diff options
Diffstat (limited to 'kernel/smp.c')
| -rw-r--r-- | kernel/smp.c | 38 |
1 files changed, 34 insertions, 4 deletions
diff --git a/kernel/smp.c b/kernel/smp.c index aeb0adfa0606..d5f0b21ab55e 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -24,6 +24,7 @@ #include <linux/sched/clock.h> #include <linux/nmi.h> #include <linux/sched/debug.h> +#include <linux/jump_label.h> #include "smpboot.h" #include "sched/smp.h" @@ -102,6 +103,20 @@ void __init call_function_init(void) #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG +static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled); + +static int __init csdlock_debug(char *str) +{ + unsigned int val = 0; + + get_option(&str, &val); + if (val) + static_branch_enable(&csdlock_debug_enabled); + + return 0; +} +early_param("csdlock_debug", csdlock_debug); + static DEFINE_PER_CPU(call_single_data_t *, cur_csd); static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func); static DEFINE_PER_CPU(void *, cur_csd_info); @@ -110,7 +125,7 @@ static DEFINE_PER_CPU(void *, cur_csd_info); static atomic_t csd_bug_count = ATOMIC_INIT(0); /* Record current CSD work for current CPU, NULL to erase. */ -static void csd_lock_record(call_single_data_t *csd) +static void __csd_lock_record(call_single_data_t *csd) { if (!csd) { smp_mb(); /* NULL cur_csd after unlock. */ @@ -125,7 +140,13 @@ static void csd_lock_record(call_single_data_t *csd) /* Or before unlock, as the case may be. */ } -static __always_inline int csd_lock_wait_getcpu(call_single_data_t *csd) +static __always_inline void csd_lock_record(call_single_data_t *csd) +{ + if (static_branch_unlikely(&csdlock_debug_enabled)) + __csd_lock_record(csd); +} + +static int csd_lock_wait_getcpu(call_single_data_t *csd) { unsigned int csd_type; @@ -140,7 +161,7 @@ static __always_inline int csd_lock_wait_getcpu(call_single_data_t *csd) * the CSD_TYPE_SYNC/ASYNC types provide the destination CPU, * so waiting on other types gets much less information. */ -static __always_inline bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, int *bug_id) +static bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, int *bug_id) { int cpu = -1; int cpux; @@ -204,7 +225,7 @@ static __always_inline bool csd_lock_wait_toolong(call_single_data_t *csd, u64 t * previous function call. For multi-cpu calls its even more interesting * as we'll have to ensure no other cpu is observing our csd. */ -static __always_inline void csd_lock_wait(call_single_data_t *csd) +static void __csd_lock_wait(call_single_data_t *csd) { int bug_id = 0; u64 ts0, ts1; @@ -218,6 +239,15 @@ static __always_inline void csd_lock_wait(call_single_data_t *csd) smp_acquire__after_ctrl_dep(); } +static __always_inline void csd_lock_wait(call_single_data_t *csd) +{ + if (static_branch_unlikely(&csdlock_debug_enabled)) { + __csd_lock_wait(csd); + return; + } + + smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK)); +} #else static void csd_lock_record(call_single_data_t *csd) { |