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  1. 10 10月, 2012 1 次提交
  3. 28 9月, 2012 1 次提交
    • A
      um: kill thread->forking · d2ce4e92
      由 Al Viro 提交于 
      we only use that to tell copy_thread() done by syscall from that
done by kernel_thread().  However, it's easier to do simply by
checking PF_KTHREAD in thread flags.

Merge sys_clone() guts for 32bit and 64bit, while we are at it...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      d2ce4e92
  5. 02 8月, 2012 2 次提交
  7. 24 5月, 2012 1 次提交
  9. 22 5月, 2012 2 次提交
  11. 10 4月, 2012 1 次提交
  13. 25 3月, 2012 1 次提交
  15. 12 12月, 2011 3 次提交
    • F
      nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu() · 1268fbc7
      由 Frederic Weisbecker 提交于 
      Those two APIs were provided to optimize the calls of
tick_nohz_idle_enter() and rcu_idle_enter() into a single
irq disabled section. This way no interrupt happening in-between would
needlessly process any RCU job.

Now we are talking about an optimization for which benefits
have yet to be measured. Let's start simple and completely decouple
idle rcu and dyntick idle logics to simplify.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      1268fbc7
    • F
      nohz: Allow rcu extended quiescent state handling seperately from tick stop · 2bbb6817
      由 Frederic Weisbecker 提交于 
      It is assumed that rcu won't be used once we switch to tickless
mode and until we restart the tick. However this is not always
true, as in x86-64 where we dereference the idle notifiers after
the tick is stopped.

To prepare for fixing this, add two new APIs:
tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu().

If no use of RCU is made in the idle loop between
tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch
must instead call the new *_norcu() version such that the arch doesn't
need to call rcu_idle_enter() and rcu_idle_exit().

Otherwise the arch must call tick_nohz_enter_idle() and
tick_nohz_exit_idle() and also call explicitly:

- rcu_idle_enter() after its last use of RCU before the CPU is put
to sleep.
- rcu_idle_exit() before the first use of RCU after the CPU is woken
up.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      2bbb6817
    • F
      nohz: Separate out irq exit and idle loop dyntick logic · 280f0677
      由 Frederic Weisbecker 提交于 
      The tick_nohz_stop_sched_tick() function, which tries to delay
the next timer tick as long as possible, can be called from two
places:

- From the idle loop to start the dytick idle mode
- From interrupt exit if we have interrupted the dyntick
idle mode, so that we reprogram the next tick event in
case the irq changed some internal state that requires this
action.

There are only few minor differences between both that
are handled by that function, driven by the ts->inidle
cpu variable and the inidle parameter. The whole guarantees
that we only update the dyntick mode on irq exit if we actually
interrupted the dyntick idle mode, and that we enter in RCU extended
quiescent state from idle loop entry only.

Split this function into:

- tick_nohz_idle_enter(), which sets ts->inidle to 1, enters
dynticks idle mode unconditionally if it can, and enters into RCU
extended quiescent state.

- tick_nohz_irq_exit() which only updates the dynticks idle mode
when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called).

To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed
into tick_nohz_idle_exit().

This simplifies the code and micro-optimize the irq exit path (no need
for local_irq_save there). This also prepares for the split between
dynticks and rcu extended quiescent state logics. We'll need this split to
further fix illegal uses of RCU in extended quiescent states in the idle
loop.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      280f0677
  17. 02 11月, 2011 2 次提交
  19. 15 9月, 2011 1 次提交
    • I
      um: Save FPU registers between task switches · fbfe9c84
      由 Ingo van Lil 提交于 
      Some time ago Jeff prepared 42daba31 ("uml: stop saving process FP
state") for UML to stop saving the process FP state between task
switches.  The assumption was that since with SKAS0 every guest process
runs inside a host process context the host OS will take care of keeping
the proper FP state.

Unfortunately this is not true for multi-threaded applications, where
all guest threads share a single host process context yet all may use
the FPU on their own.  Although I haven't verified it I suspect things
to be even worse in SKAS3 mode where all guest processes run inside a
single host process.

