user/sven/linux.git/kernel/itimer.c, branch v2.6.16.45

[PATCH] hrtimers: fix oldvalue return in setitimer

2006-02-01T16:53:12Z

This resolves bugzilla bug#5617. The oldvalue of the timer was read after the timer was cancelled, so the remaining time was always zero. Signed-off-by: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] hrtimers: fixup itimer conversion

2006-02-01T16:53:12Z

The itimer conversion removed the locking which protects the timer and variables in the shared signal structure. Steven Rostedt found the problem in the latest -rt patches. Signed-off-by: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] hrtimer: switch itimers to hrtimer

2006-01-10T16:01:38Z

switch itimers to a hrtimers-based implementation Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] itimer fixes

2005-07-27T23:25:51Z

Fix the recent off-by-one fix in the itimer code: 1. The repeating timer is figured using the requested time (not +1 as we know where we are in the jiffie). 2. The tests for interval too large are left to the time_val to jiffie code. Signed-off-by: George Anzinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] ITIMER_REAL: fix possible deadlock and race

2005-06-29T04:20:30Z

As Steven Rostedt pointed out, there are 2 problems with ITIMER_REAL timers. 1. do_setitimer() does not call del_timer_sync() in case when the timer is not pending (it_real_value() returns 0). This is wrong, the timer may still be running, and it can rearm itself. 2. It calls del_timer_sync() with tsk->sighand->siglock held. This is deadlockable, because timer's handler needs this lock too. Signed-off-by: Oleg Nesterov Acked-by: Steven Rostedt Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] setitimer timer expires too early

2005-05-05T23:36:41Z

It seems that the code responsible for this is in kernel/itimer.c:126: p->signal->real_timer.expires = jiffies + interval; add_timer(&p->signal->real_timer); If you request an interval of, lets say 900 usecs, the interval given by timeval_to_jiffies will be 1. If you request this when we are half-way between two timer ticks, the interval will only give 400 usecs. If we want to guarantee that we never ever give intervals less than requested, the simple solution would be to change that to: p->signal->real_timer.expires = jiffies + interval + 1; This however will produce pathological cases, like having a idle system being requested 1 ms timeouts will give systematically 2 ms timeouts, whereas currently it simply gives a few usecs less than 1 ms. The complex (and more computationally expensive) solution would be to check the gettimeofday time, and compute the correct number of jiffies. This way, if we request a 300 usecs timer 200 usecs inside the timer tick, we can wait just one tick, but not if we are 800 usecs inside the tick. This would also mean that we would have to lock preemption during these computations to avoid races, etc. I've searched the archives but couldn't find this particular issue being discussed before. Attached is a patch to do the simple solution, in case anybody thinks that it should be used. Signed-Off-By: Paulo Marques Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] make ITIMER_PROF, ITIMER_VIRTUAL per-process

2005-03-08T02:17:29Z

POSIX requires that setitimer, getitimer, and alarm work on a per-process basis. Currently, Linux implements these for individual threads. This patch fixes these semantics for the ITIMER_PROF timer (which generates SIGPROF) and the ITIMER_VIRTUAL timer (which generates SIGVTALRM), making them shared by all threads in a process (thread group). This patch should be applied after the one that fixes ITIMER_REAL. The essential machinery for these timers is tied into the new posix-timers code for process CPU clocks and timers. This patch requires the cputimers patch and its dependencies. Signed-off-by: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] make ITIMER_REAL per-process

2005-03-08T02:17:13Z

POSIX requires that setitimer, getitimer, and alarm work on a per-process basis. Currently, Linux implements these for individual threads. This patch fixes these semantics for the ITIMER_REAL timer (which generates SIGALRM), making it shared by all threads in a process (thread group). Signed-off-by: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] cputime: introduce cputime

2005-01-11T09:40:38Z

This patch introduces the concept of (virtual) cputime. Each architecture can define its method to measure cputime. The main idea is to define a cputime_t type and a set of operations on it (see asm-generic/cputime.h). Then use the type for utime, stime, cutime, cstime, it_virt_value, it_virt_incr, it_prof_value and it_prof_incr and use the cputime operations for each access to these variables. The default implementation is jiffies based and the effect of this patch for architectures which use the default implementation should be neglectible. There is a second type cputime64_t which is necessary for the kernel_stat cpu statistics. The default cputime_t is 32 bit and based on HZ, this will overflow after 49.7 days. This is not enough for kernel_stat (ihmo not enough for a processes too), so it is necessary to have a 64 bit type. The third thing that gets introduced by this patch is an additional field for the /proc/stat interface: cpu steal time. An architecture can account cpu steal time by calls to the account_stealtime function. The cpu which backs a virtual processor doesn't spent all of its time for the virtual cpu. To get meaningful cpu usage numbers this involuntary wait time needs to be accounted and exported to user space. From: Hugh Dickins The p->signal check in account_system_time is insufficient. If the timer interrupt hits near the end of exit_notify, after EXIT_ZOMBIE has been set, another cpu may release_task (NULLifying p->signal) in between account_system_time's check and check_rlimit's dereference. Nor should account_it_prof risk send_sig. But surely account_user_time is safe? Signed-off-by: Hugh Dickins Signed-off-by: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] add missing linux/syscalls.h includes

2004-10-18T15:54:02Z

I found that the prototypes for sys_waitid and sys_fcntl in don't match the implementation. In order to keep all prototypes in sync in the future, now include the header from each file implementing any syscall. Signed-off-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds