From: Daniel Vetter <daniel@ffwll.ch>
To: Matthew Brost <matthew.brost@intel.com>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
daniel.vetter@ffwll.ch
Subject: Re: [Intel-gfx] [PATCH 02/22] drm/i915/guc: Fix outstanding G2H accounting
Date: Tue, 17 Aug 2021 11:39:29 +0200 [thread overview]
Message-ID: <YRuD0bTDQTivDZux@phenom.ffwll.local> (raw)
In-Reply-To: <20210816135139.10060-3-matthew.brost@intel.com>
On Mon, Aug 16, 2021 at 06:51:19AM -0700, Matthew Brost wrote:
> A small race that could result in incorrect accounting of the number
> of outstanding G2H. Basically prior to this patch we did not increment
> the number of outstanding G2H if we encoutered a GT reset while sending
> a H2G. This was incorrect as the context state had already been updated
> to anticipate a G2H response thus the counter should be incremented.
>
> Fixes: f4eb1f3fe946 ("drm/i915/guc: Ensure G2H response has space in buffer")
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> Cc: <stable@vger.kernel.org>
> ---
> drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index 69faa39da178..b5d3972ae164 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -360,11 +360,13 @@ static int guc_submission_send_busy_loop(struct intel_guc *guc,
> {
> int err;
>
> - err = intel_guc_send_busy_loop(guc, action, len, g2h_len_dw, loop);
> -
> - if (!err && g2h_len_dw)
> + if (g2h_len_dw)
> atomic_inc(&guc->outstanding_submission_g2h);
>
> + err = intel_guc_send_busy_loop(guc, action, len, g2h_len_dw, loop);
I'm majorly confused by the _busy_loop naming scheme, especially here.
Like "why do we want to send a busy loop comand to guc, this doesn't make
sense".
It seems like you're using _busy_loop as a suffix for "this is ok to be
called in atomic context". The linux kernel bikeshed for this is generally
_atomic() (or _in_atomic() or something like that). Would be good to
rename to make this slightly less confusing.
-Daniel
> + if (err == -EBUSY && g2h_len_dw)
> + atomic_dec(&guc->outstanding_submission_g2h);
> +
> return err;
> }
>
> --
> 2.32.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2021-08-17 9:39 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-16 13:51 [Intel-gfx] [PATCH 00/22] Clean up GuC CI failures, simplify locking, and kernel DOC Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 01/22] drm/i915/guc: Fix blocked context accounting Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 02/22] drm/i915/guc: Fix outstanding G2H accounting Matthew Brost
2021-08-17 9:39 ` Daniel Vetter [this message]
2021-08-17 18:17 ` Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 03/22] drm/i915/guc: Unwind context requests in reverse order Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 04/22] drm/i915/guc: Don't drop ce->guc_active.lock when unwinding context Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 05/22] drm/i915/guc: Workaround reset G2H is received after schedule done G2H Matthew Brost
2021-08-17 9:32 ` Daniel Vetter
2021-08-17 15:03 ` Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 06/22] drm/i915/execlists: Do not propagate errors to dependent fences Matthew Brost
2021-08-17 9:21 ` Daniel Vetter
2021-08-17 15:08 ` Matthew Brost
2021-08-17 15:49 ` Daniel Vetter
2021-08-16 13:51 ` [Intel-gfx] [PATCH 07/22] drm/i915/selftests: Add a cancel request selftest that triggers a reset Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 08/22] drm/i915/guc: Don't enable scheduling on a banned context, guc_id invalid, not registered Matthew Brost
2021-08-17 9:47 ` Daniel Vetter
2021-08-17 9:57 ` Daniel Vetter
2021-08-17 16:44 ` Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 09/22] drm/i915/selftests: Fix memory corruption in live_lrc_isolation Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 10/22] drm/i915/selftests: Add initial GuC selftest for scrubbing lost G2H Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 11/22] drm/i915/guc: Take context ref when cancelling request Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 12/22] drm/i915/guc: Don't touch guc_state.sched_state without a lock Matthew Brost
2021-08-17 7:21 ` kernel test robot
2021-08-16 13:51 ` [Intel-gfx] [PATCH 13/22] drm/i915/guc: Reset LRC descriptor if register returns -ENODEV Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 14/22] drm/i915: Allocate error capture in atomic context Matthew Brost
2021-08-17 10:06 ` Daniel Vetter
2021-08-17 16:12 ` Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 15/22] drm/i915/guc: Flush G2H work queue during reset Matthew Brost
2021-08-17 10:06 ` Daniel Vetter
2021-08-16 13:51 ` [Intel-gfx] [PATCH 16/22] drm/i915/guc: Release submit fence from an IRQ Matthew Brost
2021-08-17 10:08 ` Daniel Vetter
2021-08-16 13:51 ` [Intel-gfx] [PATCH 17/22] drm/i915/guc: Move guc_blocked fence to struct guc_state Matthew Brost
2021-08-17 10:10 ` Daniel Vetter
2021-08-16 13:51 ` [Intel-gfx] [PATCH 18/22] drm/i915/guc: Rework and simplify locking Matthew Brost
2021-08-17 10:15 ` Daniel Vetter
2021-08-17 15:30 ` Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 19/22] drm/i915/guc: Proper xarray usage for contexts_lookup Matthew Brost
2021-08-17 10:27 ` Daniel Vetter
2021-08-17 15:26 ` Matthew Brost
2021-08-17 17:13 ` Daniel Vetter
2021-08-17 17:13 ` Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 20/22] drm/i915/guc: Drop pin count check trick between sched_disable and re-pin Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 21/22] drm/i915/guc: Move GuC priority fields in context under guc_active Matthew Brost
2021-08-16 13:51 ` [Intel-gfx] [PATCH 22/22] drm/i915/guc: Add GuC kernel doc Matthew Brost
2021-08-17 11:11 ` Daniel Vetter
2021-08-17 16:36 ` Matthew Brost
2021-08-17 17:20 ` Daniel Vetter
2021-08-17 17:27 ` Michal Wajdeczko
2021-08-17 17:34 ` Daniel Vetter
2021-08-17 20:41 ` Michal Wajdeczko
2021-08-17 21:49 ` Daniel Vetter
2021-08-17 12:49 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for Clean up GuC CI failures, simplify locking, and kernel DOC (rev2) Patchwork
2021-08-17 12:51 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-08-17 13:22 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-08-17 14:39 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
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