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2018-08-16jiffies: add utility function to calculate delta in msMatteo Croce
add jiffies_delta_to_msecs() helper func to calculate the delta between two times and eventually 0 if negative. Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Matteo Croce <mcroce@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Simon Horman <horms@verge.net.au> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-04-06jiffies: Introduce USER_TICK_USEC and redefine TICK_USECRafael J. Wysocki
Since the subsequent changes will need a TICK_USEC definition analogous to TICK_NSEC, rename the existing TICK_USEC as USER_TICK_USEC, update its users and redefine TICK_USEC accordingly. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-02frv: declare jiffies to be located in the .data sectionMatthias Kaehlcke
Commit 7c30f352c852 ("jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smp") removed a section specification from the jiffies declaration that caused conflicts on some platforms. Unfortunately this change broke the build for frv: kernel/built-in.o: In function `__do_softirq': (.text+0x6460): relocation truncated to fit: R_FRV_GPREL12 against symbol `jiffies' defined in *ABS* section in .tmp_vmlinux1 kernel/built-in.o: In function `__do_softirq': (.text+0x6574): relocation truncated to fit: R_FRV_GPREL12 against symbol `jiffies' defined in *ABS* section in .tmp_vmlinux1 kernel/built-in.o: In function `pwq_activate_delayed_work': workqueue.c:(.text+0x15b9c): relocation truncated to fit: R_FRV_GPREL12 against symbol `jiffies' defined in *ABS* section in .tmp_vmlinux1 ... Add __jiffy_arch_data to the declaration of jiffies and use it on frv to include the section specification. For all other platforms __jiffy_arch_data (currently) has no effect. Fixes: 7c30f352c852 ("jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smp") Link: http://lkml.kernel.org/r/20170516221333.177280-1-mka@chromium.org Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: David Howells <dhowells@redhat.com> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smpMatthias Kaehlcke
jiffies_64 is defined in kernel/time/timer.c with ____cacheline_aligned_in_smp, however this macro is not part of the declaration of jiffies and jiffies_64 in jiffies.h. As a result clang generates the following warning: kernel/time/timer.c:57:26: error: section does not match previous declaration [-Werror,-Wsection] __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; ^ include/linux/cache.h:39:36: note: expanded from macro '__cacheline_aligned_in_smp' ^ include/linux/cache.h:34:4: note: expanded from macro '__cacheline_aligned' __section__(".data..cacheline_aligned"))) ^ include/linux/jiffies.h:77:12: note: previous attribute is here extern u64 __jiffy_data jiffies_64; ^ include/linux/jiffies.h:70:38: note: expanded from macro '__jiffy_data' Link: http://lkml.kernel.org/r/20170403190200.70273-1-mka@chromium.org Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Cc: Grant Grundler <grundler@chromium.org> Cc: Michael Davidson <md@google.com> Cc: Greg Hackmann <ghackmann@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-01time: Introduce jiffies64_to_nsecs()Frederic Weisbecker
This will be needed for the cputime_t to nsec conversion. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-07jiffies: add time comparison functions for 64 bit jiffiesJason A. Donenfeld
Though the time_before and time_after family of functions were nicely extended to support jiffies64, so that the interface would be consistent, it was forgotten to also extend the before/after jiffies functions to support jiffies64. This commit brings the interface to parity between jiffies and jiffies64, which is quite convenient. Link: http://lkml.kernel.org/r/20160929033319.12188-1-Jason@zx2c4.com Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-01Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "Rather large, but nothing exiting: - new range check for settimeofday() to prevent that boot time becomes negative. - fix for file time rounding - a few simplifications of the hrtimer code - fix for the proc/timerlist code so the output of clock realtime timers is accurate - more y2038 work - tree wide conversion of clockevent drivers to the new callbacks" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (88 commits) hrtimer: Handle failure of tick_init_highres() gracefully hrtimer: Unconfuse switch_hrtimer_base() a bit hrtimer: Simplify get_target_base() by returning current base hrtimer: Drop return code of hrtimer_switch_to_hres() time: Introduce timespec64_to_jiffies()/jiffies_to_timespec64() time: Introduce current_kernel_time64() time: Introduce struct itimerspec64 time: Add the common weak version of update_persistent_clock() time: Always make sure wall_to_monotonic isn't positive time: Fix nanosecond file time rounding in timespec_trunc() timer_list: Add the base offset so remaining nsecs are accurate for non monotonic timers cris/time: Migrate to new 'set-state' interface kernel: broadcast-hrtimer: Migrate to new 'set-state' interface xtensa/time: Migrate to new 'set-state' interface unicore/time: Migrate to new 'set-state' interface um/time: Migrate to new 'set-state' interface sparc/time: Migrate to new 'set-state' interface sh/localtimer: Migrate to new 'set-state' interface score/time: Migrate to new 'set-state' interface s390/time: Migrate to new 'set-state' interface ...
