From fc2219d49ef1606e7fd2c88af2b423b01ff3d319 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 23 Sep 2009 09:50:41 -0700 Subject: rcu: Clean up code based on review feedback from Josh Triplett These issues identified during an old-fashioned face-to-face code review extended over many hours. o Bury various forms of the "rsp->completed == rsp->gpnum" comparison into an rcu_gp_in_progress() function, which has the beneficial side-effect of forcing consistent use of ACCESS_ONCE(). o Replace hand-coded arithmetic with DIV_ROUND_UP(). o Bury several "!list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x01])" instances into an rcu_preempted_readers() function, as this expression indicates that there are no readers blocked within RCU read-side critical sections blocking the current grace period. (Though there might well be similar readers blocking the next grace period.) o Remove a dangling rcu_restart_cpu() declaration that has been dangling for almost 20 minor releases of the kernel. Signed-off-by: Paul E. McKenney Acked-by: Peter Zijlstra Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12537246442687-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/rcutree.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 37682770e9d2..88109c87f29c 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -85,7 +85,6 @@ static inline void synchronize_rcu_bh_expedited(void) extern void __rcu_init(void); extern void rcu_check_callbacks(int cpu, int user); -extern void rcu_restart_cpu(int cpu); extern long rcu_batches_completed(void); extern long rcu_batches_completed_bh(void); -- cgit v1.2.3-58-ga151 From 1eba8f84380bede3c602bd7758dea96925cead01 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 23 Sep 2009 09:50:42 -0700 Subject: rcu: Clean up code based on review feedback from Josh Triplett, part 2 These issues identified during an old-fashioned face-to-face code review extending over many hours. o Add comments for tricky parts of code, and correct comments that have passed their sell-by date. o Get rid of the vestiges of rcu_init_sched(), which is no longer needed now that PREEMPT_RCU is gone. o Move the #include of rcutree_plugin.h to the end of rcutree.c, which means that, rather than having a random collection of forward declarations, the new set of forward declarations document the set of plugins. The new home for this #include also allows __rcu_init_preempt() to move into rcutree_plugin.h. o Fix rcu_preempt_check_callbacks() to be static. Suggested-by: Josh Triplett Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12537246443924-git-send-email-> Signed-off-by: Ingo Molnar Peter Zijlstra --- include/linux/rcupdate.h | 4 +++ include/linux/rcutree.h | 6 +--- init/main.c | 1 - kernel/rcutree.c | 72 ++++++++++++++++++++++-------------------------- kernel/rcutree.h | 31 +++++++++++++++------ kernel/rcutree_plugin.h | 23 ++++++++++++++-- 6 files changed, 82 insertions(+), 55 deletions(-) (limited to 'include') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 6fe0363724e9..70331218e4b4 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -196,6 +196,8 @@ static inline void rcu_read_lock_sched(void) __acquire(RCU_SCHED); rcu_read_acquire(); } + +/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */ static inline notrace void rcu_read_lock_sched_notrace(void) { preempt_disable_notrace(); @@ -213,6 +215,8 @@ static inline void rcu_read_unlock_sched(void) __release(RCU_SCHED); preempt_enable(); } + +/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */ static inline notrace void rcu_read_unlock_sched_notrace(void) { __release(RCU_SCHED); diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 88109c87f29c..19a3b06943e0 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -90,10 +90,6 @@ extern long rcu_batches_completed(void); extern long rcu_batches_completed_bh(void); extern long rcu_batches_completed_sched(void); -static inline void rcu_init_sched(void) -{ -} - #ifdef CONFIG_NO_HZ void rcu_enter_nohz(void); void rcu_exit_nohz(void); @@ -106,7 +102,7 @@ static inline void rcu_exit_nohz(void) } #endif /* CONFIG_NO_HZ */ -/* A context switch is a grace period for rcutree. */ +/* A context switch is a grace period for RCU-sched and RCU-bh. */ static inline int rcu_blocking_is_gp(void) { return num_online_cpus() == 1; diff --git a/init/main.c b/init/main.c index 34971becbd3c..833d675677d1 100644 --- a/init/main.c +++ b/init/main.c @@ -782,7 +782,6 @@ static void __init do_initcalls(void) */ static void __init do_basic_setup(void) { - rcu_init_sched(); /* needed by module_init stage. */ init_workqueues(); cpuset_init_smp(); usermodehelper_init(); diff --git a/kernel/rcutree.c b/kernel/rcutree.c index f85b6842d1e1..53a5ef0ca911 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -81,24 +81,29 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data); struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); -extern long rcu_batches_completed_sched(void); -static struct rcu_node *rcu_get_root(struct rcu_state *rsp); -static void cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, - struct rcu_node *rnp, unsigned long flags); -static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags); +/* Forward declarations for rcutree_plugin.h */ +static inline void rcu_bootup_announce(void); +long rcu_batches_completed(void); +static void rcu_preempt_note_context_switch(int cpu); +static int rcu_preempted_readers(struct rcu_node *rnp); +#ifdef CONFIG_RCU_CPU_STALL_DETECTOR +static void rcu_print_task_stall(struct rcu_node *rnp); +#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ +static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU -static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp); +static void rcu_preempt_offline_tasks(struct rcu_state *rsp, + struct rcu_node *rnp, + struct rcu_data *rdp); +static void rcu_preempt_offline_cpu(int cpu); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ -static void __rcu_process_callbacks(struct rcu_state *rsp, - struct rcu_data *rdp); -static void __call_rcu(struct rcu_head *head, - void (*func)(struct rcu_head *rcu), - struct rcu_state *rsp); -static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp); -static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_state *rsp, - int preemptable); +static void rcu_preempt_check_callbacks(int cpu); +static void rcu_preempt_process_callbacks(void); +void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); +static int rcu_preempt_pending(int cpu); +static int rcu_preempt_needs_cpu(int cpu); +static void __cpuinit rcu_preempt_init_percpu_data(int cpu); +static void __init __rcu_init_preempt(void); -#include "rcutree_plugin.h" /* * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s @@ -377,7 +382,7 @@ static long dyntick_recall_completed(struct rcu_state *rsp) /* * Snapshot the specified CPU's dynticks counter so that we can later * credit them with an implicit quiescent state. Return 1 if this CPU - * is already in a quiescent state courtesy of dynticks idle mode. + * is in dynticks idle mode, which is an extended quiescent state. */ static int dyntick_save_progress_counter(struct rcu_data *rdp) { @@ -624,9 +629,15 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) note_new_gpnum(rsp, rdp); /* - * Because we are first, we know that all our callbacks will - * be covered by this upcoming grace period, even the ones - * that were registered arbitrarily recently. + * Because this CPU just now started the new grace period, we know + * that all of its callbacks will be covered by this upcoming grace + * period, even the ones that were registered arbitrarily recently. + * Therefore, advance all outstanding callbacks to RCU_WAIT_TAIL. + * + * Other CPUs cannot be sure exactly when the grace period started. + * Therefore, their recently registered callbacks must pass through + * an additional RCU_NEXT_READY stage, so that they will be handled + * by the next RCU grace period. */ rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; @@ -886,7 +897,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) /* * Move callbacks from the outgoing CPU to the running CPU. - * Note that the outgoing CPU is now quiscent, so it is now + * Note that the outgoing CPU is now quiescent, so it is now * (uncharacteristically) safe to access its rcu_data structure. * Note also that we must carefully retain the order of the * outgoing CPU's callbacks in order for rcu_barrier() to work @@ -1577,25 +1588,6 @@ do { \ } \ } while (0) -#ifdef CONFIG_TREE_PREEMPT_RCU - -void __init __rcu_init_preempt(void) -{ - int i; /* All used by RCU_INIT_FLAVOR(). */ - int j; - struct rcu_node *rnp; - - RCU_INIT_FLAVOR(&rcu_preempt_state, rcu_preempt_data); -} - -#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ - -void __init __rcu_init_preempt(void) -{ -} - -#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ - void __init __rcu_init(void) { int i; /* All used by RCU_INIT_FLAVOR(). */ @@ -1612,6 +1604,8 @@ void __init __rcu_init(void) open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); } +#include "rcutree_plugin.h" + module_param(blimit, int, 0); module_param(qhimark, int, 0); module_param(qlowmark, int, 0); diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 9aa8c8a160d8..a48d11f37b4c 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -79,15 +79,21 @@ struct rcu_dynticks { * Definition for node within the RCU grace-period-detection hierarchy. */ struct rcu_node { - spinlock_t lock; + spinlock_t lock; /* Root rcu_node's lock protects some */ + /* rcu_state fields as well as following. */ long gpnum; /* Current grace period for this node. */ /* This will either be equal to or one */ /* behind the root rcu_node's gpnum. */ unsigned long qsmask; /* CPUs or groups that need to switch in */ /* order for current grace period to proceed.*/ + /* In leaf rcu_node, each bit corresponds to */ + /* an rcu_data structure, otherwise, each */ + /* bit corresponds to a child rcu_node */ + /* structure. */ unsigned long qsmaskinit; /* Per-GP initialization for qsmask. */ unsigned long grpmask; /* Mask to apply to parent qsmask. */ + /* Only one bit will be set in this mask. */ int grplo; /* lowest-numbered CPU or group here. */ int grphi; /* highest-numbered CPU or group here. */ u8 grpnum; /* CPU/group number for next level up. */ @@ -95,6 +101,9 @@ struct rcu_node { struct rcu_node *parent; struct list_head blocked_tasks[2]; /* Tasks blocked in RCU read-side critsect. */ + /* Grace period number (->gpnum) x blocked */ + /* by tasks on the (x & 0x1) element of the */ + /* blocked_tasks[] array. */ } ____cacheline_internodealigned_in_smp; /* Index values for nxttail array in struct rcu_data. */ @@ -126,19 +135,22 @@ struct rcu_data { * Any of the partitions might be empty, in which case the * pointer to that partition will be equal to the pointer for * the following partition. When the list is empty, all of - * the nxttail elements point to nxtlist, which is NULL. + * the nxttail elements point to the ->nxtlist pointer itself, + * which in that case is NULL. * - * [*nxttail[RCU_NEXT_READY_TAIL], NULL = *nxttail[RCU_NEXT_TAIL]): - * Entries that might have arrived after current GP ended - * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]): - * Entries known to have arrived before current GP ended - * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]): - * Entries that batch # <= ->completed - 1: waiting for current GP * [nxtlist, *nxttail[RCU_DONE_TAIL]): * Entries that batch # <= ->completed * The grace period for these entries has completed, and * the other grace-period-completed entries may be moved * here temporarily in rcu_process_callbacks(). + * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]): + * Entries that batch # <= ->completed - 1: waiting for current GP + * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]): + * Entries known to have arrived before current GP ended + * [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]): + * Entries that might have arrived after current GP ended + * Note that the value of *nxttail[RCU_NEXT_TAIL] will + * always be NULL, as this is the end of the list. */ struct rcu_head *nxtlist; struct rcu_head **nxttail[RCU_NEXT_SIZE]; @@ -216,6 +228,9 @@ struct rcu_state { /* Force QS state. */ long gpnum; /* Current gp number. */ long completed; /* # of last completed gp. */ + + /* End of fields guarded by root rcu_node's lock. */ + spinlock_t onofflock; /* exclude on/offline and */ /* starting new GP. */ spinlock_t fqslock; /* Only one task forcing */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 8ff1ba7b3c43..65250219ab6d 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -418,6 +418,18 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu) rcu_init_percpu_data(cpu, &rcu_preempt_state, 1); } +/* + * Initialize preemptable RCU's state structures. + */ +static void __init __rcu_init_preempt(void) +{ + int i; /* All used by RCU_INIT_FLAVOR(). */ + int j; + struct rcu_node *rnp; + + RCU_INIT_FLAVOR(&rcu_preempt_state, rcu_preempt_data); +} + /* * Check for a task exiting while in a preemptable-RCU read-side * critical section, clean up if so. No need to issue warnings, @@ -518,7 +530,7 @@ static void rcu_preempt_offline_cpu(int cpu) * Because preemptable RCU does not exist, it never has any callbacks * to check. */ -void rcu_preempt_check_callbacks(int cpu) +static void rcu_preempt_check_callbacks(int cpu) { } @@ -526,7 +538,7 @@ void rcu_preempt_check_callbacks(int cpu) * Because preemptable RCU does not exist, it never has any callbacks * to process. */ -void rcu_preempt_process_callbacks(void) +static void rcu_preempt_process_callbacks(void) { } @@ -563,4 +575,11 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu) { } +/* + * Because preemptable RCU does not exist, it need not be initialized. + */ +static void __init __rcu_init_preempt(void) +{ +} + #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ -- cgit v1.2.3-58-ga151 From 9b2619aff0332e95ea5eb7a0d75b0208818d871c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 23 Sep 2009 09:50:43 -0700 Subject: rcu: Clean up code to address Ingo's checkpatch feedback Move declarations and update storage classes to make checkpatch happy. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12537246441701-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/rcutree.h | 6 +++++- kernel/rcupdate.c | 3 --- kernel/rcutorture.c | 4 +--- kernel/rcutree.c | 23 ----------------------- kernel/rcutree.h | 26 +++++++++++++++++++++++++- kernel/rcutree_trace.c | 12 ++++++------ 6 files changed, 37 insertions(+), 37 deletions(-) (limited to 'include') diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 19a3b06943e0..46e9ab3ee6e1 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -30,10 +30,14 @@ #ifndef __LINUX_RCUTREE_H #define __LINUX_RCUTREE_H +struct notifier_block; + extern void rcu_sched_qs(int cpu); extern void rcu_bh_qs(int cpu); - +extern int rcu_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu); extern int rcu_needs_cpu(int cpu); +extern int rcu_expedited_torture_stats(char *page); #ifdef CONFIG_TREE_PREEMPT_RCU diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 37ac45483082..8e795133b33d 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -259,9 +259,6 @@ static void rcu_migrate_callback(struct rcu_head *notused) wake_up(&rcu_migrate_wq); } -extern int rcu_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu); - static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, unsigned long action, void *hcpu) { diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 233768f21f97..697c0a0229d4 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -606,8 +606,6 @@ static struct rcu_torture_ops sched_ops_sync = { .name = "sched_sync" }; -extern int rcu_expedited_torture_stats(char *page); - static struct rcu_torture_ops sched_expedited_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, @@ -650,7 +648,7 @@ rcu_torture_writer(void *arg) old_rp = rcu_torture_current; rp->rtort_mbtest = 1; rcu_assign_pointer(rcu_torture_current, rp); - smp_wmb(); + smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ if (old_rp) { i = old_rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 53a5ef0ca911..8e52cde7b8f7 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -81,29 +81,6 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data); struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); -/* Forward declarations for rcutree_plugin.h */ -static inline void rcu_bootup_announce(void); -long rcu_batches_completed(void); -static void rcu_preempt_note_context_switch(int cpu); -static int rcu_preempted_readers(struct rcu_node *rnp); -#ifdef CONFIG_RCU_CPU_STALL_DETECTOR -static void rcu_print_task_stall(struct rcu_node *rnp); -#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ -static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); -#ifdef CONFIG_HOTPLUG_CPU -static void rcu_preempt_offline_tasks(struct rcu_state *rsp, - struct rcu_node *rnp, - struct rcu_data *rdp); -static void rcu_preempt_offline_cpu(int cpu); -#endif /* #ifdef CONFIG_HOTPLUG_CPU */ -static void rcu_preempt_check_callbacks(int cpu); -static void rcu_preempt_process_callbacks(void); -void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); -static int rcu_preempt_pending(int cpu); -static int rcu_preempt_needs_cpu(int cpu); -static void __cpuinit rcu_preempt_init_percpu_data(int cpu); -static void __init __rcu_init_preempt(void); - /* * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s diff --git a/kernel/rcutree.h b/kernel/rcutree.h index a48d11f37b4c..e6ab31cc28ba 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -270,5 +270,29 @@ extern struct rcu_state rcu_preempt_state; DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ -#endif /* #ifdef RCU_TREE_NONCORE */ +#else /* #ifdef RCU_TREE_NONCORE */ +/* Forward declarations for rcutree_plugin.h */ +static inline void rcu_bootup_announce(void); +long rcu_batches_completed(void); +static void rcu_preempt_note_context_switch(int cpu); +static int rcu_preempted_readers(struct rcu_node *rnp); +#ifdef CONFIG_RCU_CPU_STALL_DETECTOR +static void rcu_print_task_stall(struct rcu_node *rnp); +#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ +static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); +#ifdef CONFIG_HOTPLUG_CPU +static void rcu_preempt_offline_tasks(struct rcu_state *rsp, + struct rcu_node *rnp, + struct rcu_data *rdp); +static void rcu_preempt_offline_cpu(int cpu); +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ +static void rcu_preempt_check_callbacks(int cpu); +static void rcu_preempt_process_callbacks(void); +void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); +static int rcu_preempt_pending(int cpu); +static int rcu_preempt_needs_cpu(int cpu); +static void __cpuinit rcu_preempt_init_percpu_data(int cpu); +static void __init __rcu_init_preempt(void); + +#endif /* #else #ifdef RCU_TREE_NONCORE */ diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index c89f5e9fd173..f09af28b8262 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -93,7 +93,7 @@ static int rcudata_open(struct inode *inode, struct file *file) return single_open(file, show_rcudata, NULL); } -static struct file_operations rcudata_fops = { +static const struct file_operations rcudata_fops = { .owner = THIS_MODULE, .open = rcudata_open, .read = seq_read, @@ -145,7 +145,7 @@ static int rcudata_csv_open(struct inode *inode, struct file *file) return single_open(file, show_rcudata_csv, NULL); } -static struct file_operations rcudata_csv_fops = { +static const struct file_operations rcudata_csv_fops = { .owner = THIS_MODULE, .open = rcudata_csv_open, .read = seq_read, @@ -159,7 +159,7 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) struct rcu_node *rnp; seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x " - "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n", + "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n", rsp->completed, rsp->gpnum, rsp->signaled, (long)(rsp->jiffies_force_qs - jiffies), (int)(jiffies & 0xffff), @@ -196,7 +196,7 @@ static int rcuhier_open(struct inode *inode, struct file *file) return single_open(file, show_rcuhier, NULL); } -static struct file_operations rcuhier_fops = { +static const struct file_operations rcuhier_fops = { .owner = THIS_MODULE, .open = rcuhier_open, .read = seq_read, @@ -222,7 +222,7 @@ static int rcugp_open(struct inode *inode, struct file *file) return single_open(file, show_rcugp, NULL); } -static struct file_operations rcugp_fops = { +static const struct file_operations rcugp_fops = { .owner = THIS_MODULE, .open = rcugp_open, .read = seq_read, @@ -276,7 +276,7 @@ static int rcu_pending_open(struct inode *inode, struct file *file) return single_open(file, show_rcu_pending, NULL); } -static struct file_operations rcu_pending_fops = { +static const struct file_operations rcu_pending_fops = { .owner = THIS_MODULE, .open = rcu_pending_open, .read = seq_read, -- cgit v1.2.3-58-ga151 From 3d76c082907e8f83c5d5c4572f38d53ad8f00c4b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 28 Sep 2009 07:46:32 -0700 Subject: rcu: Clean up code based on review feedback from Josh Triplett, part 3 Whitespace fixes, updated comments, and trivial code movement. o Fix whitespace error in RCU_HEAD_INIT() o Move "So where is rcu_write_lock()" comment so that it does not come between the rcu_read_unlock() header comment and the rcu_read_unlock() definition. o Move the module_param statements for blimit, qhimark, and qlowmark to immediately follow the corresponding definitions. o In __rcu_offline_cpu(), move the assignment to rdp_me inside the "if" statement, given that rdp_me is not used outside of that "if" statement. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12541491931164-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/rcupdate.h | 14 +++++++------- kernel/rcutree.c | 10 +++++----- 2 files changed, 12 insertions(+), 12 deletions(-) (limited to 'include') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 70331218e4b4..3ebd0b7bcb08 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -77,7 +77,7 @@ extern int rcu_scheduler_active; #error "Unknown RCU implementation specified to kernel configuration" #endif -#define RCU_HEAD_INIT { .next = NULL, .func = NULL } +#define RCU_HEAD_INIT { .next = NULL, .func = NULL } #define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT #define INIT_RCU_HEAD(ptr) do { \ (ptr)->next = NULL; (ptr)->func = NULL; \ @@ -129,12 +129,6 @@ static inline void rcu_read_lock(void) rcu_read_acquire(); } -/** - * rcu_read_unlock - marks the end of an RCU read-side critical section. - * - * See rcu_read_lock() for more information. - */ - /* * So where is rcu_write_lock()? It does not exist, as there is no * way for writers to lock out RCU readers. This is a feature, not @@ -144,6 +138,12 @@ static inline void rcu_read_lock(void) * used as well. RCU does not care how the writers keep out of each * others' way, as long as they do so. */ + +/** + * rcu_read_unlock - marks the end of an RCU read-side critical section. + * + * See rcu_read_lock() for more information. + */ static inline void rcu_read_unlock(void) { rcu_read_release(); diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 81af59b8dd88..d5597830faf5 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -122,6 +122,10 @@ static int blimit = 10; /* Maximum callbacks per softirq. */ static int qhimark = 10000; /* If this many pending, ignore blimit. */ static int qlowmark = 100; /* Once only this many pending, use blimit. */ +module_param(blimit, int, 0); +module_param(qhimark, int, 0); +module_param(qlowmark, int, 0); + static void force_quiescent_state(struct rcu_state *rsp, int relaxed); static int rcu_pending(int cpu); @@ -878,8 +882,8 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) * indefinitely delay callbacks, you have far worse things to * be worrying about. */ - rdp_me = rsp->rda[smp_processor_id()]; if (rdp->nxtlist != NULL) { + rdp_me = rsp->rda[smp_processor_id()]; *rdp_me->nxttail[RCU_NEXT_TAIL] = rdp->nxtlist; rdp_me->nxttail[RCU_NEXT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; rdp->nxtlist = NULL; @@ -1575,7 +1579,3 @@ void __init __rcu_init(void) } #include "rcutree_plugin.h" - -module_param(blimit, int, 0); -module_param(qhimark, int, 0); -module_param(qlowmark, int, 0); -- cgit v1.2.3-58-ga151 From f8d1e548931cfa5ea9a082e020c2a47d27e5d793 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Wed, 7 Oct 2009 11:13:58 +1100 Subject: futex: Fix typo in FUTEX_WAIT/WAKE_BITSET_PRIVATE definitions Looks like a typo, FUTEX_WAKE_BITS should be FUTEX_WAIT_BITSET. Signed-off-by: Anton Blanchard LKML-Reference: <20091007001358.GE16073@kryten> Signed-off-by: Thomas Gleixner --- include/linux/futex.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/futex.h b/include/linux/futex.h index 34956c8fdebf..78b92ec9edbd 100644 --- a/include/linux/futex.h +++ b/include/linux/futex.h @@ -38,8 +38,8 @@ union ktime; #define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG) #define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG) #define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG) -#define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITS | FUTEX_PRIVATE_FLAG) -#define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITS | FUTEX_PRIVATE_FLAG) +#define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG) +#define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG) #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \ FUTEX_PRIVATE_FLAG) #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \ -- cgit v1.2.3-58-ga151