The penguin logo resides in normal RAM, not in frame buffer memory, so we must
not use fb_readb()

M68k DMA address type update: Add definition for dma64_addr_t on m68k

HP300 DIO bus updates

 - Atari joystick device number updates
 - Atari ACSI hard disk driver device updates
 - Atari floppy driver device updates
 - MVME147 serial driver dev_t update

Linux/m68k configuration updates
  - Unify serial console questions
  - Move serial driver config questions together
  - The Atari mouse driver depends on the Atari keyboard driver, hence on
    CONFIG_VT
  - Don't hardcode CONFIG_VT=n on VME, you may want it for a multi-machine
    kernel
  - The IRQ_* definitions are not used on Amiga, but we need them if we
    build a multi-machine kernel, too

Fix miscellaneous compilation warnings and errors

Enable Q40 keyboard and serial, and Apollo keyboard

M68k cache handling updates
  - Add missing definition of L1_CACHE_SHIFT
  - Define L1_CACHE_BYTES in terms of L1_CACHE_SHIFT
  - Add missing include
  - Fix address types and casts

M68k bitops updates
  - use bitmap_member() for bitops data declaration
  - Make the m68k bitops really operate on unsigned long
  - Add fls()

Atari frame buffer device updates
  - Move static function definition before usage
  - Fix breakage caused by recent fbdev changes
  - Make some setup parameter parsing separate routines (strsep() must be able
    to modify the passed pointers)
  - On Atari the ATI Mach64 registers are memory mapped, but it's not on
    the PCI bus, so we cannot use writel() and friends.
  - Kill warnings by protecting unused data with the appropriate #ifdef
  - On Atari the ATI Mach64 registers are memory mapped, but it's not on the
    PCI bus, so we cannot use writel() and friends.
  - Fix assignment of addresses for Atari

Fix breakage introduced by seq_printf() changes

Fix Apollo frame buffer device breakage after the recent fbdev changes

Port Apollo mouse driver to the `new' busmouse API

 Amiga native graphics updates
  - Fix typo
  - Make monitor capability parsing a separate routine (strsep() must be able
    to modify the passed pointer)

 The Cirrus Logic frame buffer device needs access to the memory mapped VGA I/O space on Amiga

 Add video mode initialization code to the CyberVision64/3D driver

 Add S3 ViRGE register definitions for the CyberVision64/3D driver

Mac/m68k ADB updates (from 2.4.x)
 - Add support for m68k Macs
 - Add missing call to VIA CUDA initialization routine
 - Update Mac II VIA support
 - Make local functions static and add their prototypes
 - Add missing defines for Mac/m68k PMUs

Update MVME i82596 Ethernet driver (from 2.4.x)
  - Add support for BVME6000
  - Add KERN_* prefixes to printk() calls
  - Wait for config change requests

it unconditional for now.

into home.transmeta.com:/home/torvalds/v2.5/linux

This can be overridden by editing the .config file if you really want it.

into home.transmeta.com:/home/torvalds/v2.5/linux

This includes the security_* functions, and the default and capability
modules.

This is needed due to the next header file changes.

This patch changes cont_prepare_write(), in order to support a 4G-1
file for FAT32.

 int cont_prepare_write(struct page *page, unsigned offset,
-		unsigned to, get_block_t *get_block, unsigned long *bytes)
+		unsigned to, get_block_t *get_block, loff_t *bytes)

And it fixes broken adfs/affs/fat/hfs/hpfs/qnx4 by this
cont_prepare_write() change.

into home.transmeta.com:/home/torvalds/v2.5/linux

Been looking at a workload which involves several processes which seek
around and read from a large file.  There are a few problems:
generic_file_lseek is bouncing i_sem around like mad, and readahead is
doing lots of pointless pagecache probing.

This patch addresses readahead.

Presumably the change will be larger on machines which have higher
bandwidth memory than my test box, of which there are many.

This patch teaches readahead to detect the situation where no IO is
actually being performed as a result of its actions.  Now, we don't
want to sacrifice IO efficiency to save a bit of CPU, so the code is
very cautious.  But eventually, after some tens of consecutive
readahead attempts were found to perform no I/O at all, readahead will
turn itself off.

readahead will be turned on again when either generic_file_read() or
filemap_nopage() get a pagecache miss.  The function
handle_ra_thrashing() has been renamed to handle_ra_miss() to reflect
its widened role.

