linux-toradex.git/include/linux/hrtimer.h, branch v2.6.27.50

hrtimer: prevent migration of per CPU hrtimers

2008-09-29T15:09:14+00:00

Impact: per CPU hrtimers can be migrated from a dead CPU

The hrtimer code has no knowledge about per CPU timers, but we need to
prevent the migration of such timers and warn when such a timer is
active at migration time.

Explicitely mark the timers as per CPU and use a more understandable
mode descriptor for the interrupts safe unlocked callback mode, which
is used by hrtimer_sleeper and the scheduler code.

Signed-off-by: Thomas Gleixner

hrtimer: mark migration state

2008-09-29T15:09:14+00:00

Impact: during migration active hrtimers can be seen as inactive

The migration code removes the hrtimers from the queues of the dead
CPU and sets the state temporary to INACTIVE. The enqueue code sets it
to ACTIVE/PENDING again.

Prevent that the wrong state can be seen by using a separate migration
state bit.

Signed-off-by: Thomas Gleixner

hrtimer: remove duplicate helper function

2008-05-03T16:11:48+00:00

The helper function hrtimer_callback_running() is used in
kernel/hrtimer.c as well as in the updated net/can/bcm.c which now
supports hrtimers. Moving the helper function to hrtimer.h removes the
duplicate definition in the C-files.

Signed-off-by: Oliver Hartkopp 
Cc: David Miller 
Signed-off-by: Thomas Gleixner

add hrtimer specific debugobjects code

2008-04-30T15:29:53+00:00

hrtimers have now dynamic users in the network code.  Put them under
debugobjects surveillance as well.

Add calls to the generic object debugging infrastructure and provide fixup
functions which allow to keep the system alive when recoverable problems have
been detected by the object debugging core code.

Signed-off-by: Thomas Gleixner 
Cc: Greg KH 
Cc: Randy Dunlap 
Cc: Kay Sievers 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hrtimers: simplify lockdep handling

2008-04-17T10:22:31+00:00

In order to avoid the false positive from lockdep, each per-cpu base->lock has
the separate lock class and migrate_hrtimers() uses double_spin_lock().

This is overcomplicated: except for migrate_hrtimers() we never take 2 locks
at once, and migrate_hrtimers() can use spin_lock_nested().

Signed-off-by: Oleg Nesterov 
Cc: Arjan van de Ven 
Cc: Heiko Carstens 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner

hrtimer: fix *rmtp handling in hrtimer_nanosleep()

2008-02-10T09:48:03+00:00

Spotted by Pavel Emelyanov and Alexey Dobriyan.

hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to
the local variable which lives in the caller's stack frame. This means that
if sys_restart_syscall() actually happens and it is interrupted as well, we
don't update the user-space variable, but write into the already dead stack
frame.

Introduced by commit 04c227140fed77587432667a574b14736a06dd7f
hrtimer: Rework hrtimer_nanosleep to make sys_compat_nanosleep easier

Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change
hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp.

Small problem remains. man 2 nanosleep states that *rtmp should be written if
nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp
if nanosleep returns 0), but (with or without this patch) we can dirty *rem
even if nanosleep() returns 0.

NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other
bugs. Fixed by the next patch.

Signed-off-by: Oleg Nesterov 
Cc: Alexey Dobriyan 
Cc: Michael Kerrisk 
Cc: Pavel Emelyanov 
Cc: Peter Zijlstra 
Cc: Toyo Abe 
Cc: Andrew Morton 
Signed-off-by: Thomas Gleixner 

 include/linux/hrtimer.h |    2 -
 kernel/hrtimer.c        |   51 +++++++++++++++++++++++++-----------------------
 kernel/posix-timers.c   |   14 +------------
 3 files changed, 30 insertions(+), 37 deletions(-)

time: fix typo in comments

2008-02-08T17:22:29+00:00

Fix typo in comments.

BTW: I have to fix coding style in arch/ia64/kernel/time.c also, otherwise
checkpatch.pl will be complaining.

Signed-off-by: Li Zefan 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: john stultz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix compilation of powerpc asm-offsets.c with old gcc

2008-02-07T22:54:45+00:00

Commit ad7f71674ad7c3c4467e48f6ab9e85516dae2720 ("[POWERPC] Use a
sensible default for clock_getres() in the VDSO") corrected the clock
resolution reported by the VDSO clock_getres() but introduced another
problem in that older versions of gcc (gcc-4.0 and earlier) fail to
compile the new code in arch/powerpc/kernel/asm-offsets.c.

This fixes it by introducing a new MONOTONIC_RES_NSEC define in the
generic code which is equivalent to KTIME_MONOTONIC_RES but is just an
integer constant, not a ktime union.

Signed-off-by: Tony Breeds 
Signed-off-by: Paul Mackerras 
Signed-off-by: Linus Torvalds

timerfd: new timerfd API

2008-02-05T17:44:07+00:00

This is the new timerfd API as it is implemented by the following patch:

int timerfd_create(int clockid, int flags);
int timerfd_settime(int ufd, int flags,
		    const struct itimerspec *utmr,
		    struct itimerspec *otmr);
int timerfd_gettime(int ufd, struct itimerspec *otmr);

The timerfd_create() API creates an un-programmed timerfd fd.  The "clockid"
parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME.

The timerfd_settime() API give new settings by the timerfd fd, by optionally
retrieving the previous expiration time (in case the "otmr" parameter is not
NULL).

The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit
is set in the "flags" parameter.  Otherwise it's a relative time.

The timerfd_gettime() API returns the next expiration time of the timer, or
{0, 0} if the timerfd has not been set yet.

Like the previous timerfd API implementation, read(2) and poll(2) are
supported (with the same interface).  Here's a simple test program I used to
exercise the new timerfd APIs:

http://www.xmailserver.org/timerfd-test2.c

[akpm@linux-foundation.org: coding-style cleanups]
[akpm@linux-foundation.org: fix ia64 build]
[akpm@linux-foundation.org: fix m68k build]
[akpm@linux-foundation.org: fix mips build]
[akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds]
[heiko.carstens@de.ibm.com: fix s390]
[akpm@linux-foundation.org: fix powerpc build]
[akpm@linux-foundation.org: fix sparc64 more]
Signed-off-by: Davide Libenzi 
Cc: Michael Kerrisk 
Cc: Thomas Gleixner 
Cc: Davide Libenzi 
Cc: Michael Kerrisk 
Cc: Martin Schwidefsky 
Signed-off-by: Heiko Carstens 
Cc: Michael Kerrisk 
Cc: Davide Libenzi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

timerfd: introduce a new hrtimer_forward_now() function

2008-02-05T17:44:07+00:00

I think that advancing the timer against the timer's current "now" can be a
pretty common usage, so, w/out exposing hrtimer's internals, we add a new
hrtimer_forward_now() function.

Signed-off-by: Davide Libenzi 
Cc: Michael Kerrisk 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds