Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2025-01-19 06:47:48 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

rcu_sync: Simplify rcu_sync using new rcu_sync_ops structure

Browse Source 
This commit adds the new struct rcu_sync_ops which holds sync/call
methods, and turns the function pointers in rcu_sync_struct into an array
of struct rcu_sync_ops.  This simplifies the "init" helpers by collapsing
a switch statement and explicit multiple definitions into a simple
assignment and a helper macro, respectively.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Oleg Nesterov 2015-08-21 19:42:47 +02:00 committed by Paul E. McKenney
parent cc44ca848f
commit 82e8c565be
2 changed files with 45 additions and 57 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
include/linux/rcu_sync.h
View File

@ -26,6 +26,8 @@
#include <linux/wait.h>
#include <linux/rcupdate.h>
enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC };
/* Structure to mediate between updaters and fastpath-using readers. */
struct rcu_sync {
int gp_state;
@ -35,43 +37,9 @@ struct rcu_sync {
int cb_state;
struct rcu_head cb_head;
void (*sync)(void);
void (*call)(struct rcu_head *, void (*)(struct rcu_head *));
enum rcu_sync_type gp_type;
};
#define ___RCU_SYNC_INIT(name) \
.gp_state = 0, \
.gp_count = 0, \
.gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \
.cb_state = 0
#define __RCU_SCHED_SYNC_INIT(name) { \
___RCU_SYNC_INIT(name), \
.sync = synchronize_sched, \
.call = call_rcu_sched, \
}
#define __RCU_BH_SYNC_INIT(name) { \
___RCU_SYNC_INIT(name), \
.sync = synchronize_rcu_bh, \
.call = call_rcu_bh, \
}
#define __RCU_SYNC_INIT(name) { \
___RCU_SYNC_INIT(name), \
.sync = synchronize_rcu, \
.call = call_rcu, \
}
#define DEFINE_RCU_SCHED_SYNC(name) \
struct rcu_sync name = __RCU_SCHED_SYNC_INIT(name)
#define DEFINE_RCU_BH_SYNC(name) \
struct rcu_sync name = __RCU_BH_SYNC_INIT(name)
#define DEFINE_RCU_SYNC(name) \
struct rcu_sync name = __RCU_SYNC_INIT(name)
/**
* rcu_sync_is_idle() - Are readers permitted to use their fastpaths?
* @rsp: Pointer to rcu_sync structure to use for synchronization
@ -85,10 +53,28 @@ static inline bool rcu_sync_is_idle(struct rcu_sync *rsp)
return !rsp->gp_state; /* GP_IDLE */
}
enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC };
extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type);
extern void rcu_sync_enter(struct rcu_sync *);
extern void rcu_sync_exit(struct rcu_sync *);
#define __RCU_SYNC_INITIALIZER(name, type) { \
.gp_state = 0, \
.gp_count = 0, \
.gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \
.cb_state = 0, \
.gp_type = type, \
}
#define __DEFINE_RCU_SYNC(name, type) \
struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type)
#define DEFINE_RCU_SYNC(name) \
__DEFINE_RCU_SYNC(name, RCU_SYNC)
#define DEFINE_RCU_SCHED_SYNC(name) \
__DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC)
#define DEFINE_RCU_BH_SYNC(name) \
__DEFINE_RCU_SYNC(name, RCU_BH_SYNC)
#endif /* _LINUX_RCU_SYNC_H_ */

42
kernel/rcu/sync.c
View File

@ -23,6 +23,24 @@
#include <linux/rcu_sync.h>
#include <linux/sched.h>
static const struct {
void (*sync)(void);
void (*call)(struct rcu_head *, void (*)(struct rcu_head *));
} gp_ops[] = {
[RCU_SYNC] = {
.sync = synchronize_rcu,
.call = call_rcu,
},
[RCU_SCHED_SYNC] = {
.sync = synchronize_sched,
.call = call_rcu_sched,
},
[RCU_BH_SYNC] = {
.sync = synchronize_rcu_bh,
.call = call_rcu_bh,
},
};
enum { GP_IDLE = 0, GP_PENDING, GP_PASSED };
enum { CB_IDLE = 0, CB_PENDING, CB_REPLAY };
@ -37,23 +55,7 @@ void rcu_sync_init(struct rcu_sync *rsp, enum rcu_sync_type type)
{
memset(rsp, 0, sizeof(*rsp));
init_waitqueue_head(&rsp->gp_wait);
switch (type) {
case RCU_SYNC:
rsp->sync = synchronize_rcu;
rsp->call = call_rcu;
break;
case RCU_SCHED_SYNC:
rsp->sync = synchronize_sched;
rsp->call = call_rcu_sched;
break;
case RCU_BH_SYNC:
rsp->sync = synchronize_rcu_bh;
rsp->call = call_rcu_bh;
break;
}
rsp->gp_type = type;
}
/**
@ -85,7 +87,7 @@ void rcu_sync_enter(struct rcu_sync *rsp)
BUG_ON(need_wait && need_sync);
if (need_sync) {
rsp->sync();
gp_ops[rsp->gp_type].sync();
rsp->gp_state = GP_PASSED;
wake_up_all(&rsp->gp_wait);
} else if (need_wait) {
@ -138,7 +140,7 @@ static void rcu_sync_func(struct rcu_head *rcu)
* to catch a later GP.
*/
rsp->cb_state = CB_PENDING;
rsp->call(&rsp->cb_head, rcu_sync_func);
gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
} else {
/*
* We're at least a GP after rcu_sync_exit(); eveybody will now
@ -166,7 +168,7 @@ void rcu_sync_exit(struct rcu_sync *rsp)
if (!--rsp->gp_count) {
if (rsp->cb_state == CB_IDLE) {
rsp->cb_state = CB_PENDING;
rsp->call(&rsp->cb_head, rcu_sync_func);
gp_ops[rsp->gp_type].call(&rsp->cb_head, rcu_sync_func);
} else if (rsp->cb_state == CB_PENDING) {
rsp->cb_state = CB_REPLAY;
}