execution of the requests times out
for the gem_exec_suspend igt test case after executing around 800-900
of 1000 submitted requests.

Given the time we allow elsewhere for fences to signal (in the order of
seconds), increase the timeout before we mark the gt wedged and proceed.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Acked-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-4-thomas.hellstrom@linux.intel.com

81387fc4

drm/i915/gem: Implement a function to process all gem objects of a region · d80ee88e

Thomas Hellström authored Sep 22, 2021

An upcoming common pattern is to traverse the region object list and
perform certain actions on all objects in a region. It's a little tricky
to get the list locking right, in particular since a gem object may
change region unless it's pinned or the object lock is held.

Define a function that does this for us and that takes an argument that
defines the action to be performed on each object.

v3:
- Improve structure documentation a bit (Matthew Auld)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-3-thomas.hellstrom@linux.intel.com

d80ee88e

drm/i915/ttm: Implement a function to copy the contents of two TTM-based objects · 0d938863

Thomas Hellström authored Sep 22, 2021

When backing up or restoring contents of pinned objects at suspend /
resume time we need to allocate a new object as the backup. Add a function
to facilitate copies between the two. Some data needs to be copied before
the migration context is ready for operation, so make sure we can
disable accelerated copies.

v2:
- Fix a missing return value check (Matthew Auld)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-2-thomas.hellstrom@linux.intel.com

0d938863

drm/i915/gem: Fix a lockdep warning the __i915_gem_is_lmem() function · 2dfa597d

Thomas Hellström authored Sep 22, 2021

Somehow we managed to invert the test for i915_gem_object_evictable(),
which causes a warning in DG1 BAT, igt@debugfs_test@read_all_entries.

Fix the lock check to only warn if the object *is* indeed evictable and
not protected from eviction by fences.

Cc: Matthew Brost <matthew.brost@intel.com>
Fixes: 91160c83 ("drm/i915: Take pinning into account in __i915_gem_object_is_lmem")
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922083807.888206-2-thomas.hellstrom@linux.intel.com

2dfa597d

23 Sep, 2021 2 commits

drm/i915/guc, docs: Fix pdfdocs build error by removing nested grid · 017792a0

Akira Yokosawa authored Sep 20, 2021

Nested grids in grid-table cells are not specified as proper ReST
constructs.
Commit 572f2a5c ("drm/i915/guc: Update firmware to v62.0.0")
added a couple of kerneldoc tables of the form:

  +---+-------+------------------------------------------------------+
  | 1 |  31:0 |  +------------------------------------------------+  |
  +---+-------+  |                                                |  |
  |...|       |  |  Embedded `HXG Message`_                       |  |
  +---+-------+  |                                                |  |
  | n |  31:0 |  +------------------------------------------------+  |
  +---+-------+------------------------------------------------------+

For "make htmldocs", they happen to work as one might expect,
but they are incompatible with "make latexdocs" and "make pdfdocs",
and cause the generated gpu.tex file to become incomplete and
unbuildable by xelatex.

Restore the compatibility by removing those nested grids in the tables.

Size comparison of generated gpu.tex:

                  Sphinx 2.4.4  Sphinx 4.2.0
  v5.14:               3238686       3841631
  v5.15-rc1:            376270        432729
  with this fix:       3377846       3998095

Fixes: 572f2a5c ("drm/i915/guc: Update firmware to v62.0.0")
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4a227569-074f-c501-58bb-d0d8f60a8ae9@gmail.com

017792a0

drm/i915/uncore: fwtable read handlers are now used on all forcewake platforms · 54fc4f13

Matt Roper authored Sep 22, 2021

With the recent refactor of the uncore mmio handling, all
forcewake-based platforms (i.e., graphics version 6 and beyond) now use
the 'fwtable' read handlers. Let's pull the assignment out of the
per-platform if/else ladder to make this more obvious.
Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Suggested-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210923003029.2194375-1-matthew.d.roper@intel.com

54fc4f13

22 Sep, 2021 7 commits

drm/i915/debugfs: Do not report currently active engine when describing objects · 68c03c0e

Tvrtko Ursulin authored Sep 15, 2021

It is not very useful to have code which tries to report a rapidly
transient state which will not report anything majority of the time,
especially since it is currently only used from
<debugfs>/i915_gem_framebuffers.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210915114153.951670-1-tvrtko.ursulin@linux.intel.com