| Message ID | Zen126EYArNCxIYz@tpad (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,-v5] net/core/dev.c: enable timestamp static key if CPU isolation is configured | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/apply | fail | Patch does not apply to net-next-1 |
Marcelo Tosatti wrote: > > For systems that use CPU isolation (via nohz_full), creating or destroying > a socket with SO_TIMESTAMP, SO_TIMESTAMPNS or SO_TIMESTAMPING with flag > SOF_TIMESTAMPING_RX_SOFTWARE will cause a static key to be enabled/disabled. > This in turn causes undesired IPIs to isolated CPUs. > > So enable the static key unconditionally, if CPU isolation is enabled, > thus avoiding the IPIs. > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Reviewed-by: Willem de Bruijn <willemb@google.com>
On Thu, 7 Mar 2024 14:14:03 -0300 Marcelo Tosatti wrote:
> net/core/dev.c: enable timestamp static key if CPU isolation is configured
Doesn't apply to net-next, please respin.
When you do, one more nit: please use net: as the prefix,
instead of net/code/dev.c. No need to state the entire file path.
diff --git a/net/core/dev.c b/net/core/dev.c index 0d548431f3fa..7832793b2980 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -153,6 +153,7 @@ #include <linux/prandom.h> #include <linux/once_lite.h> #include <net/netdev_rx_queue.h> +#include <linux/sched/isolation.h> #include "dev.h" #include "net-sysfs.h" @@ -11596,6 +11597,10 @@ static int __init net_dev_init(void) NULL, dev_cpu_dead); WARN_ON(rc < 0); rc = 0; + + /* avoid static key IPIs to isolated CPUs */ + if (housekeeping_enabled(HK_TYPE_MISC)) + net_enable_timestamp(); out: return rc; }
For systems that use CPU isolation (via nohz_full), creating or destroying a socket with SO_TIMESTAMP, SO_TIMESTAMPNS or SO_TIMESTAMPING with flag SOF_TIMESTAMPING_RX_SOFTWARE will cause a static key to be enabled/disabled. This in turn causes undesired IPIs to isolated CPUs. So enable the static key unconditionally, if CPU isolation is enabled, thus avoiding the IPIs. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> --- v2: mention SOF_TIMESTAMPING_OPT_TX_SWHW in the commit log (Willem de Bruijn / Paolo Abeni) v3: SOF_TIMESTAMPING_OPT_TX_SWHW is irrelevant (Willem de Bruijn) v4: additional changelog improvements (Willem de Bruijn) v5: late initcall not necessary, can use subsys initcall (Willem de Bruijn)