14 Aug, 2010
1 commit
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Mark arguments to certain system calls as being const where they should be but
aren't. The list includes:(*) The filename arguments of various stat syscalls, execve(), various utimes
syscalls and some mount syscalls.(*) The filename arguments of some syscall helpers relating to the above.
(*) The buffer argument of various write syscalls.
Signed-off-by: David Howells
Acked-by: David S. Miller
Signed-off-by: Linus Torvalds
13 Aug, 2010
1 commit
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The current computation, introduced with f12a15be63, of FSEC_PER_SEC using
the multiplication of (FSEC_PER_NSEC * NSEC_PER_SEC) is performed only
with 32bit integers on small machines, resulting in an overflow and a
*very* short intervals being programmed. An interrupt storm follows.Note that we also have to specify FSEC_PER_SEC as being long long to
overcome the same limitations.Signed-off-by: Chris Wilson
Signed-off-by: John Stultz
Cc: Thomas Gleixner
Acked-by: Ingo Molnar
Acked-by: H. Peter Anvin
Signed-off-by: Linus Torvalds
27 Jul, 2010
3 commits
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This patch makes xtime and wall_to_monotonic static, as planned in
Documentation/feature-removal-schedule.txt. This will allow for
further cleanups to the timekeeping core.Signed-off-by: John Stultz
LKML-Reference:
Signed-off-by: Thomas Gleixner -
Provides an accessor function to replace hrtimer.c's
direct access of wall_to_monotonic.This will allow wall_to_monotonic to be made static as
planned in Documentation/feature-removal-schedule.txtSigned-off-by: John Stultz
LKML-Reference:
Signed-off-by: Thomas Gleixner -
After accidentally misusing timespec_add_safe, I wanted to make sure
we don't accidently trip over that issue again, so I created a simple
timespec_add() function which we can use to replace the instances
of timespec_add_safe() that don't want the overflow detection.Signed-off-by: John Stultz
LKML-Reference:
Signed-off-by: Thomas Gleixner
13 Apr, 2010
1 commit
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With the earlier logarithmic time accumulation patch, xtime will now
always be within one "tick" of the current time, instead of possibly
half a second off.This removes the need for the xtime_cache value, which always stored the
time at the last interrupt, so this patch cleans that up removing the
xtime_cache related code.This patch also addresses an issue with an earlier version of this change,
where xtime_cache was normalizing xtime, which could in some cases be
not valid (ie: tv_nsec == NSEC_PER_SEC). This is fixed by handling
the edge case in update_wall_time().Signed-off-by: John Stultz
Cc: Petr Titěra
LKML-Reference:
Signed-off-by: Thomas Gleixner
14 Nov, 2009
1 commit
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The dynamic tick allows the kernel to sleep for periods longer than a
single tick, but it does not limit the sleep time currently. In the
worst case the kernel could sleep longer than the wrap around time of
the time keeping clock source which would result in losing track of
time.Prevent this by limiting it to the safe maximum sleep time of the
current time keeping clock source. The value is calculated when the
clock source is registered.[ tglx: simplified the code a bit and massaged the commit msg ]
Signed-off-by: Jon Hunter
Cc: John Stultz
LKML-Reference:
Signed-off-by: Thomas Gleixner
24 Sep, 2009
1 commit
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There are many similar code in kernel for one object: convert time between
calendar time and broken-down time.Here is some source I found:
fs/ncpfs/dir.c
fs/smbfs/proc.c
fs/fat/misc.c
fs/udf/udftime.c
fs/cifs/netmisc.c
net/netfilter/xt_time.c
drivers/scsi/ips.c
drivers/input/misc/hp_sdc_rtc.c
drivers/rtc/rtc-lib.c
arch/ia64/hp/sim/boot/fw-emu.c
arch/m68k/mac/misc.c
arch/powerpc/kernel/time.c
arch/parisc/include/asm/rtc.h
...We can make a common function for this type of conversion, At least we
can get following benefit:1: Make kernel simple and unify
2: Easy to fix bug in converting code
3: Reduce clone of code in future
For example, I'm trying to make ftrace display walltime,
this patch will make me easy.This code is based on code from glibc-2.6
Signed-off-by: Zhao Lei
Cc: OGAWA Hirofumi
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Pavel Machek
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Sep, 2009
1 commit
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set_normalized_timespec() nsec argument is of type long. The recent
timekeeping changes of ktime_get_ts() feedts->tv_nsec + tomono.tv_nsec + nsecs
to set_normalized_timespec(). On 32 bit machines that sum can be
larger than (1 << 31) and therefor result in a negative value which
screws up the result completely.Make the nsec argument of set_normalized_timespec() s64 to fix the
problem at hand. This also prevents similar problems for future users
of set_normalized_timespec().Signed-off-by: Thomas Gleixner
Tested-by: Carsten Emde
LKML-Reference:
Cc: Martin Schwidefsky
Cc: John Stultz
22 Aug, 2009
1 commit
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After talking with some application writers who want very fast, but not
fine-grained timestamps, I decided to try to implement new clock_ids
to clock_gettime(): CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE
which returns the time at the last tick. This is very fast as we don't
