- 02 May, 2008 1 commit
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H. Peter Anvin authored
Force constants in kernel/timeconst.h (except shift counts) to be 64 bits, using U64_C() constructor macros, and eliminate constants that cannot be represented at all in 64 bits. This avoids warnings with some gcc versions. Drop generating 64-bit constants, since we have no real hope of getting a full set (operation on 64-bit values requires a 128-bit intermediate result, which gcc only supports on 64-bit platforms, and only with libgcc support on some.) Note that the use of these constants does not depend on if we are on a 32- or 64-bit architecture. This resolves Bugzilla 10153. Signed-off-by:H. Peter Anvin <hpa@zytor.com>
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- 01 May, 2008 2 commits
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Roman Zippel authored
x86 is the only arch right now, which provides an optimized for div_long_long_rem and it has the downside that one has to be very careful that the divide doesn't overflow. The API is a little akward, as the arguments for the unsigned divide are signed. The signed version also doesn't handle a negative divisor and produces worse code on 64bit archs. There is little incentive to keep this API alive, so this converts the few users to the new API. Signed-off-by:
Roman Zippel <zippel@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Roman Zippel authored
This converts a few users of do_div to div_[su]64 and this demonstrates nicely how it can reduce some expressions to one-liners. Signed-off-by:
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- 29 Apr, 2008 1 commit
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Robert P. J. Day authored
Following an experimental deletion of the unnecessary directive #include <linux/slab.h> from the header file <linux/percpu.h>, these files under kernel/ were exposed as needing to include one of <linux/slab.h> or <linux/gfp.h>, so explicit includes were added where necessary. Signed-off-by:
Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by:
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- 21 Apr, 2008 1 commit
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YOSHIFUJI Hideaki authored
Sorry I have just realized set_normalized_timespec() (used in timespec_sub()) is not exported, and link will fail because of it... Signed-off-by:
YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by:
David S. Miller <davem@davemloft.net>
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- 08 Feb, 2008 2 commits
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H. Peter Anvin authored
When the conversion factor between jiffies and milli- or microseconds is not a single multiply or divide, as for the case of HZ == 300, we currently do a multiply followed by a divide. The intervening result, however, is subject to overflows, especially since the fraction is not simplified (for HZ == 300, we multiply by 300 and divide by 1000). This is exposed to the user when passing a large timeout to poll(), for example. This patch replaces the multiply-divide with a reciprocal multiplication on 32-bit platforms. When the input is an unsigned long, there is no portable way to do this on 64-bit platforms there is no portable way to do this since it requires a 128-bit intermediate result (which gcc does support on 64-bit platforms but may generate libgcc calls, e.g. on 64-bit s390), but since the output is a 32-bit integer in the cases affected, just simplify the multiply-divide (*3/10 instead of *300/1000). The reciprocal multiply used can have off-by-one errors in the upper half of the valid output range. This could be avoided at the expense of having to deal with a potential 65-bit intermediate result. Since the intent is to avoid overflow problems and most of the other time conversions are only semiexact, the off-by-one errors were considered an acceptable tradeoff. At Ralf Baechle's suggestion, this version uses a Perl script to compute the necessary constants. We already have dependencies on Perl for kernel compiles. This does, however, require the Perl module Math::BigInt, which is included in the standard Perl distribution starting with version 5.8.0. In order to support older versions of Perl, include a table of canned constants in the script itself, and structure the script so that Math::BigInt isn't required if pulling values from said table. Running the script requires that the HZ value is available from the Makefile. Thus, this patch also adds the Kconfig variable CONFIG_HZ to the architectures which didn't already have it (alpha, cris, frv, h8300, m32r, m68k, m68knommu, sparc, v850, and xtensa.) It does *not* touch the sh or sh64 architectures, since Paul Mundt has dealt with those separately in the sh tree. Signed-off-by:
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Li Zefan authored
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 <lizf@cn.fujitsu.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by:
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- 06 Feb, 2008 2 commits
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Andrew Morton authored
