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rcu/nocb: Turn enabled/offload states into a common flag

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This commit gathers the rcu_segcblist ->enabled and ->offloaded property
field into a single ->flags bitmask to avoid further proliferation of
individual u8 fields in the structure.  This change prepares for the
state formerly known as ->offloaded state to be modified at runtime.

Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Inspired-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Frederic Weisbecker 2020-11-13 13:13:16 +01:00 committed by Paul E. McKenney
parent b4e6039e8a
commit 65e560327f
3 changed files with 28 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/rcu_segcblist.h
View File

@ -63,6 +63,9 @@ struct rcu_cblist {
#define RCU_NEXT_TAIL 3
#define RCU_CBLIST_NSEGS 4
#define SEGCBLIST_ENABLED BIT(0)
#define SEGCBLIST_OFFLOADED BIT(1)
struct rcu_segcblist {
struct rcu_head *head;
struct rcu_head **tails[RCU_CBLIST_NSEGS];
@ -73,8 +76,7 @@ struct rcu_segcblist {
long len;
#endif
long seglen[RCU_CBLIST_NSEGS];
u8 enabled;
u8 offloaded;
u8 flags;
};
#define RCU_SEGCBLIST_INITIALIZER(n) \

6
kernel/rcu/rcu_segcblist.c
View File

@ -246,7 +246,7 @@ void rcu_segcblist_init(struct rcu_segcblist *rsclp)
rcu_segcblist_set_seglen(rsclp, i, 0);
}
rcu_segcblist_set_len(rsclp, 0);
rsclp->enabled = 1;
rcu_segcblist_set_flags(rsclp, SEGCBLIST_ENABLED);
}
/*
@ -257,7 +257,7 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
{
WARN_ON_ONCE(!rcu_segcblist_empty(rsclp));
WARN_ON_ONCE(rcu_segcblist_n_cbs(rsclp));
rsclp->enabled = 0;
rcu_segcblist_clear_flags(rsclp, SEGCBLIST_ENABLED);
}
/*
@ -266,7 +266,7 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
*/
void rcu_segcblist_offload(struct rcu_segcblist *rsclp)
{
rsclp->offloaded = 1;
rcu_segcblist_set_flags(rsclp, SEGCBLIST_OFFLOADED);
}
/*

23
kernel/rcu/rcu_segcblist.h
View File

@ -53,19 +53,38 @@ static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
#endif
}
static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
int flags)
{
rsclp->flags |= flags;
}
static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
int flags)
{
rsclp->flags &= ~flags;
}
static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,
int flags)
{
return READ_ONCE(rsclp->flags) & flags;
}
/*
* Is the specified rcu_segcblist enabled, for example, not corresponding
* to an offline CPU?
*/
static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
{
return rsclp->enabled;
return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
}
/* Is the specified rcu_segcblist offloaded? */
static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
{
return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded;
return IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
rcu_segcblist_test_flags(rsclp, SEGCBLIST_OFFLOADED);
}
/*