1. 27 Jan, 2013 3 commits
    • Frederic Weisbecker's avatar
      cputime: Generic on-demand virtual cputime accounting · abf917cd
      Frederic Weisbecker authored
      If we want to stop the tick further idle, we need to be
      able to account the cputime without using the tick.
      
      Virtual based cputime accounting solves that problem by
      hooking into kernel/user boundaries.
      
      However implementing CONFIG_VIRT_CPU_ACCOUNTING require
      low level hooks and involves more overhead. But we already
      have a generic context tracking subsystem that is required
      for RCU needs by archs which plan to shut down the tick
      outside idle.
      
      This patch implements a generic virtual based cputime
      accounting that relies on these generic kernel/user hooks.
      
      There are some upsides of doing this:
      
      - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING
      if context tracking is already built (already necessary for RCU in full
      tickless mode).
      
      - We can rely on the generic context tracking subsystem to dynamically
      (de)activate the hooks, so that we can switch anytime between virtual
      and tick based accounting. This way we don't have the overhead
      of the virtual accounting when the tick is running periodically.
      
      And one downside:
      
      - There is probably more overhead than a native virtual based cputime
      accounting. But this relies on hooks that are already set anyway.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      abf917cd
    • Frederic Weisbecker's avatar
      cputime: Move default nsecs_to_cputime() to jiffies based cputime file · ae8dda5c
      Frederic Weisbecker authored
      If the architecture doesn't provide an implementation of
      nsecs_to_cputime(), the cputime accounting core uses a
      default one that converts the nanoseconds to jiffies. However
      this only makes sense if we use the jiffies based cputime.
      
      For now it doesn't matter much because this API is only
      called on code that uses jiffies based cputime accounting.
      
      But the code may evolve and this API may be used more
      broadly in the future. Keeping this default implementation
      around is very error prone as it may introduce a bug and
      hide it on architectures that don't override this API.
      
      Fix this by moving this definition to the jiffies based
      cputime headers as it is the only place where it belongs to.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      ae8dda5c
    • Frederic Weisbecker's avatar
      cputime: Librarize per nsecs resolution cputime definitions · 39613766
      Frederic Weisbecker authored
      The full dynticks cputime accounting that we'll soon introduce
      will rely on sched_clock(). And its clock can have a per
      nanosecond granularity.
      
      To prepare for this, we need to have a cputime_t implementation
      that has this precision.
      
      ia64 virtual cputime accounting already uses that granularity
      so all we need is to librarize its implementation in the asm
      generic headers.
      
      Also librarize the default per jiffy granularity cputime_t
      as well so that we can easily pick either implementation
      depending on the cputime accounting config we choose.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Fenghua Yu <fenghua.yu@intel.com>
      39613766
  2. 26 Jan, 2013 1 commit
    • Frederic Weisbecker's avatar
      context_tracking: Export context state for generic vtime · 95a79fd4
      Frederic Weisbecker authored
      Export the context state: whether we run in user / kernel
      from the context tracking subsystem point of view.
      
      This is going to be used by the generic virtual cputime
      accounting subsystem that is needed to implement the full
      dynticks.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Li Zhong <zhong@linux.vnet.ibm.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      95a79fd4
  3. 18 Jan, 2013 1 commit
  4. 17 Jan, 2013 2 commits
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux · 72ffaa48
      Linus Torvalds authored
      Pull more s390 patches from Martin Schwidefsky:
       "A couple of bug fixes: one of the transparent huge page primitives is
        broken, the sched_clock function overflows after 417 days, the XFS
        module has grown too large for -fpic and the new pci code has broken
        normal channel subsystem notifications."
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
        s390/chsc: fix SEI usage
        s390/time: fix sched_clock() overflow
        s390: use -fPIC for module compile
        s390/mm: fix pmd_pfn() for thp
      72ffaa48
    • Linus Torvalds's avatar
      Merge tag 'for-linus-v3.8-rc4' of git://oss.sgi.com/xfs/xfs · dfdebc24
      Linus Torvalds authored
      Pull xfs bugfixes from Ben Myers:
      
       - fix(es) for compound buffers
      
       - fix for dquot soft timer asserts due to overflow of d_blk_softlimit
      
       - fix for regression in dir v2 code introduced in commit 20f7e9f3
         ("xfs: factor dir2 block read operations")
      
      * tag 'for-linus-v3.8-rc4' of git://oss.sgi.com/xfs/xfs:
        xfs: recalculate leaf entry pointer after compacting a dir2 block
        xfs: remove int casts from debug dquot soft limit timer asserts
        xfs: fix the multi-segment log buffer format
        xfs: fix segment in xfs_buf_item_format_segment
        xfs: rename bli_format to avoid confusion with bli_formats
        xfs: use b_maps[] for discontiguous buffers
      dfdebc24
  5. 16 Jan, 2013 24 commits
  6. 15 Jan, 2013 9 commits