2015-08-31Merge branch 'timers-nohz-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull NOHZ updates from Ingo Molnar: "The main changes, mostly written by Frederic Weisbecker, include: - Fix some jiffies based cputime assumptions. (No real harm because the concerned code isn't used by full dynticks.) - Simplify jiffies <-> usecs conversions. Remove dead code. - Remove early hacks on nohz full code that avoided messing up idle nohz internals. Now nohz integrates well full and idle and such hack have become needless. - Restart nohz full tick from irq exit. (A simplification and a preparation for future optimization on scheduler kick to nohz full) - Code cleanups. - Tile driver isolation enhancement on top of nohz. (Chris Metcalf)" * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: nohz: Remove useless argument on tick_nohz_task_switch() nohz: Move tick_nohz_restart_sched_tick() above its users nohz: Restart nohz full tick from irq exit nohz: Remove idle task special case nohz: Prevent tilegx network driver interrupts alpha: Fix jiffies based cputime assumption apm32: Fix cputime == jiffies assumption jiffies: Remove HZ > USEC_PER_SEC special case
2015-08-17time: Introduce timespec64_to_jiffies()/jiffies_to_timespec64()Baolin Wang
The conversion between struct timespec and jiffies is not year 2038 safe on 32bit systems. Introduce timespec64_to_jiffies() and jiffies_to_timespec64() functions which use struct timespec64 to make it ready for 2038 issue. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-08-05jiffies: Force inlining of {m,u}msecs_to_jiffies()Denys Vlasenko
With this config: http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os gcc-4.7.2 generates many copies of these tiny functions: msecs_to_jiffies (45 copies): 55 push %rbp 48 89 e5 mov %rsp,%rbp e8 59 ec 03 00 callq __msecs_to_jiffies 5d pop %rbp c3 retq usecs_to_jiffies (10 copies): 55 push %rbp 48 89 e5 mov %rsp,%rbp e8 5d 54 5e ff callq __usecs_to_jiffies 5d pop %rbp c3 retq See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122 This patch fixes this via s/inline/__always_inline/ text data bss dec filename 86970954 17195912 36659200 140826066 vmlinux.before 86966150 17195912 36659200 140821262 vmlinux Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Graf <tgraf@suug.ch> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1438697716-28121-3-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-29jiffies: Remove HZ > USEC_PER_SEC special caseFrederic Weisbecker
HZ never goes much further 1000 and a bit. And if we ever reach one tick per microsecond, we might be having a problem. Lets stop maintaining this special case, just leave a paranoid check. Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@kernel.org> Cc; John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2015-06-10time: Allow gcc to fold usecs_to_jiffies(constant)Nicholas Mc Guire
To allow constant folding in usecs_to_jiffies() conditionally calls the HZ dependent _usecs_to_jiffies() helpers or, when gcc can not figure out constant folding, __usecs_to_jiffies, which is the renamed original usecs_to_jiffies() function. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Cc: Masahiro Yamada <yamada.m@jp.panasonic.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Joe Perches <joe@perches.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Andrew Hunter <ahh@google.com> Cc: Paul Turner <pjt@google.com> Cc: Michal Marek <mmarek@suse.cz> Link: http://lkml.kernel.org/r/1432832996-12129-2-git-send-email-hofrat@osadl.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-10time: Refactor usecs_to_jiffiesNicholas Mc Guire
Refactor the usecs_to_jiffies conditional code part in time.c and jiffies.h putting it into conditional functions rather than #ifdefs to improve readability. This is analogous to the msecs_to_jiffies() cleanup in commit ca42aaf0c861 ("time: Refactor msecs_to_jiffies") Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Cc: Masahiro Yamada <yamada.m@jp.panasonic.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Joe Perches <joe@perches.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Andrew Hunter <ahh@google.com> Cc: Paul Turner <pjt@google.com> Cc: Michal Marek <mmarek@suse.cz> Link: http://lkml.kernel.org/r/1432832996-12129-1-git-send-email-hofrat@osadl.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-19jiffies: Remove the extra indentation levelThomas Gleixner
