Hi Spencer & Joern,
On Thu, Jul 23, 2015 at 02:54:32PM -0700, Spencer Baugh wrote:
> From: Joern Engel <joern@xxxxxxxxx>
>
> Multiple nested loops. I have observed 590ms scheduler latency caused
> by this loop and interrupts. Interrupts were responsible for 190ms, the
> rest could have been avoided with a cond_resched.
I'm not disagreeing with this patch, but it would be helpful to sketch
the outline of the "multiple nested loop" problem here. This might be
a hint that we could do even better by rethinking the algorithm reduce
the nesting.
> Signed-off-by: Joern Engel <joern@xxxxxxxxx>
> Signed-off-by: Spencer Baugh <sbaugh@xxxxxxxxxx>
> ---
> drivers/pci/pcie/aer/aerdrv_core.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
> index 9803e3d..32b1b5c 100644
> --- a/drivers/pci/pcie/aer/aerdrv_core.c
> +++ b/drivers/pci/pcie/aer/aerdrv_core.c
> @@ -780,8 +780,10 @@ void aer_isr(struct work_struct *work)
> struct aer_err_source uninitialized_var(e_src);
>
> mutex_lock(&rpc->rpc_mutex);
> - while (get_e_source(rpc, &e_src))
> + while (get_e_source(rpc, &e_src)) {
> aer_isr_one_error(p_device, &e_src);
> + cond_resched();
> + }
> mutex_unlock(&rpc->rpc_mutex);
>
> wake_up(&rpc->wait_release);
> --
> 2.5.0.rc3
>
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