| Message ID | 20230505113315.3307723-8-liujian56@huawei.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | fix softlockup in run_timer_softirq | expand |
On Fri, May 5, 2023 at 7:27 PM Liu Jian <liujian56@huawei.com> wrote: > > From: Peter Zijlstra <peterz@infradead.org> > > SoftIRQs provide their own timeout/break code now, use that. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Signed-off-by: Liu Jian <liujian56@huawei.com> > --- > Documentation/admin-guide/sysctl/net.rst | 11 +---------- > net/core/dev.c | 6 +----- > net/core/dev.h | 1 - > net/core/sysctl_net_core.c | 8 -------- > 4 files changed, 2 insertions(+), 24 deletions(-) > > diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst > index 466c560b0c30..095c60788c61 100644 > --- a/Documentation/admin-guide/sysctl/net.rst > +++ b/Documentation/admin-guide/sysctl/net.rst > @@ -267,16 +267,7 @@ netdev_budget > > Maximum number of packets taken from all interfaces in one polling cycle (NAPI > poll). In one polling cycle interfaces which are registered to polling are > -probed in a round-robin manner. Also, a polling cycle may not exceed > -netdev_budget_usecs microseconds, even if netdev_budget has not been > -exhausted. > - > -netdev_budget_usecs > ---------------------- > - > -Maximum number of microseconds in one NAPI polling cycle. Polling > -will exit when either netdev_budget_usecs have elapsed during the > -poll cycle or the number of packets processed reaches netdev_budget. > +probed in a round-robin manner. > > netdev_max_backlog > ------------------ > diff --git a/net/core/dev.c b/net/core/dev.c > index 735096d42c1d..70b6726beee6 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -4321,7 +4321,6 @@ int netdev_tstamp_prequeue __read_mostly = 1; > unsigned int sysctl_skb_defer_max __read_mostly = 64; > int netdev_budget __read_mostly = 300; > /* Must be at least 2 jiffes to guarantee 1 jiffy timeout */ > -unsigned int __read_mostly netdev_budget_usecs = 2 * USEC_PER_SEC / HZ; > int weight_p __read_mostly = 64; /* old backlog weight */ > int dev_weight_rx_bias __read_mostly = 1; /* bias for backlog weight */ > int dev_weight_tx_bias __read_mostly = 1; /* bias for output_queue quota */ > @@ -6659,8 +6658,6 @@ static int napi_threaded_poll(void *data) > static __latent_entropy void net_rx_action(struct softirq_action *h) > { > struct softnet_data *sd = this_cpu_ptr(&softnet_data); > - unsigned long time_limit = jiffies + > - usecs_to_jiffies(READ_ONCE(netdev_budget_usecs)); > int budget = READ_ONCE(netdev_budget); > LIST_HEAD(list); > LIST_HEAD(repoll); > @@ -6699,8 +6696,7 @@ static __latent_entropy void net_rx_action(struct softirq_action *h) > * Allow this to run for 2 jiffies since which will allow > * an average latency of 1.5/HZ. > */ > - if (unlikely(budget <= 0 || > - time_after_eq(jiffies, time_limit))) { > + if (unlikely(budget <= 0 || softirq_needs_break(h))) { > sd->time_squeeze++; > break; > } > diff --git a/net/core/dev.h b/net/core/dev.h > index e075e198092c..e64a60c767ab 100644 > --- a/net/core/dev.h > +++ b/net/core/dev.h > @@ -39,7 +39,6 @@ void dev_addr_check(struct net_device *dev); > > /* sysctls not referred to from outside net/core/ */ > extern int netdev_budget; > -extern unsigned int netdev_budget_usecs; > extern unsigned int sysctl_skb_defer_max; > extern int netdev_tstamp_prequeue; > extern int netdev_unregister_timeout_secs; > diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c > index 782273bb93c2..59765c805f5b 100644 > --- a/net/core/sysctl_net_core.c > +++ b/net/core/sysctl_net_core.c > @@ -595,14 +595,6 @@ static struct ctl_table net_core_table[] = { > .extra1 = SYSCTL_ONE, > .extra2 = &max_skb_frags, > }, > - { > - .procname = "netdev_budget_usecs", > - .data = &netdev_budget_usecs, > - .maxlen = sizeof(unsigned int), > - .mode = 0644, > - .proc_handler = proc_dointvec_minmax, > - .extra1 = SYSCTL_ZERO, > - }, I cannot help asking whether we really need to remove the sysctl knob because it can let some users tune this. It's useful for some cases, I believe. Do you have any evidence/number to prove we can get rid of this? Thanks, Jason > { > .procname = "fb_tunnels_only_for_init_net", > .data = &sysctl_fb_tunnels_only_for_init_net, > -- > 2.34.1 > >
diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index 466c560b0c30..095c60788c61 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -267,16 +267,7 @@ netdev_budget Maximum number of packets taken from all interfaces in one polling cycle (NAPI poll). In one polling cycle interfaces which are registered to polling are -probed in a round-robin manner. Also, a polling cycle may not exceed -netdev_budget_usecs microseconds, even if netdev_budget has not been -exhausted. - -netdev_budget_usecs ---------------------- - -Maximum number of microseconds in one NAPI polling cycle. Polling -will exit when either netdev_budget_usecs have elapsed during the -poll cycle or the number of packets processed reaches netdev_budget. +probed in a round-robin manner. netdev_max_backlog ------------------ diff --git a/net/core/dev.c b/net/core/dev.c index 735096d42c1d..70b6726beee6 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4321,7 +4321,6 @@ int netdev_tstamp_prequeue __read_mostly = 1; unsigned int sysctl_skb_defer_max __read_mostly = 64; int netdev_budget __read_mostly = 300; /* Must be at least 2 jiffes to guarantee 1 jiffy timeout */ -unsigned int __read_mostly netdev_budget_usecs = 2 * USEC_PER_SEC / HZ; int weight_p __read_mostly = 64; /* old backlog weight */ int dev_weight_rx_bias __read_mostly = 1; /* bias for backlog weight */ int dev_weight_tx_bias __read_mostly = 1; /* bias for output_queue quota */ @@ -6659,8 +6658,6 @@ static int napi_threaded_poll(void *data) static __latent_entropy void net_rx_action(struct softirq_action *h) { struct softnet_data *sd = this_cpu_ptr(&softnet_data); - unsigned long time_limit = jiffies + - usecs_to_jiffies(READ_ONCE(netdev_budget_usecs)); int budget = READ_ONCE(netdev_budget); LIST_HEAD(list); LIST_HEAD(repoll); @@ -6699,8 +6696,7 @@ static __latent_entropy void net_rx_action(struct softirq_action *h) * Allow this to run for 2 jiffies since which will allow * an average latency of 1.5/HZ. */ - if (unlikely(budget <= 0 || - time_after_eq(jiffies, time_limit))) { + if (unlikely(budget <= 0 || softirq_needs_break(h))) { sd->time_squeeze++; break; } diff --git a/net/core/dev.h b/net/core/dev.h index e075e198092c..e64a60c767ab 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -39,7 +39,6 @@ void dev_addr_check(struct net_device *dev); /* sysctls not referred to from outside net/core/ */ extern int netdev_budget; -extern unsigned int netdev_budget_usecs; extern unsigned int sysctl_skb_defer_max; extern int netdev_tstamp_prequeue; extern int netdev_unregister_timeout_secs; diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 782273bb93c2..59765c805f5b 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -595,14 +595,6 @@ static struct ctl_table net_core_table[] = { .extra1 = SYSCTL_ONE, .extra2 = &max_skb_frags, }, - { - .procname = "netdev_budget_usecs", - .data = &netdev_budget_usecs, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec_minmax, - .extra1 = SYSCTL_ZERO, - }, { .procname = "fb_tunnels_only_for_init_net", .data = &sysctl_fb_tunnels_only_for_init_net,