On Thu, Aug 01, 2024 at 04:58:17AM +0000, Mingwei Zhang wrote:
> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
>
> The current perf tracks two timestamps for the normal ctx and cgroup.
> The same type of variables and similar codes are used to track the
> timestamps. In the following patch, the third timestamp to track the
> guest time will be introduced.
> To avoid the code duplication, add a new struct perf_time_ctx and factor
> out a generic function update_perf_time_ctx().
>
> No functional change.
>
> Suggested-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -801,11 +801,22 @@ static inline u64 perf_cgroup_event_time
return now;
}
-static inline void update_perf_time_ctx(struct perf_time_ctx *time, u64 now, bool adv);
-
-static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
+static inline void update_perf_time_ctx(struct perf_time_ctx *time, u64 now, bool adv)
{
- update_perf_time_ctx(&info->time, now, adv);
+ if (adv)
+ time->time += now - time->stamp;
+ time->stamp = now;
+
+ /*
+ * The above: time' = time + (now - timestamp), can be re-arranged
+ * into: time` = now + (time - timestamp), which gives a single value
+ * offset to compute future time without locks on.
+ *
+ * See perf_event_time_now(), which can be used from NMI context where
+ * it's (obviously) not possible to acquire ctx->lock in order to read
+ * both the above values in a consistent manner.
+ */
+ WRITE_ONCE(time->offset, time->time - time->stamp);
}
static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
@@ -821,7 +832,7 @@ static inline void update_cgrp_time_from
cgrp = container_of(css, struct perf_cgroup, css);
info = this_cpu_ptr(cgrp->info);
- __update_cgrp_time(info, now, true);
+ update_perf_time_ctx(&info->time, now, true);
if (final)
__store_release(&info->active, 0);
}
@@ -844,7 +855,7 @@ static inline void update_cgrp_time_from
* Do not update time when cgroup is not active
*/
if (info->active)
- __update_cgrp_time(info, perf_clock(), true);
+ update_perf_time_ctx(&info->time, perf_clock(), true);
}
static inline void
@@ -868,7 +879,7 @@ perf_cgroup_set_timestamp(struct perf_cp
for (css = &cgrp->css; css; css = css->parent) {
cgrp = container_of(css, struct perf_cgroup, css);
info = this_cpu_ptr(cgrp->info);
- __update_cgrp_time(info, ctx->time.stamp, false);
+ update_perf_time_ctx(&info->time, ctx->time.stamp, false);
__store_release(&info->active, 1);
}
}
@@ -1478,24 +1489,6 @@ static void perf_unpin_context(struct pe
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
-static inline void update_perf_time_ctx(struct perf_time_ctx *time, u64 now, bool adv)
-{
- if (adv)
- time->time += now - time->stamp;
- time->stamp = now;
-
- /*
- * The above: time' = time + (now - timestamp), can be re-arranged
- * into: time` = now + (time - timestamp), which gives a single value
- * offset to compute future time without locks on.
- *
- * See perf_event_time_now(), which can be used from NMI context where
- * it's (obviously) not possible to acquire ctx->lock in order to read
- * both the above values in a consistent manner.
- */
- WRITE_ONCE(time->offset, time->time - time->stamp);
-}
-
/*
* Update the record of the current time in a context.
*/