Somehow I missed to clean that up when applying the patches. Fix it up now. Reported-by: Joe Perches <joe@perches.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Nicholas Mc Guire <der.herr@hofr.at>
2015-05-19time: Allow gcc to fold constants when possibleNicholas Mc Guire
To allow constant folding in msecs_to_jiffies() conditionally calls the HZ dependent _msecs_to_jiffies() helpers or, when gcc can not figure out constant folding, __msecs_to_jiffies which is the renamed original msecs_to_jiffies() function. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Cc: Masahiro Yamada <yamada.m@jp.panasonic.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Joe Perches <joe@perches.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Andrew Hunter <ahh@google.com> Cc: Paul Turner <pjt@google.com> Cc: Michal Marek <mmarek@suse.cz> Link: http://lkml.kernel.org/r/1431951554-5563-3-git-send-email-hofrat@osadl.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-19time: Refactor msecs_to_jiffiesNicholas Mc Guire
Refactor the msecs_to_jiffies conditional code part in time.c and jiffies.h putting it into conditional functions rather than #ifdefs to improve readability. [ tglx: Verified that there is no binary code change ] Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Cc: Masahiro Yamada <yamada.m@jp.panasonic.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Joe Perches <joe@perches.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Andrew Hunter <ahh@google.com> Cc: Paul Turner <pjt@google.com> Cc: Michal Marek <mmarek@suse.cz> Link: http://lkml.kernel.org/r/1431951554-5563-2-git-send-email-hofrat@osadl.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-09-12jiffies: Fix timeval conversion to jiffiesAndrew Hunter
timeval_to_jiffies tried to round a timeval up to an integral number of jiffies, but the logic for doing so was incorrect: intervals corresponding to exactly N jiffies would become N+1. This manifested itself particularly repeatedly stopping/starting an itimer: setitimer(ITIMER_PROF, &val, NULL); setitimer(ITIMER_PROF, NULL, &val); would add a full tick to val, _even if it was exactly representable in terms of jiffies_ (say, the result of a previous rounding.) Doing this repeatedly would cause unbounded growth in val. So fix the math. Here's what was wrong with the conversion: we essentially computed (eliding seconds) jiffies = usec * (NSEC_PER_USEC/TICK_NSEC) by using scaling arithmetic, which took the best approximation of NSEC_PER_USEC/TICK_NSEC with denominator of 2^USEC_JIFFIE_SC = x/(2^USEC_JIFFIE_SC), and computed: jiffies = (usec * x) >> USEC_JIFFIE_SC and rounded this calculation up in the intermediate form (since we can't necessarily exactly represent TICK_NSEC in usec.) But the scaling arithmetic is a (very slight) *over*approximation of the true value; that is, instead of dividing by (1 usec/ 1 jiffie), we effectively divided by (1 usec/1 jiffie)-epsilon (rounding down). This would normally be fine, but we want to round timeouts up, and we did so by adding 2^USEC_JIFFIE_SC - 1 before the shift; this would be fine if our division was exact, but dividing this by the slightly smaller factor was equivalent to adding just _over_ 1 to the final result (instead of just _under_ 1, as desired.) In particular, with HZ=1000, we consistently computed that 10000 usec was 11 jiffies; the same was true for any exact multiple of TICK_NSEC. We could possibly still round in the intermediate form, adding something less than 2^USEC_JIFFIE_SC - 1, but easier still is to convert usec->nsec, round in nanoseconds, and then convert using time*spec*_to_jiffies. This adds one constant multiplication, and is not observably slower in microbenchmarks on recent x86 hardware. Tested: the following program: int main() { struct itimerval zero = {{0, 0}, {0, 0}}; /* Initially set to 10 ms. */ struct itimerval initial = zero; initial.it_interval.tv_usec = 10000; setitimer(ITIMER_PROF, &initial, NULL); /* Save and restore several times. */ for (size_t i = 0; i < 10; ++i) { struct itimerval prev; setitimer(ITIMER_PROF, &zero, &prev); /* on old kernels, this goes up by TICK_USEC every iteration */ printf("previous value: %ld %ld %ld %ld\n", prev.it_interval.tv_sec, prev.it_interval.tv_usec, prev.it_value.tv_sec, prev.it_value.tv_usec); setitimer(ITIMER_PROF, &prev, NULL); } return 0; } Cc: stable@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Paul Turner <pjt@google.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Reviewed-by: Paul Turner <pjt@google.com> Reported-by: Aaron Jacobs <jacobsa@google.com> Signed-off-by: Andrew Hunter <ahh@google.com> [jstultz: Tweaked to apply to 3.17-rc] Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-01-16sched/nohz: Fix overflow error in scheduler_tick_max_deferment()Kevin Hilman
