Messages in this thread | | | Date | Mon, 28 Jan 2008 10:48:23 +0300 | From | Pavel Emelyanov <> | Subject | Re: [RFC] Per-thread getrusage |
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Andrew Morton wrote: > On Thu, 17 Jan 2008 13:57:05 +0530 Vinay Sridhar <vinay@linux.vnet.ibm.com> wrote: > >> Hi All, >> >> Last year, there was discussion about per-thread getrusage by adding >> RUSAGE_THREAD flag to getrusage(). Please refer to the thread >> http://lkml.org/lkml/2007/4/4/308. Ulrich had suggested that we should >> design a better user-space API. Specifically, we need a >> pthread_getrusage interface in the thread library, which accepts >> pthread_t, converts pthread_t into the corresponding tid and passes it >> down to the syscall. >> >> There are two ways to implement this in the kernel: >> 1) Introduce an additional parameter 'tid' to sys_getrusage() and put >> code in glibc to handle getrusage() and pthread_getrusage() calls >> correctly. >> 2) Introduce a new system call to handle pthread_getrusage() and leave >> sys_getrusage() untouched. >> >> We implemented the second idea above, simply because it avoids touching >> any existing code. We have implemented a new syscall, thread_getrusage() >> and we have exposed pthread_getrusage() API to applications. >> >> Could you please share your thoughts on this? Does the approach look >> alright? The code is hardly complete. It is just a prototype that works >> on IA32 at the moment. >> >> ... >> >> +asmlinkage long sys_thread_getrusage(int tid, struct rusage __user *ru); > > What happens if `tid' refers to a thread in a different pid namespace? >
That's impossible. I explicitly deny namespace creation in case the CLONE_THREAD is specified. So all threads of a single process always live in one pid namespace.
Thanks, Pavel
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