1. 30 11月, 2010 1 次提交
    • M
      sched: Add 'autogroup' scheduling feature: automated per session task groups · 5091faa4
      Mike Galbraith 提交于
      A recurring complaint from CFS users is that parallel kbuild has
      a negative impact on desktop interactivity.  This patch
      implements an idea from Linus, to automatically create task
      groups.  Currently, only per session autogroups are implemented,
      but the patch leaves the way open for enhancement.
      
      Implementation: each task's signal struct contains an inherited
      pointer to a refcounted autogroup struct containing a task group
      pointer, the default for all tasks pointing to the
      init_task_group.  When a task calls setsid(), a new task group
      is created, the process is moved into the new task group, and a
      reference to the preveious task group is dropped.  Child
      processes inherit this task group thereafter, and increase it's
      refcount.  When the last thread of a process exits, the
      process's reference is dropped, such that when the last process
      referencing an autogroup exits, the autogroup is destroyed.
      
      At runqueue selection time, IFF a task has no cgroup assignment,
      its current autogroup is used.
      
      Autogroup bandwidth is controllable via setting it's nice level
      through the proc filesystem:
      
        cat /proc/<pid>/autogroup
      
      Displays the task's group and the group's nice level.
      
        echo <nice level> > /proc/<pid>/autogroup
      
      Sets the task group's shares to the weight of nice <level> task.
      Setting nice level is rate limited for !admin users due to the
      abuse risk of task group locking.
      
      The feature is enabled from boot by default if
      CONFIG_SCHED_AUTOGROUP=y is selected, but can be disabled via
      the boot option noautogroup, and can also be turned on/off on
      the fly via:
      
        echo [01] > /proc/sys/kernel/sched_autogroup_enabled
      
      ... which will automatically move tasks to/from the root task group.
      Signed-off-by: NMike Galbraith <efault@gmx.de>
      Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Paul Turner <pjt@google.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      [ Removed the task_group_path() debug code, and fixed !EVENTFD build failure. ]
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      LKML-Reference: <1290281700.28711.9.camel@maggy.simson.net>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      5091faa4
  2. 28 10月, 2010 6 次提交
  3. 23 10月, 2010 2 次提交
    • A
      SYSFS: Allow boot time switching between deprecated and modern sysfs layout · e52eec13
      Andi Kleen 提交于
      I have some systems which need legacy sysfs due to old tools that are
      making assumptions that a directory can never be a symlink to another
      directory, and it's a big hazzle to compile separate kernels for them.
      
      This patch turns CONFIG_SYSFS_DEPRECATED into a run time option
      that can be switched on/off the kernel command line. This way
      the same binary can be used in both cases with just a option
      on the command line.
      
      The old CONFIG_SYSFS_DEPRECATED_V2 option is still there to set
      the default. I kept the weird name to not break existing
      config files.
      
      Also the compat code can be still completely disabled by undefining
      CONFIG_SYSFS_DEPRECATED_SWITCH -- just the optimizer takes
      care of this now instead of lots of ifdefs. This makes the code
      look nicer.
      
      v2: This is an updated version on top of Kay's patch to only
      handle the block devices. I tested it on my old systems
      and that seems to work.
      
      Cc: axboe@kernel.dk
      Signed-off-by: NAndi Kleen <ak@linux.intel.com>
      Cc: Kay Sievers <kay.sievers@vrfy.org>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      e52eec13
    • K
      driver core: remove CONFIG_SYSFS_DEPRECATED_V2 but keep it for block devices · 39aba963
      Kay Sievers 提交于
      This patch removes the old CONFIG_SYSFS_DEPRECATED_V2 config option,
      but it keeps the logic around to handle block devices in the old manner
      as some people like to run new kernel versions on old (pre 2007/2008)
      distros.
      Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Stephen Hemminger <shemminger@vyatta.com>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Alan Stern <stern@rowland.harvard.edu>
      Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
      Cc: Randy Dunlap <randy.dunlap@oracle.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Jaroslav Kysela <perex@perex.cz>
      Cc: Takashi Iwai <tiwai@suse.de>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: David Howells <dhowells@redhat.com>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      
      39aba963
  4. 21 10月, 2010 1 次提交
    • A
      BKL: introduce CONFIG_BKL. · 6de5bd12
      Arnd Bergmann 提交于
      With all the patches we have queued in the BKL removal tree, only a
      few dozen modules are left that actually rely on the BKL, and even
      there are lots of low-hanging fruit. We need to decide what to do
      about them, this patch illustrates one of the options:
      