Avoid calling do_div(x, 1) in this case. Cc: David Fries <david@fries.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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David Fries authored
The kernel has a divide by zero crash when trying to run the system timer less than 100Hz. The problem is x/(HZ/USER_HZ) and related. Now x*(USER_HZ/HZ) will be used if HZ<USER_HZ. I'm running the Linux kernel under qemu and went to run a slower system timer to take less CPU (and battery) on the host. I found that the kernel paniced under emulation because of a divide by zero in three places. Here is the patch. The base git was updated today 01-05-2008. I went for a 20Hz system time by adding config HZ_20 etc to kernel/Kconfig.hz. With this patch I verified the system timer by looking at /proc/interrupts. [akpm@linux-foundation.org: partially clean up the macro maze] Signed-off-by:
David Fries <david@fries.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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- 01 Feb, 2008 1 commit
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Thomas Gleixner authored
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 <tglx@linutronix.de> Acked-by:
John Stultz <johnstul@us.ibm.com> Tested-by:
Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by:
Ingo Molnar <mingo@elte.hu>
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- 18 Oct, 2007 2 commits
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Daniel Walker authored
Signed-off-by:
Daniel Walker <dwalker@mvista.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Tony Breeds authored
On platforms that copy sys_tz into the vdso (currently only x86_64, soon to include powerpc), it is possible for the vdso to get out of sync if a user calls (admittedly unusual) settimeofday(NULL, ptr). This patch adds a hook for architectures that set CONFIG_GENERIC_TIME_VSYSCALL to ensure when sys_tz is updated they can also updatee their copy in the vdso. Signed-off-by:
Tony Breeds <tony@bakeyournoodle.com> Cc: Andi Kleen <ak@suse.de> Cc: Tony Luck <tony.luck@intel.com> Acked-by:
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- 17 Oct, 2007 1 commit
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Jesper Juhl authored
This patch cleans up duplicate includes in kernel/ Signed-off-by:
Jesper Juhl <jesper.juhl@gmail.com> Acked-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Satyam Sharma <ssatyam@cse.iitk.ac.in> Signed-off-by:
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- 16 Oct, 2007 1 commit
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Ingo Molnar authored
improve performance of sys_time(). sys_time() returns time in seconds, but it does so by calling do_gettimeofday() and then returning the tv_sec portion of the GTOD time. But the data structure "xtime", which is updated by every timer/scheduler tick, already offers HZ granularity time. the patch improves the sysbench oltp macrobenchmark by 4-5% on an AMD dual-core system: v2.6.23: #threads 1: transactions: 4073 (407.23 per sec.) 2: transactions: 8530 (852.81 per sec.) 3: transactions: 8321 (831.88 per sec.) 4: transactions: 8407 (840.58 per sec.) 5: transactions: 8070 (806.74 per sec.) v2.6.23 + sys_time-speedup.patch: 1: transactions: 4281 (428.09 per sec.) 2: transactions: 8910 (890.85 per sec.) 3: transactions: 8659 (865.79 per sec.) 4: transactions: 8676 (867.34 per sec.) 5: transactions: 8532 (852.91 per sec.) and by 4-5% on an Intel dual-core system too: 2.6.23: 1: transactions: 4560 (455.94 per sec.) 2: transactions: 10094 (1009.30 per sec.) 3: transactions: 9755 (975.36 per sec.) 4: transactions: 9859 (985.78 per sec.) 5: transactions: 9701 (969.72 per sec.) 2.6.23 + sys_time-speedup.patch: 1: transactions: 4779 (477.84 per sec.) 2: transactions: 10103 (1010.14 per sec.) 3: transactions: 10141 (1013.93 per sec.) 4: transactions: 10371 (1036.89 per sec.) 5: transactions: 10178 (1017.50 per sec.) (the more CPUs the system has, the more speedup this patch gives for this particular workload.) Signed-off-by:
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- 25 Jul, 2007 1 commit
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john stultz authored
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:
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- 20 Jul, 2007 2 commits
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Linus Torvalds authored
This basically reverts commit 4e44f349 , while waiting for it to be re-done more completely. There are cases of people mixing "time()" with higher-resolution time sources, and we need to take the nanosecond offsets into account. Ingo has a patch that does that, but it's still under some discussion. In the meantime, just revert back to the old simple situation of just doing the whole exact timesource calculations. But rather than using do_gettimeofday(), use the internal nanosecond resolution getnstimeofday(), which at least avoids one unnecessary conversion (since we really don't care about whether the fractional seconds are nanoseconds or microseconds - we'll just throw them away). Signed-off-by:
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Bob Picco authored
Remove time_interpolator code (This is generic code, but only user was ia64. It has been superseded by the CONFIG_GENERIC_TIME code). Signed-off-by:
Bob Picco <bob.picco@hp.com> Signed-off-by:
Peter Keilty <peter.keilty@hp.com> Signed-off-by:
Tony Luck <tony.luck@intel.com>
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- 16 Jul, 2007 1 commit
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Ingo Molnar authored
Improve performance of sys_time(). sys_time() returns time in seconds, but it does so by calling do_gettimeofday() and then returning the tv_sec portion of the GTOD time. But the data structure "xtime", which is updated by every timer/scheduler tick, already offers HZ granularity time. The patch improves the sysbench OLTP macrobenchmark significantly: 2.6.22-rc6: #threads 1: transactions: 3733 (373.21 per sec.) 2: transactions: 6676 (667.46 per sec.) 3: transactions: 6957 (695.50 per sec.) 4: transactions: 7055 (705.48 per sec.) 5: transactions: 6596 (659.33 per sec.) 2.6.22-rc6 + sys_time.patch: 1: transactions: 4005 (400.47 per sec.) 2: transactions: 7379 (737.77 per sec.) 3: transactions: 7347 (734.49 per sec.) 4: transactions: 7468 (746.65 per sec.) 5: transactions: 7428 (742.47 per sec.) Mixed API uses of gettimeofday() and time() are guaranteed to be coherent via the use of a at-most-once-per-second slowpath that updates xtime. [akpm@linux-foundation.org: build fixes] Signed-off-by:
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- 08 May, 2007 2 commits
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Randy Dunlap authored
Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
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Eric Dumazet authored
The first thing done by timespec_trunc() is : if (gran <= jiffies_to_usecs(1) * 1000) This should really be a test against a constant known at compile time. Alas, it isnt. jiffies_to_usec() was unilined so C compiler emits a function call and a multiply to compute : a CONSTANT. mov $0x1,%edi mov %rbx,0xffffffffffffffe8(%rbp) mov %r12,0xfffffffffffffff0(%rbp) mov %edx,%ebx mov %rsi,0xffffffffffffffc8(%rbp) mov %rsi,%r12 callq ffffffff80232010 <jiffies_to_usecs> imul $0x3e8,%eax,%eax cmp %ebx,%eax This patch reorders kernel/time.c a bit so that jiffies_to_usecs() is defined before timespec_trunc() so that compiler now generates : cmp $0x3d0900,%edx (HZ=250 on my machine) This gives a better code (timespec_trunc() becoming a leaf function), and shorter kernel size as well. Signed-off-by:
Eric Dumazet <dada1@cosmosbay.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by:
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- 26 Apr, 2007 2 commits
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Stephen Hemminger authored
Change tcp_probe to use ktime (needed to add one export). Add option to only get events when cwnd changes - from Doug Leith Signed-off-by:
Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by:
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Eric Dumazet authored
We currently use a special structure (struct skb_timeval) and plain 'struct timeval' to store packet timestamps in sk_buffs and struct sock. This has some drawbacks : - Fixed resolution of micro second. - Waste of space on 64bit platforms where sizeof(struct timeval)=16 I suggest using ktime_t that is a nice abstraction of high resolution time services, currently capable of nanosecond resolution. As sizeof(ktime_t) is 8 bytes, using ktime_t in 'struct sock' permits a 8 byte shrink of this structure on 64bit architectures. Some other structures also benefit from this size reduction (struct ipq in ipv4/ip_fragment.c, struct frag_queue in ipv6/reassembly.c, ...) Once this ktime infrastructure adopted, we can more easily provide nanosecond resolution on top of it. (ioctl SIOCGSTAMPNS and/or SO_TIMESTAMPNS/SCM_TIMESTAMPNS) Note : this patch includes a bug correction in compat_sock_get_timestamp() where a "err = 0;" was missing (so this syscall returned -ENOENT instead of 0) Signed-off-by:
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- 04 Apr, 2007 1 commit
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Thomas Bittermann authored
This patch adds 2 missing symbol exports: jiffies_to_timeval() and timeval_to_jiffies(). The (not yet merged) dm-raid4-5 module will need them, and they used to be indirectly exported by virtue of being inline functions. Commit 8b9365d7 ("[PATCH] Uninline jiffies.h functions") uninlined them, and thus modules now need them explicitly exported to use them. Signed-off-by:
Thomas Bittermann <t.bittermann@online.de> Acked-by:
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- 16 Feb, 2007 2 commits
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Ingo Molnar authored
Fix multiple conversion bugs in msecs_to_jiffies(). The main problem is that this condition: if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) overflows if HZ is smaller than 1000! This change is user-visible: for HZ=250 SUS-compliant poll()-timeout value of -20 is mistakenly converted to 'immediate timeout'. (The new dyntick code also triggered this, that's how we noticed.) Signed-off-by:
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Ingo Molnar authored
There are loads of fat functions hidden in jiffies.h. Uninline them. No code changes. [jeremy@goop.org: export fix] Signed-off-by:
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- 01 Oct, 2006 1 commit
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john stultz authored
Move all the NTP related code to ntp.c [akpm@osdl.org: cleanups, build fix] Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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- 26 Jun, 2006 1 commit
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john stultz authored
Introduces clocksource switching code and the arch generic time accessor functions that use the clocksource infrastructure. Signed-off-by:
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- 31 Mar, 2006 1 commit
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Kalin KOZHUHAROV authored
I was grepping through the code and some `grep ganularity -R .` didn't catch what I thought. Then looking closer I saw the term "granuality" used in only four places (in comments) and granularity in many more places describing the same idea. Some other facts: dictionary.com does not know such a word define:granuality on google is not found (and pages for granuality are mostly related to patches to the kernel) it has not been discussed as a term on LKML, AFAICS (=Can Search) To be consistent, I think granularity should be used everywhere. Signed-off-by:
Kalin KOZHUHAROV <kalin@thinrope.net> Signed-off-by:
Adrian Bunk <bunk@stusta.de>
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- 26 Mar, 2006 1 commit
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Roman Zippel authored
nsec_t predates ktime_t and has mostly been superseded by it. In the few places that are left it's better to make it explicit that we're dealing with 64 bit values here. Signed-off-by:
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- 25 Mar, 2006 1 commit
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Roman Zippel authored
This removes the support for pps. It's completely unused within the kernel and is basically in the way for further cleanups. It should be easier to readd proper support for it after the rest has been converted to NTP4 (where the pps mechanisms are quite different from NTP3 anyway). Signed-off-by:
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- 03 Feb, 2006 1 commit
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George Anzinger authored
- In case of a negative nsec value the result of the division must be normalized. - Remove inline from an exported function. Signed-off-by:
George Anzinger <george@wildturkeyranch.net> Signed-off-by:
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- 31 Jan, 2006 1 commit
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Linus Torvalds authored
settime() with a NULL timeval is silly but legal. Noticed by Dave Jones <davej@redhat.com> Signed-off-by:
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- 11 Jan, 2006 1 commit
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Randy.Dunlap authored
- Move capable() from sched.h to capability.h; - Use <linux/capability.h> where capable() is used (in include/, block/, ipc/, kernel/, a few drivers/, mm/, security/, & sound/; many more drivers/ to go) Signed-off-by:
Randy Dunlap <rdunlap@xenotime.net> Signed-off-by:
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- 10 Jan, 2006 6 commits
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Matt Helsley authored
Remove getnstimestamp() in favor of ktime.h's ktime_get_ts() Signed-off-by:
Matt Helsley <matthltc@us.ibm.com> Cc: john stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Thomas Gleixner authored
- introduce the nsec_t type - basic nsec conversion routines: timespec_to_ns(), timeval_to_ns(), ns_to_timespec(), ns_to_timeval(). Signed-off-by:
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Thomas Gleixner authored
Check if the timespec which is provided from user space is normalized. Signed-off-by:
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Andrew Morton authored
This is now uninlined, but some modules use it. Make it a non-GPL export, since the inlined mktime() was also available that way. Signed-off-by:
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Ingo Molnar authored
add 'const' to mktime arguments, and clean it up a bit Signed-off-by:
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Thomas Gleixner authored
mktime() and set_normalized_timespec() are large inline functions used in many places: deinline them. From: George Anzinger, off-by-1 bugfix Signed-off-by:
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- 12 Dec, 2005 1 commit
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Matt Helsley authored
There are several functions that might seem appropriate for a timestamp: get_cycles() current_kernel_time() do_gettimeofday() <read jiffies/jiffies_64> Each has problems with combinations of SMP-safety, low resolution, and monotonicity. This patch adds a new function that returns a monotonic SMP-safe timestamp with nanosecond resolution where available. Changes: Split timestamp into separate patch Moved to kernel/time.c Renamed to getnstimestamp Fixed unintended-pointer-arithmetic bug Signed-off-by:
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