have to access any hardware (which can be very painful if you're using
something like the acpi_pm clocksource), and we can even use the vdso
clock_gettime() method to avoid the syscall. The only trade off is you
only get low-res tick grained time resolution.This isn't a new idea, I know Ingo has a patch in the -rt tree that made
the vsyscall gettimeofday() return coarse grained time when the
vsyscall64 sysctrl was set to 2. However this affects all applications
on a system.With this method, applications can choose the proper speed/granularity
trade-off for themselves.Signed-off-by: John Stultz
Cc: Andi Kleen
Cc: nikolag@ca.ibm.com
Cc: Darren Hart
Cc: arjan@infradead.org
Cc: jonathan@jonmasters.org
LKML-Reference:
Signed-off-by: Thomas Gleixner
15 Aug, 2009
3 commits
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Add the new function read_boot_clock to get the exact time the system
has been started. For architectures without support for exact boot
time a new weak function is added that returns 0. Use the exact boot
time to initialize wall_to_monotonic, or xtime if the read_boot_clock
returned 0.Signed-off-by: Martin Schwidefsky
Cc: Ingo Molnar
Acked-by: John Stultz
Cc: Daniel Walker
LKML-Reference:
Signed-off-by: Thomas Gleixner -
The persistent clock of some architectures (e.g. s390) have a
better granularity than seconds. To reduce the delta between the
host clock and the guest clock in a virtualized system change the
read_persistent_clock function to return a struct timespec.Signed-off-by: Martin Schwidefsky
Cc: Ingo Molnar
Acked-by: John Stultz
Cc: Daniel Walker
LKML-Reference:
Signed-off-by: Thomas Gleixner -
Move the adjustment of xtime, wall_to_monotonic and the update of the
vsyscall variables to the timekeeping code.Signed-off-by: John Stultz
Signed-off-by: Martin Schwidefsky
LKML-Reference:
Signed-off-by: Thomas Gleixner
02 May, 2009
1 commit
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Some arches don't supply their own clocksource. This is mainly the
case in architectures that get their inter-tick times by reading the
counter on their interval timer. Since these timers wrap every tick,
they're not really useful as clocksources. Wrapping them to act like
one is possible but not very efficient. So we provide a callout these
arches can implement for use with the jiffies clocksource to provide
finer then tick granular time.[ Impact: ease the migration to generic time keeping ]
Signed-off-by: John Stultz
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner
27 Mar, 2009
1 commit
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A number of standard posix types are used in exported headers, which
is not allowed if __STRICT_KERNEL_NAMES is defined. In order to
get rid of the non-__STRICT_KERNEL_NAMES part and to make sane headers
the default, we have to change them all to safe types.There are also still some leftovers in reiserfs_fs.h, elfcore.h
and coda.h, but these files have not compiled in user space for
a long time.This leaves out the various integer types ({u_,u,}int{8,16,32,64}_t),
which we take care of separately.Signed-off-by: Arnd Bergmann
Acked-by: Mauro Carvalho Chehab
Cc: David Airlie
Cc: Arnaldo Carvalho de Melo
Cc: YOSHIFUJI Hideaki
Cc: netdev@vger.kernel.org
Cc: linux-ppp@vger.kernel.org
Cc: Jaroslav Kysela
Cc: Takashi Iwai
Cc: David Woodhouse
Signed-off-by: H. Peter Anvin
Signed-off-by: Ingo Molnar
31 Dec, 2008
1 commit
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Redo:
5b7dba4: sched_clock: prevent scd->clock from moving backwards
which had to be reverted due to s2ram hangs:
ca7e716: Revert "sched_clock: prevent scd->clock from moving backwards"
... this time with resume restoring GTOD later in the sequence
taken into account as well.The "timekeeping_suspended" flag is not very nice but we cannot call into
GTOD before it has been properly resumed and the scheduler will run very
early in the resume sequence.Cc:
Signed-off-by: Ingo Molnar
22 Oct, 2008
1 commit
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Conflicts:
kernel/time/tick-sched.c
Signed-off-by: Thomas Gleixner
20 Oct, 2008
1 commit
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…tp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
18 Oct, 2008
1 commit
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Conflicts:
arch/x86/kvm/i8254.c
17 Oct, 2008
1 commit
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Nothing arch specific in get/settimeofday. The details of the timeval
conversion varied a little from arch to arch, but all with the same
results.Also add an extern declaration for sys_tz to linux/time.h because externs
in .c files are fowned upon. I'll kill the externs in various other files
in a sparate patch.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Christoph Hellwig
Acked-by: David S. Miller [ sparc bits ]
Cc: "Luck, Tony"
Cc: Ralf Baechle
Acked-by: Kyle McMartin
Cc: Matthew Wilcox
Cc: Grant Grundler
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: "H. Peter Anvin"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Sep, 2008
1 commit
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Overview
This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together
with the help of Roland McGrath, the owner and original writer of this code.The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads. It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."
