1. 28 5月, 2013 3 次提交
  2. 10 5月, 2013 1 次提交
  3. 07 5月, 2013 2 次提交
  4. 06 5月, 2013 5 次提交
    • L
      Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 534c97b0
      Linus Torvalds 提交于
      Pull 'full dynticks' support from Ingo Molnar:
       "This tree from Frederic Weisbecker adds a new, (exciting! :-) core
        kernel feature to the timer and scheduler subsystems: 'full dynticks',
        or CONFIG_NO_HZ_FULL=y.
      
        This feature extends the nohz variable-size timer tick feature from
        idle to busy CPUs (running at most one task) as well, potentially
        reducing the number of timer interrupts significantly.
      
        This feature got motivated by real-time folks and the -rt tree, but
        the general utility and motivation of full-dynticks runs wider than
        that:
      
         - HPC workloads get faster: CPUs running a single task should be able
           to utilize a maximum amount of CPU power.  A periodic timer tick at
           HZ=1000 can cause a constant overhead of up to 1.0%.  This feature
           removes that overhead - and speeds up the system by 0.5%-1.0% on
           typical distro configs even on modern systems.
      
         - Real-time workload latency reduction: CPUs running critical tasks
           should experience as little jitter as possible.  The last remaining
           source of kernel-related jitter was the periodic timer tick.
      
         - A single task executing on a CPU is a pretty common situation,
           especially with an increasing number of cores/CPUs, so this feature
           helps desktop and mobile workloads as well.
      
        The cost of the feature is mainly related to increased timer
        reprogramming overhead when a CPU switches its tick period, and thus
        slightly longer to-idle and from-idle latency.
      
        Configuration-wise a third mode of operation is added to the existing
        two NOHZ kconfig modes:
      
         - CONFIG_HZ_PERIODIC: [formerly !CONFIG_NO_HZ], now explicitly named
           as a config option.  This is the traditional Linux periodic tick
           design: there's a HZ tick going on all the time, regardless of
           whether a CPU is idle or not.
      
         - CONFIG_NO_HZ_IDLE: [formerly CONFIG_NO_HZ=y], this turns off the
           periodic tick when a CPU enters idle mode.
      
         - CONFIG_NO_HZ_FULL: this new mode, in addition to turning off the
           tick when a CPU is idle, also slows the tick down to 1 Hz (one
           timer interrupt per second) when only a single task is running on a
           CPU.
      
        The .config behavior is compatible: existing !CONFIG_NO_HZ and
        CONFIG_NO_HZ=y settings get translated to the new values, without the
        user having to configure anything.  CONFIG_NO_HZ_FULL is turned off by
        default.
      
        This feature is based on a lot of infrastructure work that has been
        steadily going upstream in the last 2-3 cycles: related RCU support
        and non-periodic cputime support in particular is upstream already.
      
        This tree adds the final pieces and activates the feature.  The pull
        request is marked RFC because:
      
         - it's marked 64-bit only at the moment - the 32-bit support patch is
           small but did not get ready in time.
      
         - it has a number of fresh commits that came in after the merge
           window.  The overwhelming majority of commits are from before the
           merge window, but still some aspects of the tree are fresh and so I
           marked it RFC.
      
         - it's a pretty wide-reaching feature with lots of effects - and
           while the components have been in testing for some time, the full
           combination is still not very widely used.  That it's default-off
           should reduce its regression abilities and obviously there are no
           known regressions with CONFIG_NO_HZ_FULL=y enabled either.
      
         - the feature is not completely idempotent: there is no 100%
           equivalent replacement for a periodic scheduler/timer tick.  In
           particular there's ongoing work to map out and reduce its effects
           on scheduler load-balancing and statistics.  This should not impact
           correctness though, there are no known regressions related to this
           feature at this point.
      
         - it's a pretty ambitious feature that with time will likely be
           enabled by most Linux distros, and we'd like you to make input on
           its design/implementation, if you dislike some aspect we missed.
           Without flaming us to crisp! :-)
      
        Future plans:
      
         - there's ongoing work to reduce 1Hz to 0Hz, to essentially shut off
           the periodic tick altogether when there's a single busy task on a
           CPU.  We'd first like 1 Hz to be exposed more widely before we go
           for the 0 Hz target though.
      
         - once we reach 0 Hz we can remove the periodic tick assumption from
           nr_running>=2 as well, by essentially interrupting busy tasks only
           as frequently as the sched_latency constraints require us to do -
           once every 4-40 msecs, depending on nr_running.
      
        I am personally leaning towards biting the bullet and doing this in
        v3.10, like the -rt tree this effort has been going on for too long -
        but the final word is up to you as usual.
      