A performance bug in page_cache_readround() was fixed - if
ra->next_size is zero, that function needs to leave it well alone,
because next_size==0 is a magic value meaning that the file has just
been opened and that readahead needs to get aggressive.  This change
makes a `make dep' run at the same speed as in the 2.4 kernel.  It used
to take 4x as long...

`make dep' is an interesting test because it uses mmap to read the files.

The kernel has a number of problems wrt heavy write traffic to multiple
spindles.  What keeps on happening is that all processes which are
responsible for writeback get blocked on one of the queues and all the
others fall idle.

This happens in the balance_dirty_pages() path (balance_dirty() in 2.4)
and in the page reclaim code, when a dirty page is found on the LRU.

The latter is particularly bad because it causes "innocent" processes
to be suspended for long periods due to the activity of heavy writers.

The general idea is: the primary resource for writeback should be the
process which is dirtying memory.  The secondary resource is the
pdflush pool (although this is mainly for providing async writeback in
the presence of light-moderate loads).  Add the final
oh-gee-we-screwed-up resource for writeback is a caller to
shrink_cache().

This patch addresses the balance_dirty_pages() path.  This code was
initially modelled on the 2.4 writeback scheme: throttled processes
writeback all data regardless of its queue.  Instead, the patch changes
it so that the balance_dirty_pages() caller only writes back pages
which are dirty against the queue which that caller just dirtied.

So the effect is a better allocation of writeback resources across the
queues and increased parallelism.

The per-queue writeback is implemented by using
mapping->backing_dev_info as a search key during the walk across the
superblocks and inodes.

The patch also fixes an initialisation problem in
block_dev.c:do_open(): it was setting up the blockdev's
mapping->backing_dev_info too early, before the queue has been
identified.

Generally, this patch doesn't help much, because of the stalls in the
page allocator.  I have a patch which mostly fixes that up, and taken
together the kernel is achieving almost platter speed against six
spindles, but only when the system has a small amount of memory.  More
work is needed there.

A tasty patch from Hugh Dickens.  radix_tree_insert() fails if something
was already present at the target index, so that error can be
propagated back through add_to_page_cache().  Hence
add_to_page_cache_unique() is obsolete.

Hugh's patch removes add_to_page_cache_unique() and cleans up a bunch of
stuff.

Some cleanup from the surprise direct-to-bio for O_DIRECT merge.

- Remove bits and pieces from the kiobuf implementation

- Replace the waitqueue in struct dio with just a task_struct pointer
  and use wake_up_process.  (Ben).

- Only take mmap_sem around the individual calls to get_user_pages().
   (It pins the vmas, yes?)

- Remove some debug code.

- Fix JFS.

Cleanup patch from Martin Bligh: convert some loops which want to be
`for' loops into that, and add some commentary.

generic_writepages() is just a wrapper around mpage_writepages(), so
inline it.

Put the CHECK_EMERGENCY_SYNC back into the kupdate function.  I seem to
keep removing it.

Updated forward-port of Aodrea's O_DIRECT open() checks.  If the user
asked for O_DIRECT and the inode has no mapping or no a_ops then fail
the open up-front.

A patch from Rik which adds some operational statitics to the VM.

In /proc/meminfo:

PageTables:	Amount of memory used for process pagetables
PteChainTot:	Amount of memory allocated for pte_chain objects
PteChainUsed:	Amount of memory currently in use for pte chains.

In /proc/stat:

pageallocs:	Number of pages allocated in the page allocator
pagefrees:	Number of pages returned to the page allocator

		(These can be used to measure the allocation rate)

pageactiv:	Number of pages activated (moved to the active list)
pagedeact:	Number of pages deactivated (moved to the inactive list)
pagefault:	Total pagefaults
majorfault:	Major pagefaults
pagescan:	Number of pages which shrink_cache looked at
pagesteal:	Number of pages which shrink_cache freed
pageoutrun:	Number of calls to try_to_free_pages()
allocstall:	Number of calls to balance_classzone()


Rik will be writing a userspace app which interprets these things.

