linux-toradex.git/mm, branch v2.6.18-rc7

[PATCH] invalidate_complete_page() race fix

2006-09-08T17:22:50+00:00

If a CPU faults this page into pagetables after invalidate_mapping_pages()
checked page_mapped(), invalidate_complete_page() will still proceed to remove
the page from pagecache.  This leaves the page-faulting process with a
detached page.  If it was MAP_SHARED then file data loss will ensue.

Fix that up by checking the page's refcount after taking tree_lock.

Cc: Nick Piggin 
Cc: Hugh Dickins 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] IA64,sparc: local DoS with corrupted ELFs

2006-09-08T15:40:46+00:00

This prevents cross-region mappings on IA64 and SPARC which could lead
to system crash.  They were correctly trapped for normal mmap() calls,
but not for the kernel internal calls generated by executable loading.

This code just moves the architecture-specific cross-region checks into
an arch-specific "arch_mmap_check()" macro, and defines that for the
architectures that needed it (ia64, sparc and sparc64).

Architectures that don't have any special requirements can just ignore
the new cross-region check, since the mmap() code will just notice on
its own when the macro isn't defined.

Signed-off-by: Pavel Emelianov 
Signed-off-by: Kirill Korotaev 
Acked-by: David Miller 
Signed-off-by: Greg Kroah-Hartman 
[ Cleaned up to not affect architectures that don't need it ]
Signed-off-by: Linus Torvalds

[PATCH] fix NUMA interleaving for huge pages

2006-09-01T18:39:10+00:00

Since vma->vm_pgoff is in units of smallpages, VMAs for huge pages have the
lower HPAGE_SHIFT - PAGE_SHIFT bits always cleared, which results in badd
offsets to the interleave functions.  Take this difference from small pages
into account when calculating the offset.  This does add a 0-bit shift into
the small-page path (via alloc_page_vma()), but I think that is negligible.
 Also add a BUG_ON to prevent the offset from growing due to a negative
right-shift, which probably shouldn't be allowed anyways.

Tested on an 8-memory node ppc64 NUMA box and got the interleaving I
expected.

Signed-off-by: Nishanth Aravamudan 
Signed-off-by: Adam Litke 
Cc: Andi Kleen 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] dm: work around mempool_alloc, bio_alloc_bioset deadlocks

2006-09-01T18:39:09+00:00

This patch works around a complex dm-related deadlock/livelock down in the
mempool allocator.

Alasdair said:

  Several dm targets suffer from this.

  Mempools are not yet used correctly everywhere in device-mapper: they can
  get shared when devices are stacked, and some targets share them across
  multiple instances.  I made fixing this one of the prerequisites for this
  patch:

    md-dm-reduce-stack-usage-with-stacked-block-devices.patch

  which in some cases makes people more likely to hit the problem.

  There's been some progress on this recently with (unfinished) dm-crypt
  patches at:

    http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/
      (dm-crypt-move-io-to-workqueue.patch plus dependencies)

and:

  I've no problems with a temporary workaround like that, but Milan Broz (a
  new Redhat developer in the Czech Republic) has started reviewing all the
  mempool usage in device-mapper so I'm expecting we'll soon have a proper fix
  for this associated problems.  [He's back from holiday at the start of next
  week.]

For now, this sad-but-safe little patch will allow the machine to recover.

[akpm@osdl.org: rewrote changelog]
Cc: Alasdair G Kergon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] ZVC: Scale thresholds depending on the size of the system

2006-09-01T18:39:08+00:00

The ZVC counter update threshold is currently set to a fixed value of 32.
This patch sets up the threshold depending on the number of processors and
the sizes of the zones in the system.

With the current threshold of 32, I was able to observe slight contention
when more than 130-140 processors concurrently updated the counters.  The
contention vanished when I either increased the threshold to 64 or used
Andrew's idea of overstepping the interval (see ZVC overstep patch).

However, we saw contention again at 220-230 processors.  So we need higher
values for larger systems.

But the current default is already a bit of an overkill for smaller
systems.  Some systems have tiny zones where precision matters.  For
example i386 and x86_64 have 16M DMA zones and either 900M ZONE_NORMAL or
ZONE_DMA32.  These are even present on SMP and NUMA systems.

