From 81e294cba2596f5f10848bbe19d98b344c2a2d5c Mon Sep 17 00:00:00 2001 From: Richard Cochran Date: Tue, 1 Feb 2011 13:52:32 +0000 Subject: posix-timers: Add support for fd based clocks Extend the negative clockids which are currently used by posix cpu timers to encode the PID with a file descriptor based type which encodes the fd in the upper bits. Originally-from: Richard Cochran Signed-off-by: Thomas Gleixner Acked-by: John Stultz LKML-Reference: <20110201134420.062860200@linutronix.de> --- include/linux/posix-timers.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux/posix-timers.h') diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 79a1cea7f6e..88b9256169f 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -18,6 +18,17 @@ struct cpu_timer_list { int firing; }; +/* + * Bit fields within a clockid: + * + * The most significant 29 bits hold either a pid or a file descriptor. + * + * Bit 2 indicates whether a cpu clock refers to a thread or a process. + * + * Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3. + * + * A clockid is invalid if bits 2, 1, and 0 are all set. + */ #define CPUCLOCK_PID(clock) ((pid_t) ~((clock) >> 3)) #define CPUCLOCK_PERTHREAD(clock) \ (((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0) @@ -29,6 +40,8 @@ struct cpu_timer_list { #define CPUCLOCK_VIRT 1 #define CPUCLOCK_SCHED 2 #define CPUCLOCK_MAX 3 +#define CLOCKFD CPUCLOCK_MAX +#define CLOCKFD_MASK (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK) #define MAKE_PROCESS_CPUCLOCK(pid, clock) \ ((~(clockid_t) (pid) << 3) | (clockid_t) (clock)) -- cgit v1.2.3