If a page is "freed" while in the deferred-lru-addition queue, the
final reference to it is the deferred lru addition queue.  When that
queue gets spilled onto the LRU, the page is actually freed.

Which is all expected and natural and works fine - it's a weird case.

But one of the AIM9 tests was taking a 20% performance hit (relative to
2.4) because it was going into the page allocator for new pages while
cache-hot pages were languishiung out in the deferred-addition queue.

So the patch changes things so that we spill the CPU's
deferred-lru-addition queue before starting to free pages.  This way,
the recently-used pages actually make it to the hot/cold lists and are
available for new allocations.

It gets back 15 of the lost 20%.  The other 5% is lost to the general
additional complexity of all this stuff.  (But we're 250% faster than
2.4 when running four instances of the test on 4-way).

This patch optimises the truncate of a zero-length file, which is a
sufficiently common case to justify the extra test-n-branch.

It does this by skipping the entire call into the fs if i_size is not
being altered.

The AIM9 `open_clo' test just loops, creating and unlinking a file.
This patch speeds it up 50% for ext2, 600% for reiserfs.

The buffer-stripping code gets upset when it sees a non-uptodate buffer
against an uptodate page.  This happens because the write end_io
handler clears BH_Uptodate.

Add a buffer_req() test to suppress these warnings.

Patch from Hugh Dickins and Robert Love.

Fixes up the PF_MEMDIE handling so that it actually works.

(PF_MEMDIE allows an oom-killed task to use the emergency memory
reserves so that it can actually get out of the page allocator and
die)

2.5's signal delivery is 20% slower than 2.4.  A signal send/handle
cycle is performing a total of 24 copy_*_user() calls, and
copy_*_user() got optimised for large copies.

The patch reduces that to six copy_*_user() calls, and gets us up to
about 5% slower than 2.4.  We'd have to go back to some additional
inlined copy_user() code to get the last 3% back.  And HZ=100 to get
the 2% back.

It is noteworthy that the benchmark is not using float at all during
the body of the test, yet the kernel is still doing all that floating
point stuff.

Patch from Mingming Cao <cmm@us.ibm.com>

- ipc_lock() need a read_barrier_depends() to prevent indexing
  uninitialized new array on the read side.  This is corresponding to
  the write memory barrier added in grow_ary() from Dipankar's patch to
  prevent indexing uninitialized array.

- Replaced "wmb()" in IPC code with "smp_wmb()"."wmb()" produces a
  full write memory barrier in both UP and SMP kernels, while
  "smp_wmb()" provides a full write memory barrier in an SMP kernel,
  but only a compiler directive in a UP kernel.  The same change are
  made for "rmb()".

- Removed rmb() in ipc_get().  We do not need a read memory barrier
  there since ipc_get() is protected by ipc_ids.sem semaphore.

- Added more comments about why write barriers and read barriers are
  needed (or not needed) here or there.

With some workloads a large number of pages coming off the LRU are
pinned blockdev pagecache - things like ext2 group descriptors, pages
which have buffers in the per-cpu buffer LRUs, etc.

They keep churning around the inactive list, reducing the overall page
reclaim effectiveness.

So move these pages onto the active list.

Pages from memory-backed filesystems are supposed to be moved up onto
the active list, but that's not working because fail_writepage() is
called when the page is not on the LRU.

So look for this case in page reclaim and handle it there.

And it's more efficient, the VM knows more about what is going on and
it later leads to the removal of fail_writepage().

The patch addresses some search complexity failures which occur when
there is a large amount of dirty data on the inactive list.

Normally we attempt to write out those pages and then move them to the
head of the inactive list.  But this goes against page aging, and means
that the page has to traverse the entire list again before it can be
reclaimed.

But the VM really wants to reclaim that page - it has reached the tail
of the LRU.

So what we do in this patch is to mark the page as needing reclamation,
and then start I/O.  In the IO completion handler we check to see if
the page is still probably reclaimable and if so, move it to the tail of
the inactive list, where it can be reclaimed immediately.

Under really heavy swap-intensive loads this increases the page reclaim
efficiency (pages reclaimed/pages scanned) from 10% to 25%.  Which is
OK for that sort of load.  Not great, but OK.