      Every user of the BKL is marked as 'depends on BKL' in Kconfig,
      and the CONFIG_BKL becomes a user-visible option. If it gets
      disabled, no BKL using module can be built any more and the BKL
      code itself is compiled out.
      
      The one exception is file locking, which is practically always
      enabled and does a 'select BKL' instead. This effectively forces
      CONFIG_BKL to be enabled until we have solved the fs/lockd
      mess and can apply the patch that removes the BKL from fs/locks.c.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      6de5bd12
  5. 19 10月, 2010 1 次提交
    • P
      irq_work: Add generic hardirq context callbacks · e360adbe
      Peter Zijlstra 提交于
      Provide a mechanism that allows running code in IRQ context. It is
      most useful for NMI code that needs to interact with the rest of the
      system -- like wakeup a task to drain buffers.
      
      Perf currently has such a mechanism, so extract that and provide it as
      a generic feature, independent of perf so that others may also
      benefit.
      
      The IRQ context callback is generated through self-IPIs where
      possible, or on architectures like powerpc the decrementer (the
      built-in timer facility) is set to generate an interrupt immediately.
      
      Architectures that don't have anything like this get to do with a
      callback from the timer tick. These architectures can call
      irq_work_run() at the tail of any IRQ handlers that might enqueue such
      work (like the perf IRQ handler) to avoid undue latencies in
      processing the work.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: NKyle McMartin <kyle@mcmartin.ca>
      Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      [ various fixes ]
      Signed-off-by: NHuang Ying <ying.huang@intel.com>
      LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      e360adbe
  6. 04 10月, 2010 1 次提交
  7. 16 9月, 2010 1 次提交
  8. 23 8月, 2010 1 次提交
  9. 20 8月, 2010 3 次提交
    • P
      rcu: Add a TINY_PREEMPT_RCU · a57eb940
      Paul E. McKenney 提交于
      Implement a small-memory-footprint uniprocessor-only implementation of
      preemptible RCU.  This implementation uses but a single blocked-tasks
      list rather than the combinatorial number used per leaf rcu_node by
      TREE_PREEMPT_RCU, which reduces memory consumption and greatly simplifies
      processing.  This version also takes advantage of uniprocessor execution
      to accelerate grace periods in the case where there are no readers.
      
      The general design is otherwise broadly similar to that of TREE_PREEMPT_RCU.
      
      This implementation is a step towards having RCU implementation driven
      off of the SMP and PREEMPT kernel configuration variables, which can
      happen once this implementation has accumulated sufficient experience.
      
      Removed ACCESS_ONCE() from __rcu_read_unlock() and added barrier() as
      suggested by Steve Rostedt in order to avoid the compiler-reordering
      issue noted by Mathieu Desnoyers (http://lkml.org/lkml/2010/8/16/183).
      
      As can be seen below, CONFIG_TINY_PREEMPT_RCU represents almost 5Kbyte
      savings compared to CONFIG_TREE_PREEMPT_RCU.  Of course, for non-real-time
      workloads, CONFIG_TINY_RCU is even better.
      
