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  1. 15 5月, 2008 2 次提交
  3. 06 5月, 2008 2 次提交
  5. 30 4月, 2008 2 次提交
    • T
      infrastructure to debug (dynamic) objects · 3ac7fe5a
      由 Thomas Gleixner 提交于 
      We can see an ever repeating problem pattern with objects of any kind in the
kernel:

1) freeing of active objects
2) reinitialization of active objects

Both problems can be hard to debug because the crash happens at a point where
we have no chance to decode the root cause anymore.  One problem spot are
kernel timers, where the detection of the problem often happens in interrupt
context and usually causes the machine to panic.

While working on a timer related bug report I had to hack specialized code
into the timer subsystem to get a reasonable hint for the root cause.  This
debug hack was fine for temporary use, but far from a mergeable solution due
to the intrusiveness into the timer code.

The code further lacked the ability to detect and report the root cause
instantly and keep the system operational.

Keeping the system operational is important to get hold of the debug
information without special debugging aids like serial consoles and special
knowledge of the bug reporter.

The problems described above are not restricted to timers, but timers tend to
expose it usually in a full system crash.  Other objects are less explosive,
but the symptoms caused by such mistakes can be even harder to debug.

Instead of creating specialized debugging code for the timer subsystem a
generic infrastructure is created which allows developers to verify their code
and provides an easy to enable debug facility for users in case of trouble.

The debugobjects core code keeps track of operations on static and dynamic
objects by inserting them into a hashed list and sanity checking them on
object operations and provides additional checks whenever kernel memory is
freed.

The tracked object operations are:
- initializing an object
- adding an object to a subsystem list
- deleting an object from a subsystem list

Each operation is sanity checked before the operation is executed and the
subsystem specific code can provide a fixup function which allows to prevent
the damage of the operation.  When the sanity check triggers a warning message
and a stack trace is printed.

The list of operations can be extended if the need arises.  For now it's
limited to the requirements of the first user (timers).

The core code enqueues the objects into hash buckets.  The hash index is
generated from the address of the object to simplify the lookup for the check
on kfree/vfree.  Each bucket has it's own spinlock to avoid contention on a
global lock.

The debug code can be compiled in without being active.  The runtime overhead
is minimal and could be optimized by asm alternatives.  A kernel command line
option enables the debugging code.

Thanks to Ingo Molnar for review, suggestions and cleanup patches.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Greg KH <greg@kroah.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3ac7fe5a
    • S
      Basic braille screen reader support · f7511d5f
      由 Samuel Thibault 提交于 
      This adds a minimalistic braille screen reader support.  This is meant to
be used by blind people e.g.  on boot failures or when / cannot be mounted
etc and thus the userland screen readers can not work.

[akpm@linux-foundation.org: fix exports]
Signed-off-by: NSamuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Jiri Kosina <jikos@jikos.cz>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: NAlan Cox <alan@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f7511d5f
  7. 29 4月, 2008 2 次提交
  9. 27 4月, 2008 1 次提交
  11. 21 4月, 2008 2 次提交
    • M
      PCI: iommu: iotlb flushing · 5e0d2a6f
      由 mark gross 提交于 
      This patch is for batching up the flushing of the IOTLB for the DMAR
implementation found in the Intel VT-d hardware.  It works by building a list
of to be flushed IOTLB entries and a bitmap list of which DMAR engine they are
from.

After either a high water mark (250 accessible via debugfs) or 10ms the list
of iova's will be reclaimed and the DMAR engines associated are IOTLB-flushed.

This approach recovers 15 to 20% of the performance lost when using the IOMMU
for my netperf udp stream benchmark with small packets.  It can be disabled
with a kernel boot parameter "intel_iommu=strict".

Its use does weaken the IOMMU protections a bit.
Signed-off-by: NMark Gross <mgross@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      5e0d2a6f
    • G
      PCI: remove initial bios sort of PCI devices on x86 · 1ba6ab11
      由 Greg Kroah-Hartman 提交于 
      We currently keep 2 lists of PCI devices in the system, one in the
driver core, and one all on its own.  This second list is sorted at boot
time, in "BIOS" order, to try to remain compatible with older kernels
(2.2 and earlier days).  There was also a "nosort" option to turn this
sorting off, to remain compatible with even older kernel versions, but
that just ends up being what we have been doing from 2.5 days...

Unfortunately, the second list of devices is not really ever used to 
determine the probing order of PCI devices or drivers[1].  That is done
using the driver core list instead.  This change happened back in the
early 2.5 days.

Relying on BIOS ording for the binding of drivers to specific device
names is problematic for many reasons, and userspace tools like udev
exist to properly name devices in a persistant manner if that is needed,
no reliance on the BIOS is needed.

Matt Domsch and others at Dell noticed this back in 2006, and added a
boot option to sort the PCI device lists (both of them) in a
breadth-first manner to help remain compatible with the 2.4 order, if
needed for any reason.  This option is not going away, as some systems
rely on them.

This patch removes the sorting of the internal PCI device list in "BIOS"
mode, as it's not needed at all anymore, and hasn't for many years.
I've also removed the PCI flags for this from some other arches that for
some reason defined them, but never used them.

This should not change the ordering of any drivers or device probing.

[1] The old-style pci_get_device and pci_find_device() still used this
sorting order, but there are very few drivers that use these functions,
as they are deprecated for use in this manner.  If for some reason, a
driver rely on the order and uses these functions, the breadth-first
boot option will resolve any problem.

Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      1ba6ab11
  13. 20 4月, 2008 1 次提交
  15. 19 4月, 2008 1 次提交
    • A
      Security: Introduce security= boot parameter · 076c54c5
      由 Ahmed S. Darwish 提交于 
      Add the security= boot parameter. This is done to avoid LSM
registration clashes in case of more than one bult-in module.

User can choose a security module to enable at boot. If no
security= boot parameter is specified, only the first LSM
asking for registration will be loaded. An invalid security
module name will be treated as if no module has been chosen.

LSM modules must check now if they are allowed to register
by calling security_module_enable(ops) first. Modify SELinux
and SMACK to do so.

Do not let SMACK register smackfs if it was not chosen on
boot. Smackfs assumes that smack hooks are registered and
the initial task security setup (swapper->security) is done.
Signed-off-by: NAhmed S. Darwish <darwish.07@gmail.com>
Acked-by: NJames Morris <jmorris@namei.org>
      076c54c5
  17. 18 4月, 2008 3 次提交
  19. 17 4月, 2008 2 次提交
  21. 12 4月, 2008 1 次提交
  23. 05 4月, 2008 2 次提交
    • P
      cgroups: add cgroup support for enabling controllers at boot time · 8bab8dde
      由 Paul Menage 提交于 
      The effects of cgroup_disable=foo are:

- foo isn't auto-mounted if you mount all cgroups in a single hierarchy
- foo isn't visible as an individually mountable subsystem

As a result there will only ever be one call to foo->create(), at init time;
all processes will stay in this group, and the group will never be mounted on
a visible hierarchy.  Any additional effects (e.g.  not allocating metadata)
are up to the foo subsystem.

This doesn't handle early_init subsystems (their "disabled" bit isn't set be,
but it could easily be extended to do so if any of the early_init systems
wanted it - I think it would just involve some nastier parameter processing
since it would occur before the command-line argument parser had been run.

Hugh said:

  Ballpark figures, I'm trying to get this question out rather than
  processing the exact numbers: CONFIG_CGROUP_MEM_RES_CTLR adds 15% overhead
  to the affected paths, booting with cgroup_disable=memory cuts that back to
  1% overhead (due to slightly bigger struct page).

  I'm no expert on distros, they may have no interest whatever in
  CONFIG_CGROUP_MEM_RES_CTLR=y; and the rest of us can easily build with or
  without it, or apply the cgroup_disable=memory patches.

Unix bench's execl test result on x86_64 was

== just after boot without mounting any cgroup fs.==
mem_cgorup=off : Execl Throughput       43.0     3150.1      732.6
mem_cgroup=on  : Execl Throughput       43.0     2932.6      682.0
==

[lizf@cn.fujitsu.com: fix boot option parsing]
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8bab8dde
    • F
      [IA64] Kernel parameter for max number of concurrent global TLB purges · a6c75b86
      由 Fenghua Yu 提交于 
      The patch defines kernel parameter "nptcg=". The parameter overrides max number
of concurrent global TLB purges which is reported from either PAL_VM_SUMMARY or
SAL PALO.
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>
      a6c75b86
  25. 02 4月, 2008 1 次提交
    • R
      ACPI PM: Restore the 2.6.24 suspend ordering · 7731ce63
      由 Rafael J. Wysocki 提交于 
      Some time ago it turned out that our suspend code ordering broke some
NVidia-based systems that hung if _PTS was executed with one of the PCI
devices, specifically a USB controller, in a low power state.

