[RFC][PATCH 0/4] perf: remove __weak function hw_perf_group_sched_in()

[Lin Ming <ming.m.lin@intel.com>]

Hi, all

>From the discussion of thread "[RFC] perf_events: support for uncore
a.k.a. nest units", in order to support multiple hw pmu, Peter suggested
the first thing that needs to be done is get rid of all the __weak
functions (with exception of perf_callchain*, since that really is arch
specific), includes 

hw_perf_group_sched_in
hw_perf_event_init
hw_perf_disable
hw_perf_enable

Peter Zijlstra <peterz@infradead.org> wrote:
> One thing not on that list, which should happen first I guess, is to
> remove hw_perf_group_sched_in(). The idea is to add some sort of
> transactional API to the struct pmu, so that we can delay the
> schedulability check until commit time (and roll back when it fails).
>
> Something as simple as:
>
>  struct pmu {
>    void start_txn(struct pmu *);
>    void commit_txn(struct pmu *);
>
>    ,,,
>  };
>
> and then change group_sched_in() to use this instead of
> hw_perf_group_sched_in(), whose implementations mostly replicate
> group_sched_in() in various buggy ways anyway.
>

This patch series is to remove hw_perf_group_sched_in() first.

patch 1: core, add group scheduling transactional APIs
patch 2: x86, implement group scheduling transactional APIs
patch 3: powerpc, implement group scheduling transactional APIs
patch 4: sparc, implement group scheduling transactional APIs

Thanks for any comment.

Lin Ming