      	CONFIG_TREE_PREEMPT_RCU
      
      	   text	   data	    bss	    dec	   filename
      	     13	      0	      0	     13	   kernel/rcupdate.o
      	   6170	    825	     28	   7023	   kernel/rcutree.o
      				   ----
      				   7026    Total
      
      	CONFIG_TINY_PREEMPT_RCU
      
      	   text	   data	    bss	    dec	   filename
      	     13	      0	      0	     13	   kernel/rcupdate.o
      	   2081	     81	      8	   2170	   kernel/rcutiny.o
      				   ----
      				   2183    Total
      
      	CONFIG_TINY_RCU (non-preemptible)
      
      	   text	   data	    bss	    dec	   filename
      	     13	      0	      0	     13	   kernel/rcupdate.o
      	    719	     25	      0	    744	   kernel/rcutiny.o
      				    ---
      				    757    Total
      Requested-by: NLoïc Minier <loic.minier@canonical.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      a57eb940
    • P
      rcu: Fix RCU_FANOUT help message · 4d87ffad
      Paul E. McKenney 提交于
      Commit cf244dc0 added a fourth level to the TREE_RCU hierarchy,
      but the RCU_FANOUT help message still said "cube root".  This commit
      fixes this to "fourth root" and also emphasizes that production
      systems are well-served by the default.  (Stress-testing RCU itself
      uses small RCU_FANOUT values in order to test large-system code paths
      on small(er) systems.)
      Located-by: NJohn Kacur <jkacur@redhat.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      4d87ffad
    • P
      rcu: restrict TREE_RCU to SMP builds with !PREEMPT · 687d7a96
      Paul E. McKenney 提交于
      Because both TINY_RCU and TREE_PREEMPT_RCU have been in mainline for
      several releases, it is time to restrict the use of TREE_RCU to SMP
      non-preemptible systems.  This reduces testing/validation effort.  This
      commit is a first step towards driving the selection of RCU implementation
      directly off of the SMP and PREEMPT configuration parameters.
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      687d7a96
  10. 11 8月, 2010 1 次提交
  11. 28 7月, 2010 3 次提交
  12. 23 7月, 2010 1 次提交
  13. 16 5月, 2010 2 次提交
    • F
      lockup_detector: Introduce CONFIG_HARDLOCKUP_DETECTOR · 23637d47
      Frederic Weisbecker 提交于
      This new config is deemed to simplify even more the lockup detector
      dependencies and can make it easier to bring a smooth sorting
      between archs that support the new generic lockup detector and those
      that still have their own, especially for those that are in the
      middle of this migration.
      
      Instead of checking whether we have CONFIG_LOCKUP_DETECTOR +
      CONFIG_PERF_EVENTS_NMI each time an arch wants to know if it needs
      to build its own lockup detector, take a shortcut with this new
      config. It is enabled only if the hardlockup detection part of
      the whole lockup detector is on.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Don Zickus <dzickus@redhat.com>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      23637d47
    • F
      lockup_detector: Adapt CONFIG_PERF_EVENT_NMI to other archs · c01d4323
      Frederic Weisbecker 提交于
      CONFIG_PERF_EVENT_NMI is something that need to be enabled from the
      arch. This is fine on x86 as PERF_EVENTS is builtin but if other
      archs select it, they will need to handle the PERF_EVENTS dependency.
      
      Instead, handle the dependency in the generic layer:
      
      - archs need to tell what they support through HAVE_PERF_EVENTS_NMI
      - Enable magically PERF_EVENTS_NMI if we have PERF_EVENTS and
        HAVE_PERF_EVENTS_NMI.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Don Zickus <dzickus@redhat.com>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      c01d4323
  14. 13 5月, 2010 1 次提交
    • D
      lockup_detector: Combine nmi_watchdog and softlockup detector · 58687acb
      Don Zickus 提交于
      The new nmi_watchdog (which uses the perf event subsystem) is very
      similar in structure to the softlockup detector.  Using Ingo's
      suggestion, I combined the two functionalities into one file:
      kernel/watchdog.c.
      
      Now both the nmi_watchdog (or hardlockup detector) and softlockup
      detector sit on top of the perf event subsystem, which is run every
      60 seconds or so to see if there are any lockups.
      
      To detect hardlockups, cpus not responding to interrupts, I
      implemented an hrtimer that runs 5 times for every perf event
      overflow event.  If that stops counting on a cpu, then the cpu is
      most likely in trouble.
      
