into hostme.bitkeeper.com:/ua/repos/j/jfs/linux-2.5

SERIAL_IO_GSC was a mistake and should never have been added.

When drivers/serial was split off, the following helptexts should have
been deleted, but weren't.

The reason for the ftape messup of export-objs is the usage of the
strange FT_KSYM macro in ftape_syms.c.

That exist solely for backwards compatibility for kernel 2.1.18 and older.

Better clean it up.

 - Add FL_SLEEP flag to indicate we intend to sleep and therefore desire
   to be placed on the block list.  Use it for POSIX & flock locks.
 - Remove locks_block_on.
 - Change posix_unblock_lock to eliminate a race that will appear once we
   don't use the BKL any more.
 - Update the comment for locks_same_owner() and rename it to
   posix_same_owner().
 - Change locks_mandatory_area() to allocate its lock on the stack and
   call posix_lock_file() instead of repeating that logic.
 - Rename the "caller" parameter to posix_lock_file() to "request"
   to better show that this is not to be inserted directly.
 - Redo some of the proc code a little.  Stop exposing kernel addresses
   to userspace (whoever thought _that_ was a good idea?!) and show how
   we should be printing the device name.  The last part is ifdeffed
   out to avoid breaking lslk.
 - Remove FL_BROKEN.  And there was much rejoicing.

  Here are some patches for C99 initializers in fs/nfs. Patches
  are against 2.5.32.

  The function save_flags must use unsigned long instead long (signed)
  This trivial patch solves the problem

  The function save_flags must use an unsigned long parameter instead a
  long (signed) one
  This trivial patch solves the problem

  The function save_flags must use an unsigned long parameter instead a
  long (signed) one
  This trivial patch solves the problem

  <asm/io.h> has the normal idempotent construction on every architecture.

  The attached file removes the second #include.

  <linux/init.h> has the normal idempotent construction.

  The attached file removes the second #include.

  The function save_flags must use unsigned long instead long (signed)
  This trivial patch solves the problem

  This is a trivial patch already applied in the -ac tree for the 2.4.19 kernel.
  Patch for lp.c avoid +/- operations with 0 and explicit some debug information
  as KERN_INFO or KERN_ERR.

  drivers/char/Config.in still has a complete copy of agp/Config.in.
  It's an exact cut-n-paste - the md5sums even match. (:

  Bad error path..

  ret is already set to -ENODEV, no need to set them again before
  jumping out.

The old form of designated initializers are obsolete: we need to
replace them with the ISO C forms before 2.6.  Gcc has always supported
both forms anyway.

The old form of designated initializers are obsolete: we need to
replace them with the ISO C forms before 2.6.  Gcc has always supported
both forms anyway.

  The function save_flags must use unsigned long instead long (signed)
  This trivial patch solves the problem

  The function save_flags must use an unsigned long parameter instead a
  long (signed) one

  This trivial patch solves the problem

  <linux/serial.h> has the normal idempotent construction.

  The attached file removes the second #include.

  Trivial patch changes my zip code.  Applies to 2.4.x and 2.5.x trees.

  The function save_flags must use unsigned long instead long (signed)
  This trivial patch solves the problem

  The function save_flags must use unsigned long instead long (signed)
  This trivial patch solves the problem

  The function save_flags must use unsigned long instead long (signed)
  This trivial patch solves the problem

  The function save_flags must use an unsigned long parameter instead a
  long (signed) one

  This trivial patch solves the problem

but also about being called whenever we're holding any
other preemption locks.

version in include/linux didn't get deleted.

Bill Irwin's patch to fix up pte's in highmem.

With CONFIG_HIGHPTE, the direct pte pointer in struct page becomes the
64-bit physical address of the single pte which is mapping this page.

If the page is not PageDirect then page->pte.chain points at a list of
pte_chains, which each now contain an array of 64-bit physical
addresses of the pte's which are mapping the page.

The functions rmap_ptep_map() and rmap_ptep_unmap() are used for
mapping and unmapping the page which backs the target pte.

The patch touches all architectures (adding do-nothing compatibility
macros and inlines).  It generally mangles lots of header files and may
break non-ia32 compiles.  I've had it in testing since 2.5.31.

The pte_chains presently consist of a pte pointer and a `next' link.
So there's a 50% memory wastage here as well as potential for a lot of
misses during walks of the singly-linked per-page list.

This patch increases the pte_chain structure to occupy a full
cacheline.  There are 7, 15 or 31 pte pointers per structure rather
than just one.  So the wastage falls to a few percent and the number of
misses during the walk is reduced.

The patch doesn't make much difference in simple testing, because in
those tests the pte_chain list from the previous page has good cache
locality with the next page's list.

The patch sped up Anton's "10,000 concurrently exitting shells" test by
3x or 4x.  It gives a 10% reduction in system time for a kernel build
on 16p NUMAQ.

It saves memory and reduces the amount of work performed in the slab
allocator.

Pages which are mapped by only a single process continue to not have a
pte_chain.  The pointer in struct page points directly at the mapping
pte (a "PageDirect" pte pointer).  Once the page is shared a pte_chain
is allocated and both the new and old pte pointers are moved into it.

We used to collapse the pte_chain back to a PageDirect representation
in page_remove_rmap().  That has been changed.  That collapse is now
performed inside page reclaim, via page_referenced().  The thinking
here is that if a page was previously shared then it may become shared
again, so leave the pte_chain structure in place.  But if the system is
under memory pressure then start reaping them anyway.

