diff options
author | Ben Hutchings <ben@decadent.org.uk> | 2018-08-10 14:46:09 +0100 |
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committer | Ben Hutchings <ben@decadent.org.uk> | 2018-09-13 01:52:52 +0100 |
commit | 26224f8bb88d96d9cbe261277fc4713f611d70b1 (patch) | |
tree | 93e7489ebcf9a2b173c63677121dfb4c874508fa /debian/patches-rt/rcu-merge-rcu-bh-into-rcu-preempt-for-rt.patch | |
parent | 07b57afec5de4a495564a09151407d1d4a44cbbc (diff) | |
download | linux-debian-26224f8bb88d96d9cbe261277fc4713f611d70b1.tar.gz |
Move featureset patches and series file to debian/patches-<featureset>.
Fixes lintian warning patch-file-present-but-not-mentioned-in-series.
Also preparation for using dgit, which will remove everything except
the main patch series under debian/patches.
Diffstat (limited to 'debian/patches-rt/rcu-merge-rcu-bh-into-rcu-preempt-for-rt.patch')
-rw-r--r-- | debian/patches-rt/rcu-merge-rcu-bh-into-rcu-preempt-for-rt.patch | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/debian/patches-rt/rcu-merge-rcu-bh-into-rcu-preempt-for-rt.patch b/debian/patches-rt/rcu-merge-rcu-bh-into-rcu-preempt-for-rt.patch new file mode 100644 index 000000000..cacef31c4 --- /dev/null +++ b/debian/patches-rt/rcu-merge-rcu-bh-into-rcu-preempt-for-rt.patch @@ -0,0 +1,348 @@ +Subject: rcu: Merge RCU-bh into RCU-preempt +Date: Wed, 5 Oct 2011 11:59:38 -0700 +From: Thomas Gleixner <tglx@linutronix.de> +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.18/older/patches-4.18.5-rt3.tar.xz + +The Linux kernel has long RCU-bh read-side critical sections that +intolerably increase scheduling latency under mainline's RCU-bh rules, +which include RCU-bh read-side critical sections being non-preemptible. +This patch therefore arranges for RCU-bh to be implemented in terms of +RCU-preempt for CONFIG_PREEMPT_RT_FULL=y. + +This has the downside of defeating the purpose of RCU-bh, namely, +handling the case where the system is subjected to a network-based +denial-of-service attack that keeps at least one CPU doing full-time +softirq processing. This issue will be fixed by a later commit. + +The current commit will need some work to make it appropriate for +mainline use, for example, it needs to be extended to cover Tiny RCU. + +[ paulmck: Added a useful changelog ] + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> +Link: http://lkml.kernel.org/r/20111005185938.GA20403@linux.vnet.ibm.com +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> + +--- + include/linux/rcupdate.h | 19 +++++++++++++++++++ + include/linux/rcutree.h | 8 ++++++++ + kernel/rcu/rcu.h | 14 +++++++++++--- + kernel/rcu/rcutorture.c | 7 +++++++ + kernel/rcu/tree.c | 24 ++++++++++++++++++++++++ + kernel/rcu/tree.h | 2 ++ + kernel/rcu/update.c | 2 ++ + 7 files changed, 73 insertions(+), 3 deletions(-) + +--- a/include/linux/rcupdate.h ++++ b/include/linux/rcupdate.h +@@ -56,7 +56,11 @@ void call_rcu(struct rcu_head *head, rcu + #define call_rcu call_rcu_sched + #endif /* #else #ifdef CONFIG_PREEMPT_RCU */ + ++#ifdef CONFIG_PREEMPT_RT_FULL ++#define call_rcu_bh call_rcu ++#else + void call_rcu_bh(struct rcu_head *head, rcu_callback_t func); ++#endif + void call_rcu_sched(struct rcu_head *head, rcu_callback_t func); + void synchronize_sched(void); + void rcu_barrier_tasks(void); +@@ -264,7 +268,14 @@ extern struct lockdep_map rcu_sched_lock + extern struct lockdep_map rcu_callback_map; + int debug_lockdep_rcu_enabled(void); + int rcu_read_lock_held(void); ++#ifdef CONFIG_PREEMPT_RT_FULL ++static inline int rcu_read_lock_bh_held(void) ++{ ++ return rcu_read_lock_held(); ++} ++#else + int rcu_read_lock_bh_held(void); ++#endif + int rcu_read_lock_sched_held(void); + + #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +@@ -665,10 +676,14 @@ static inline void rcu_read_unlock(void) + static inline void rcu_read_lock_bh(void) + { + local_bh_disable(); ++#ifdef