        More technical details can be found in Documentation/timers/NO_HZ.txt"
      
      * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
        sched: Keep at least 1 tick per second for active dynticks tasks
        rcu: Fix full dynticks' dependency on wide RCU nocb mode
        nohz: Protect smp_processor_id() in tick_nohz_task_switch()
        nohz_full: Add documentation.
        cputime_nsecs: use math64.h for nsec resolution conversion helpers
        nohz: Select VIRT_CPU_ACCOUNTING_GEN from full dynticks config
        nohz: Reduce overhead under high-freq idling patterns
        nohz: Remove full dynticks' superfluous dependency on RCU tree
        nohz: Fix unavailable tick_stop tracepoint in dynticks idle
        nohz: Add basic tracing
        nohz: Select wide RCU nocb for full dynticks
        nohz: Disable the tick when irq resume in full dynticks CPU
        nohz: Re-evaluate the tick for the new task after a context switch
        nohz: Prepare to stop the tick on irq exit
        nohz: Implement full dynticks kick
        nohz: Re-evaluate the tick from the scheduler IPI
        sched: New helper to prevent from stopping the tick in full dynticks
        sched: Kick full dynticks CPU that have more than one task enqueued.
        perf: New helper to prevent full dynticks CPUs from stopping tick
        perf: Kick full dynticks CPU if events rotation is needed
        ...
      534c97b0
    • L
      Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 64049d19
      Linus Torvalds 提交于
      Pull perf fixes from Ingo Molnar:
       "Misc fixes plus a small hw-enablement patch for Intel IB model 58
        uncore events"
      
      * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL
        perf/x86/intel/lbr: Fix LBR filter
        perf/x86: Blacklist all MEM_*_RETIRED events for Ivy Bridge
        perf: Fix vmalloc ring buffer pages handling
        perf/x86/intel: Fix unintended variable name reuse
        perf/x86/intel: Add support for IvyBridge model 58 Uncore
        perf/x86/intel: Fix typo in perf_event_intel_uncore.c
        x86: Eliminate irq_mis_count counted in arch_irq_stat
      64049d19
    • L
      Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux · f8ce1faf
      Linus Torvalds 提交于
      Pull mudule updates from Rusty Russell:
       "We get rid of the general module prefix confusion with a binary config
        option, fix a remove/insert race which Never Happens, and (my
        favorite) handle the case when we have too many modules for a single
        commandline.  Seriously, the kernel is full, please go away!"
      
      * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
        modpost: fix unwanted VMLINUX_SYMBOL_STR expansion
        X.509: Support parse long form of length octets in Authority Key Identifier
        module: don't unlink the module until we've removed all exposure.
        kernel: kallsyms: memory override issue, need check destination buffer length
        MODSIGN: do not send garbage to stderr when enabling modules signature
        modpost: handle huge numbers of modules.
        modpost: add -T option to read module names from file/stdin.
        modpost: minor cleanup.
        genksyms: pass symbol-prefix instead of arch
        module: fix symbol versioning with symbol prefixes
        CONFIG_SYMBOL_PREFIX: cleanup.
      f8ce1faf
    • L
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 24d0c254
      Linus Torvalds 提交于
      Pull single_open() leak fixes from Al Viro:
       "A bunch of fixes for a moderately common class of bugs: file with
        single_open() done by its ->open() and seq_release as its ->release().
      
        That leaks; fortunately, it's not _too_ common (either people manage
        to RTFM that says "When using single_open(), the programmer should use
        single_release() instead of seq_release() in the file_operations
        structure to avoid a memory leak", or they just copy a correct
        instance), but grepping through the tree has caught quite a pile.
      
        All of that is, AFAICS, -stable fodder, for as far as the patches
        apply.  I tried to carve it up into reasonably-sized pieces (more or
        less "comes from the same tree")"
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
        rcutrace: single_open() leaks
        gadget: single_open() leaks
        staging: single_open() leaks
        megaraid: single_open() leak
        wireless: single_open() leaks
        input: single_open() leak
        rtc: single_open() leaks
        ds1620: single_open() leak
        sh: single_open() leaks
        parisc: single_open() leaks
        mips: single_open() leaks
        ia64: single_open() leaks
        h8300: single_open() leaks
        cris: single_open() leaks
        arm: single_open() leaks
      24d0c254
    • L
      Merge branch 'ipc-cleanups' · 802d0db8
      Linus Torvalds 提交于
      Merge ipc fixes and cleanups from my IPC branch.
      
      The ipc locking has always been pretty ugly, and the scalability fixes
      to some degree made it even less readable.  We had two cases of double
      unlocks in error paths due to this (one rcu read unlock, one semaphore
      unlock), and this fixes the bugs I found while trying to clean things up
      a bit so that we are less likely to have more.
      
      * ipc-cleanups:
        ipc: simplify rcu_read_lock() in semctl_nolock()
        ipc: simplify semtimedop/semctl_main() common error path handling
        ipc: move sem_obtain_lock() rcu locking into the only caller
        ipc: fix double sem unlock in semctl error path
        ipc: move the rcu_read_lock() from sem_lock_and_putref() into callers
        ipc: sem_putref() does not need the semaphore lock any more
        ipc: move rcu_read_unlock() out of sem_unlock() and into callers
      802d0db8
  5. 05 5月, 2013 29 次提交