Code Changes
This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine. (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.) To do this, at each tick we now update fields in
signal_struct as well as task_struct. The run_posix_cpu_timers() function
uses those fields to make its decisions.We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:struct thread_group_cputime {
struct task_cputime totals;
};struct thread_group_cputime {
struct task_cputime *totals;
};We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers). The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends. In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention). For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu(). The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel. The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields. The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures. The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated. The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU. Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.Non-SMP operation is trivial and will not be mentioned further.
The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away. All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline. When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.Performance
The fix appears not to add significant overhead to existing operations. It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below). Overall it's a wash except in those
two cases.I've since done somewhat more involved testing on a dual-core Opteron system.
Case 1: With no itimer running, for a test with 100,000 threads, the fixed
kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
all of which was spent in the system. There were twice as many
voluntary context switches with the fix as without it.Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
an unmodified kernel can handle), the fixed kernel ran the test in
eight percent of the time (5.8 seconds as opposed to 70 seconds) and
had better tick accuracy (.012 seconds per tick as opposed to .023
seconds per tick).Case 3: A 4000-thread test with an initial timer tick of .01 second and an
interval of 10,000 seconds (i.e. a timer that ticks only once) had
very nearly the same performance in both cases: 6.3 seconds elapsed
for the fixed kernel versus 5.5 seconds for the unfixed kernel.With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.Since the fix affected the rlimit code, I also tested soft and hard CPU limits.
Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
running), the modified kernel was very slightly favored in that while
it killed the process in 19.997 seconds of CPU time (5.002 seconds of
wall time), only .003 seconds of that was system time, the rest was
user time. The unmodified kernel killed the process in 20.001 seconds
of CPU (5.014 seconds of wall time) of which .016 seconds was system
time. Really, though, the results were too close to call. The results
were essentially the same with no itimer running.Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
(where the hard limit would never be reached) and an itimer running,
the modified kernel exhibited worse tick accuracy than the unmodified
kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise,
performance was almost indistinguishable. With no itimer running this
test exhibited virtually identical behavior and times in both cases.In times past I did some limited performance testing. those results are below.
