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  1. 31 7月, 2008 1 次提交
  3. 27 7月, 2008 1 次提交
  5. 25 7月, 2008 3 次提交
  7. 24 7月, 2008 1 次提交
    • J
      UML - Fix boot crash · 7c1fed03
      由 Jeff Dike 提交于 
      My copying of linux/init.h didn't go far enough.  The definition of
__used singled out gcc minor version 3, but didn't care what the major
version was.  This broke when unit-at-a-time was added and gcc started
throwing out initcalls.

This results in an early boot crash when ptrace tries to initialize a
process with an empty, uninitialized register set.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7c1fed03
  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. 08 7月, 2008 1 次提交
    • J
      [UML] fix gcc ICEs and unresolved externs · 4f81c535
      由 Jeff Dike 提交于 
      There are various constraints on the use of unit-at-a-time:
 - i386 uses no-unit-at-a-time for pre-4.0 (not 4.3)
 - x86_64 uses unit-at-a-time always

Uli reported a crash on x86_64 with gcc 4.1.2 with unit-at-a-time,
resulting in commit c0a18111

Ingo reported a gcc internal error with gcc 4.3 with no-unit-at-a-timem,
resulting in 22eecde2

Benny Halevy is seeing extern inlines not resolved with gcc 4.3 with
no-unit-at-a-time

This patch reintroduces unit-at-a-time for gcc >= 4.0, bringing back the
possibility of Uli's crash.  If that happens, we'll debug it.

I started seeing both the internal compiler errors and unresolved
inlines on Fedora 9.  This patch fixes both problems, without so far
reintroducing the crash reported by Uli.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Benny Halevy <bhalevy@panasas.com>
Cc: Adrian Bunk <bunk@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4f81c535
  13. 03 7月, 2008 3 次提交
  15. 26 6月, 2008 1 次提交
  17. 13 6月, 2008 2 次提交
  19. 07 6月, 2008 6 次提交
  21. 22 5月, 2008 5 次提交
  23. 17 5月, 2008 1 次提交
  25. 13 5月, 2008 14 次提交