CONFIG_PREEMPT_RT_FULL ++ rcu_read_lock(); ++#else + __acquire(RCU_BH); + rcu_lock_acquire(&rcu_bh_lock_map); + RCU_LOCKDEP_WARN(!rcu_is_watching(), + "rcu_read_lock_bh() used illegally while idle"); ++#endif + } + + /* +@@ -678,10 +693,14 @@ static inline void rcu_read_lock_bh(void + */ + static inline void rcu_read_unlock_bh(void) + { ++#ifdef CONFIG_PREEMPT_RT_FULL ++ rcu_read_unlock(); ++#else + RCU_LOCKDEP_WARN(!rcu_is_watching(), + "rcu_read_unlock_bh() used illegally while idle"); + rcu_lock_release(&rcu_bh_lock_map); + __release(RCU_BH); ++#endif + local_bh_enable(); + } + +--- a/include/linux/rcutree.h ++++ b/include/linux/rcutree.h +@@ -44,7 +44,11 @@ static inline void rcu_virt_note_context + rcu_note_context_switch(false); + } + ++#ifdef CONFIG_PREEMPT_RT_FULL ++# define synchronize_rcu_bh synchronize_rcu ++#else + void synchronize_rcu_bh(void); ++#endif + void synchronize_sched_expedited(void); + void synchronize_rcu_expedited(void); + +@@ -72,7 +76,11 @@ static inline void synchronize_rcu_bh_ex + } + + void rcu_barrier(void); ++#ifdef CONFIG_PREEMPT_RT_FULL ++# define rcu_barrier_bh rcu_barrier ++#else + void rcu_barrier_bh(void); ++#endif + void rcu_barrier_sched(void); + bool rcu_eqs_special_set(int cpu); + unsigned long get_state_synchronize_rcu(void); +--- a/kernel/rcu/rcu.h ++++ b/kernel/rcu/rcu.h +@@ -478,20 +478,28 @@ static inline void show_rcu_gp_kthreads( + extern unsigned long rcutorture_testseq; + extern unsigned long rcutorture_vernum; + unsigned long rcu_batches_started(void); +-unsigned long rcu_batches_started_bh(void); + unsigned long rcu_batches_started_sched(void); + unsigned long rcu_batches_completed(void); +-unsigned long rcu_batches_completed_bh(void); + unsigned long rcu_batches_completed_sched(void); + unsigned long rcu_exp_batches_completed(void); + unsigned long rcu_exp_batches_completed_sched(void); + unsigned long srcu_batches_completed(struct srcu_struct *sp); + void show_rcu_gp_kthreads(void); + void rcu_force_quiescent_state(void); +-void rcu_bh_force_quiescent_state(void); + void rcu_sched_force_quiescent_state(void); + extern struct workqueue_struct *rcu_gp_wq; + extern struct workqueue_struct *rcu_par_gp_wq; ++ ++#ifndef CONFIG_PREEMPT_RT_FULL ++void rcu_bh_force_quiescent_state(void); ++unsigned long rcu_batches_started_bh(void); ++unsigned long rcu_batches_completed_bh(void); ++#else ++# define rcu_bh_force_quiescent_state rcu_force_quiescent_state ++# define rcu_batches_completed_bh rcu_batches_completed ++# define rcu_batches_started_bh rcu_batches_completed ++#endif ++ + #endif /* #else #ifdef CONFIG_TINY_RCU */ + + #ifdef CONFIG_RCU_NOCB_CPU +--- a/kernel/rcu/rcutorture.c ++++ b/kernel/rcu/rcutorture.c +@@ -413,6 +413,7 @@ static struct rcu_torture_ops rcu_ops = + .name = "rcu" + }; + ++#ifndef CONFIG_PREEMPT_RT_FULL + /* + * Definitions for rcu_bh torture testing. + */ +@@ -452,6 +453,12 @@ static struct rcu_torture_ops rcu_bh_ops + .name = "rcu_bh" + }; + ++#else ++static struct rcu_torture_ops rcu_bh_ops = { ++ .ttype = INVALID_RCU_FLAVOR, ++}; ++#endif ++ + /* + * Don't even think about trying any of these in real life!!! + * The names includes "busted", and they really means it! +--- a/kernel/rcu/tree.c ++++ b/kernel/rcu/tree.c +@@ -243,6 +243,7 @@ void rcu_sched_qs(void) + this_cpu_ptr(&rcu_sched_data), true); + } + ++#ifndef CONFIG_PREEMPT_RT_FULL + void rcu_bh_qs(void) + { + RCU_LOCKDEP_WARN(preemptible(), "rcu_bh_qs() invoked with preemption enabled!!!"); +@@ -253,6 +254,7 @@ void rcu_bh_qs(void) + __this_cpu_write(rcu_bh_data.cpu_no_qs.b.norm, false); + } + } ++#endif + + /* + * Steal a bit from the bottom of ->dynticks for idle entry/exit +@@ -549,11 +551,13 @@ EXPORT_SYMBOL_GPL(rcu_batches_started_sc + /* + * Return the number of RCU BH batches started thus far for debug & stats. + */ ++#ifndef CONFIG_PREEMPT_RT_FULL + unsigned long rcu_batches_started_bh(void) + { + return rcu_bh_state.gpnum; + } + EXPORT_SYMBOL_GPL(rcu_batches_started_bh); ++#endif + + /* + * Return the number of RCU batches completed thus far for debug & stats. +@@ -573,6 +577,7 @@ unsigned long rcu_batches_completed_sche + } + EXPORT_SYMBOL_GPL(rcu_batches_completed_sched); + ++#ifndef CONFIG_PREEMPT_RT_FULL + /* + * Return the number of RCU BH batches completed thus far for debug & stats. + */ +@@ -581,6 +586,7 @@ unsigned long rcu_batches_completed_bh(v + return rcu_bh_state.completed; + } + EXPORT_SYMBOL_GPL(rcu_batches_completed_bh); ++#endif + + /* + * Return the number of RCU expedited batches completed thus far for +@@ -604,6 +610,7 @@ unsigned long rcu_exp_batches_completed_ + } + EXPORT_SYMBOL_GPL(rcu_exp_batches_completed_sched); + ++#ifndef CONFIG_PREEMPT_RT_FULL + /* + * Force a quiescent state. + */ +@@ -622,6 +629,13 @@ void rcu_bh_force_quiescent_state(void) + } + EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state); + ++#else ++void rcu_force_quiescent_state(void) ++{ ++} ++EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); ++#endif ++ + /* + * Force a quiescent state for RCU-sched. + */ +@@ -672,9 +686,11 @@ void rcutorture_get_gp_data(enum rcutort + case RCU_FLAVOR: + rsp = rcu_state_p; + break; ++#ifndef CONFIG_PREEMPT_RT_FULL + case RCU_BH_FLAVOR: + rsp = &rcu_bh_state; + break; ++#endif + case RCU_SCHED_FLAVOR: + rsp = &rcu_sched_state; + break; +@@ -2986,6 +3002,7 @@ void call_rcu_sched(struct rcu_head *hea + } + EXPORT_SYMBOL_GPL(call_rcu_sched); + ++#ifndef CONFIG_PREEMPT_RT_FULL + /** + * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period. + * @head: structure to be used for queueing the RCU updates. +@@ -3013,6 +3030,7 @@ void call_rcu_bh(struct rcu_head *head, + __call_rcu(head, func, &rcu_bh_state, -1, 0); + } + EXPORT_SYMBOL_GPL(call_rcu_bh); ++#endif + + /* + * Queue an RCU callback for lazy invocation after a grace period. +@@ -3098,6 +3116,7 @@ void synchronize_sched(void) + } + EXPORT_SYMBOL_GPL(synchronize_sched); + ++#ifndef CONFIG_PREEMPT_RT_FULL + /** + * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. + * +@@ -3124,6 +3143,7 @@ void synchronize_rcu_bh(void) + wait_rcu_gp(call_rcu_bh); + } + EXPORT_SYMBOL_GPL(synchronize_rcu_bh); ++#endif + + /** + * get_state_synchronize_rcu - Snapshot current RCU state +@@ -3457,6 +3477,7 @@ static void _rcu_barrier(struct rcu_stat + mutex_unlock(&rsp->barrier_mutex); + } + ++#ifndef CONFIG_PREEMPT_RT_FULL + /** + * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete. + */ +@@ -3465,6 +3486,7 @@ void rcu_barrier_bh(void) + _rcu_barrier(&rcu_bh_state); + } + EXPORT_SYMBOL_GPL(rcu_barrier_bh); ++#endif + + /** + * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks. +@@ -4081,7 +4103,9 @@ void __init rcu_init(void) + + rcu_bootup_announce(); + rcu_init_geometry(); ++#ifndef CONFIG_PREEMPT_RT_FULL + rcu_init_one(&rcu_bh_state); ++#endif + rcu_init_one(&rcu_sched_state); + if (dump_tree) + rcu_dump_rcu_node_tree(&rcu_sched_state); +--- a/kernel/rcu/tree.h ++++ b/kernel/rcu/tree.h +@@ -422,7 +422,9 @@ extern struct list_head rcu_struct_flavo + */ + extern struct rcu_state rcu_sched_state; + ++#ifndef CONFIG_PREEMPT_RT_FULL + extern struct rcu_state rcu_bh_state; ++#endif + + #ifdef CONFIG_PREEMPT_RCU + extern struct rcu_state rcu_preempt_state; +--- a/kernel/rcu/update.c ++++ b/kernel/rcu/update.c +@@ -286,6 +286,7 @@ int rcu_read_lock_held(void) + } + EXPORT_SYMBOL_GPL(rcu_read_lock_held); + ++#ifndef CONFIG_PREEMPT_RT_FULL + /** + * rcu_read_lock_bh_held() - might we be in RCU-bh read-side critical section? + * +@@ -312,6 +313,7 @@ int rcu_read_lock_bh_held(void) + return in_softirq() || irqs_disabled(); + } + EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held); ++#endif + + #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + |