Re: [PATCH 5/6 v3] syscalls: Remove start and number from syscall_get_arguments() args

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

On Mon, 1 Apr 2019, Steven Rostedt wrote:

> From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
> 
> At Linux Plumbers, Andy Lutomirski approached me and pointed out that the
> function call syscall_get_arguments() implemented in x86 was horribly
> written and not optimized for the standard case of passing in 0 and 6 for
> the starting index and the number of system calls to get. When looking at
> all the users of this function, I discovered that all instances pass in only
> 0 and 6 for these arguments. Instead of having this function handle
> different cases that are never used, simply rewrite it to return the first 6
> arguments of a system call.
> 
> This should help out the performance of tracing system calls by ptrace,
> ftrace and perf.
> 
> Link: http://lkml.kernel.org/r/20161107213233.754809394@xxxxxxxxxxx

For x86:

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>