Page reclaim is currently a bit schitzo: sometimes we say "go and scan this
many pages and tell me how many pages were freed" and at other times we say
"go and scan this many pages, but stop if you freed this many".

It makes the logic harder to control and to understand.  This patch coverts
everything into the "go and scan this many pages and tell me how many pages
were freed" model.

It doesn't seem to affect performance much either way.

We currently have a problem with the balancing of reclaim between zones: much
more reclaim happens against highmem than against lowmem.

This patch partially fixes this by changing the direct reclaim path so it
does not bale out of the zone walk after having reclaimed sufficient pages
from highmem: go on to reclaim from lowmem regardless of how many pages we
reclaimed from lowmem.

The patch which went in six months or so back which said "only reclaim slab
if we're scanning lowmem pagecache" was wrong.  I must have been asleep at
the time.

We do need to scan slab in response to highmem page reclaim as well.  Because
all the math is based around the total amount of memory in the machine, and
we know that if we're performing highmem page reclaim then the lower zones
have no free memory.

From: Nick Piggin <piggin@cyberone.com.au>

The logic which calculates the numberof pages which were scanned is mucked
up.  Fix.

From: Nick Piggin <piggin@cyberone.com.au>

In try_to_free_pages(), put even pressure on the slab even if we have
reclaimed enough pages from the LRU.

From: Nick Piggin <piggin@cyberone.com.au>

In shrink_slab(), do the multiply before the divide to avoid losing
precision.

From: Nick Piggin <piggin@cyberone.com.au>

If refill_inactive_zone() is running in its dont-reclaim-mapped-memory mode
we are tossing away the referenced infomation on active mapped pages.

So put that info back if we're not going to deactivate the page.

The logic in balance_pgdat() is all bollixed up.

- the incoming arg `nr_pages' should be used to determine if we're being
  asked to free a specific number of pages, not `to_free'.

- local variable `to_free' is not appropriate for the determination of
  whether we failed to bring all zones to appropriate free pages levels.

  Fix this by correctly calculating `all_zones_ok' and then use
  all_zones_ok to determine whether we need to throttle kswapd.

So the logic now is:


	for (increasing priority) {

		all_zones_ok = 1;

		for (all zones) {
			to_reclaim = number of pages to try to reclaim
				     from this zone;
			max_scan = number of pages to scan in this pass
				   (gets larger as `priority' decreases)
			/*
			 * set `reclaimed' to the number of pages which were
			 * actually freed up
			 */
			reclaimed = scan(max_scan pages);
			reclaimed += shrink_slab();

			to_free -= reclaimed;	/* for the `nr_pages>0' case */

			/*
			 * If this scan failed to reclaim `to_reclaim' or more
			 * pages, we're getting into trouble.  Need to scan
			 * some more, and throttle kswapd.   Note that this
			 * zone may now have sufficient free pages due to
			 * freeing activity by some other process.   That's
			 * OK - we'll pick that info up on the next pass
			 * through the loop.
			 */
			if (reclaimed < to_reclaim)
				all_zones_ok = 0;
		}
		if (to_free > 0)
			continue;	/* swsusp: need to do more work */
		if (all_zones_ok)
			break;		/* kswapd is done */
		/*
		 * OK, kswapd is getting into trouble.  Take a nap, then take
		 * another pass across the zones.
		 */
		blk_congestion_wait();
	}

From: Nikita Danilov <Nikita@Namesys.COM>

Now that decision to reclaim mapped memory is taken on the basis of
zone->prev_priority, priority argument is no longer needed.

From: Nick Piggin <piggin@cyberone.com.au>

The addition of the smp_mb and the other change is to try to close the
window for races a bit.  Obviously they can still happen, it's a racy
interface and it doesn't matter much.

Teach blk_congestion_wait() to return the number of jiffies remaining.  This
is for debug, but it is also nicely consistent.

To check on zone balancing, split the /proc/vmstat:pgsteal, pgreclaim pgalloc
and pgscan stats into per-zone counters.

Additionally, split the pgscan stats into pgscan_direct and pgscan_kswapd to
see who's doing how much scanning.

And add a metric for the number of slab objects which were scanned.