Then, it was noticed that the suspend code ordering was not compliant
with ACPI 1.0, although it was compliant with ACPI 2.0 (and later), and
it was argued that the code had to be changed for that reason (ref.
http://bugzilla.kernel.org/show_bug.cgi?id=9528).

So we did, but evidently we did wrong, because it's now turning out that
some systems have been broken by this change. Refs:
	http://bugzilla.kernel.org/show_bug.cgi?id=10340
	https://bugzilla.novell.com/show_bug.cgi?id=374217#c16

[ I said at that time that something like this might happend, but the
  majority of people involved thought that it was improbable due to the
  necessity to preserve the compliance of hardware with ACPI 1.0. ]

This actually is a quite serious regression from 2.6.24.

Moreover, the ACPI 1.0 ordering of suspend code introduced another issue
that I have only noticed recently.  Namely, if the suspend of one of
devices fails, the already suspended devices will be resumed without
executing _WAK before, which leads to problems on some systems (for
example, in such situations thermal management is broken on my HP
nx6325).  Consequently, it also breaks suspend debugging on the affected
systems.

Note also, that the requirement to execute _PTS before suspending
devices does not really make sense, because the device in question may
be put into a low power state at run time for a reason unrelated to a
system-wide suspend.

For the reasons outlined above, the change of the suspend ordering
should be reverted, which is done by the patch below.

[ Felix Möller: "I am the reporter from the original Novell Bug:

	https://bugzilla.novell.com/show_bug.cgi?id=374217

  I just tried current git head (two hours ago) with the patch (the one
  from the beginning of this thread) from Rafael and without it.  With
  the patch my MacBook does suspend without it does not." ]
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Tested-by: NFelix Möller <felix@derklecks.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7731ce63
  27. 01 4月, 2008 1 次提交
  29. 25 3月, 2008 1 次提交
  31. 16 3月, 2008 1 次提交
    • L
      ACPI: Remove ACPI_CUSTOM_DSDT_INITRD option · 9a9e0d68
      由 Linus Torvalds 提交于 
      This essentially reverts commit 71fc47a9
("ACPI: basic initramfs DSDT override support"), because the code simply
isn't ready.

It did ugly things to the init sequence to populate the rootfs image
early, but that just ended up showing other problems with the whole
approach.  The fact is, the VFS layer simply isn't initialized this
early, and the relevant ACPI code should either run much later, or this
shouldn't be done at all.

For 2.6.25, we'll just pick the latter option.  We can revisit this
concept later if necessary.

Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Tilman Schmidt <tilman@imap.cc>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Cc: Len Brown <len.brown@intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Markus Gaugusch <dsdt@gaugusch.at>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9a9e0d68
  33. 14 3月, 2008 1 次提交
  35. 13 3月, 2008 1 次提交
  37. 08 3月, 2008 1 次提交
  39. 21 2月, 2008 1 次提交
    • T
      libata: implement libata.force module parameter · 33267325
      由 Tejun Heo 提交于 
      This patch implements libata.force module parameter which can
selectively override ATA port, link and device configurations
including cable type, SATA PHY SPD limit, transfer mode and NCQ.

For example, you can say "use 1.5Gbps for all fan-out ports attached
to the second port but allow 3.0Gbps for the PMP device itself, oh,
the device attached to the third fan-out port chokes on NCQ and
shouldn't go over UDMA4" by the following.

 libata.force=2:1.5g,2.15:3.0g,2.03:noncq,udma4
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>
      33267325
  41. 19 2月, 2008 1 次提交
  43. 09 2月, 2008 1 次提交
  45. 07 2月, 2008 2 次提交
  47. 06 2月, 2008 1 次提交
  49. 03 2月, 2008 3 次提交
  51. 02 2月, 2008 1 次提交
  53. 30 1月, 2008 2 次提交