While calculating the scheduler tick max deferment, the delta is converted from microseconds to nanoseconds through a multiplication against NSEC_PER_USEC. But this microseconds operand is an unsigned int, thus the result may likely overflow. The result is cast to u64 but only once the operation is completed, which is too late to avoid overflown result. This is currently not a problem because the scheduler tick max deferment is 1 second. But this may become an issue as we plan to make this value tunable. So lets fix this by casting the usecs value to u64 before multiplying by NSECS_PER_USEC. Also to prevent from this kind of mistake to happen again, move this ad-hoc jiffies -> nsecs conversion to a new helper. Signed-off-by: Kevin Hilman <khilman@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alex Shi <alex.shi@linaro.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Kevin Hilman <khilman@linaro.org> Link: http://lkml.kernel.org/r/1387315388-31676-2-git-send-email-khilman@linaro.org [move ad-hoc conversion to jiffies_to_nsecs helper] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2013-08-20jiffies: Avoid undefined behavior from signed overflowPaul E. McKenney
According to the C standard 3.4.3p3, overflow of a signed integer results in undefined behavior. This commit therefore changes the definitions of time_after(), time_after_eq(), time_after64(), and time_after_eq64() to avoid this undefined behavior. The trick is that the subtraction is done using unsigned arithmetic, which according to 6.2.5p9 cannot overflow because it is defined as modulo arithmetic. This has the added (though admittedly quite small) benefit of shortening four lines of code by four characters each. Note that the C standard considers the cast from unsigned to signed to be implementation-defined, see 6.3.1.3p3. However, on a two's-complement system, an implementation that defines anything other than a reinterpretation of the bits is free to come to me, and I will be happy to act as a witness for its being committed to an insane asylum. (Although I have nothing against saturating arithmetic or signals in some cases, these things really should not be the default when compiling an operating-system kernel.) Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Kevin Easton <kevin@guarana.org> [ paulmck: Included time_after64() and time_after_eq64(), as suggested by Eric Dumazet, also fixed commit message.] Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-07-02net: convert lls to use time_in_range()Eliezer Tamir
Time in range will fail safely if we move to a different cpu with an extremely large clock skew. Add time_in_range64() and convert lls to use it. changelog: v2 - fixed double call to sched_clock in can_poll_ll - fixed checkpatchisms Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-22timekeeping: Make jiffies_lock internalThomas Gleixner
Nothing outside of the timekeeping core needs that lock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-11-13time: Kill xtime_lock, replacing it with jiffies_lockJohn Stultz
Now that timekeeping is protected by its own locks, rename the xtime_lock to jifffies_lock to better describe what it protects. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-10-12Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer core update from Thomas Gleixner: - Bug fixes (one for a longstanding dead loop issue) - Rework of time related vsyscalls - Alarm timer updates - Jiffies updates to remove compile time dependencies * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Cast raw_interval to u64 to avoid shift overflow timers: Fix endless looping between cascade() and internal_add_timer() time/jiffies: bring back unconditional LATCH definition time: Convert x86_64 to using new update_vsyscall time: Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems time: Introduce new GENERIC_TIME_VSYSCALL time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD time: Move update_vsyscall definitions to timekeeper_internal.h time: Move timekeeper structure to timekeeper_internal.h for vsyscall changes jiffies: Remove compile time assumptions about CLOCK_TICK_RATE jiffies: Kill unused TICK_USEC_TO_NSEC alarmtimer: Rename alarmtimer_remove to alarmtimer_dequeue alarmtimer: Remove unused helpers & defines alarmtimer: Use hrtimer per-alarm instead of per-base alarmtimer: Implement minimum alarm interval for allowing suspend
