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Steven Rostedt (Red Hat)
b35f549df1
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/[email protected] Cc: Oleg Nesterov <[email protected]> Cc: Kees Cook <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Dominik Brodowski <[email protected]> Cc: Dave Martin <[email protected]> Cc: "Dmitry V. Levin" <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Acked-by: Paul Burton <[email protected]> # MIPS parts Acked-by: Max Filippov <[email protected]> # For xtensa changes Acked-by: Will Deacon <[email protected]> # For the arm64 bits Reviewed-by: Thomas Gleixner <[email protected]> # for x86 Reviewed-by: Dmitry V. Levin <[email protected]> Reported-by: Andy Lutomirski <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>