From: Paul Fulghum <paulkf@microgate.com>

* track driver API changes
* remove cast (kernel janitor)

From: Paul Fulghum <paulkf@microgate.com>

* Track driver API changes
* Remove cast (kernel janitor)

From: Paul Fulghum <paulkf@microgate.com>

Patch for synclinkmp.c

* Track driver API changes
* Remove cast (kernel janitor)
* Replace page_free call with kfree (to match kmalloc allocation)

From: Chris Mason <mason@suse.com>

mempool_alloc() and mempool_free() check pool->curr_nr without any locks
held.  This can lead to skipping a wakeup when there are people waiting,
and sleeping when there are free elements in the pool.

I can't trigger this reliably, but sooner or later someone on ppc is
probably going to hit it.

From: Geert Uytterhoeven <geert@linux-m68k.org>

M68k interrupt management: rename routines to not confuse them with
syscalls

- sys_{request,free}_irq() -> cpu_{request,free}_irq()

- q40_sys_default_handler[] -> q40_default_handler

- sys_default_handler() -> default_handler()

From: Geert Uytterhoeven <geert@linux-m68k.org>

Mac IDE: Make sure the core IDE driver doesn't try to request the MMIO
ports a second time, since this will fail.

From: Geert Uytterhoeven <geert@linux-m68k.org>

Apollo fb: Add sysfs support (from James Simmons)

From: Geert Uytterhoeven <geert@linux-m68k.org>

Amiga Framemaster II fb: Add sysfs support (from James Simmons)

From: Geert Uytterhoeven <geert@linux-m68k.org>

Add missing implementation for non-atomic __test_and_set_bit()

From: James Simmons <jsimmons@infradead.org>,
      Kronos <kronos@kronoz.cjb.net>

Various fixes and enhancements to the monitor hardware detection code.  The
only driver that uses it is the radeon driver.

Old EDID parsing code was very verbose, half of the patch address this (ie.
print lots of stuff iff DEBUG).  The other big change is the FB_MODE_IS_*
stuff: we really need a way to know the origin of a video mode.  In this way
we can select video mode that comes from EDID instead of VESA or GTF.

Drivers other than radeonfb won't be affected because they cannot (yet) get
EDID from the monitor and don't use EDID related code.

From: Michel Marti <michel.marti@objectxp.com>

The blkmtd driver oopses in add_device().  The following trivial patch
fixes this.

From: Arjan van de Ven <arjanv@redhat.com>

Readahead of raid0 was suboptimal; it read only 1 stride ahead.  The
problem with this is that while it will keep all spindles busy, it will not
actually manage to make larger IO's, eg each disk would just do the chunk
size IO.  Doing at least 2 chunks is more than appropriate so that each
spindle will get a chance to merge IO's.

(Neil fixed raid6 and raid6 too)

From: Rusty Russell <rusty@rustcorp.com.au>

Someone added __attribute_used__ throughout module.h, but didn't remove the
", unused".  Looks like some arch/gcc combos still consider it unused, and
discard the fn.

From: Geert Uytterhoeven <geert@linux-m68k.org>

Make CONFIG_NVRAM depend on the prerequisites that are explicitly checked
for in drivers/char/nvram.c, or on CONFIG_GENERIC_NVRAM (for PPC).

From: Geert Uytterhoeven <geert@linux-m68k.org>

Add missing include (needed for struct inode)

From: Marc-Christian Petersen <m.c.p@wolk-project.de>

The attached patch is needed to stop showing us "Macintosh device drivers"
for all architectures via menuconfig || xconfig || gconfig.  It's only
necessary for PPC and/or MAC.

ACKed by benh.

From: Arjan van de Ven <arjanv@redhat.com>

Several of the pte_chain_alloc() allocators that use GFP_ATOMIC have a
fallback for failure that sleeps; they thus need to not warn on failure..
Seen during a big fork on a busy system.

From: "Randy.Dunlap" <rddunlap@osdl.org>

cciss_scsi_detect() can be called after init (for TAPE support).