The patch reintroduces the saving and restoring of the FP context
between task switches.

[richard@nod.at: Ingo posted this patch in 2009, sadly it was never applied
and got lost. Now in 2011 the problem was reported by Gunnar.]
Signed-off-by: NIngo van Lil <inguin@gmx.de>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reported-by: <gunnarlindroth@hotmail.com>
Tested-by: <gunnarlindroth@hotmail.com>
Cc: Stanislav Meduna <stano@meduna.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fbfe9c84
  21. 30 3月, 2010 1 次提交
    • T
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      由 Tejun Heo 提交于 
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  23. 16 12月, 2009 1 次提交
  25. 03 4月, 2009 1 次提交
  27. 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
  29. 29 4月, 2008 1 次提交
  31. 25 2月, 2008 1 次提交
  33. 09 2月, 2008 1 次提交
    • D
      aout: suppress A.OUT library support if !CONFIG_ARCH_SUPPORTS_AOUT · 7fa30315
      由 David Howells 提交于 
      Suppress A.OUT library support if CONFIG_ARCH_SUPPORTS_AOUT is not set.

Not all architectures support the A.OUT binfmt, so the ELF binfmt should not
be permitted to go looking for A.OUT libraries to load in such a case.  Not
only that, but under such conditions A.OUT core dumps are not produced either.

To make this work, this patch also does the following:

 (1) Makes the existence of the contents of linux/a.out.h contingent on
     CONFIG_ARCH_SUPPORTS_AOUT.

 (2) Renames dump_thread() to aout_dump_thread() as it's only called by A.OUT
     core dumping code.

 (3) Moves aout_dump_thread() into asm/a.out-core.h and makes it inline.  This
     is then included only where needed.  This means that this bit of arch
     code will be stored in the appropriate A.OUT binfmt module rather than
     the core kernel.

 (4) Drops A.OUT support for Blackfin (according to Mike Frysinger it's not
     needed) and FRV.

This patch depends on the previous patch to move STACK_TOP[_MAX] out of
asm/a.out.h and into asm/processor.h as they're required whether or not A.OUT
format is available.

[jdike@addtoit.com: uml: re-remove accidentally restored code]
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7fa30315
  35. 06 2月, 2008 9 次提交
  37. 17 10月, 2007 9 次提交
    • J
      uml: eliminate interrupts in the idle loop · b160fb63
      由 Jeff Dike 提交于 
      Now, the idle loop now longer needs SIGALRM firing - it can just sleep for the
requisite amount of time and fake a timer interrupt when it finishes.

Any use of ITIMER_REAL now goes away.  disable_timer only turns off
ITIMER_VIRTUAL.  switch_timers is no longer needed, so it, and all calls, goes
away.

disable_timer now returns the amount of time remaining on the timer.
default_idle uses this to tell idle_sleep how long to sleep.  idle_sleep will
call alarm_handler if nanosleep returns 0, which is the case if it didn't
return early due to an interrupt.  Otherwise, it just returns.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b160fb63
    • J
      uml: tickless support · d2753a6d
      由 Jeff Dike 提交于 
      Enable tickless support.

CONFIG_TICK_ONESHOT and CONFIG_NO_HZ are enabled.

itimer_clockevent gets CLOCK_EVT_FEAT_ONESHOT and an implementation of
.set_next_event.

CONFIG_UML_REAL_TIME_CLOCK goes away because it only makes sense when there is
a clock ticking away all the time.  timer_handler now just calls do_IRQ once
without trying to figure out how many ticks to emulate.

The idle loop now needs to turn ticking on and off.

Userspace ticks keep happening as usual.  However, the userspace loop keep
track of when the next wakeup should happen and suppresses process ticks until
that happens.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d2753a6d
    • J
      uml: fix timer switching · 181bde80
      由 Jeff Dike 提交于 
      Fix up the switching between virtual and real timers.  The idle loop sleeps,
so the timer at that point must be real time.  At all other times, the timer
must be virtual.  Even when userspace is running, and the kernel is asleep,
the virtual timer is correct because the process timer will be running and the
process timer will be firing.