On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds. Performance with eight, four and one
thread were comparable. Interestingly, the timer ticks with the fix seemed
more accurate: The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick. Both cases were configured for an interval of
0.01 seconds. Again, the other tests were comparable. Each thread in this
test computed the primes up to 25,000,000.I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix. In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable). System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite
accurate. There is obviously no comparable test without the fix.Signed-off-by: Frank Mayhar
Cc: Roland McGrath
Cc: Alexey Dobriyan
Cc: Andrew Morton
Signed-off-by: Ingo Molnar
06 Sep, 2008
1 commit
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For the select() rework, it's important to be able to add timespec
structures in an overflow-safe manner.This patch adds a timespec_add_safe() function for this which is similar in
operation to ktime_add_safe(), but works on a struct timespec.Signed-off-by: Thomas Gleixner
Signed-off-by: Arjan van de Ven
21 Aug, 2008
1 commit
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In talking with Josip Loncaric, and his work on clock synchronization (see
btime.sf.net), he mentioned that for really close synchronization, it is
useful to have access to "hardware time", that is a notion of time that is
not in any way adjusted by the clock slewing done to keep close time sync.Part of the issue is if we are using the kernel's ntp adjusted
representation of time in order to measure how we should correct time, we
can run into what Paul McKenney aptly described as "Painting a road using
the lines we're painting as the guide".I had been thinking of a similar problem, and was trying to come up with a
way to give users access to a purely hardware based time representation
that avoided users having to know the underlying frequency and mask values
needed to deal with the wide variety of possible underlying hardware
counters.My solution is to introduce CLOCK_MONOTONIC_RAW. This exposes a
nanosecond based time value, that increments starting at bootup and has no
frequency adjustments made to it what so ever.The time is accessed from userspace via the posix_clock_gettime() syscall,
passing CLOCK_MONOTONIC_RAW as the clock_id.Signed-off-by: John Stultz
Signed-off-by: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Ingo Molnar
12 Jun, 2008
2 commits
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timespec_add_ns is used from the x86-64 vdso, which cannot call out to
other kernel code. Make sure that timespec_add_ns is always inlined
(and only uses always_inlined functions) to make sure there are no
unexpected calls.Signed-off-by: Jeremy Fitzhardinge
Signed-off-by: Ingo Molnar -
We have a few instances of the open-coded iterative div/mod loop, used
when we don't expcet the dividend to be much bigger than the divisor.
Unfortunately modern gcc's have the tendency to strength "reduce" this
into a full mod operation, which isn't necessarily any faster, and
even if it were, doesn't exist if gcc implements it in libgcc.The workaround is to put a dummy asm statement in the loop to prevent
gcc from performing the transformation.This patch creates a single implementation of this loop, and uses it
to replace the open-coded versions I know about.Signed-off-by: Jeremy Fitzhardinge
Cc: Andrew Morton
Cc: john stultz
Cc: Segher Boessenkool
Cc: Christian Kujau
Cc: Robert Hancock
Signed-off-by: Ingo Molnar
09 Mar, 2008
1 commit
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Since some architectures don't support __udivdi3().
Signed-off-by: Segher Boessenkool
Cc: john stultz
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner
09 Feb, 2008
1 commit
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Function timekeeping_is_continuous() no longer checks flag
CLOCK_IS_CONTINUOUS, and it checks CLOCK_SOURCE_VALID_FOR_HRES now. So rename
the function accordingly.Signed-off-by: Li Zefan
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: john stultz
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Feb, 2008
1 commit
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xtime_cache needs to be updated whenever xtime and or wall_to_monotic
are changed. Otherwise users of xtime_cache might see a stale (and in
the case of timezone changes utterly wrong) value until the next
update happens.Fixup the obvious places, which miss this update.
Signed-off-by: Thomas Gleixner
Acked-by: John Stultz
Tested-by: Dhaval Giani
Signed-off-by: Ingo Molnar
17 Oct, 2007
1 commit
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- remove the no longer required __attribute__((weak)) of xtime_lock
- remove the following no longer used EXPORT_SYMBOL's:
- xtime
- xtime_lockSigned-off-by: Adrian Bunk
Cc: Thomas Gleixner
Cc: john stultz
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
26 Jul, 2007
2 commits
-
This avoids xtime lag seen with dynticks, because while 'xtime' itself
is still not updated often, we keep a 'xtime_cache' variable around that
contains the approximate real-time that _is_ updated each time we do a
'update_wall_time()', and is thus never off by more than one tick.IOW, this restores the original semantics for 'xtime' users, as long as
you use the proper abstraction functions (ie 'current_kernel_time()' or
'get_seconds()' depending on whether you want a timespec or just the
seconds field).[ Updated Patch. As penance for my sins I've also yanked another #ifdef
that was added to avoid the xtime lag w/ hrtimers. ]Signed-off-by: John Stultz
Cc: Ingo Molnar
Cc: Thomas Gleixner
Signed-off-by: Linus Torvalds -
This avoids use of the kernel-internal "xtime" variable directly outside
of the actual time-related functions. Instead, use the helper functions
that we already have available to us.This doesn't actually change any behaviour, but this will allow us to
fix the fact that "xtime" isn't updated very often with CONFIG_NO_HZ
(because much of the realtime information is maintained as separate
offsets to 'xtime'), which has caused interfaces that use xtime directly
to get a time that is out of sync with the real-time clock by up to a
third of a second or so.Signed-off-by: John Stultz
Cc: Ingo Molnar
Cc: Thomas Gleixner
Signed-off-by: Linus Torvalds
22 Jul, 2007
1 commit
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i386 and sparc64 have the identical code to update the cmos clock. Move it
into kernel/time/ntp.c as there are other architectures coming along with the
same requirements.[akpm@linux-foundation.org: build fixes]
Signed-off-by: Thomas Gleixner
Cc: Chris Wright
Cc: Ingo Molnar
Cc: john stultz
Cc: David Miller
Cc: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
18 Jul, 2007
1 commit
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Make arguments of timespec_equal() const struct timespec.