2012-09-28Merge branch 'arnds-jiffies-fix' into fortglx/3.7/timeJohn Stultz
Sort out conflict with Arnd's patch that preserves the unconditional LATCH value. Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-09-28time/jiffies: bring back unconditional LATCH definitionArnd Bergmann
Patch a7ea3bbf5d "time/jiffies: Allow CLOCK_TICK_RATE to be undefined" breaks the compilation of targets that rely on the LATCH definition, because of recursive header file inclusion not defining CLOCK_TICK_RATE before it is checked here. This fixes the problem by moving LATCH back to where it was, but it seems that there are still cases where SHIFTED_HZ is defined incorrectly because of the same problem. Need to investigate further. Without this patch, building h7201_defconfig results in: arch/arm/mach-h720x/common.c: In function 'h720x_gettimeoffset': arch/arm/mach-h720x/common.c:50:73: error: 'LATCH' undeclared (first use in this function) arch/arm/mach-h720x/common.c:50:73: note: each undeclared identifier is reported only once for each function it appears in arch/arm/mach-h720x/common.c:51:1: warning: control reaches end of non-void function [-Wreturn-type] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-09-24jiffies: Remove compile time assumptions about CLOCK_TICK_RATEJohn Stultz
CLOCK_TICK_RATE is used to accurately caclulate exactly how a tick will be at a given HZ. This is useful, because while we'd expect NSEC_PER_SEC/HZ, the underlying hardware will have some granularity limit, so we won't be able to have exactly HZ ticks per second. This slight error can cause timekeeping quality problems when using the jiffies or other jiffies driven clocksources. Thus we currently use compile time CLOCK_TICK_RATE value to generate SHIFTED_HZ and NSEC_PER_JIFFIES, which we then use to adjust the jiffies clocksource to correct this error. Unfortunately though, since CLOCK_TICK_RATE is a compile time value, and the jiffies clocksource is registered very early during boot, there are a number of cases where there are different possible hardware timers that have different tick rates. This causes problems in cases like ARM where there are numerous different types of hardware, each having their own compile-time CLOCK_TICK_RATE, making it hard to accurately support different hardware with a single kernel. For the most part, this doesn't matter all that much, as not too many systems actually utilize the jiffies or jiffies driven clocksource. Usually there are other highres clocksources who's granularity error is negligable. Even so, we have some complicated calcualtions that we do everywhere to handle these edge cases. This patch removes the compile time SHIFTED_HZ value, and introduces a register_refined_jiffies() function. This results in the default jiffies clock as being assumed a perfect HZ freq, and allows archtectures that care about jiffies accuracy to call register_refined_jiffies() with the tick rate, specified dynamically at boot. This allows us, where necessary, to not have a compile time CLOCK_TICK_RATE constant, simplifies the jiffies code, and still provides a way to have an accurate jiffies clock. NOTE: Since this patch does not add register_refinied_jiffies() calls for every arch, it may cause time quality regressions in some cases. Its likely these will not be noticable, but if they are an issue, adding the following to the end of setup_arch() should resolve the regression: register_refinied_jiffies(CLOCK_TICK_RATE) Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-09-24jiffies: Kill unused TICK_USEC_TO_NSECJohn Stultz
No one is using TICK_USEC_TO_NSEC, so kill it. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-08-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
