summaryrefslogtreecommitdiffstats
path: root/debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch299
1 files changed, 299 insertions, 0 deletions
diff --git a/debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch b/debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch
new file mode 100644
index 000000000..a289ccc4f
--- /dev/null
+++ b/debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch
@@ -0,0 +1,299 @@
+From a996bcbd8188409882599175697a464fa6265193 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 14 Sep 2016 17:36:35 +0200
+Subject: [PATCH 186/323] net/Qdisc: use a seqlock instead seqcount
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The seqcount disables preemption on -RT while it is held which can't
+remove. Also we don't want the reader to spin for ages if the writer is
+scheduled out. The seqlock on the other hand will serialize / sleep on
+the lock while writer is active.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/net/gen_stats.h | 11 ++++++-----
+ include/net/net_seq_lock.h | 24 ++++++++++++++++++++++++
+ include/net/sch_generic.h | 19 +++++++++++++++++--
+ net/core/gen_estimator.c | 6 +++---
+ net/core/gen_stats.c | 12 ++++++------
+ net/sched/sch_api.c | 2 +-
+ net/sched/sch_generic.c | 10 ++++++++++
+ 7 files changed, 67 insertions(+), 17 deletions(-)
+ create mode 100644 include/net/net_seq_lock.h
+
+diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
+index 1424e02cef90..163f8415e5db 100644
+--- a/include/net/gen_stats.h
++++ b/include/net/gen_stats.h
+@@ -6,6 +6,7 @@
+ #include <linux/socket.h>
+ #include <linux/rtnetlink.h>
+ #include <linux/pkt_sched.h>
++#include <net/net_seq_lock.h>
+
+ /* Note: this used to be in include/uapi/linux/gen_stats.h */
+ struct gnet_stats_basic_packed {
+@@ -42,15 +43,15 @@ int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
+ spinlock_t *lock, struct gnet_dump *d,
+ int padattr);
+
+-int gnet_stats_copy_basic(const seqcount_t *running,
++int gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_dump *d,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b);
+-void __gnet_stats_copy_basic(const seqcount_t *running,
++void __gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b);
+-int gnet_stats_copy_basic_hw(const seqcount_t *running,
++int gnet_stats_copy_basic_hw(net_seqlock_t *running,
+ struct gnet_dump *d,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b);
+@@ -70,13 +71,13 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **rate_est,
+ spinlock_t *lock,
+- seqcount_t *running, struct nlattr *opt);
++ net_seqlock_t *running, struct nlattr *opt);
+ void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
+ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **ptr,
+ spinlock_t *lock,
+- seqcount_t *running, struct nlattr *opt);
++ net_seqlock_t *running, struct nlattr *opt);
+ bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
+ bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
+ struct gnet_stats_rate_est64 *sample);
+diff --git a/include/net/net_seq_lock.h b/include/net/net_seq_lock.h
+new file mode 100644
+index 000000000000..95a497a72e51
+--- /dev/null
++++ b/include/net/net_seq_lock.h
+@@ -0,0 +1,24 @@
++#ifndef __NET_NET_SEQ_LOCK_H__
++#define __NET_NET_SEQ_LOCK_H__
++
++#ifdef CONFIG_PREEMPT_RT
++# define net_seqlock_t seqlock_t
++# define net_seq_begin(__r) read_seqbegin(__r)
++# define net_seq_retry(__r, __s) read_seqretry(__r, __s)
++
++static inline int try_write_seqlock(seqlock_t *sl)
++{
++ if (spin_trylock(&sl->lock)) {
++ write_seqcount_begin(&sl->seqcount);
++ return 1;
++ }
++ return 0;
++}
++
++#else
++# define net_seqlock_t seqcount_t
++# define net_seq_begin(__r) read_seqcount_begin(__r)
++# define net_seq_retry(__r, __s) read_seqcount_retry(__r, __s)
++#endif
++
++#endif
+diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
+index a62677be7452..8ce663a9b4f4 100644
+--- a/include/net/sch_generic.h
++++ b/include/net/sch_generic.h
+@@ -10,6 +10,7 @@
+ #include <linux/percpu.h>
+ #include <linux/dynamic_queue_limits.h>
+ #include <linux/list.h>
++#include <net/net_seq_lock.h>
+ #include <linux/refcount.h>
+ #include <linux/workqueue.h>
+ #include <linux/mutex.h>
+@@ -101,7 +102,7 @@ struct Qdisc {
+ struct sk_buff_head gso_skb ____cacheline_aligned_in_smp;
+ struct qdisc_skb_head q;
+ struct gnet_stats_basic_packed bstats;
+- seqcount_t running;
++ net_seqlock_t running;
+ struct gnet_stats_queue qstats;
+ unsigned long state;
+ struct Qdisc *next_sched;
+@@ -142,7 +143,11 @@ static inline bool qdisc_is_running(struct Qdisc *qdisc)
+ {
+ if (qdisc->flags & TCQ_F_NOLOCK)
+ return spin_is_locked(&qdisc->seqlock);
++#ifdef CONFIG_PREEMPT_RT
++ return spin_is_locked(&qdisc->running.lock) ? true : false;
++#else
+ return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
++#endif
+ }
+
+ static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
+@@ -183,17 +188,27 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
+ } else if (qdisc_is_running(qdisc)) {
+ return false;
+ }
++#ifdef CONFIG_PREEMPT_RT
++ if (try_write_seqlock(&qdisc->running))
++ return true;
++ return false;
++#else
+ /* Variant of write_seqcount_begin() telling lockdep a trylock
+ * was attempted.
+ */
+ raw_write_seqcount_begin(&qdisc->running);
+ seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
+ return true;
++#endif
+ }
+
+ static inline void qdisc_run_end(struct Qdisc *qdisc)
+ {
++#ifdef CONFIG_PREEMPT_RT
++ write_sequnlock(&qdisc->running);
++#else
+ write_seqcount_end(&qdisc->running);
++#endif
+ if (qdisc->flags & TCQ_F_NOLOCK) {
+ spin_unlock(&qdisc->seqlock);
+
+@@ -583,7 +598,7 @@ static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
+ return qdisc_lock(root);
+ }
+
+-static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
++static inline net_seqlock_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
+ {
+ struct Qdisc *root = qdisc_root_sleeping(qdisc);
+
+diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
+index 8e582e29a41e..e51f4854d8b2 100644
+--- a/net/core/gen_estimator.c
++++ b/net/core/gen_estimator.c
+@@ -42,7 +42,7 @@
+ struct net_rate_estimator {
+ struct gnet_stats_basic_packed *bstats;
+ spinlock_t *stats_lock;
+- seqcount_t *running;
++ net_seqlock_t *running;
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats;
+ u8 ewma_log;
+ u8 intvl_log; /* period : (250ms << intvl_log) */
+@@ -125,7 +125,7 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **rate_est,
+ spinlock_t *lock,
+- seqcount_t *running,
++ net_seqlock_t *running,
+ struct nlattr *opt)
+ {
+ struct gnet_estimator *parm = nla_data(opt);
+@@ -226,7 +226,7 @@ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ struct net_rate_estimator __rcu **rate_est,
+ spinlock_t *lock,
+- seqcount_t *running, struct nlattr *opt)
++ net_seqlock_t *running, struct nlattr *opt)
+ {
+ return gen_new_estimator(bstats, cpu_bstats, rate_est,
+ lock, running, opt);
+diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
+index e491b083b348..ef432cea2e10 100644
+--- a/net/core/gen_stats.c
++++ b/net/core/gen_stats.c
+@@ -137,7 +137,7 @@ __gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats,
+ }
+
+ void
+-__gnet_stats_copy_basic(const seqcount_t *running,
++__gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_stats_basic_packed *bstats,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b)
+@@ -150,15 +150,15 @@ __gnet_stats_copy_basic(const seqcount_t *running,
+ }
+ do {
+ if (running)
+- seq = read_seqcount_begin(running);
++ seq = net_seq_begin(running);
+ bstats->bytes = b->bytes;
+ bstats->packets = b->packets;
+- } while (running && read_seqcount_retry(running, seq));
++ } while (running && net_seq_retry(running, seq));
+ }
+ EXPORT_SYMBOL(__gnet_stats_copy_basic);
+
+ static int
+-___gnet_stats_copy_basic(const seqcount_t *running,
++___gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_dump *d,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b,
+@@ -204,7 +204,7 @@ ___gnet_stats_copy_basic(const seqcount_t *running,
+ * if the room in the socket buffer was not sufficient.
+ */
+ int
+-gnet_stats_copy_basic(const seqcount_t *running,
++gnet_stats_copy_basic(net_seqlock_t *running,
+ struct gnet_dump *d,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b)
+@@ -228,7 +228,7 @@ EXPORT_SYMBOL(gnet_stats_copy_basic);
+ * if the room in the socket buffer was not sufficient.
+ */
+ int
+-gnet_stats_copy_basic_hw(const seqcount_t *running,
++gnet_stats_copy_basic_hw(net_seqlock_t *running,
+ struct gnet_dump *d,
+ struct gnet_stats_basic_cpu __percpu *cpu,
+ struct gnet_stats_basic_packed *b)
+diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
+index 5c2d230790db..a5430619ca5f 100644
+--- a/net/sched/sch_api.c
++++ b/net/sched/sch_api.c
+@@ -1275,7 +1275,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
+ rcu_assign_pointer(sch->stab, stab);
+ }
+ if (tca[TCA_RATE]) {
+- seqcount_t *running;
++ net_seqlock_t *running;
+
+ err = -EOPNOTSUPP;
+ if (sch->flags & TCQ_F_MQROOT) {
+diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
+index ecdd9e83f2f4..73b5aa797645 100644
+--- a/net/sched/sch_generic.c
++++ b/net/sched/sch_generic.c
+@@ -578,7 +578,11 @@ struct Qdisc noop_qdisc = {
+ .ops = &noop_qdisc_ops,
+ .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
+ .dev_queue = &noop_netdev_queue,
++#ifdef CONFIG_PREEMPT_RT
++ .running = __SEQLOCK_UNLOCKED(noop_qdisc.running),
++#else
+ .running = SEQCNT_ZERO(noop_qdisc.running),
++#endif
+ .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
+ .gso_skb = {
+ .next = (struct sk_buff *)&noop_qdisc.gso_skb,
+@@ -889,9 +893,15 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
+ lockdep_set_class(&sch->seqlock,
+ dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
+
++#ifdef CONFIG_PREEMPT_RT
++ seqlock_init(&sch->running);
++ lockdep_set_class(&sch->running.lock,
++ dev->qdisc_running_key ?: &qdisc_running_key);
++#else
+ seqcount_init(&sch->running);
+ lockdep_set_class(&sch->running,
+ dev->qdisc_running_key ?: &qdisc_running_key);
++#endif
+
+ sch->ops = ops;
+ sch->flags = ops->static_flags;
+--
+2.43.0
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 05:12:33 +0000