Hi, Roland McGrath wrote: >>> It will never be in the fast path. It will always require >>> TIF_SYSCALL_TRACE to bet set on each thread, which means the slow path. >>> [...] >> OK, I must have misunderstood your original posting: >> >> # [...] >> # d. Kernel already has checks here, so "almost free". > > This refers to all the other cases, where there is just a check at the time > of the event. The syscall case is special, requiring TIF_SYSCALL_TRACE.
Actually, this point is where I'm stuck on these weeks. If we add marker or tracepoint to trace every syscalls, we might have to put it in the tracehook or audit and set TIF_SYSCALL_TRACE for every process, or put tracepoint in the syscall entrance/exit asm-code and check another flag. Since latter adds additional flag-checking in fast-path, I think it is not acceptable. Thank you, > > > Thanks, > Roland > -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division e-mail: [EMAIL PROTECTED]