2012-08-09time: jiffies_delta_to_clock_t() helper to the rescueEric Dumazet
Various /proc/net files sometimes report crazy timer values, expressed in clock_t units. This happens when an expired timer delta (expires - jiffies) is passed to jiffies_to_clock_t(). This function has an overflow in : return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); commit cbbc719fccdb8cb (time: Change jiffies_to_clock_t() argument type to unsigned long) only got around the problem. As we cant output negative values in /proc/net/tcp without breaking various tools, I suggest adding a jiffies_delta_to_clock_t() wrapper that caps the negative delta to a 0 value. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Maciej Żenczykowski <maze@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: hank <pyu@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-31time/jiffies: Rename ACTHZ to SHIFTED_HZJohn Stultz
Ingo noted that ACTHZ is a confusing name, and requested it be renamed, so this patch renames ACTHZ to SHIFTED_HZ to better describe it. Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1343414893-45779-3-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-07-31time/jiffies: Allow CLOCK_TICK_RATE to be undefinedCatalin Marinas
CLOCK_TICK_RATE is a legacy constant that defines the timer device's granularity. On hardware with particularly coarse granularity, this constant is used to reduce accumulated time error when using jiffies as a clocksource, by calculating the hardware's actual tick length rather then just assuming it is 1sec/HZ. However, for the most part this is unnecessary, as most modern systems don't use jiffies for their clocksource, and their tick device is sufficiently fine grained to avoid major error. Thus, this patch allows an architecture to not define CLOCK_TICK_RATE, in which case ACTHZ defaults to (HZ << 8). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> [ Commit log & intention tweaks ] Signed-off-by: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/1343414893-45779-2-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2011-09-21time: Change jiffies_to_clock_t() argument type to unsigned longhank
The parameter's origin type is long. On an i386 architecture, it can easily be larger than 0x80000000, causing this function to convert it to a sign-extended u64 type. Change the type to unsigned long so we get the correct result. Signed-off-by: hank <pyu@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <stable@kernel.org> [ build fix ] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-31Fix common misspellingsLucas De Marchi
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-01-26time: Add nsecs_to_cputime64 interface for asm-genericVenkatesh Pallipadi
Add nsecs_to_cputime64 interface. This is used in following patches that updates cpu irq stat based on ns granularity info in IRQ_TIME_ACCOUNTING. Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292980144-28796-3-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-26sched, time: Define nsecs_to_jiffies()Hidetoshi Seto
Use of msecs_to_jiffies() for nsecs_to_cputime() have some problems: - The type of msecs_to_jiffies()'s argument is unsigned int, so it cannot convert msecs greater than UINT_MAX = about 49.7 days. - msecs_to_jiffies() returns MAX_JIFFY_OFFSET if MSB of argument is set, assuming that input was negative value. So it cannot convert msecs greater than INT_MAX = about 24.8 days too. This patch defines a new function nsecs_to_jiffies() that can deal greater values, and that can deal all incoming values as unsigned. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Spencer Candland <spencer@bluehost.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Amrico Wang <xiyou.wangcong@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <johnstul@linux.vnet.ibm.com> LKML-Reference: <4B0E16E7.5070307@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-23optimize attribute timeouts for "noac" and "actimeo=0"Peter Staubach