      To detect softlockups, tasks not yielding to the scheduler, I used the
      previous kthread idea that now gets kicked every time the hrtimer fires.
      If the kthread isn't being scheduled neither is anyone else and the
      warning is printed to the console.
      
      I tested this on x86_64 and both the softlockup and hardlockup paths
      work.
      
      V2:
      - cleaned up the Kconfig and softlockup combination
      - surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI
      - seperated out the softlockup case from perf event subsystem
      - re-arranged the enabling/disabling nmi watchdog from proc space
      - added cpumasks for hardlockup failure cases
      - removed fallback to soft events if no PMU exists for hard events
      
      V3:
      - comment cleanups
      - drop support for older softlockup code
      - per_cpu cleanups
      - completely remove software clock base hardlockup detector
      - use per_cpu masking on hard/soft lockup detection
      - #ifdef cleanups
      - rename config option NMI_WATCHDOG to LOCKUP_DETECTOR
      - documentation additions
      
      V4:
      - documentation fixes
      - convert per_cpu to __get_cpu_var
      - powerpc compile fixes
      
      V5:
      - split apart warn flags for hard and soft lockups
      
      TODO:
      - figure out how to make an arch-agnostic clock2cycles call
        (if possible) to feed into perf events as a sample period
      
      [fweisbec: merged conflict patch]
      Signed-off-by: NDon Zickus <dzickus@redhat.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      Cc: Eric Paris <eparis@redhat.com>
      Cc: Randy Dunlap <randy.dunlap@oracle.com>
      LKML-Reference: <1273266711-18706-2-git-send-email-dzickus@redhat.com>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      58687acb
  15. 27 4月, 2010 1 次提交
    • V
      blk-cgroup: config options re-arrangement · afc24d49
      Vivek Goyal 提交于
      This patch fixes few usability and configurability issues.
      
      o All the cgroup based controller options are configurable from
        "Genral Setup/Control Group Support/" menu. blkio is the only exception.
        Hence make this option visible in above menu and make it configurable from
        there to bring it inline with rest of the cgroup based controllers.
      
      o Get rid of CONFIG_DEBUG_CFQ_IOSCHED.
      
        This option currently does two things.
      
        - Enable printing of cgroup paths in blktrace
        - Enables CONFIG_DEBUG_BLK_CGROUP, which in turn displays additional stat
          files in cgroup.
      
        If we are using group scheduling, blktrace data is of not really much use
        if cgroup information is not present. To get this data, currently one has to
        also enable CONFIG_DEBUG_CFQ_IOSCHED, which in turn brings the overhead of
        all the additional debug stat files which is not desired.
      
        Hence, this patch moves printing of cgroup paths under
        CONFIG_CFQ_GROUP_IOSCHED.
      
        This allows us to get rid of CONFIG_DEBUG_CFQ_IOSCHED completely. Now all
        the debug stat files are controlled only by CONFIG_DEBUG_BLK_CGROUP which
        can be enabled through config menu.
      Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
      Acked-by: NDivyesh Shah <dpshah@google.com>
      Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
      Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      afc24d49
  16. 03 4月, 2010 1 次提交
  17. 13 3月, 2010 1 次提交
    • K
      cgroup: implement eventfd-based generic API for notifications · 0dea1168
      Kirill A. Shutemov 提交于
      This patchset introduces eventfd-based API for notifications in cgroups
      and implements memory notifications on top of it.
      
      It uses statistics in memory controler to track memory usage.
      
      Output of time(1) on building kernel on tmpfs:
      
      Root cgroup before changes:
      	make -j2  506.37 user 60.93s system 193% cpu 4:52.77 total
      Non-root cgroup before changes:
      	make -j2  507.14 user 62.66s system 193% cpu 4:54.74 total
      Root cgroup after changes (0 thresholds):
      	make -j2  507.13 user 62.20s system 193% cpu 4:53.55 total
      Non-root cgroup after changes (0 thresholds):
      	make -j2  507.70 user 64.20s system 193% cpu 4:55.70 total
      Root cgroup after changes (1 thresholds, never crossed):
      	make -j2  506.97 user 62.20s system 193% cpu 4:53.90 total
      Non-root cgroup after changes (1 thresholds, never crossed):
      	make -j2  507.55 user 64.08s system 193% cpu 4:55.63 total
      
      This patch:
      
      Introduce the write-only file "cgroup.event_control" in every cgroup.
      