The timer switch used to be in the context switch and timer handler code.
This is moved to the idle loop and the signal handler, making it much more
clear why it is happening.

switch_timers now returns the old timer type so that it may be restored.  The
signal handler uses this in order to restore the previous timer type when it
returns.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      181bde80
    • J
      uml: rename pt_regs general-purpose register file · 18baddda
      由 Jeff Dike 提交于 
      Before the removal of tt mode, access to a register on the skas-mode side of a
pt_regs struct looked like pt_regs.regs.skas.regs.regs[FOO].  This was bad
enough, but it became pt_regs.regs.regs.regs[FOO] with the removal of the
union from the middle.  To get rid of the run of three "regs", the last field
is renamed to "gp".
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      18baddda
    • J
      uml: style fixes pass 3 · ba180fd4
      由 Jeff Dike 提交于 
      Formatting changes in the files which have been changed in the course
of folding foo_skas functions into their callers.  These include:
	copyright updates
	header file trimming
	style fixes
	adding severity to printks

These changes should be entirely non-functional.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ba180fd4
    • J
      uml: remove code made redundant by CHOOSE_MODE removal · 77bf4400
      由 Jeff Dike 提交于 
      This patch makes a number of simplifications enabled by the removal of
CHOOSE_MODE.  There were lots of functions that looked like

	int foo(args){
		foo_skas(args);
	}

The bodies of foo_skas are now folded into foo, and their declarations (and
sometimes entire header files) are deleted.

In addition, the union uml_pt_regs, which was a union between the tt and skas
register formats, is now a struct, with the tt-mode arm of the union being
removed.

It turns out that usr2_handler was unused, so it is gone.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      77bf4400
    • J
      uml: throw out CHOOSE_MODE · 6aa802ce
      由 Jeff Dike 提交于 
      The next stage after removing code which depends on CONFIG_MODE_TT is removing
the CHOOSE_MODE abstraction, which provided both compile-time and run-time
branching to either tt-mode or skas-mode code.

This patch removes choose-mode.h and all inclusions of it, and replaces all
CHOOSE_MODE invocations with the skas branch.  This leaves a number of trivial
functions which will be dealt with in a later patch.

There are some changes in the uaccess and tls support which go somewhat beyond
this and eliminate some of the now-redundant functions.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6aa802ce
    • J
      uml: throw out CONFIG_MODE_TT · 42fda663
      由 Jeff Dike 提交于 
      This patchset throws out tt mode, which has been non-functional for a while.

This is done in phases, interspersed with code cleanups on the affected files.

The removal is done as follows:
	remove all code, config options, and files which depend on
CONFIG_MODE_TT
	get rid of the CHOOSE_MODE macro, which decided whether to
call tt-mode or skas-mode code, and replace invocations with their
skas portions
	replace all now-trivial procedures with their skas equivalents

There are now a bunch of now-redundant pieces of data structures, including
mode-specific pieces of the thread structure, pt_regs, and mm_context.  These
are all replaced with their skas-specific contents.

As part of the ongoing style compliance project, I made a style pass over all
files that were changed.  There are three such patches, one for each phase,
covering the files affected by that phase but no later ones.

I noticed that we weren't freeing the LDT state associated with a process when
it exited, so that's fixed in one of the later patches.

The last patch is a tidying patch which I've had for a while, but which caused
inexplicable crashes under tt mode.  Since that is no longer a problem, this
can now go in.

This patch:

Start getting rid of tt mode support.

This patch throws out CONFIG_MODE_TT and all config options, code, and files
which depend on it.

CONFIG_MODE_SKAS is gone and everything that depends on it is included
unconditionally.

The few changed lines are in re-written Kconfig help, lines which needed
something skas-related removed from them, and a few more which weren't
strictly deletions.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      42fda663
    • J
      uml: stop specially protecting kernel stacks · 5c8aacea
      由 Jeff Dike 提交于 
      Map all of physical memory as executable to avoid having to change stack
protections during fork and exit.

unprotect_stack is now called only from MODE_TT code, so it is marked as such.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5c8aacea