This code path takes the LRU lock once per page.  I didn't bother
playing games with batching up the locking work - it's a rare code
path, and the machine has plenty of CPU to spare when this is
happening.

This removes the last remnant of the 2.4 way of throttling page
allocators: the wait_on_page_writeback() against mapped-or-swapcache
pages.

I did this because:

a) It's not used much.
b) It's already causing big latencies
c) With Jens' large-queue stuff, it can cause huuuuuuuuge latencies.
   Like: ninety seconds.

So kill it, and rely on blk_congestion_wait() to slow the allocator
down to match the rate at which the IO system can retire writes.

These are the mount options which turn off and on the Orlov allocator.
ext2 supports them but Ted forgot to wire them up for ext3.

Patch from Arnd Bergmann <arnd@bergmann-dalldorf.de>

- revert accidental reversion of the timer initialisation in fbcon.

- init a timer in drivers/net/pcmcia/fmvj18x_cs.c
  (OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>)

When testing the XFS 1.2 release we found a problem that was caused
by inodes made unusable by make_bad_inode() still beeing returned by
iget() and friends.  The workaround was to call remove_inode_hash()
before each call to make_bad_inode().

I think the proper fix is to let make_bad_inode() remove the inodes
from the hash chains.

into samba.org:/scratch/anton/linux-2.5_ppc64_work

into samba.org:/scratch/anton/linux-2.5_ppc64_work

into samba.org:/scratch/anton/linux-2.5_ppc64_work

This converts the PA-RISC PS/2 keyboard & mouse driver to the input
layer.  New driver written by Laurent Canet & Thibaut Varene.

Fix the documentation to match the code fix.

    "static structi2c_clientclient_template" works much better
when spaces are added at appropriate places.

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

Without this, time runs 50x too slow after resume, since nothing
knows to tell the timer to re-initialize.

Here are a few fixes I needed when porting oprofile to ppc64:

 - __PAGE_OFFSET isnt defined for all architectures, use PAGE_OFFSET
   instead
 - include linux/cache.h everywhere we use ____cacheline_aligned etc.
   Otherwise we end up with a structure called ____cacheline_aligned
   and no alignment :(

This changes sys_getppid() to be more POSIX-threading conformant.

sys_getppid() needs to return the PID of the "process' parent" (ie.  the
tgid of the parent thread), not the thread parent's PID.  The patch has
no effect on non-CLONE_THREAD users, for them current->group_leader ==
current.  The effect on CLONE_THREAD threads is that getppid() does not
return any PID within the thread group anymore.  Plus if a threaded
application starts up a (non-thread) child then the child sees the
process PID of the parent process, not the thread PID of the parent
thread.

in theory we could introduce the getttid() variant to get to the TID of
the parent thread, but i doubt it would be of any use.  (and we can add
it if the need arises.)

The lockless algorithm is still safe because the ->group_leader pointer
never changes asynchronously.  (the ->real_parent pointer might still
change asynchronously so the SMP checks are still needed.)

I've also updated the comments (they referenced the nonexistent p_ooptr
field.), plus i've changed the mb() to rmb() - we need to order the
reads, we dont do any global writes that need some predictable ordering.

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

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

This removes the include of (the now empty) Rules.make, gets rid of the
ifndef clause and fixes the indentation.

This fixes threaded coredumps and streamlines the code.  The old code
caused crashes and hung coredumps.  The new code has been tested for
some time already and appears to be robust.  Changes:

 - the code now uses completions instead of a semaphore and a waitqueue,
   attached to mm_struct:

        /* coredumping support */
        int core_waiters;
        struct completion *core_startup_done, core_done;

 - extended the completion concept with a 'complete all' call - all pending
   threads are woken up in that case.

 - core_waiters is a plain integer now - it's always accessed from under
   the mmap_sem. It's also used as the fastpath-check in the sys_exit()
   path, instead of ->dumpable (which was incorrect).

 - got rid of the ->core_waiter task flag - it's not needed anymore.

Update Stelian Pop's contact information in CREDITS and MAINTAINERS.

This corrects a small typo in the previous patch (in the ZOOM button
definition) and adds events generated by the Memory Stick reader on VAIO
U3 laptops (thanks to Kunihiko IMAI).

into hera.kernel.org:/home/hch/BK/xfs/linux-2.5