      To register new notification handler you need:
      - create an eventfd;
      - open a control file to be monitored. Callbacks register_event() and
        unregister_event() must be defined for the control file;
      - write "<event_fd> <control_fd> <args>" to cgroup.event_control.
        Interpretation of args is defined by control file implementation;
      
      eventfd will be woken up by control file implementation or when the
      cgroup is removed.
      
      To unregister notification handler just close eventfd.
      
      If you need notification functionality for a control file you have to
      implement callbacks register_event() and unregister_event() in the
      struct cftype.
      
      [kamezawa.hiroyu@jp.fujitsu.com: Kconfig fix]
      Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
      Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Paul Menage <menage@google.com>
      Cc: Li Zefan <lizf@cn.fujitsu.com>
      Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
      Cc: Pavel Emelyanov <xemul@openvz.org>
      Cc: Dan Malek <dan@embeddedalley.com>
      Cc: Vladislav Buzov <vbuzov@embeddedalley.com>
      Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
      Cc: Alexander Shishkin <virtuoso@slind.org>
      Cc: Davide Libenzi <davidel@xmailserver.org>
      Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0dea1168
  18. 26 2月, 2010 1 次提交
  19. 25 2月, 2010 1 次提交
    • P
      rcu: Accelerate grace period if last non-dynticked CPU · 8bd93a2c
      Paul E. McKenney 提交于
      Currently, rcu_needs_cpu() simply checks whether the current CPU
      has an outstanding RCU callback, which means that the last CPU
      to go into dyntick-idle mode might wait a few ticks for the
      relevant grace periods to complete.  However, if all the other
      CPUs are in dyntick-idle mode, and if this CPU is in a quiescent
      state (which it is for RCU-bh and RCU-sched any time that we are
      considering going into dyntick-idle mode), then the grace period
      is instantly complete.
      
      This patch therefore repeatedly invokes the RCU grace-period
      machinery in order to force any needed grace periods to complete
      quickly.  It does so a limited number of times in order to
      prevent starvation by an RCU callback function that might pass
      itself to call_rcu().
      
      However, if any CPU other than the current one is not in
      dyntick-idle mode, fall back to simply checking (with fix to bug
      noted by Lai Jiangshan).  Also, take advantage of last
      grace-period forcing, the opportunity to do so noted by Steve
      Rostedt.  And apply simplified #ifdef condition suggested by
      Frederic Weisbecker.
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: laijs@cn.fujitsu.com
      Cc: dipankar@in.ibm.com
      Cc: mathieu.desnoyers@polymtl.ca
      Cc: josh@joshtriplett.org
      Cc: dvhltc@us.ibm.com
      Cc: niv@us.ibm.com
      Cc: peterz@infradead.org
      Cc: rostedt@goodmis.org
      Cc: Valdis.Kletnieks@vt.edu
      Cc: dhowells@redhat.com
      LKML-Reference: <1266887105-1528-15-git-send-email-paulmck@linux.vnet.ibm.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      8bd93a2c
  20. 14 2月, 2010 1 次提交
  21. 02 2月, 2010 1 次提交
    • R
      kconfig CROSS_COMPILE option · 84336466
      Roland McGrath 提交于
      This adds CROSS_COMPILE as a kconfig string so you can store it in
      .config.  Then you can use plain "make" in the configured kernel build
      directory to do the right cross compilation without setting the
      command-line or environment variable every time.
      
      With this, you can set up different build directories for different kernel
      configurations, whether native or cross-builds, and then use the simple:
      
      	make -C /build/dir M=module-source-dir
      
      idiom to build modules for any given target kernel, indicating which one
      by nothing but the build directory chosen.
      
      I tried a version that defaults the string with env="CROSS_COMPILE" so
      that in a "make oldconfig" with CROSS_COMPILE in the environment you can
      just hit return to store the way you're building it.  But the kconfig
      prompt for strings doesn't give you any way to say you want an empty
      string instead of the default, so I punted that.
      Signed-off-by: NRoland McGrath <roland@redhat.com>
      Cc: Sam Ravnborg <sam@ravnborg.org>
      Cc: Anibal Monsalve Salazar <anibal@debian.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Michal Marek <mmarek@suse.cz>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NMichal Marek <mmarek@suse.cz>
      84336466
  22. 21 1月, 2010 1 次提交
  23. 12 1月, 2010 1 次提交
    • A
      lib: add support for LZO-compressed kernels · 7dd65feb
      Albin Tonnerre 提交于
      This patch series adds generic support for creating and extracting
      LZO-compressed kernel images, as well as support for using such images on
      the x86 and ARM architectures, and support for creating and using
      LZO-compressed initrd and initramfs images.
      
      Russell King said:
      
      : Testing on a Cortex A9 model:
      : - lzo decompressor is 65% of the time gzip takes to decompress a kernel
      : - lzo kernel is 9% larger than a gzip kernel
      :
      : which I'm happy to say confirms your figures when comparing the two.
      :
      : However, when comparing your new gzip code to the old gzip code:
      : - new is 99% of the size of the old code
      : - new takes 42% of the time to decompress than the old code
      :
      : What this means is that for a proper comparison, the results get even better:
      : - lzo is 7.5% larger than the old gzip'd kernel image
      : - lzo takes 28% of the time that the old gzip code took
      :
      : So the expense seems definitely worth the effort.  The only reason I
      : can think of ever using gzip would be if you needed the additional
      : compression (eg, because you have limited flash to store the image.)
      :
      : I would argue that the default for ARM should therefore be LZO.
      
      This patch:
      
      The lzo compressor is worse than gzip at compression, but faster at
      extraction.  Here are some figures for an ARM board I'm working on:
      
      Uncompressed size: 3.24Mo
      gzip  1.61Mo 0.72s
      lzo   1.75Mo 0.48s
      
      So for a compression ratio that is still relatively close to gzip, it's
      much faster to extract, at least in that case.
      
      This part contains:
       - Makefile routine to support lzo compression
       - Fixes to the existing lzo compressor so that it can be used in
         compressed kernels
       - wrapper around the existing lzo1x_decompress, as it only extracts one
         block at a time, while we need to extract a whole file here
       - config dialog for kernel compression
      
      [akpm@linux-foundation.org: coding-style fixes]
      [akpm@linux-foundation.org: cleanup]
      Signed-off-by: NAlbin Tonnerre <albin.tonnerre@free-electrons.com>
      Tested-by: NWu Zhangjin <wuzhangjin@gmail.com>
      Acked-by: N"H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Tested-by: NRussell King <rmk@arm.linux.org.uk>
      Acked-by: NRussell King <rmk@arm.linux.org.uk>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7dd65feb
  24. 06 1月, 2010 1 次提交
  25. 28 12月, 2009 1 次提交
    • L
      perf events: Remove CONFIG_EVENT_PROFILE · 07b139c8
      Li Zefan 提交于
      Quoted from Ingo:
      
      | This reminds me - i think we should eliminate CONFIG_EVENT_PROFILE -
      | it's an unnecessary Kconfig complication. If both PERF_EVENTS and
      | EVENT_TRACING is enabled we should expose generic tracepoints.
      |
      | Nor is it limited to event 'profiling', so it has become a misnomer as
      | well.
      Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Paul Mackerras <paulus@samba.org>
      LKML-Reference: <4B2F1557.2050705@cn.fujitsu.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      07b139c8
  26. 16 12月, 2009 1 次提交
  27. 09 12月, 2009 1 次提交
  28. 02 12月, 2009 2 次提交