From: Martin Schwidefsky <schwidefsky@de.ibm.com>

Common i/o layer changes:
 - Delay unregister/register of ccw devices reappering on a different
   subchannel. Search for the old ccw_device & subchannel for the
   reattached device and deregister it too to avoid inconsistencies.
 - Fix path grouping for devices that present command reject for
   SetPGID but not for SensePGID.

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390 core changes:
 - Rename idle_cpu_mask to nohz_cpu_mask as agreed with Dipankar.
 - Refine compiler version check for "Q" constraints in uaccess.h.
 - Store per process ptrace information to the correct place.
 - Fix per cpu data access for 64-bit modules.
 - Add topology_init function for cpu hotplug.
 - Define TASK_SIZE dependent on TIF_31BIT and define MM_VM_SIZE
   to 4TB to get rid of elf_map32 and arch_get_unmapped_area.

From: Geoff Gustafson <geoff@linux.jf.intel.com>,
      "Chen, Kenneth W" <kenneth.w.chen@intel.com>,
      Ingo Molnar <mingo@elte.hu>,
      me.

The big-SMP guys are seeing high CPU load due to del_timer_sync()'s
inefficiencies.  The callers are fs/aio.c and schedule_timeout().

We note that neither of these callers' timer handlers actually re-add the
timer - they are single-shot.

So we don't need all that complexity in del_timer_sync() - we can just run
del_timer() and if that worked we know the timer is dead.

Add del_single_shot_timer(), export it to modules and use it in AIO and
schedule_timeout().


(these numbers are for an earlier patch, but they'll be close)

Before:             32p     4p
     Warm cache   29,000    505
     Cold cache   37,800   1220

After:              32p     4p
     Warm cache       95     88
     Cold cache    1,800    140

[Measurements are CPU cycles spent in a call to del_timer_sync, the average
of 1000 calls. 32p is 16-node NUMA, 4p is SMP.]

(I cleaned up a few things and added some commentary)

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- gcc-3.4 warning fix.
- io access address fix.
- cleanup code.

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- Delete obsolete header files

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- Separate taget depends config.

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- ne2k compatible NIC support

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- fix h8300 depend setup sequence

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- add preempt support
- add new syscalls
- code cleanup

From: Yoshinori Sato <ysato@users.sourceforge.jp>

Sorry. There was the file which lacked.

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- add PIC binary support

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- symbol prefix (use h8300 and v850) support
- include headers

From: Yoshinori Sato <ysato@users.sourceforge.jp>

- add find_next_bit

Lookup typically touches three fields of the dentry: d_bucket, d_name.hash and
d_parent.

Change the layout of things so that these will always be in the same
cacheline.

- d_vfs_flags can be removed - just use d_flags.  All modifications of
  dentry->d_flags are under dentry->d_lock.

On x86 this takes the internal string size up to 40 bytes.  The
internal/external ratio on my 1.5M files hits 96%.

The gap between checking d_bucket and sampling d_move_count looks like a bug
to me.

It feels safer to be checking d_bucket after taking the lock, when we know
that it is stable.

And it's a little faster to check d_bucket after having checked the hash
rather than before.

When dentries are given an external name we currently allocate an entire qstr
for the external name.

This isn't needed.  We can use the internal qstr and kmalloc only the string
itself.  This saves 12 bytes from externally-allocated names and 4 bytes from
the dentry itself.

The saving of 4 bytes from the dentry doesn't actually decrease the dentry's
storage requirements, but it makes four more bytes available for internal
names, taking the internal/external ratio from 89% up to 93% on my 1.5M files.


Fix:

The qstr consolidation wasn't quite right, because it can cause qstr->len to
be unstable during lookup lockless traverasl.

Fix that up by taking d_lock earlier in lookup.  This serialises against
d_move.

Take the lock after comparing the parent and hash to preserve the
mostly-lockless behaviour.

This obsoletes d_movecount, which is removed.

Rework dentries so that the inline name length is between 31 and 48 bytes.

On SMP P4-compiled x86 each dentry consumes 160 bytes (24 per page).

