From: Dave Airlie <airlied at redhat.com>
I'm pretty sure this optimisation is actually not a great idea,
and is racy with other things waiting for fences.
Just nuke it, there should be no need to do fence waits in a
busy CPU loop.
Signed-off-by: Dave Airlie <airlied at redhat.com>
---
drivers/gpu/drm/nouveau/nouveau_bo.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_chan.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_dmem.c | 2 +-
drivers/gpu/drm/nouveau/nouveau_fence.c | 30 +------------------------
drivers/gpu/drm/nouveau/nouveau_fence.h | 2 +-
drivers/gpu/drm/nouveau/nouveau_gem.c | 2 +-
6 files changed, 6 insertions(+), 34 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c
b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 8a30f5a0525b..a4e8f625fce6 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -902,7 +902,7 @@ nouveau_bo_move_m2mf(struct ttm_buffer_object *bo, int
evict,
* Without this the operation can timeout and we'll fallback to a
* software copy, which might take several minutes to finish.
*/
- nouveau_fence_wait(fence, false, false);
+ nouveau_fence_wait(fence, false);
ret = ttm_bo_move_accel_cleanup(bo, &fence->base, evict, false,
new_reg);
nouveau_fence_unref(&fence);
diff --git a/drivers/gpu/drm/nouveau/nouveau_chan.c
b/drivers/gpu/drm/nouveau/nouveau_chan.c
index 7c97b2886807..66fca95c10c7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_chan.c
+++ b/drivers/gpu/drm/nouveau/nouveau_chan.c
@@ -72,7 +72,7 @@ nouveau_channel_idle(struct nouveau_channel *chan)
ret = nouveau_fence_new(&fence, chan);
if (!ret) {
- ret = nouveau_fence_wait(fence, false, false);
+ ret = nouveau_fence_wait(fence, false);
nouveau_fence_unref(&fence);
}
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c
b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 12feecf71e75..033a09cd3c8f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -128,7 +128,7 @@ static void nouveau_dmem_page_free(struct page *page)
static void nouveau_dmem_fence_done(struct nouveau_fence **fence)
{
if (fence) {
- nouveau_fence_wait(*fence, true, false);
+ nouveau_fence_wait(*fence, false);
nouveau_fence_unref(fence);
} else {
/*
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c
b/drivers/gpu/drm/nouveau/nouveau_fence.c
index c3ea3cd933cd..8de941379324 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -312,39 +312,11 @@ nouveau_fence_wait_legacy(struct dma_fence *f, bool intr,
long wait)
return timeout - t;
}
-static int
-nouveau_fence_wait_busy(struct nouveau_fence *fence, bool intr)
-{
- int ret = 0;
-
- while (!nouveau_fence_done(fence)) {
- if (time_after_eq(jiffies, fence->timeout)) {
- ret = -EBUSY;
- break;
- }
-
- __set_current_state(intr ?
- TASK_INTERRUPTIBLE :
- TASK_UNINTERRUPTIBLE);
-
- if (intr && signal_pending(current)) {
- ret = -ERESTARTSYS;
- break;
- }
- }
-
- __set_current_state(TASK_RUNNING);
- return ret;
-}
-
int
-nouveau_fence_wait(struct nouveau_fence *fence, bool lazy, bool intr)
+nouveau_fence_wait(struct nouveau_fence *fence, bool intr)
{
long ret;
- if (!lazy)
- return nouveau_fence_wait_busy(fence, intr);
-
ret = dma_fence_wait_timeout(&fence->base, intr, 15 * HZ);
if (ret < 0)
return ret;
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.h
b/drivers/gpu/drm/nouveau/nouveau_fence.h
index bc13110bdfa4..88213014b675 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.h
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.h
@@ -23,7 +23,7 @@ void nouveau_fence_unref(struct nouveau_fence **);
int nouveau_fence_emit(struct nouveau_fence *);
bool nouveau_fence_done(struct nouveau_fence *);
-int nouveau_fence_wait(struct nouveau_fence *, bool lazy, bool intr);
+int nouveau_fence_wait(struct nouveau_fence *, bool intr);
int nouveau_fence_sync(struct nouveau_bo *, struct nouveau_channel *, bool
exclusive, bool intr);
struct nouveau_fence_chan {
diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c
b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 49c2bcbef129..f715e381da69 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -928,7 +928,7 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void
*data,
}
if (sync) {
- if (!(ret = nouveau_fence_wait(fence, false, false))) {
+ if (!(ret = nouveau_fence_wait(fence, false))) {
if ((ret = dma_fence_get_status(&fence->base)) == 1)
ret = 0;
}
--
2.43.2
On 17/4/24 15:40, Dave Airlie wrote:> External email: Use caution opening links or attachments > > > From: Dave Airlie <airlied at redhat.com> > > I'm pretty sure this optimisation is actually not a great idea, > and is racy with other things waiting for fences. > > Just nuke it, there should be no need to do fence waits in a > busy CPU loop. > > Signed-off-by: Dave Airlie <airlied at redhat.com>Reviewed-by: Ben Skeggs <bskeggs at nvidia.com>> --- > drivers/gpu/drm/nouveau/nouveau_bo.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_chan.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_dmem.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_fence.c | 30 +------------------------ > drivers/gpu/drm/nouveau/nouveau_fence.h | 2 +- > drivers/gpu/drm/nouveau/nouveau_gem.c | 2 +- > 6 files changed, 6 insertions(+), 34 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c > index 8a30f5a0525b..a4e8f625fce6 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_bo.c > +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c > @@ -902,7 +902,7 @@ nouveau_bo_move_m2mf(struct ttm_buffer_object *bo, int evict, > * Without this the operation can timeout and we'll fallback to a > * software copy, which might take several minutes to finish. > */ > - nouveau_fence_wait(fence, false, false); > + nouveau_fence_wait(fence, false); > ret = ttm_bo_move_accel_cleanup(bo, &fence->base, evict, false, > new_reg); > nouveau_fence_unref(&fence); > diff --git a/drivers/gpu/drm/nouveau/nouveau_chan.c b/drivers/gpu/drm/nouveau/nouveau_chan.c > index 7c97b2886807..66fca95c10c7 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_chan.c > +++ b/drivers/gpu/drm/nouveau/nouveau_chan.c > @@ -72,7 +72,7 @@ nouveau_channel_idle(struct nouveau_channel *chan) > > ret = nouveau_fence_new(&fence, chan); > if (!ret) { > - ret = nouveau_fence_wait(fence, false, false); > + ret = nouveau_fence_wait(fence, false); > nouveau_fence_unref(&fence); > } > > diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c > index 12feecf71e75..033a09cd3c8f 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_dmem.c > +++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c > @@ -128,7 +128,7 @@ static void nouveau_dmem_page_free(struct page *page) > static void nouveau_dmem_fence_done(struct nouveau_fence **fence) > { > if (fence) { > - nouveau_fence_wait(*fence, true, false); > + nouveau_fence_wait(*fence, false); > nouveau_fence_unref(fence); > } else { > /* > diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c > index c3ea3cd933cd..8de941379324 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_fence.c > +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c > @@ -312,39 +312,11 @@ nouveau_fence_wait_legacy(struct dma_fence *f, bool intr, long wait) > return timeout - t; > } > > -static int > -nouveau_fence_wait_busy(struct nouveau_fence *fence, bool intr) > -{ > - int ret = 0; > - > - while (!nouveau_fence_done(fence)) { > - if (time_after_eq(jiffies, fence->timeout)) { > - ret = -EBUSY; > - break; > - } > - > - __set_current_state(intr ? > - TASK_INTERRUPTIBLE : > - TASK_UNINTERRUPTIBLE); > - > - if (intr && signal_pending(current)) { > - ret = -ERESTARTSYS; > - break; > - } > - } > - > - __set_current_state(TASK_RUNNING); > - return ret; > -} > - > int > -nouveau_fence_wait(struct nouveau_fence *fence, bool lazy, bool intr) > +nouveau_fence_wait(struct nouveau_fence *fence, bool intr) > { > long ret; > > - if (!lazy) > - return nouveau_fence_wait_busy(fence, intr); > - > ret = dma_fence_wait_timeout(&fence->base, intr, 15 * HZ); > if (ret < 0) > return ret; > diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.h b/drivers/gpu/drm/nouveau/nouveau_fence.h > index bc13110bdfa4..88213014b675 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_fence.h > +++ b/drivers/gpu/drm/nouveau/nouveau_fence.h > @@ -23,7 +23,7 @@ void nouveau_fence_unref(struct nouveau_fence **); > > int nouveau_fence_emit(struct nouveau_fence *); > bool nouveau_fence_done(struct nouveau_fence *); > -int nouveau_fence_wait(struct nouveau_fence *, bool lazy, bool intr); > +int nouveau_fence_wait(struct nouveau_fence *, bool intr); > int nouveau_fence_sync(struct nouveau_bo *, struct nouveau_channel *, bool exclusive, bool intr); > > struct nouveau_fence_chan { > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c > index 49c2bcbef129..f715e381da69 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c > @@ -928,7 +928,7 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data, > } > > if (sync) { > - if (!(ret = nouveau_fence_wait(fence, false, false))) { > + if (!(ret = nouveau_fence_wait(fence, false))) { > if ((ret = dma_fence_get_status(&fence->base)) == 1) > ret = 0; > } > -- > 2.43.2 >
On 4/17/24 07:40, Dave Airlie wrote:> From: Dave Airlie <airlied at redhat.com> > > I'm pretty sure this optimisation is actually not a great idea, > and is racy with other things waiting for fences.Yes, I tried to use it in the past on scheduler tear down, to have an indicator whether all jobs had the chance to finish. However, it happened that using a CPU busy loop saw the fence as signaled, while an (event based) dma_fence was still seen as unsignaled.> > Just nuke it, there should be no need to do fence waits in a > busy CPU loop. > > Signed-off-by: Dave Airlie <airlied at redhat.com>Applied to drm-misc-next.> --- > drivers/gpu/drm/nouveau/nouveau_bo.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_chan.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_dmem.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_fence.c | 30 +------------------------ > drivers/gpu/drm/nouveau/nouveau_fence.h | 2 +- > drivers/gpu/drm/nouveau/nouveau_gem.c | 2 +- > 6 files changed, 6 insertions(+), 34 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c > index 8a30f5a0525b..a4e8f625fce6 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_bo.c > +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c > @@ -902,7 +902,7 @@ nouveau_bo_move_m2mf(struct ttm_buffer_object *bo, int evict, > * Without this the operation can timeout and we'll fallback to a > * software copy, which might take several minutes to finish. > */ > - nouveau_fence_wait(fence, false, false); > + nouveau_fence_wait(fence, false); > ret = ttm_bo_move_accel_cleanup(bo, &fence->base, evict, false, > new_reg); > nouveau_fence_unref(&fence); > diff --git a/drivers/gpu/drm/nouveau/nouveau_chan.c b/drivers/gpu/drm/nouveau/nouveau_chan.c > index 7c97b2886807..66fca95c10c7 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_chan.c > +++ b/drivers/gpu/drm/nouveau/nouveau_chan.c > @@ -72,7 +72,7 @@ nouveau_channel_idle(struct nouveau_channel *chan) > > ret = nouveau_fence_new(&fence, chan); > if (!ret) { > - ret = nouveau_fence_wait(fence, false, false); > + ret = nouveau_fence_wait(fence, false); > nouveau_fence_unref(&fence); > } > > diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c > index 12feecf71e75..033a09cd3c8f 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_dmem.c > +++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c > @@ -128,7 +128,7 @@ static void nouveau_dmem_page_free(struct page *page) > static void nouveau_dmem_fence_done(struct nouveau_fence **fence) > { > if (fence) { > - nouveau_fence_wait(*fence, true, false); > + nouveau_fence_wait(*fence, false); > nouveau_fence_unref(fence); > } else { > /* > diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c > index c3ea3cd933cd..8de941379324 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_fence.c > +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c > @@ -312,39 +312,11 @@ nouveau_fence_wait_legacy(struct dma_fence *f, bool intr, long wait) > return timeout - t; > } > > -static int > -nouveau_fence_wait_busy(struct nouveau_fence *fence, bool intr) > -{ > - int ret = 0; > - > - while (!nouveau_fence_done(fence)) { > - if (time_after_eq(jiffies, fence->timeout)) { > - ret = -EBUSY; > - break; > - } > - > - __set_current_state(intr ? > - TASK_INTERRUPTIBLE : > - TASK_UNINTERRUPTIBLE); > - > - if (intr && signal_pending(current)) { > - ret = -ERESTARTSYS; > - break; > - } > - } > - > - __set_current_state(TASK_RUNNING); > - return ret; > -} > - > int > -nouveau_fence_wait(struct nouveau_fence *fence, bool lazy, bool intr) > +nouveau_fence_wait(struct nouveau_fence *fence, bool intr) > { > long ret; > > - if (!lazy) > - return nouveau_fence_wait_busy(fence, intr); > - > ret = dma_fence_wait_timeout(&fence->base, intr, 15 * HZ); > if (ret < 0) > return ret; > diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.h b/drivers/gpu/drm/nouveau/nouveau_fence.h > index bc13110bdfa4..88213014b675 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_fence.h > +++ b/drivers/gpu/drm/nouveau/nouveau_fence.h > @@ -23,7 +23,7 @@ void nouveau_fence_unref(struct nouveau_fence **); > > int nouveau_fence_emit(struct nouveau_fence *); > bool nouveau_fence_done(struct nouveau_fence *); > -int nouveau_fence_wait(struct nouveau_fence *, bool lazy, bool intr); > +int nouveau_fence_wait(struct nouveau_fence *, bool intr); > int nouveau_fence_sync(struct nouveau_bo *, struct nouveau_channel *, bool exclusive, bool intr); > > struct nouveau_fence_chan { > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c > index 49c2bcbef129..f715e381da69 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c > @@ -928,7 +928,7 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data, > } > > if (sync) { > - if (!(ret = nouveau_fence_wait(fence, false, false))) { > + if (!(ret = nouveau_fence_wait(fence, false))) { > if ((ret = dma_fence_get_status(&fence->base)) == 1) > ret = 0; > }