Add hazptr reader and synchronize operations so that synchronize latency can be measured alongside RCU and SRCU.
Use a small set of objects so readers do not always protect the same target. Each reader protects the object selected by its CPU, while the updater round-robins through the objects. Use hazptr_synchronize() for both normal and expedited scale operations, since hazptr has no separate expedited operation. Link: https://lore.kernel.org/lkml/[email protected]/ Signed-off-by: Kunwu Chan <[email protected]> --- kernel/rcu/rcuscale.c | 70 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 69 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 1097ec15879c..5aca31c3c01d 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -39,6 +39,7 @@ #include <linux/torture.h> #include <linux/vmalloc.h> #include <linux/rcupdate_trace.h> +#include <linux/hazptr.h> #include <linux/sched/debug.h> #include "rcu.h" @@ -418,6 +419,71 @@ static struct rcu_scale_ops tasks_tracing_ops = { #endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU +#if IS_ENABLED(CONFIG_HAZPTR_TORTURE_TEST) + +#define HAZPTR_SCALE_NR_OBJS 8 +static int hazptr_scale_obj[HAZPTR_SCALE_NR_OBJS]; +static atomic_t hazptr_scale_sync_idx = ATOMIC_INIT(0); + +struct hazptr_scale_state { + struct hazptr_ctx ctx; + void *addr; +}; +static DEFINE_PER_CPU(struct hazptr_scale_state, hazptr_scale_state); + +static int hazptr_scale_read_lock(void) +{ + struct hazptr_scale_state *state = this_cpu_ptr(&hazptr_scale_state); + int idx = smp_processor_id() % HAZPTR_SCALE_NR_OBJS; + void *ptr = &hazptr_scale_obj[idx]; + + state->addr = hazptr_acquire(&state->ctx, &ptr); + return 0; +} + +static void hazptr_scale_read_unlock(int idx) +{ + struct hazptr_scale_state *state = this_cpu_ptr(&hazptr_scale_state); + + hazptr_release(&state->ctx, state->addr); +} + +static unsigned long hazptr_scale_completed(void) +{ + return 0; +} + +static void hazptr_scale_sync(void) +{ + int idx = atomic_fetch_inc(&hazptr_scale_sync_idx) % HAZPTR_SCALE_NR_OBJS; + + hazptr_synchronize(&hazptr_scale_obj[idx]); +} + +static void hazptr_scale_sync_exp(void) +{ + int idx = atomic_fetch_inc(&hazptr_scale_sync_idx) % HAZPTR_SCALE_NR_OBJS; + + hazptr_synchronize(&hazptr_scale_obj[idx]); +} + +static struct rcu_scale_ops hazptr_scale_ops = { + .ptype = 0, + .readlock = hazptr_scale_read_lock, + .readunlock = hazptr_scale_read_unlock, + .get_gp_seq = hazptr_scale_completed, + .gp_diff = NULL, + .exp_completed = hazptr_scale_completed, + .sync = hazptr_scale_sync, + .exp_sync = hazptr_scale_sync_exp, + .name = "hazptr", +}; + +#define HAZPTR_SCALE_OPS &hazptr_scale_ops, +#else +#define HAZPTR_SCALE_OPS +#endif + static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old) { if (!cur_ops->gp_diff) @@ -1110,7 +1176,9 @@ rcu_scale_init(void) long i; long j; static struct rcu_scale_ops *scale_ops[] = { - &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS + &rcu_ops, &srcu_ops, &srcud_ops, + TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS + HAZPTR_SCALE_OPS }; if (!torture_init_begin(scale_type, verbose)) -- 2.43.0