Signed-off-by: Jan Engelhardt
Cc: Thomas Gleixner
Cc: john stultz
Cc: Roman Zippel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Jul, 2007
1 commit
-
The commits
411187fb05cd11676b0979d9fbf3291db69dbce2 (GTOD: persistent clock support)
c1d370e167d66b10bca3b602d3740405469383de (i386: use GTOD persistent clock
support)changed the monotonic time so that it no longer jumps after resume, but it's
not possible to use it for boot time and process start time calculations then.
Also, the uptime no longer increases during suspend.I add a variable to track the wall_to_monotonic changes, a function to get the
real boot time and a function to get the boot based time from the monotonic
one.[akpm@linux-foundation.org: remove exports, add comment]
Signed-off-by: Tomas Janousek
Cc: Tomas Smetana
Cc: John Stultz
Cc: Thomas Gleixner
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 May, 2007
2 commits
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Implement utimensat(2) which is an extension to futimesat(2) in that it
a) supports nano-second resolution for the timestamps
b) allows to selectively ignore the atime/mtime value
c) allows to selectively use the current time for either atime or mtime
d) supports changing the atime/mtime of a symlink itself along the lines
of the BSD lutimes(3) functionsFor this change the internally used do_utimes() functions was changed to
accept a timespec time value and an additional flags parameter.Additionally the sys_utime function was changed to match compat_sys_utime
which already use do_utimes instead of duplicating the work.Also, the completely missing futimensat() functionality is added. We have
such a function in glibc but we have to resort to using /proc/self/fd/* which
not everybody likes (chroot etc).Test application (the syscall number will need per-arch editing):
#include
#include
#include
#include
#include
#include#define __NR_utimensat 280
#define UTIME_NOW ((1l << 30) - 1l)
#define UTIME_OMIT ((1l << 30) - 2l)int
main(void)
{
int status = 0;int fd = open("ttt", O_RDWR|O_CREAT|O_EXCL, 0666);
if (fd == -1)
error (1, errno, "failed to create test file \"ttt\"");struct stat64 st1;
if (fstat64 (fd, &st1) != 0)
error (1, errno, "fstat failed");struct timespec t[2];
t[0].tv_sec = 0;
t[0].tv_nsec = 0;
t[1].tv_sec = 0;
t[1].tv_nsec = 0;
if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0)
error (1, errno, "utimensat failed");struct stat64 st2;
if (fstat64 (fd, &st2) != 0)
error (1, errno, "fstat failed");if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0)
{
puts ("atim not reset to zero");
status = 1;
}
if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0)
{
puts ("mtim not reset to zero");
status = 1;
}
if (status != 0)
goto out;t[0] = st1.st_atim;
t[1].tv_sec = 0;
t[1].tv_nsec = UTIME_OMIT;
if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0)
error (1, errno, "utimensat failed");if (fstat64 (fd, &st2) != 0)
error (1, errno, "fstat failed");if (st2.st_atim.tv_sec != st1.st_atim.tv_sec
|| st2.st_atim.tv_nsec != st1.st_atim.tv_nsec)
{
puts ("atim not set");
status = 1;
}
if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0)
{
puts ("mtim changed from zero");
status = 1;
}
if (status != 0)
goto out;t[0].tv_sec = 0;
t[0].tv_nsec = UTIME_OMIT;
t[1] = st1.st_mtim;
if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0)
error (1, errno, "utimensat failed");if (fstat64 (fd, &st2) != 0)
error (1, errno, "fstat failed");if (st2.st_atim.tv_sec != st1.st_atim.tv_sec
|| st2.st_atim.tv_nsec != st1.st_atim.tv_nsec)
{
puts ("mtim changed from original time");
status = 1;
}
if (st2.st_mtim.tv_sec != st1.st_mtim.tv_sec
|| st2.st_mtim.tv_nsec != st1.st_mtim.tv_nsec)
{
puts ("mtim not set");
status = 1;
}
if (status != 0)