This patch addresses the excessive consumption of ZONE_NORMAL by
buffer_heads on highmem machines.  The algorithms which decide which
buffers to shoot down are fairly dumb, but they only cut in on machines
with large highmem:lowmem ratios and the code footprint is tiny.

The buffer.c change implements the buffer_head accounting - it sets the
upper limit on buffer_head memory occupancy to 10% of ZONE_NORMAL.

A possible side-effect of this change is that the kernel will perform
more calls to get_block() to map pages to disk.  This will only be
observed when a file is being repeatadly overwritten - this is the only
case in which the "cached get_block result" in the buffers is useful.

I did quite some testing of this back in the delalloc ext2 days, and
was not able to come up with a test in which the cached get_block
result was measurably useful.  That's for ext2, which has a fast
get_block().

A desirable side effect of this patch is that the kernel will be able
to cache much more blockdev pagecache in ZONE_NORMAL, so there are more
ext2/3 indirect blocks in cache, so with some workloads, less I/O will
be performed.

In mpage_writepage(): if the number of buffer_heads is excessive then
buffers are stripped from pages as they are submitted for writeback.
This change is only useful for filesystems which are using the mpage
code.  That's ext2 and ext3-writeback and JFS.  An mpage patch for
reiserfs was floating about but seems to have got lost.

There is no need to strip buffers for reads because the mpage code does
not attach buffers for reads.

These are perhaps not the most appropriate buffer_heads to toss away.
Perhaps something smarter should be done to detect file overwriting, or
to toss the 'oldest' buffer_heads first.

In refill_inactive(): if the number of buffer_heads is excessive then
strip buffers from pages as they move onto the inactive list.  This
change is useful for all filesystems.  This approach is good because
pages which are being repeatedly overwritten will remain on the active
list and will retain their buffers, whereas pages which are not being
overwritten will be stripped.

Writeback parameter tuning.  Somewhat experimental, but heading in the
right direction, I hope.

- Allowing 40% of physical memory to be dirtied on massive ia32 boxes
  is unreasonable.  It pins too many buffer_heads and contribues to
  page reclaim latency.

  The patch changes the initial value of
  /proc/sys/vm/dirty_background_ratio, dirty_async_ratio and (the
  presently non-functional) dirty_sync_ratio so that they are reduced
  when the highmem:lowmem ratio exceeds 4:1.

  These ratios are scaled so that as the highmem:lowmem ratio goes
  beyond 4:1, the maximum amount of allowed dirty memory ceases to
  increase.  It is clamped at the amount of memory which a 4:1 machine
  is allowed to use.

- Aggressive reduction in the dirty memory threshold at which
  background writeback cuts in.  2.4 uses 30% of ZONE_NORMAL.  2.5 uses
  40% of total memory.  This patch changes it to 10% of total memory
  (if total memory <= 4G.  Even less otherwise - see above).

This means that:

- Much more writeback is performed by pdflush.

- When the application is generating dirty data at a moderate
  rate, background writeback cuts in much earlier, so memory is
  cleaned more promptly.

- Reduces the risk of user applications getting stalled by writeback.

- Will damage dbench numbers.  It turns out that the damage is
  fairly small, and dbench isn't a worthwhile workload for
  optimisation.

- Moderate reduction in the dirty level at which the write(2) caller
  is forced to perform writeback (throttling).  Was 40% of total
  memory.  Is now 30% of total memory (if total memory <= 4G, less
  otherwise).

This is to reduce page reclaim latency, and generally because
allowing processes to flood the machine with dirty data is a bad
thing in mixed workloads.

Patch from Martin Bligh

"This mainly just rips out some magic extra structures in the boot time
 code to determine node sizes, and counts in pages instead of bytes.
 Oh, and I put the code that allocates pgdat into allocage_pgdat,
 instead of find_max_pfn_node, which seems like an incongruous home for
 it.

 No functionality changes, nothing touched outside i386 discontigmem ...
 just makes code cleaner and more readable.  Tested on 16-way NUMA-Q."

Patch from Martin Bligh.

"This mainly changes the PLAT_MY_MACRO_IS_ALL_CAPS() stuff to be
 normal_macro(), and takes out some unnecessary redirection of function
 names.  No functionality changes, nothing touched outside i386
 discontigmem ...  just makes code readable.  Rumour has it that the
 PLAT_* stuff came from IRIX - I don't see that as a good reason to make
 the Linux code unreadable.  Tested on 16-way NUMA-Q."

Some adjustments to global dirty page accounting.

Previously, dirty page accounting counted all dirty pages.  Even dirty
anonymous pages.  This has potential to upset the throttling logic in
balance_dirty_pages().  Particularly as I suspect we should decrease
the dirty memory writeback thresholds by a lot.

So this patch changes it so that we only account for dirty pagecache
pages which have backing store.  Not anonymous pages, not swapcache,
not in-memory filesystem pages.

To support this, the `memory_backed' boolean has been added to struct
backing_dev_info.  When an address space's backing device is marked as
memory-backed, the core kernel knows to not include that mapping's
pages in the dirty memory accounting.

For memory-backed mappings, dirtiness is a way of pinning the page, and
there's nothing the kernel can to do clean the page to make it freeable.

driverfs, tmpfs, and ranfs have been coverted to mark their mappings as
memory-backed.

The ramdisk driver hasn't been converted.  I have a separate patch for
ramdisk, which fails to fix the longstanding problems in there :(

With this patch, /bin/sync now sends /proc/meminfo:Dirty to zero, which
is rather comforting.