Here's the histogram of name lengths on all 1.5M files on my workstation:

1:  0%
2:  0%
3:  1%
4:  5%
5:  8%
6:  13%
7:  19%
8:  26%
9:  33%
10:  42%
11:  49%
12:  55%
13:  60%
14:  64%
15:  67%
16:  69%
17:  71%
18:  73%
19:  75%
20:  76%
21:  78%
22:  79%
23:  80%
24:  81%
25:  82%
26:  83%
27:  85%
28:  86%
29:  87%
30:  88%
31:  89%
32:  90%
33:  91%
34:  92%
35:  93%
36:  94%
37:  95%
38:  96%
39:  96%
40:  96%
41:  96%
42:  96%
43:  96%
44:  97%
45:  97%
46:  97%
47:  97%
48:  97%
49:  98%
50:  98%
51:  98%
52:  98%
53:  98%
54:  98%
55:  98%
56:  98%
57:  98%
58:  98%
59:  98%
60:  99%
61:  99%
62:  99%
63:  99%
64:  99%

So on x86 we'll fit 89% of filenames into the inline name.


The patch also removes the NAME_ALLOC_LEN() rounding-up of the storage for the
out-of-line names.  That seems unnecessary.

Be consistent about d_vfs_flags locking: take dentry->d_lock when modifying
it.

A few filesystems modify dentry.d_flags under non-obvious locking.  To
consolidate that field wth d_vfs_flags they need to take ->d_lock

From: Markus Lidel <Markus.Lidel@shadowconnect.com>

* The Kconfig and Makefile in drivers/message/i2o still got a CONFIG_I2O_PCI
  entry, which is not used anymore.  This one is replaced by a
  CONFIG_I2O_CONFIG entry, which now builds the i2o_config module.

From: Markus Lidel <Markus.Lidel@shadowconnect.com>

* provides i2o_context_list_*() functions, which maps 64-bit pointers to
  32-bit context id's in a dynamic list.  On 32-bit systems the functions are
  replaced with a static inline.

* i2o_scsi now uses the i2o_context_list_*() functions for transaction
  context, and therefore now work on 64-bit systems too.

From: Markus Lidel <Markus.Lidel@shadowconnect.com>

* more than 3 "visible" disks (hda, hdb, hdc, hdd) lead to kernel panics.

* removes some unused code with partitions.

* I2O_LOCK was often called with the addresses of the controller, and not
  with the address of the device.  Fixed.

* the cleanup function for gendisk (del_gendisk) doesn't work if the queue
  is shared between different devices.  To workaround the queue is removed
  before.

* redundant code removed in module initialization and remove, use
  i2ob_new_device and i2ob_del_device instead.

* removed atomic_t queue_depth

* removed unnecessary and bogus code for queue handling

From: Markus Lidel <Markus.Lidel@shadowconnect.com>

Fix 64-bit problems.

From: Markus Lidel <Markus.Lidel@shadowconnect.com>

* Add a pass-thru ioctl to i2o_config, which is needed to work with the
  Adaptec management software.

From: Markus Lidel <Markus.Lidel@shadowconnect.com>

* Changes the formating of the header in i2o_config.c

From: Herbert Xu <herbert@gondor.apana.org.au>

The following patch adds basic module reference counting to vt console
drivers.  Currently modules like fbcon are not counted at all.

From: Ashok Raj <ashok.raj@intel.com>

Supports basic ability to enable hotplug functions for IA64.
Code is just evolving, and there are several loose ends to tie up.

What this code drop does
- Support logical online and offline
- Handles interrupt migration without loss of interrupts.
- Handles stress fine > 24+ hrs with make -j/ftp/rcp workloads
- Handles irq migration from a dying cpu without loss of interrupts.

What needs to be done
- Boot CPU removal support, with platform level authentication
- Putting cpu being removed in BOOT_RENDEZ mode.

From: Paul Jackson <pj@sgi.com>

With a hotplug capable kernel, there is a requirement to distinguish a
possible CPU from one actually present.  The set of possible CPU numbers
doesn't change during a single system boot, but the set of present CPUs
changes as CPUs are physically inserted into or removed from a system.  The
cpu_possible_map does not change once initialized at boot, but the
cpu_present_map changes dynamically as CPUs are inserted or removed.


