Re: [PATCH v2 bpf-next 1/3] perf: enable branch record for software events
From: Peter Zijlstra <peterz@infradead.org>
Date: 2021-08-30 10:25:51
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On Thu, Aug 26, 2021 at 03:13:04PM -0700, Song Liu wrote:
quoted hunk ↗ jump to hunk
+int dummy_perf_snapshot_branch_stack(struct perf_branch_snapshot *br_snapshot); + +DECLARE_STATIC_CALL(perf_snapshot_branch_stack, dummy_perf_snapshot_branch_stack); + #endif /* _LINUX_PERF_EVENT_H */diff --git a/kernel/events/core.c b/kernel/events/core.c index 011cc5069b7ba..c53fe90e630ac 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c@@ -13437,3 +13437,6 @@ struct cgroup_subsys perf_event_cgrp_subsys = { .threaded = true, }; #endif /* CONFIG_CGROUP_PERF */ + +DEFINE_STATIC_CALL_NULL(perf_snapshot_branch_stack, + dummy_perf_snapshot_branch_stack);
This isn't right... The whole dummy_perf_snapshot_branch_stack() thing is a declaration only and used as a typedef. Also, DEFINE_STATIC_CALL_NULL() and static_call_cond() rely on a void return value, which it doesn't have. Did you want: DECLARE_STATIC_CALL(perf_snapshot_branch_stack, void (*)(struct perf_branch_snapshot *)); DEFINE_STATIC_CALL_NULL(perf_snapshot_branch_stack, void (*)(struct perf_branch_snapshot *)); static_call_cond(perf_snapshot_branch_stack)(...); *OR*, do you actually need that return value, in which case you're probably looking for: DECLARE_STATIC_CALL(perf_snapshot_branch_stack, int (*)(struct perf_branch_snapshot *)); DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, int (*)(struct perf_branch_snapshot *)); ret = static_call(perf_snapshot_branch_stack)(...); ?