[PATCH] drm/ttm: Break out the loops if need_resched in bo delayed delete worker

[PATCH] drm/ttm: Break out the loops if need_resched in bo delayed delete worker

[xinhui pan]

The delayed delete list is per device which might be very huge. And in
a heavy workload test, the list might always not be empty. That will
trigger any RCU stall warnings or softlockups in non-preemptible kernels
Lets do break out the loops in that case.

Signed-off-by: xinhui pan <xinhui.pan@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 9e07c3f75156..c5b516fa4eae 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -518,7 +518,7 @@ static bool ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all)
 	INIT_LIST_HEAD(&removed);
 
 	spin_lock(&glob->lru_lock);
-	while (!list_empty(&bdev->ddestroy)) {
+	while (!list_empty(&bdev->ddestroy) && !need_resched()) {
 		struct ttm_buffer_object *bo;
 
 		bo = list_first_entry(&bdev->ddestroy, struct ttm_buffer_object,
-- 
2.17.1

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Re: [PATCH] drm/ttm: Break out the loops if need_resched in bo delayed delete worker

[Alex Deucher]

Can you make sure this lands in drm-misc?

Thanks,

Alex

On Fri, Apr 10, 2020 at 8:15 AM Koenig, Christian
<Christian.Koenig@amd.com> wrote:
>
>
>
> Am 10.04.2020 12:58 schrieb "Pan, Xinhui" <Xinhui.Pan@amd.com>:
>
> The delayed delete list is per device which might be very huge. And in
> a heavy workload test, the list might always not be empty. That will
> trigger any RCU stall warnings or softlockups in non-preemptible kernels
> Lets do break out the loops in that case.
>
> Signed-off-by: xinhui pan <xinhui.pan@amd.com>
>
>
> Reviewed-by: Christian König <christian.koenig@amd.com>
>
> ---
>  drivers/gpu/drm/ttm/ttm_bo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 9e07c3f75156..c5b516fa4eae 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -518,7 +518,7 @@ static bool ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all)
>          INIT_LIST_HEAD(&removed);
>
>          spin_lock(&glob->lru_lock);
> -       while (!list_empty(&bdev->ddestroy)) {
> +       while (!list_empty(&bdev->ddestroy) && !need_resched()) {
>                  struct ttm_buffer_object *bo;
>
>                  bo = list_first_entry(&bdev->ddestroy, struct ttm_buffer_object,
> --
> 2.17.1
>
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
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Re: [PATCH] drm/ttm: Break out the loops if need_resched in bo delayed delete worker

[Koenig, Christian]

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Am 10.04.2020 12:58 schrieb "Pan, Xinhui" <Xinhui.Pan@amd.com>:
The delayed delete list is per device which might be very huge. And in
a heavy workload test, the list might always not be empty. That will
trigger any RCU stall warnings or softlockups in non-preemptible kernels
Lets do break out the loops in that case.

Signed-off-by: xinhui pan <xinhui.pan@amd.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

---
 drivers/gpu/drm/ttm/ttm_bo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 9e07c3f75156..c5b516fa4eae 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -518,7 +518,7 @@ static bool ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all)
         INIT_LIST_HEAD(&removed);

         spin_lock(&glob->lru_lock);
-       while (!list_empty(&bdev->ddestroy)) {
+       while (!list_empty(&bdev->ddestroy) && !need_resched()) {
                 struct ttm_buffer_object *bo;

                 bo = list_first_entry(&bdev->ddestroy, struct ttm_buffer_object,
--
2.17.1



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