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authorChris Wilson <chris@chris-wilson.co.uk>2020-07-13 17:05:49 +0100
committerJani Nikula <jani.nikula@intel.com>2020-07-14 20:31:23 +0300
commit110f9efa858f584c6bed177cd48d0c0f526940e1 (patch)
tree9db4cb71462c2db88ed19882e273aa741eebb312 /drivers/gpu
parent858f1299fd6f7518ddef19ddd304c8398ac79fa5 (diff)
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 (cherry picked from commit 90a987205c6cf74116a102ed446d22d92cdaf915) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/i915/gt/intel_lrc.c18
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 d270d2db6f0a..cb07e1d2a353 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -5396,13 +5396,8 @@ 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)
@@ -5415,15 +5410,9 @@ 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)
@@ -5770,6 +5759,7 @@ 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: