mirror of
https://github.com/torvalds/linux.git
synced 2024-11-26 14:12:06 +00:00
rcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT
This commit introduces an RCU_FANOUT C-preprocessor macro so that RCU will build even when CONFIG_RCU_FANOUT is undefined. The RCU_FANOUT macro is set to the value of CONFIG_RCU_FANOUT when defined, otherwise it is set to 32 for 32-bit systems and 64 for 64-bit systems. This commit then makes CONFIG_RCU_FANOUT depend on CONFIG_RCU_EXPERT, so that Kconfig users won't be asked about CONFIG_RCU_FANOUT unless they want to be. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
This commit is contained in:
parent
8739c5cb0f
commit
05c5df31af
@ -583,7 +583,7 @@ config RCU_FANOUT
|
||||
int "Tree-based hierarchical RCU fanout value"
|
||||
range 2 64 if 64BIT
|
||||
range 2 32 if !64BIT
|
||||
depends on TREE_RCU || PREEMPT_RCU
|
||||
depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT
|
||||
default 64 if 64BIT
|
||||
default 32 if !64BIT
|
||||
help
|
||||
|
@ -3971,7 +3971,7 @@ static void __init rcu_init_levelspread(struct rcu_state *rsp)
|
||||
if (rcu_fanout_exact) {
|
||||
rsp->levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
|
||||
for (i = rcu_num_lvls - 2; i >= 0; i--)
|
||||
rsp->levelspread[i] = CONFIG_RCU_FANOUT;
|
||||
rsp->levelspread[i] = RCU_FANOUT;
|
||||
} else {
|
||||
int ccur;
|
||||
int cprv;
|
||||
@ -4111,7 +4111,7 @@ static void __init rcu_init_geometry(void)
|
||||
rcu_capacity[0] = 1;
|
||||
rcu_capacity[1] = rcu_fanout_leaf;
|
||||
for (i = 2; i <= MAX_RCU_LVLS; i++)
|
||||
rcu_capacity[i] = rcu_capacity[i - 1] * CONFIG_RCU_FANOUT;
|
||||
rcu_capacity[i] = rcu_capacity[i - 1] * RCU_FANOUT;
|
||||
|
||||
/*
|
||||
* The boot-time rcu_fanout_leaf parameter is only permitted
|
||||
|
@ -35,11 +35,23 @@
|
||||
* In practice, this did work well going from three levels to four.
|
||||
* Of course, your mileage may vary.
|
||||
*/
|
||||
|
||||
#define MAX_RCU_LVLS 4
|
||||
|
||||
#ifdef CONFIG_RCU_FANOUT
|
||||
#define RCU_FANOUT CONFIG_RCU_FANOUT
|
||||
#else /* #ifdef CONFIG_RCU_FANOUT */
|
||||
# ifdef CONFIG_64BIT
|
||||
# define RCU_FANOUT 64
|
||||
# else
|
||||
# define RCU_FANOUT 32
|
||||
# endif
|
||||
#endif /* #else #ifdef CONFIG_RCU_FANOUT */
|
||||
|
||||
#define RCU_FANOUT_1 (CONFIG_RCU_FANOUT_LEAF)
|
||||
#define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT)
|
||||
#define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT)
|
||||
#define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT)
|
||||
#define RCU_FANOUT_2 (RCU_FANOUT_1 * RCU_FANOUT)
|
||||
#define RCU_FANOUT_3 (RCU_FANOUT_2 * RCU_FANOUT)
|
||||
#define RCU_FANOUT_4 (RCU_FANOUT_3 * RCU_FANOUT)
|
||||
|
||||
#if NR_CPUS <= RCU_FANOUT_1
|
||||
# define RCU_NUM_LVLS 1
|
||||
|
@ -60,10 +60,10 @@ static void __init rcu_bootup_announce_oddness(void)
|
||||
{
|
||||
if (IS_ENABLED(CONFIG_RCU_TRACE))
|
||||
pr_info("\tRCU debugfs-based tracing is enabled.\n");
|
||||
if ((IS_ENABLED(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 64) ||
|
||||
(!IS_ENABLED(CONFIG_64BIT) && CONFIG_RCU_FANOUT != 32))
|
||||
if ((IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 64) ||
|
||||
(!IS_ENABLED(CONFIG_64BIT) && RCU_FANOUT != 32))
|
||||
pr_info("\tCONFIG_RCU_FANOUT set to non-default value of %d\n",
|
||||
CONFIG_RCU_FANOUT);
|
||||
RCU_FANOUT);
|
||||
if (rcu_fanout_exact)
|
||||
pr_info("\tHierarchical RCU autobalancing is disabled.\n");
|
||||
if (IS_ENABLED(CONFIG_RCU_FAST_NO_HZ))
|
||||
|
Loading…
Reference in New Issue
Block a user