From: Chris Wilson <chris@chris-wilson.co.uk>
To: DRI Development <dri-devel@lists.freedesktop.org>,
Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org, linux-rdma@vger.kernel.org,
Daniel Vetter <daniel.vetter@ffwll.ch>,
intel-gfx@lists.freedesktop.org,
LKML <linux-kernel@vger.kernel.org>,
linaro-mm-sig@lists.linaro.org,
VMware Graphics <linux-graphics-maintainer@vmware.com>,
Ben Skeggs <bskeggs@redhat.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Alex Deucher <alexander.deucher@amd.com>,
Daniel Vetter <daniel.vetter@intel.com>,
linux-media@vger.kernel.org,
Christian König <christian.koenig@amd.com>
Subject: Re: [PATCH] dma-fence: add might_sleep annotation to _wait()
Date: Tue, 19 May 2020 22:51:54 +0100 [thread overview]
Message-ID: <158992511426.8153.12953280000513890247@build.alporthouse.com> (raw)
In-Reply-To: <20200519132756.682888-1-daniel.vetter@ffwll.ch>
Quoting Daniel Vetter (2020-05-19 14:27:56)
> Do it uncontionally, there's a separate peek function with
> dma_fence_is_signalled() which can be called from atomic context.
>
> v2: Consensus calls for an unconditional might_sleep (Chris,
> Christian)
>
> Full audit:
> - dma-fence.h: Uses MAX_SCHEDULE_TIMOUT, good chance this sleeps
> - dma-resv.c: Timeout always at least 1
> - st-dma-fence.c: Save to sleep in testcases
> - amdgpu_cs.c: Both callers are for variants of the wait ioctl
> - amdgpu_device.c: Two callers in vram recover code, both right next
> to mutex_lock.
> - amdgpu_vm.c: Use in the vm_wait ioctl, next to _reserve/unreserve
> - remaining functions in amdgpu: All for test_ib implementations for
> various engines, caller for that looks all safe (debugfs, driver
> load, reset)
> - etnaviv: another wait ioctl
> - habanalabs: another wait ioctl
> - nouveau_fence.c: hardcoded 15*HZ ... glorious
> - nouveau_gem.c: hardcoded 2*HZ ... so not even super consistent, but
> this one does have a WARN_ON :-/ At least this one is only a
> fallback path for when kmalloc fails. Maybe this should be put onto
> some worker list instead, instead of a work per unamp ...
> - i915/selftests: Hardecoded HZ / 4 or HZ / 8
> - i915/gt/selftests: Going up the callchain looks safe looking at
> nearby callers
> - i915/gt/intel_gt_requests.c. Wrapped in a mutex_lock
> - i915/gem_i915_gem_wait.c: The i915-version which is called instead
> for i915 fences already has a might_sleep() annotation, so all good
>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Ben Skeggs <bskeggs@redhat.com>
> Cc: "VMware Graphics" <linux-graphics-maintainer@vmware.com>
> Cc: Oded Gabbay <oded.gabbay@gmail.com>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org
> Cc: linux-rdma@vger.kernel.org
> Cc: amd-gfx@lists.freedesktop.org
> Cc: intel-gfx@lists.freedesktop.org
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Christian König <christian.koenig@amd.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
> drivers/dma-buf/dma-fence.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> index 90edf2b281b0..656e9ac2d028 100644
> --- a/drivers/dma-buf/dma-fence.c
> +++ b/drivers/dma-buf/dma-fence.c
> @@ -208,6 +208,8 @@ dma_fence_wait_timeout(struct dma_fence *fence, bool intr, signed long timeout)
> if (WARN_ON(timeout < 0))
> return -EINVAL;
>
> + might_sleep();
git grep matches your synopsis.
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris
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next prev parent reply other threads:[~2020-05-19 21:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 13:27 [PATCH] dma-fence: add might_sleep annotation to _wait() Daniel Vetter
2020-05-19 21:51 ` Chris Wilson [this message]
2020-05-20 6:54 ` Christian König
2020-05-20 11:03 ` Daniel Vetter
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