The /proc/meminfo stats are efficient, but the /proc/stat accumulators
will cause undesirable cacheline bouncing.  We need to break the disk
statistics out of struct kernel_stat and make everything else in there
per-cpu.  If that doesn't happen in time for 2.6 then we disable
KERNEL_STAT_INC().

Patch from David McCracken.  It is an optimisation to the rmap
pte_chains.

In the common case where a page is mapped by only a single pte, we
don't need to allocate a pte_chain structure.  Just make the page's
pte_chain pointer point straight at that pte and flag this with
PG_direct.

Fix to the page reclaim code from Rik.

Anonymous pages which have buffers arise when
truncate_complete_page()'s call to ->releasepage() failed.  Those pages
may still be mapped into process address spaces.

We should not remove them from the LRU, because that makes them
unswappable and they hang around until process exit.

This is the "minimal rmap" patch, writen by Rik, ported to 2.5 by Craig
Kulsea.

Basically,

before: When the page reclaim code decides that is has scanned too many
unreclaimable pages on the LRU it does a scan of process virtual
address spaces for pages to add to swapcache.  ptes pointing at the
page are unmapped as the scan proceeds.  When all ptes referring to a
page have been unmapped and it has been written to swap the page is
reclaimable.

after: When an anonymous page is encountered on the tail of the LRU we
use the rmap to see if it hasn't been referenced lately.  If so then
add it to swapcache.  When the page is again encountered on the LRU, if
it is still unreferenced then try to unmap all ptes which refer to it
in one hit, and if it is clean (ie: on swap) then free it.

The rest of the VM - list management, the classzone concept, etc
remains unchanged.

There are a number of things which the per-page pte chain could be
used for.  Bill Irwin has identified the following.


(1)  page replacement no longer goes around randomly unmapping things

(2)  referenced bits are more accurate because there aren't several ms
        or even seconds between find the multiple pte's mapping a page

(3)  reduces page replacement from O(total virtually mapped) to O(physical)

(4)  enables defragmentation of physical memory

(5)  enables cooperative offlining of memory for friendly guest instance
        behavior in UML and/or LPAR settings

(6)  demonstrable benefit in performance of swapping which is common in
        end-user interactive workstation workloads (I don't like the word
        "desktop"). c.f. Craig Kulesa's post wrt. swapping performance

(7)  evidence from 2.4-based rmap trees indicates approximate parity
        with mainline in kernel compiles with appropriate locking bits

(8)  partitioning of physical memory can reduce the complexity of page
        replacement searches by scanning only the "interesting" zones
        implemented and merged in 2.4-based rmap

(9)  partitioning of physical memory can increase the parallelism of page
        replacement searches by independently processing different zones
        implemented, but not merged in 2.4-based rmap

(10) the reverse mappings may be used for efficiently keeping pte cache
        attributes coherent

(11) they may be used for virtual cache invalidation (with changes)

(12) the reverse mappings enable proper RSS limit enforcement
        implemented and merged in 2.4-based rmap



The code adds a pointer to struct page, consumes additional storage for
the pte chains and adds computational expense to the page reclaim code
(I measured it at 3% additional load during streaming I/O).  The
benefits which we get back for all this are, I must say, theoretical
and unproven.  If it has real advantages (or, indeed, disadvantages)
then why has nobody demonstrated them?



There are a number of things remaining to be done:

1: Demonstrate the above advantages.

2: Make it work with pte-highmem  (Bill Irwin is signed up for this)

3: Don't add pte_chains to non-shared pages optimisation (Dave McCracken's
   patch does this)

4: Move the pte_chains into highmem too (Bill, I guess)

5: per-cpu pte_chain freelists (Rik?)

6: maybe GC the pte_chain backing pages. (Seems unavoidable.  Rik?)

7: multithread the page reclaim code.  (I have patches).

8: clustered add-to-swap.  Not sure if I buy this.  anon pages are
   often well-ordered-by-virtual-address on the LRU, so it "just
   works" for benchmarky loads.  But there may be some other loads...

9: Fix bad IO latency in page reclaim (I have lame patches)

10: Develop tuning tools, use them.

11: The nightly updatedb run is still evicting everything.

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