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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2020-07-13 19:05:49 +0300 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2020-07-13 19:57:38 +0300 |
| commit | 90a987205c6cf74116a102ed446d22d92cdaf915 (patch) | |
| tree | 1075790bafa99846d46e7850ded195c4b51fe4d3 /drivers/gpu/drm/i915 | |
| parent | d2921096e707bdde92bc635cd89ec1fe85a9faee (diff) | |
| download | linux-90a987205c6cf74116a102ed446d22d92cdaf915.tar.xz | |
drm/i915/gt: Only swap to a random sibling once upon creation
The danger in switching at random upon intel_context_pin is that the
context may still actually be inflight, as it will not be scheduled out
until a context switch after it is complete -- that may be a long time
after we do a final intel_context_unpin.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2118
Fixes: 6d06779e8672 ("drm/i915: Load balancing across a virtual engine")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: <stable@vger.kernel.org> # v5.3+
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200713160549.17344-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915')
| -rw-r--r-- | drivers/gpu/drm/i915/gt/intel_lrc.c | 18 |
1 files changed, 4 insertions, 14 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 028d698a7f98..e0280a672f1d 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -5432,13 +5432,8 @@ static void virtual_engine_initial_hint(struct virtual_engine *ve) * typically be the first we inspect for submission. */ swp = prandom_u32_max(ve->num_siblings); - if (!swp) - return; - - swap(ve->siblings[swp], ve->siblings[0]); - if (!intel_engine_has_relative_mmio(ve->siblings[0])) - virtual_update_register_offsets(ve->context.lrc_reg_state, - ve->siblings[0]); + if (swp) + swap(ve->siblings[swp], ve->siblings[0]); } static int virtual_context_alloc(struct intel_context *ce) @@ -5451,15 +5446,9 @@ static int virtual_context_alloc(struct intel_context *ce) static int virtual_context_pin(struct intel_context *ce) { struct virtual_engine *ve = container_of(ce, typeof(*ve), context); - int err; /* Note: we must use a real engine class for setting up reg state */ - err = __execlists_context_pin(ce, ve->siblings[0]); - if (err) - return err; - - virtual_engine_initial_hint(ve); - return 0; + return __execlists_context_pin(ce, ve->siblings[0]); } static void virtual_context_enter(struct intel_context *ce) @@ -5806,6 +5795,7 @@ intel_execlists_create_virtual(struct intel_engine_cs **siblings, ve->base.flags |= I915_ENGINE_IS_VIRTUAL; + virtual_engine_initial_hint(ve); return &ve->context; err_put: |