The patch here sets up a threshold based on the number of processors in the
system and the size of the zone that these counters are used for.  The
threshold should grow logarithmically, so we use fls() as an easy
approximation.

Results of tests on a system with 1024 processors (4TB RAM)

The following output is from a test allocating 1GB of memory concurrently
on each processor (Forking the process.  So contention on mmap_sem and the
pte locks is not a factor):

                       X                   MIN
TYPE:               CPUS       WALL       WALL        SYS     USER     TOTCPU
fork                   1      0.552      0.552      0.540    0.012      0.552
fork                   4      0.552      0.548      2.164    0.036      2.200
fork                  16      0.564      0.548      8.812    0.164      8.976
fork                 128      0.580      0.572     72.204    1.208     73.412
fork                 256      1.300      0.660    310.400    2.160    312.560
fork                 512      3.512      0.696   1526.836    4.816   1531.652
fork                1020     20.024      0.700  17243.176    6.688  17249.863

So a threshold of 32 is fine up to 128 processors. At 256 processors contention
becomes a factor.

Overstepping the counter (earlier patch) improves the numbers a bit:

fork                   4      0.552      0.548      2.164    0.040      2.204
fork                  16      0.552      0.548      8.640    0.148      8.788
fork                 128      0.556      0.548     69.676    0.956     70.632
fork                 256      0.876      0.636    212.468    2.108    214.576
fork                 512      2.276      0.672    997.324    4.260   1001.584
fork                1020     13.564      0.680  11586.436    6.088  11592.523

Still contention at 512 and 1020. Contention at 1020 is down by a third.
256 still has a slight bit of contention.

After this patch the counter threshold will be set to 125 which reduces
contention significantly:

fork                 128      0.560      0.548     69.776    0.932     70.708
fork                 256      0.636      0.556    143.460    2.036    145.496
fork                 512      0.640      0.548    284.244    4.236    288.480
fork                1020      1.500      0.588   1326.152    8.892   1335.044

[akpm@osdl.org: !SMP build fix]
Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] ZVC: Overstep counters

2006-09-01T18:39:08+00:00

Increments and decrements are usually grouped rather than mixed.  We can
optimize the inc and dec functions for that case.

Increment and decrement the counters by 50% more than the threshold in
those cases and set the differential accordingly.  This decreases the need
to update the atomic counters.

The idea came originally from Andrew Morton.  The overstepping alone was
sufficient to address the contention issue found when updating the global
and the per zone counters from 160 processors.

Also remove some code in dec_zone_page_state.

Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] swsusp: Fix swap_type_of

2006-08-27T18:01:28+00:00

There is a bug in mm/swapfile.c#swap_type_of() that makes swsusp only be
able to use the first active swap partition as the resume device.  Fix it.

Signed-off-by: Rafael J. Wysocki 
Cc: Hugh Dickins 
Acked-by: Pavel Machek 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fuse: fix error case in fuse_readpages

2006-08-14T19:54:29+00:00

Don't let fuse_readpages leave the @pages list not empty when exiting
on error.

[akpm@osdl.org: kernel-doc fixes]
Signed-off-by: Alexander Zarochentsev 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

[PATCH] memory hotadd fixes: enhance collision check

2006-08-06T15:57:49+00:00

This patch is for collision check enhancement for memory hot add.

It's better to do resouce collision check before doing memory hot add,
which will touch memory management structures.

And add_section() should check section exists or not before calling
sparse_add_one_section(). (sparse_add_one_section() will do another
check anyway. but checking in memory_hotplug.c will be easy to understand.)

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: keith mannthey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] memory hotadd fixes: find_next_system_ram catch range fix

2006-08-06T15:57:48+00:00

find_next_system_ram() is used to find available memory resource at onlining
newly added memory.  This patch fixes following problem.

find_next_system_ram() cannot catch this case.

Resource:      (start)-------------(end)
Section :                (start)-------------(end)

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Keith Mannthey 
Cc: Yasunori Goto 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds