linux.git/mm, branch v2.6.23

fix page release issue in filemap_fault

2007-10-08T19:58:14+00:00

find_lock_page increases page's usage count, we should decrease it
before return VM_FAULT_SIGBUS

Signed-off-by: Yan Zheng
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fix VM_CAN_NONLINEAR check in sys_remap_file_pages

2007-10-08T19:58:14+00:00

The test for VM_CAN_NONLINEAR always fails

Signed-off-by: Yan Zheng
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: set_page_dirty_balance() vs ->page_mkwrite()

2007-10-08T19:58:14+00:00

All the current page_mkwrite() implementations also set the page dirty. Which
results in the set_page_dirty_balance() call to _not_ call balance, because the
page is already found dirty.

This allows us to dirty a _lot_ of pages without ever hitting
balance_dirty_pages().  Not good (tm).

Force a balance call if ->page_mkwrite() was successful.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Linus Torvalds

xen: disable split pte locks for now

2007-10-06T16:31:30+00:00

When pinning and unpinning pagetables, we must protect them against
being used by other CPUs, lest they see the pagetable in an
intermediate read-only-but-not-pinned state.

When using split pte locks, doing this properly would require taking
all the pte locks for the pagetable while pinning, but this may overflow
the PREEMPT_BITS part of the preempt counter if the process has mapped
more than about 512M of memory.

However, failing to take the pte locks causes write-protect faults when
the pageout code is trying to clear the Access bit on a pte which is part
of a freshy created and still being pinned process after fork.

This is a short-term fix until the problem is solved properly.

Signed-off-by: Jeremy Fitzhardinge 
Acked-by: Rik van Riel 
Acked-by: Hugh Dickins 
Cc: David Rientjes 
Cc: Andrew Morton 
Cc: Andi Kleen 
Cc: Keir Fraser 
Cc: Jan Beulich 
Signed-off-by: Linus Torvalds

Fix sys_remap_file_pages BUG at highmem.c:15!

2007-10-04T17:13:09+00:00

Gurudas Pai reports kernel BUG at arch/i386/mm/highmem.c:15! below
sys_remap_file_pages, while running Oracle database test on x86 in 6GB
RAM: kunmap thinks we're in_interrupt because the preempt count has
wrapped.

That's because __do_fault expected to unmap page_table, but one of its
two callers do_nonlinear_fault already unmapped it: let do_linear_fault
unmap it first too, and then there's no need to pass the page_table arg
down.

Why have we been so slow to notice this? Probably through forgetting
that the mapping_cap_account_dirty test means that sys_remap_file_pages
nowadays only goes the full nonlinear vma route on a few memory-backed
filesystems like ramfs, tmpfs and hugetlbfs.

[ It also depends on CONFIG_HIGHPTE, so it becomes even harder to
  trigger in practice. Many who have need of large memory have probably
  migrated to x86-64..

  Problem introduced by commit d0217ac04ca6591841e5665f518e38064f4e65bd
  ("mm: fault feedback #1")                -- Linus ]

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

hugetlb: fix clear_user_highpage arguments

2007-10-01T14:52:23+00:00

The virtual address space argument of clear_user_highpage is supposed to be
the virtual address where the page being cleared will eventually be mapped.
 This allows architectures with virtually indexed caches a few clever
tricks.  That sort of trick falls over in painful ways if the virtual
address argument is wrong.

Signed-off-by: Ralf Baechle 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix NUMA Memory Policy Reference Counting

2007-09-19T18:24:18+00:00

This patch proposes fixes to the reference counting of memory policy in the
page allocation paths and in show_numa_map().  Extracted from my "Memory
Policy Cleanups and Enhancements" series as stand-alone.

Shared policy lookup [shmem] has always added a reference to the policy,
but this was never unrefed after page allocation or after formatting the
numa map data.

Default system policy should not require additional ref counting, nor
should the current task's task policy.  However, show_numa_map() calls
get_vma_policy() to examine what may be [likely is] another task's policy.
The latter case needs protection against freeing of the policy.

This patch adds a reference count to a mempolicy returned by
get_vma_policy() when the policy is a vma policy or another task's
mempolicy.  Again, shared policy is already reference counted on lookup.  A
matching "unref" [__mpol_free()] is performed in alloc_page_vma() for
shared and vma policies, and in show_numa_map() for shared and another
task's mempolicy.  We can call __mpol_free() directly, saving an admittedly
inexpensive inline NULL test, because we know we have a non-NULL policy.

Handling policy ref counts for hugepages is a bit trickier.
huge_zonelist() returns a zone list that might come from a shared or vma
'BIND policy.  In this case, we should hold the reference until after the
huge page allocation in dequeue_hugepage().  The patch modifies
huge_zonelist() to return a pointer to the mempolicy if it needs to be
unref'd after allocation.

Kernel Build [16cpu, 32GB, ia64] - average of 10 runs:

		w/o patch	w/ refcount patch
	    Avg	  Std Devn	   Avg	  Std Devn
Real:	 100.59	    0.38	 100.63	    0.43
User:	1209.60	    0.37	1209.91	    0.31
System:   81.52	    0.42	  81.64	    0.34

Signed-off-by:  Lee Schermerhorn 
Acked-by: Andi Kleen 
Cc: Christoph Lameter 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

SLUB: accurately compare debug flags during slab cache merge

2007-09-12T00:21:27+00:00

This was posted on Aug 28 and fixes an issue that could cause troubles
when slab caches >=128k are created.

http://marc.info/?l=linux-mm&m=118798149918424&w=2

Currently we simply add the debug flags unconditional when checking for a
matching slab.  This creates issues for sysfs processing when slabs exist
that are exempt from debugging due to their huge size or because only a
subset of slabs was selected for debugging.

We need to only add the flags if kmem_cache_open() would also add them.

Create a function to calculate the flags that would be set
if the cache would be opened and use that function to determine
the flags before looking for a compatible slab.

[akpm@linux-foundation.org: fixlets]
Signed-off-by: Christoph Lameter 
Cc: Chuck Ebbert 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Page migration: Do not accept invalid nodes in the target nodeset

2007-08-31T08:42:23+00:00

Page migration currently does not check if the target of the move contains
nodes that that are invalid (if root attempts to migrate pages)
and may try to allocate from invalid nodes if these are specified
leading to oopses.

Return -EINVAL if an offline node is specified.

Signed-off-by: Christoph Lameter 
Cc: Shaohua Li 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds

slub: do not fail if we cannot register a slab with sysfs

2007-08-31T08:42:22+00:00

Do not BUG() if we cannot register a slab with sysfs.  Just print an error.
 The only consequence of not registering is that the slab cache is not
visible via /sys/slab.  A BUG() may not be visible that early during boot
and we have had multiple issues here already.

Signed-off-by: Christoph Lameter 
Acked-by: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds