tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev head: 3981406d6621b8a72a873bdc88d0a95d2e928c9e commit: 3981406d6621b8a72a873bdc88d0a95d2e928c9e [117/117] rcu: Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds config: x86_64-randconfig-x018-201826 (attached as .config) compiler: gcc-7 (Debian 7.3.0-16) 7.3.0 reproduce: git checkout 3981406d6621b8a72a873bdc88d0a95d2e928c9e # save the attached .config to linux build tree make ARCH=x86_64
All error/warnings (new ones prefixed by >>):
>> kernel//rcu/tree.c:2996:6: error: redefinition of 'call_rcu_sched'
void call_rcu_sched(struct rcu_head *head, rcu_callback_t func)
^~~~~~~~~~~~~~
In file included from include/linux/rcupdate_wait.h:9:0,
from kernel//rcu/tree.c:38:
include/linux/rcupdate.h:53:18: note: previous definition of
'call_rcu_sched' was here
#define call_rcu call_rcu_sched
^
>> kernel//rcu/tree.c:2983:6: note: in expansion of macro 'call_rcu'
void call_rcu(struct rcu_head *head, rcu_callback_t func)
^~~~~~~~
vim +/call_rcu_sched +2996 kernel//rcu/tree.c
64db4cff kernel/rcutree.c Paul E. McKenney 2008-12-18 2950
a68a2bb2 kernel/rcu/tree.c Paul E. McKenney 2017-05-03 2951 /**
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2952 * call_rcu() -
Queue an RCU callback for invocation after a grace period.
a68a2bb2 kernel/rcu/tree.c Paul E. McKenney 2017-05-03 2953 * @head:
structure to be used for queueing the RCU updates.
a68a2bb2 kernel/rcu/tree.c Paul E. McKenney 2017-05-03 2954 * @func: actual
callback function to be invoked after the grace period
a68a2bb2 kernel/rcu/tree.c Paul E. McKenney 2017-05-03 2955 *
a68a2bb2 kernel/rcu/tree.c Paul E. McKenney 2017-05-03 2956 * The callback
function will be invoked some time after a full grace
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2957 * period
elapses, in other words after all pre-existing RCU read-side
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2958 * critical
sections have completed. However, the callback function
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2959 * might well
execute concurrently with RCU read-side critical sections
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2960 * that started
after call_rcu() was invoked. RCU read-side critical
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2961 * sections are
delimited by rcu_read_lock() and rcu_read_unlock(),
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2962 * and may be
nested.
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2963 *
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2964 * Note that all
CPUs must agree that the grace period extended beyond
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2965 * all
pre-existing RCU read-side critical section. On systems with more
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2966 * than one CPU,
this means that when "func()" is invoked, each CPU is
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2967 * guaranteed to
have executed a full memory barrier since the end of its
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2968 * last RCU
read-side critical section whose beginning preceded the call
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2969 * to call_rcu().
It also means that each CPU executing an RCU read-side
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2970 * critical
section that continues beyond the start of "func()" must have
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2971 * executed a
memory barrier after the call_rcu() but before the beginning
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2972 * of that RCU
read-side critical section. Note that these guarantees
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2973 * include CPUs
that are offline, idle, or executing in user mode, as
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2974 * well as CPUs
that are executing in the kernel.
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2975 *
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2976 * Furthermore,
if CPU A invoked call_rcu() and CPU B invoked the
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2977 * resulting RCU
callback function "func()", then both CPU A and CPU B are
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2978 * guaranteed to
execute a full memory barrier during the time interval
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2979 * between the
call to call_rcu() and the invocation of "func()" -- even
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2980 * if CPU A and
CPU B are the same CPU (but again only if the system has
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2981 * more than one
CPU).
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2982 */
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 @2983 void
call_rcu(struct rcu_head *head, rcu_callback_t func)
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2984 {
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2985
__call_rcu(head, func, rcu_state_p, -1, 0);
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2986 }
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2987
EXPORT_SYMBOL_GPL(call_rcu);
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2988
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2989 /**
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2990 *
call_rcu_sched() - Queue an RCU for invocation after sched grace period.
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2991 * @head:
structure to be used for queueing the RCU updates.
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2992 * @func: actual
callback function to be invoked after the grace period
a68a2bb2 kernel/rcu/tree.c Paul E. McKenney 2017-05-03 2993 *
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2994 * This is
transitional.
64db4cff kernel/rcutree.c Paul E. McKenney 2008-12-18 2995 */
b6a4ae76 kernel/rcu/tree.c Boqun Feng 2015-07-29 @2996 void
call_rcu_sched(struct rcu_head *head, rcu_callback_t func)
64db4cff kernel/rcutree.c Paul E. McKenney 2008-12-18 2997 {
3981406d kernel/rcu/tree.c Paul E. McKenney 2018-07-02 2998 call_rcu(head,
func);
64db4cff kernel/rcutree.c Paul E. McKenney 2008-12-18 2999 }
d6714c22 kernel/rcutree.c Paul E. McKenney 2009-08-22 3000
EXPORT_SYMBOL_GPL(call_rcu_sched);
64db4cff kernel/rcutree.c Paul E. McKenney 2008-12-18 3001
:::::: The code at line 2996 was first introduced by commit
:::::: b6a4ae766e3133a4db73fabc81e522d1601cb623 rcu: Use rcu_callback_t in
call_rcu*() and friends
:::::: TO: Boqun Feng <boqun.f...@gmail.com>
:::::: CC: Paul E. McKenney <paul...@linux.vnet.ibm.com>
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