Give the scheduler a chance to breathe by calling cond_resched() as some of the loops may take some time on old machines (apl/bsw/pnv), and so catch the attention of the watchdogs.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12904 Signed-off-by: Nitin Gote <nitin.r.g...@intel.com> --- Cc: Christian Konig <christian.koe...@amd.com> Hi Konig, This is not a functional issue in test. We wish to prevent softlock and allow the dma-fence-chain test run to completion to verify it's functional correctness. The performance issue takes about 5ms for the dma-fence-chain to be signalled on older hardware which is an orthogonal issue and to be debugged separately for which the test has to run to completion. So, reverting to cond_resched() which fixes the issue instead of delay functions. - Nitin drivers/dma-buf/st-dma-fence-chain.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/st-dma-fence-chain.c b/drivers/dma-buf/st-dma-fence-chain.c index ed4b323886e4..328a66ed59e5 100644 --- a/drivers/dma-buf/st-dma-fence-chain.c +++ b/drivers/dma-buf/st-dma-fence-chain.c @@ -505,6 +505,7 @@ static int signal_forward(void *arg) for (i = 0; i < fc.chain_length; i++) { dma_fence_signal(fc.fences[i]); + cond_resched(); if (!dma_fence_is_signaled(fc.chains[i])) { pr_err("chain[%d] not signaled!\n", i); @@ -537,6 +538,7 @@ static int signal_backward(void *arg) for (i = fc.chain_length; i--; ) { dma_fence_signal(fc.fences[i]); + cond_resched(); if (i > 0 && dma_fence_is_signaled(fc.chains[i])) { pr_err("chain[%d] is signaled!\n", i); @@ -587,8 +589,10 @@ static int wait_forward(void *arg) get_task_struct(tsk); yield_to(tsk, true); - for (i = 0; i < fc.chain_length; i++) + for (i = 0; i < fc.chain_length; i++) { dma_fence_signal(fc.fences[i]); + cond_resched(); + } err = kthread_stop_put(tsk); @@ -616,8 +620,10 @@ static int wait_backward(void *arg) get_task_struct(tsk); yield_to(tsk, true); - for (i = fc.chain_length; i--; ) + for (i = fc.chain_length; i--; ) { dma_fence_signal(fc.fences[i]); + cond_resched(); + } err = kthread_stop_put(tsk); @@ -663,8 +669,10 @@ static int wait_random(void *arg) get_task_struct(tsk); yield_to(tsk, true); - for (i = 0; i < fc.chain_length; i++) + for (i = 0; i < fc.chain_length; i++) { dma_fence_signal(fc.fences[i]); + cond_resched(); + } err = kthread_stop_put(tsk); -- 2.25.1
