On 10/12/26 2:54 AM, Marco Crivellari wrote:
Currently the code enqueue work items using {queue|mod}_delayed_work(),
using system_long_wq. This workqueue should be used when long works are
expected and it is a per-cpu workqueue.
The function(s) end up calling __queue_delayed_work(), which set a global
timer that could fire anywhere, enqueuing the work where the timer fired.
Unbound works could benefit from scheduler task placement, to optimize
performance and power consumption. Long work shouldn't stick to a single
CPU.
Recently, a new unbound workqueue specific for long running work has
been added:
c116737e972e ("workqueue: Add system_dfl_long_wq for long unbound works")
Since the workqueue work doesn't rely on per-cpu variables, there is no
obvious reason that justify the use of a per-cpu workqueue. So change
system_long_wq with system_dfl_long_wq so that the work may benefit from
scheduler task placement.
Cc: Haren Myneni <[email protected]>
Cc: Rick Lindsley <[email protected]>
Cc: Nick Child <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy (CS GROUP) <[email protected]>
Cc: [email protected]
Signed-off-by: Marco Crivellari <[email protected]>
---
drivers/net/ethernet/ibm/ibmvnic.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c
b/drivers/net/ethernet/ibm/ibmvnic.c
index 5a510eed335e..d4c284c8ef43 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -3229,7 +3229,7 @@ static void __ibmvnic_reset(struct work_struct *work)
if (adapter->state == VNIC_PROBING &&
!wait_for_completion_timeout(&adapter->probe_done, timeout)) {
dev_err(dev, "Reset thread timed out on probe");
- queue_delayed_work(system_long_wq,
+ queue_delayed_work(system_dfl_long_wq,
&adapter->ibmvnic_delayed_reset,
IBMVNIC_RESET_DELAY);
return;
@@ -3267,7 +3267,7 @@ static void __ibmvnic_reset(struct work_struct *work)
spin_lock(&adapter->rwi_lock);
if (!list_empty(&adapter->rwi_list)) {
if (test_and_set_bit_lock(0, &adapter->resetting)) {
- queue_delayed_work(system_long_wq,
+ queue_delayed_work(system_dfl_long_wq,
&adapter->ibmvnic_delayed_reset,
IBMVNIC_RESET_DELAY);
} else {
@@ -3454,7 +3454,7 @@ static int ibmvnic_reset(struct ibmvnic_adapter *adapter,
list_add_tail(&rwi->list, &adapter->rwi_list);
netdev_dbg(adapter->netdev, "Scheduling reset (reason %s)\n",
reset_reason_to_string(reason));
- queue_work(system_long_wq, &adapter->ibmvnic_reset);
+ queue_work(system_dfl_long_wq, &adapter->ibmvnic_reset);
ret = 0;
err:
On 10/12/26 2:54 AM, Marco Crivellari wrote:
> Currently the code enqueue work items using {queue|mod}_delayed_work(),
> using system_long_wq. This workqueue should be used when long works are
> expected and it is a per-cpu workqueue.
>
> The function(s) end up calling __queue_delayed_work(), which set a global
> timer that could fire anywhere, enqueuing the work where the timer fired.
>
> Unbound works could benefit from scheduler task placement, to optimize
> performance and power consumption. Long work shouldn't stick to a single
> CPU.
>
> Recently, a new unbound workqueue specific for long running work has
> been added:
>
> c116737e972e ("workqueue: Add system_dfl_long_wq for long
unbound works")
>
> Since the workqueue work doesn't rely on per-cpu variables, there is no
> obvious reason that justify the use of a per-cpu workqueue. So change
> system_long_wq with system_dfl_long_wq so that the work may benefit from
> scheduler task placement.
>
> Cc: Haren Myneni <[email protected]>
> Cc: Rick Lindsley <[email protected]>
> Cc: Nick Child <[email protected]>
> Cc: Madhavan Srinivasan <[email protected]>
> Cc: Michael Ellerman <[email protected]>
> Cc: Nicholas Piggin <[email protected]>
> Cc: Christophe Leroy (CS GROUP) <[email protected]>
> Cc: [email protected]
> Signed-off-by: Marco Crivellari <[email protected]>
> ---
> drivers/net/ethernet/ibm/ibmvnic.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/ibm/ibmvnic.c
b/drivers/net/ethernet/ibm/ibmvnic.c
> index 5a510eed335e..d4c284c8ef43 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.c
> +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> @@ -3229,7 +3229,7 @@ static void __ibmvnic_reset(struct work_struct
*work)
> if (adapter->state == VNIC_PROBING &&
> !wait_for_completion_timeout(&adapter->probe_done, timeout)) {
> dev_err(dev, "Reset thread timed out on probe");
> - queue_delayed_work(system_long_wq,
> + queue_delayed_work(system_dfl_long_wq,
> &adapter->ibmvnic_delayed_reset,
> IBMVNIC_RESET_DELAY);
> return;
> @@ -3267,7 +3267,7 @@ static void __ibmvnic_reset(struct work_struct
*work)
> spin_lock(&adapter->rwi_lock);
> if (!list_empty(&adapter->rwi_list)) {
> if (test_and_set_bit_lock(0, &adapter->resetting)) {
> - queue_delayed_work(system_long_wq,
> + queue_delayed_work(system_dfl_long_wq,
> &adapter->ibmvnic_delayed_reset,
> IBMVNIC_RESET_DELAY);
> } else {
> @@ -3454,7 +3454,7 @@ static int ibmvnic_reset(struct ibmvnic_adapter
*adapter,
> list_add_tail(&rwi->list, &adapter->rwi_list);
> netdev_dbg(adapter->netdev, "Scheduling reset (reason %s)\n",
> reset_reason_to_string(reason));
> - queue_work(system_long_wq, &adapter->ibmvnic_reset);
> + queue_work(system_dfl_long_wq, &adapter->ibmvnic_reset);
>
> ret = 0;
> err:
I walked through the reset path and the conversion looks fine.
All three system_long_wq users move together and there are no
remaining users in the driver. The work items don't rely on per-CPU
state, so system_dfl_long_wq seems appropriate here.
Minor commit message nit: ibmvnic doesn't use mod_delayed_work(), and
one of the conversions is queue_work() rather than delayed work.
Acked-by: Mingming Cao <[email protected]>
