Skip to content

R
raspberrypi-kernel

openeuler / raspberrypi-kernel

通知 13
Star 1
Fork 0
R
raspberrypi-kernel
切换分支/标签
  1. 26 7月, 2008 2 次提交
    • K
      powerpc: clean up the Book-E HW watchpoint support · 0b21bb49
      由 Kumar Gala 提交于 
      * CONFIG_BOOKE is selected by CONFIG_44x so we dont need both
* Fixed a few comments
* Go back to only using DBCR0_IDM to determine if we are using
  debug resources.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
      0b21bb49
    • S
      kprobes: improve kretprobe scalability with hashed locking · ef53d9c5
      由 Srinivasa D S 提交于 
      Currently list of kretprobe instances are stored in kretprobe object (as
used_instances,free_instances) and in kretprobe hash table.  We have one
global kretprobe lock to serialise the access to these lists.  This causes
only one kretprobe handler to execute at a time.  Hence affects system
performance, particularly on SMP systems and when return probe is set on
lot of functions (like on all systemcalls).

Solution proposed here gives fine-grain locks that performs better on SMP
system compared to present kretprobe implementation.

Solution:

 1) Instead of having one global lock to protect kretprobe instances
    present in kretprobe object and kretprobe hash table.  We will have
    two locks, one lock for protecting kretprobe hash table and another
    lock for kretporbe object.

 2) We hold lock present in kretprobe object while we modify kretprobe
    instance in kretprobe object and we hold per-hash-list lock while
    modifying kretprobe instances present in that hash list.  To prevent
    deadlock, we never grab a per-hash-list lock while holding a kretprobe
    lock.

 3) We can remove used_instances from struct kretprobe, as we can
    track used instances of kretprobe instances using kretprobe hash
    table.

Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system
with return probes set on all systemcalls looks like this.

cacheline              non-cacheline             Un-patched kernel
aligned patch 	       aligned patch
===============================================================================
real    9m46.784s       9m54.412s                  10m2.450s
user    40m5.715s       40m7.142s                  40m4.273s
sys     2m57.754s       2m58.583s                  3m17.430s
===========================================================

Time duration for kernel compilation ("make -j 8) on the same system, when
kernel is not probed.
=========================
real    9m26.389s
user    40m8.775s
sys     2m7.283s
=========================
Signed-off-by: NSrinivasa DS <srinivasa@in.ibm.com>
Signed-off-by: NJim Keniston <jkenisto@us.ibm.com>
Acked-by: NAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ef53d9c5
  3. 25 7月, 2008 15 次提交
  5. 24 7月, 2008 1 次提交
    • J
      kgdb, powerpc: arch specific powerpc kgdb support · 17ce452f
      由 Jason Wessel 提交于 
      This patch removes the old kgdb reminants from ARCH=powerpc and
implements the new style arch specific stub for the common kgdb core
interface.

It is possible to have xmon and kgdb in the same kernel, but you
cannot use both at the same time because there is only one set of
debug hooks.

The arch specific kgdb implementation saves the previous state of the
debug hooks and restores them if you unconfigure the kgdb I/O driver.
Kgdb should have no impact on a kernel that has no kgdb I/O driver
configured.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
      17ce452f
  7. 22 7月, 2008 6 次提交
  9. 19 7月, 2008 1 次提交
    • T
      nohz: prevent tick stop outside of the idle loop · b8f8c3cf
      由 Thomas Gleixner 提交于 
      Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:

	scheduler switch to idle task
	enable interrupts

Window starts here

	----> interrupt happens (does not set NEED_RESCHED)
	      	irq_exit() stops the tick

	----> interrupt happens (does set NEED_RESCHED)

	return from schedule()
	
	cpu_idle(): preempt_disable();

Window ends here

The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.

The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.

Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.

cpu_idle()
{
	preempt_disable();

	while(1) {
		 tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we
		 			          are in the idle loop

		 while (!need_resched())
		       halt();

		 tick_nohz_restart_sched_tick(); <- disables NOHZ mode
		 preempt_enable_no_resched();
		 schedule();
		 preempt_disable();
	}
}

In hindsight we should have done this forever, but ... 

/me grabs a large brown paperbag.

Debugged-by: Jack Ren <jack.ren@marvell.com>, 
Debugged-by: Neric miao <eric.y.miao@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      b8f8c3cf
  11. 17 7月, 2008 2 次提交
  13. 15 7月, 2008 5 次提交
  15. 14 7月, 2008 2 次提交
    • S
      generic-ipi: powerpc/generic-ipi tree build failure · 7798ed0f
      由 Stephen Rothwell 提交于 
      Today's linux-next build (powerpc allmodconfig) failed like this:

ERROR: ".save_stack_trace" [tests/backtracetest.ko] undefined!

But save_stack_trace is exported in arch/powerpc/kernel/stacktrace.c

I couldn't figure it out until I noticed these earlier warnings:

arch/powerpc/kernel/stacktrace.c:47: warning: data definition has no type or storage class
arch/powerpc/kernel/stacktrace.c:47: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/powerpc/kernel/stacktrace.c:47: warning: parameter names (without types) in function declaration

I applied the patch below.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <linuxppc-dev@ozlabs.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      7798ed0f
    • K
      powerpc/booke: don't reinitialize time base · ddb107e9
      由 Kumar Gala 提交于 
      For some reason long ago I decided that we should zero out the time base
when we calibrate the decrementer.  The problem is that this can be
harmful in SMP systems where the firmware has already synchronized the
time bases on the various cores.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
      ddb107e9
  17. 10 7月, 2008 1 次提交
  19. 09 7月, 2008 5 次提交