Hi. I've been looking at a bugzilla which describes a problem where a customer was advised to use either the "noac" or "actimeo=0" mount options to solve a consistency problem that they were seeing in the file attributes. It turned out that this solution did not work reliably for them because sometimes, the local attribute cache was believed to be valid and not timed out. (With an attribute cache timeout of 0, the cache should always appear to be timed out.) In looking at this situation, it appears to me that the problem is that the attribute cache timeout code has an off-by-one error in it. It is assuming that the cache is valid in the region, [read_cache_jiffies, read_cache_jiffies + attrtimeo]. The cache should be considered valid only in the region, [read_cache_jiffies, read_cache_jiffies + attrtimeo). With this change, the options, "noac" and "actimeo=0", work as originally expected. This problem was previously addressed by special casing the attrtimeo == 0 case. However, since the problem is only an off- by-one error, the cleaner solution is address the off-by-one error and thus, not require the special case. Thanx... ps Signed-off-by: Peter Staubach <staubach@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-05-01remove div_long_long_remRoman Zippel
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>
2008-04-21Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/juhl/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/juhl/trivial: (24 commits) DOC: A couple corrections and clarifications in USB doc. Generate a slightly more informative error msg for bad HZ fix typo "is" -> "if" in Makefile ext*: spelling fix prefered -> preferred DOCUMENTATION: Use newer DEFINE_SPINLOCK macro in docs. KEYS: Fix the comment to match the file name in rxrpc-type.h. RAID: remove trailing space from printk line DMA engine: typo fixes Remove unused MAX_NODES_SHIFT MAINTAINERS: Clarify access to OCFS2 development mailing list. V4L: Storage class should be before const qualifier (sn9c102) V4L: Storage class should be before const qualifier sonypi: Storage class should be before const qualifier intel_menlow: Storage class should be before const qualifier DVB: Storage class should be before const qualifier arm: Storage class should be before const qualifier ALSA: Storage class should be before const qualifier acpi: Storage class should be before const qualifier firmware_sample_driver.c: fix coding style MAINTAINERS: Add ati_remote2 driver ... Fixed up trivial conflicts in firmware_sample_driver.c
2008-04-21Generate a slightly more informative error msg for bad HZRobert P. J. Day
Generate a slightly more informative error msg for bad HZ in include/linux/jiffies.h Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
2008-04-21jiffies: add time_is_after_jiffies and others which compare with jiffiesDave Young
Most of time_after like macros usages just compare jiffies and another number, so here add some time_is_* macros for convenience. Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-08time: fix typo in commentsLi Zefan
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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-25timers: don't #error on higher HZ valuesPavel Machek
For some crazy reason (trying to work around hw problem in i810) I wanted to use HZ around 4000. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-16slow down printk during bootRandy Dunlap
Optionally add a boot delay after each kernel printk() call, crudely measured in milliseconds, with a maximum delay of 10 seconds per printk. Enable CONFIG_BOOT_PRINTK_DELAY=y and then add (e.g.): "lpj=loops_per_jiffy boot_delay=100" to the kernel command line. It has been useful in cases like "during boot, my machine just reboots or the screen goes black" by slowing down printk, (and adding initcall_debug), we can usually see the last thing that happened before the lights went out which is usually a valuable clue. [akpm@linux-foundation.org: not all architectures implement CONFIG_HZ] [akpm@linux-foundation.org: fix lots of stuff] [bunk@stusta.de: kernel/printk.c: make 2 variables static] [heiko.carstens@de.ibm.com: fix slow down printk on boot compile error] Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-15Merge git://git.linux-nfs.org/pub/linux/nfs-2.6Linus Torvalds