goto out;sleep (2);
t[0].tv_sec = 0;
t[0].tv_nsec = UTIME_NOW;
t[1].tv_sec = 0;
t[1].tv_nsec = UTIME_NOW;
if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0)
error (1, errno, "utimensat failed");if (fstat64 (fd, &st2) != 0)
error (1, errno, "fstat failed");struct timeval tv;
gettimeofday(&tv,NULL);if (st2.st_atim.tv_sec tv.tv_sec)
{
puts ("atim not set to NOW");
status = 1;
}
if (st2.st_mtim.tv_sec tv.tv_sec)
{
puts ("mtim not set to NOW");
status = 1;
}if (symlink ("ttt", "tttsym") != 0)
error (1, errno, "cannot create symlink");t[0].tv_sec = 0;
t[0].tv_nsec = 0;
t[1].tv_sec = 0;
t[1].tv_nsec = 0;
if (syscall(__NR_utimensat, AT_FDCWD, "tttsym", t, AT_SYMLINK_NOFOLLOW) != 0)
error (1, errno, "utimensat failed");if (lstat64 ("tttsym", &st2) != 0)
error (1, errno, "lstat failed");if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0)
{
puts ("symlink atim not reset to zero");
status = 1;
}
if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0)
{
puts ("symlink mtim not reset to zero");
status = 1;
}
if (status != 0)
goto out;t[0].tv_sec = 1;
t[0].tv_nsec = 0;
t[1].tv_sec = 1;
t[1].tv_nsec = 0;
if (syscall(__NR_utimensat, fd, NULL, t, 0) != 0)
error (1, errno, "utimensat failed");if (fstat64 (fd, &st2) != 0)
error (1, errno, "fstat failed");if (st2.st_atim.tv_sec != 1 || st2.st_atim.tv_nsec != 0)
{
puts ("atim not reset to one");
status = 1;
}
if (st2.st_mtim.tv_sec != 1 || st2.st_mtim.tv_nsec != 0)
{
puts ("mtim not reset to one");
status = 1;
}if (status == 0)
puts ("all OK");out:
close (fd);
unlink ("ttt");
unlink ("tttsym");return status;
}[akpm@linux-foundation.org: add missing i386 syscall table entry]
Signed-off-by: Ulrich Drepper
Cc: Alexey Dobriyan
Cc: Michael Kerrisk
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move the timekeeping code out of kernel/timer.c and into
kernel/time/timekeeping.c. I made no cleanups or other changes in transit.[akpm@linux-foundation.org: build fix]
Signed-off-by: John Stultz
Cc: Ingo Molnar
Cc: Thomas Gleixner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Feb, 2007
1 commit
-
Persistent clock support: do proper timekeeping across suspend/resume.
[bunk@stusta.de: cleanup]
Signed-off-by: John Stultz
Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
Cc: Roman Zippel
Cc: Adrian Bunk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Feb, 2007
1 commit
-
ARCH_HAVE_XTIME_LOCK is used by x86_64 arch . This arch needs to place a
read only copy of xtime_lock into vsyscall page. This read only copy is
named __xtime_lock, and xtime_lock is defined in
arch/x86_64/kernel/vmlinux.lds.S as an alias. So the declaration of
xtime_lock in kernel/timer.c was guarded by ARCH_HAVE_XTIME_LOCK define,
defined to true on x86_64.We can get same result with _attribute__((weak)) in the declaration. linker
should do the job.Signed-off-by: Eric Dumazet
Signed-off-by: Andi Kleen
Cc: Andi Kleen
Signed-off-by: Andrew Morton
12 Feb, 2007
1 commit
-
The arguments are really const. Mark them const to allow these functions
being called from places where the arguments are const without getting
useless compiler warnings.Signed-off-by: Rolf Eike Beer
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Jul, 2006
1 commit
-
Initialization code related to collection of per-task "delay" statistics which
measure how long it had to wait for cpu, sync block io, swapping etc. The
collection of statistics and the interface are in other patches. This patch
sets up the data structures and allows the statistics collection to be
disabled through a kernel boot parameter.Signed-off-by: Shailabh Nagar
Signed-off-by: Balbir Singh
Cc: Jes Sorensen
Cc: Peter Chubb
Cc: Erich Focht
Cc: Levent Serinol
Cc: Jay Lan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
