Re: [RFC PATCH 06/10] ftrace: Release the function hlist if we don'tneed it anymore

From: Lai Jiangshan
Date: Mon Jan 25 2010 - 01:44:07 EST


Frederic Weisbecker wrote:
> After we disable the function profiler, the function hashlist
> stays in memory. This is wasteful as nobody needs it anymore,
> until the next use if any.
>
> Release it when we disable the function profiler instead of
> resetting it in the next use.
>
> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
> Cc: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
> ---
> kernel/trace/ftrace.c | 1 +
> kernel/trace/functions_hlist.c | 61 +++++++++++++++++-----------------------
> kernel/trace/functions_hlist.h | 1 +
> 3 files changed, 28 insertions(+), 35 deletions(-)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index dfd8f7c..0ded01c 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -509,6 +509,7 @@ ftrace_profile_write(struct file *filp, const char __user *ubuf,

> /*
> * unregister_ftrace_profiler calls stop_machine
> * so this acts like an synchronize_sched.
> */
> unregister_ftrace_profiler();

unluckily, when !CONFIG_DYNAMIC_FTRACE, it does not call stop_machine()
nor synchronize_sched(), bug here?

> + function_hlist_release();


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