Paul Jackson <pj@sgi.com> provided an expanded explanation:


Ashok's cpu hot plug patch adds a cpu_present_map, resulting in the following
cpu maps being available.  All the following maps are fixed size bitmaps of
size NR_CPUS.

#ifdef CONFIG_HOTPLUG_CPU
	cpu_possible_map - map with all NR_CPUS bits set
	cpu_present_map - map with bit 'cpu' set iff cpu is populated
	cpu_online_map - map with bit 'cpu' set iff cpu available to scheduler
#else
	cpu_possible_map - map with bit 'cpu' set iff cpu is populated
	cpu_present_map - copy of cpu_possible_map
	cpu_online_map - map with bit 'cpu' set iff cpu available to scheduler
#endif

In either case, NR_CPUS is fixed at compile time, as the static size of these
bitmaps.  The cpu_possible_map is fixed at boot time, as the set of CPU id's
that it is possible might ever be plugged in at anytime during the life of
that system boot.  The cpu_present_map is dynamic(*), representing which CPUs
are currently plugged in.  And cpu_online_map is the dynamic subset of
cpu_present_map, indicating those CPUs available for scheduling.

If HOTPLUG is enabled, then cpu_possible_map is forced to have all NR_CPUS
bits set, otherwise it is just the set of CPUs that ACPI reports present at
boot.

If HOTPLUG is enabled, then cpu_present_map varies dynamically, depending on
what ACPI reports as currently plugged in, otherwise cpu_present_map is just a
copy of cpu_possible_map.

(*) Well, cpu_present_map is dynamic in the hotplug case.  If not hotplug,
    it's the same as cpu_possible_map, hence fixed at boot.

From: Ashok Raj <ashok.raj@intel.com>

Changes proc entries for cpu hotplug to be created via the cpu hotplug
notifier callbacks.  Also fixed a bug in the removal code that did not remove
proc entries as expected.

From: Ashok Raj <ashok.raj@intel.com>

irq affinity setting via /proc was forcing iosapic rte programming by force.
The correct way to do this is to perform this when a interrupt is pending.

From: Ashok Raj <ashok.raj@intel.com>

Creation of sysfs via topology_init() creates sysfs entries.  The creation of
the online control file is created separately when the cpu_up is invoked in
arch independent code.

From: Ashok Raj <ashok.raj@intel.com>

Contains changes from __init to __devinit to support cpu hotplug Changes only
arch/ia64 portions of the kernel tree.

From: Ashok Raj <ashok.raj@intel.com>

This patch changes __init to __devinit to init_idle so that when a new cpu
arrives, it can call these functions at a later time.

From: Andrea Arcangeli <andrea@suse.de>

I don't think we need an install_swap_bdev/remove_swap_bdev anymore, we should
use the swap_info->bdev, not the swap_bdevs.  the swap_info already has a
->bdev field, the only point of remove_swap_bdev/install_swap_bdev was to
unplug all devices as efficiently as possible, we don't need that anymore with
the page parameter.

Plus the semaphore should be a rwsem to allow parallel unplug from multiple
pages.

After that I don't need to take the semaphore anymore during swapon, no
swapcache with swp_type() pointing to such bdev, will be allowed until swapon
is complete (SWP_ACTIVE is set a lot later after setting p->bdev).

In swapoff I only need a dummy serialization with the readers, after
try_to_unuse is complete:

 	err = try_to_unuse(type);
 	current->flags &= ~PF_SWAPOFF;

 	/* wait for any unplug function to finish */
 	down_write(&swap_unplug_sem);
 	up_write(&swap_unplug_sem);


that's all, no other locking and no install_swap_bdev/remove_swap_bdev.

(and the swap_bdevs[] compression code was busted)

We don't trust bh->b_page to point to the right thing across all filesystems,
so revert this bit.

From: Andrea Arcangeli <andrea@suse.de>

From: Jens Axboe

Add blk_run_page() API.  This is so that we can pass the target page all the
way down to (for example) the swap unplug function.  So swap can work out
which blockdevs back this particular page.

Revert the pre-2.6.6 per-address-space unplugging changes.  This removes a
swapper_space exceptionality, syncs things with Andrea and provides for
simplification of the swap unplug function.

Sync this up with Andrea's patches.