From: Matt Domsch <Matt_Domsch@dell.com>

Patch below from Patrick J. LoPresti and myself.  Patrick describes:

Why this patch?  The problem is that the legacy BIOS interface
(INT13/AH=3D08) for querying the disk geometry returns different values
than the extended INT13 interface which the EDD code currently uses.  This
is because the legacy interface only provides a 10-bit cylinder field, so
modern BIOSes "lie" about the head/sector counts in order to make more of
the disk visible within the first 1024 cylinders.

Many non-Linux applications, including the stock Windows boot loader, DOS
fdisk, etc., rely upon the legacy interface and geometry.  So it is useful
to be able to obtain the legacy values from a running Linux kernel.

What this patch does is to add new entries under
/sys/firmware/edd/int13_devXX named "legacy_cylinders", "legacy_heads", and
"legacy_sectors".  These provide the geometry given by the legacy
INT13/AH=3D08 BIOS interface, just like the current "default_cylinders"
etc.  provide the the geometry given by the INT13/AH=3D48 interface.

Without this patch, I cannot use Linux to partition a drive and install
Windows, which happens to be my application.

 - Pat
   http://unattended.sourceforge.net/

In addition, this adds two buggy BIOS workarounds  in the EDD int13
calls as suggested by Ralf Brown's interrupt list.

I'm also interested in moving this code out of arch/i386/kernel/edd.c and
include/asm-i386/edd.h, as I believe it is applicable on x86-64 as well.
However, there's no good place under drivers/ to put edd.c when it's not
tied to a bus, but to several CPU architectures and their firmwares...
Maybe a new directory drivers/firmware?

sound/oss/wavfront.c: In function `wavefront_download_firmware':
sound/oss/wavfront.c:2524: warning: implicit declaration of function `sys_open'
sound/oss/wavfront.c:2533: warning: implicit declaration of function `sys_read'
sound/oss/wavfront.c:2582: warning: implicit declaration of function `sys_close

From: Chris Mason <mason@suse.com>

This patch fixes a problem we're hitting on ia64 with page sizes > 4k.

When the page size is greater than the block size, and parts of the page
fall past the end of the device, readpage will fail because
blkdev_get_block returns -EIO for blocks past i_size.

The attached patch changes blkdev_get_block to return holes when reading
past the end of the device, which allows us to read that last valid 4k
block and then fill the rest of the page with zeros.  Writes will still
fail with -EIO.

From: vda <vda@port.imtp.ilyichevsk.odessa.ua>

Add a missing test for the "root=/dev/ram" kernel boot option.  It's just an
alias for /dev/ram0, but it worked in 2.4...

From: Srivatsa Vaddagiri <vatsa@in.ibm.com>

current_is_keventd() doesn't need to search across all the CPUs to identify
itself.

From: Andi Kleen <ak@muc.de>

I was debugging some code that corrupted the vma rb lists and for that I
fixed validate_mm to not be recursive and do some more checks.

It's slower now, but that shouldn't be a problem.

Also make it non static to allow easier checks elsewhere.

From: WU Fengguang <wfg@mail.ustc.edu.cn>

- In sys_fadvise64_64(): if the start and/or end offsets do not fall on
  page boundaries, preserve the partial pages.  The thinking here is that it
  is better to preserve needed memory than to not shoot down unneeded memory.

- In invalidate_mapping_pages(): we were invalidating an entire pagevec's
  worth of pages each time around, even if that went beyond the part of the
  file which the caller asked to be invalidated.  Fix that up.

From: Adrian Bunk <bunk@fs.tum.de>

- remove an MELAN entry that was forgotten in the i386 processor
  selection menu

- s/CONFIG_MELAN/CONFIG_X86_ELAN/ was missing in module.h

From: Wim Van Sebroeck <wim@iguana.be>

Convert last set of watchdog drivers to new moduleparam system.

From: Andreas Gruenbacher <agruen@suse.de>

Remove the arbitrary limit of 32 ACL entries on ext[23] when reading from
disk.  This change is backward compatible; we need to have this change in
to be able to also allow writing big ACLs.

The second patch that removes the ACL entry limit for writes is not
included.  I don't want to push that patch now, because large ACLs would
cause 2.4 and current 2.6 kernels to fail.  My plan is to remove the second
limit later, in a half-year or year or so.