* git://git.linux-nfs.org/pub/linux/nfs-2.6: (131 commits) NFSv4: Fix a typo in nfs_inode_reclaim_delegation NFS: Add a boot parameter to disable 64 bit inode numbers NFS: nfs_refresh_inode should clear cache_validity flags on success NFS: Fix a connectathon regression in NFSv3 and NFSv4 NFS: Use nfs_refresh_inode() in ops that aren't expected to change the inode SUNRPC: Don't call xprt_release in call refresh SUNRPC: Don't call xprt_release() if call_allocate fails SUNRPC: Fix buggy UDP transmission [23/37] Clean up duplicate includes in [2.6 patch] net/sunrpc/rpcb_clnt.c: make struct rpcb_program static SUNRPC: Use correct type in buffer length calculations SUNRPC: Fix default hostname created in rpc_create() nfs: add server port to rpc_pipe info file NFS: Get rid of some obsolete macros NFS: Simplify filehandle revalidation NFS: Ensure that nfs_link() returns a hashed dentry NFS: Be strict about dentry revalidation when doing exclusive create NFS: Don't zap the readdir caches upon error NFS: Remove the redundant nfs_reval_fsid() NFSv3: Always use directory post-op attributes in nfs3_proc_lookup ... Fix up trivial conflict due to sock_owned_by_user() cleanup manually in net/sunrpc/xprtsock.c
2007-10-12jiffies: remove unused macrosChris Wright
The x86 hpet cleanups allow removal of some unused macros. Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-09Re: [NFS] [PATCH] Attribute timeout handling and wrapping u32 jiffiesFabio Olive Leite
I would like to discuss the idea that the current checks for attribute timeout using time_after are inadequate for 32bit architectures, since time_after works correctly only when the two timestamps being compared are within 2^31 jiffies of each other. The signed overflow caused by comparing values more than 2^31 jiffies apart will flip the result, causing incorrect assumptions of validity. 2^31 jiffies is a fairly large period of time (~25 days) when compared to the lifetime of most kernel data structures, but for long lived NFS mounts that can sit idle for months (think that for some reason autofs cannot be used), it is easy to compare inode attribute timestamps with very disparate or even bogus values (as in when jiffies have wrapped many times, where the comparison doesn't even make sense). Currently the code tests for attribute timeout by simply adding the desired amount of jiffies to the stored timestamp and comparing that with the current timestamp of obtained attribute data with time_after. This is incorrect, as it returns true for the desired timeout period and another full 2^31 range of jiffies. In testing with artificial jumps (several small jumps, not one big crank) of the jiffies I was able to reproduce a problem found in a server with very long lived NFS mounts, where attributes would not be refreshed even after touching files and directories in the server: Initial uptime: 03:42:01 up 6 min, 0 users, load average: 0.01, 0.12, 0.07 NFS volume is mounted and time is advanced: 03:38:09 up 25 days, 2 min, 0 users, load average: 1.22, 1.05, 1.08 # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Dec 17 03:38 /local/A/foo/bar -rw-r--r-- 1 root root 0 Nov 22 00:36 /nfs/A/foo/bar # touch /local/A/foo/bar # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Dec 17 03:47 /local/A/foo/bar -rw-r--r-- 1 root root 0 Nov 22 00:36 /nfs/A/foo/bar We can see the local mtime is updated, but the NFS mount still shows the old value. The patch below makes it work: Initial setup... 07:11:02 up 25 days, 1 min, 0 users, load average: 0.15, 0.03, 0.04 # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:11 /local/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:11 /nfs/A/foo/bar # touch /local/A/foo/bar # ls -l /local/A/foo/bar /nfs/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:14 /local/A/foo/bar -rw-r--r-- 1 root root 0 Jan 11 07:14 /nfs/A/foo/bar Signed-off-by: Fabio Olive Leite <fleite@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2007-02-16[PATCH] Fix timeout overflow with jiffiesIngo Molnar
Prevent timeout overflow if timer ticks are behind jiffies (due to high softirq load or due to dyntick), by limiting the valid timeout range to MAX_LONG/2. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] Uninline jiffies.h functionsIngo Molnar
There are loads of fat functions hidden in jiffies.h. Uninline them. No code changes. [jeremy@goop.org: export fix] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-11-30Fix jiffies.h commentChase Venters
jiffies.h includes a comment informing that jiffies_64 must be read with the assistance of the xtime_lock seqlock. The comment text, however, calls jiffies_64 "not volatile", which should probably read "not atomic". Signed-off-by: Chase Venters <chase.venters@clientec.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>