Because of page order checks in __alloc_pages(), hugepage (and similarly
large order) allocations will not retry unless explicitly marked
__GFP_REPEAT. However, the current retry logic is nearly an infinite
loop (or until reclaim does no progress whatsoever). For these costly
allocations, that seems like overkill and could potentially never
terminate. Mel observed that allowing current __GFP_REPEAT semantics for
hugepage allocations essentially killed the system. I believe this is
because we may continue to reclaim small orders of pages all over, but
never have enough to satisfy the hugepage allocation request. This is
clearly only a problem for large order allocations, of which hugepages
are the most obvious (to me).

Modify try_to_free_pages() to indicate how many pages were reclaimed.
Use that information in __alloc_pages() to eventually fail a large
__GFP_REPEAT allocation when we've reclaimed an order of pages equal to
or greater than the allocation's order. This relies on lumpy reclaim
functioning as advertised. Due to fragmentation, lumpy reclaim may not
be able to free up the order needed in one invocation, so multiple
iterations may be requred. In other words, the more fragmented memory
is, the more retry attempts __GFP_REPEAT will make (particularly for
higher order allocations).

This changes the semantics of __GFP_REPEAT subtly, but *only* for
allocations > PAGE_ALLOC_COSTLY_ORDER. With this patch, for those size
allocations, we will try up to some point (at least 1<<order reclaimed
pages), rather than forever (which is the case for allocations <=
PAGE_ALLOC_COSTLY_ORDER).

This change improves the /proc/sys/vm/nr_hugepages interface with a
follow-on patch that makes pool allocations use __GFP_REPEAT. Rather
than administrators repeatedly echo'ing a particular value into the
sysctl, and forcing reclaim into action manually, this change allows for
the sysctl to attempt a reasonable effort itself. Similarly, dynamic
pool growth should be more successful under load, as lumpy reclaim can
try to free up pages, rather than failing right away.

Choosing to reclaim only up to the order of the requested allocation
strikes a balance between not failing hugepage allocations and returning
to the caller when it's unlikely to every succeed. Because of lumpy
reclaim, if we have freed the order requested, hopefully it has been in
big chunks and those chunks will allow our allocation to succeed. If
that isn't the case after freeing up the current order, I don't think it
is likely to succeed in the future, although it is possible given a
particular fragmentation pattern.
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Tested-by: NMel Gorman <mel@csn.ul.ie>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The definition and use of __GFP_REPEAT, __GFP_NOFAIL and __GFP_NORETRY in the
core VM have somewhat differing comments as to their actual semantics.
Annoyingly, the flags definition has inline and header comments, which might
be interpreted as not being equivalent.  Just add references to the header
comments in the inline ones so they don't go out of sync in the future.  In
their use in __alloc_pages() clarify that the current implementation treats
low-order allocations and __GFP_REPEAT allocations as distinct cases.

To clarify, the flags' semantics are:

__GFP_NORETRY means try no harder than one run through __alloc_pages

__GFP_REPEAT means __GFP_NOFAIL

__GFP_NOFAIL means repeat forever

order <= PAGE_ALLOC_COSTLY_ORDER means __GFP_NOFAIL
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

usemap must be initialized only when pfn is within zone.  If not, it corrupts
memory.

And this patch also reduces the number of calls to set_pageblock_migratetype()
from
	(pfn & (pageblock_nr_pages -1)
to
	!(pfn & (pageblock_nr_pages-1)
it should be called once per pageblock.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Shi Weihua <shiwh@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c:207:11: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch fixes the following compile error caused by commit
04753278 ("memory hotplug: register
section/node id to free"):

    CC      mm/memory_hotplug.o
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c: In function ‘put_page_bootmem’:
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c:82: error: implicit declaration of function ‘__free_pages_bootmem’
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c: At top level:
  /home/bunk/linux/kernel-2.6/git/linux-2.6/mm/memory_hotplug.c:87: warning: no previous prototype for ‘register_page_bootmem_info_section’
  make[2]: *** [mm/memory_hotplug.o] Error 1

[ Andrew: "Argh.  The -mm-only memory-hotplug-add-removable-to-sysfs-
  to-show-memblock-removability.patch debugging patch adds that include
  so nobody hit this before. ]
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Don't perform kobjsize operations on objects the kernel doesn't manage.

On Blackfin, drivers can get dma coherent memory by calling a function
dma_alloc_coherent(). We do this in nommu by configuring a chunk of uncached
memory at the top of memory.

Since we don't want the kernel to use the uncached memory, we lie to the
kernel, and tell it that it's max memory is between 0, and the start of the
uncached dma coherent section.

this all works well, until this memory gets exposed into userspace (with a
frame buffer), when you look at the process's maps, it shows the framebuf:

root:/proc> cat maps
[snip]
03f0ef00-03f34700 rw-p 00000000 1f:00 192        /dev/fb0
root:/proc>

This is outside the "normal" range for the kernel. When the kernel tries to
find the size of this object (when you run ps), it dies in nommu.c in
kobjsize.

BUG_ON(page->index >= MAX_ORDER);

since the page we are referring to is outside what the kernel thinks is it's
max valid memory.

root:~> while [ 1 ]; ps > /dev/null; done
kernel BUG at mm/nommu.c:119!
Kernel panic - not syncing: BUG!

We fixed this by adding a check to reject out of range object pointers as it
already does that for NULL pointers.
Signed-off-by: NMichael Hennerich <Michael.Hennerich@analog.com>
Signed-off-by: NRobin Getz <rgetz@blackfin.uclinux.org>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We've found that it can take quite a bit of time (100's of usec) to get
through the zone loop in refresh_cpu_vm_stats().

Adding a cond_resched() to allow other threads to run in the non-preemptive
case.
Signed-off-by: NDimitri Sivanich <sivanich@sgi.com>
Acked-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove hand-coded get_order() from page_alloc.c.
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit 4c4a2214, we moved the
memcontroller-related code from badness() to select_bad_process(), so the
parameter 'mem' in badness() is unused now.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is to free memmaps which is allocated by bootmem.

Freeing usemap is not necessary.  The pages of usemap may be necessary for
other sections.

If removing section is last section on the node, its section is the final user
of usemap page.  (usemaps are allocated on its section by previous patch.) But
it shouldn't be freed too, because the section must be logical offline state
which all pages are isolated against page allocater.  If it is freed, page
alloctor may use it which will be removed physically soon.  It will be
disaster.  So, this patch keeps it as it is.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Usemaps are allocated on the section which has pgdat by this.

Because usemap size is very small, many other sections usemaps are allocated
on only one page.  If a section has usemap, it can't be removed until removing
other sections.  This dependency is not desirable for memory removing.

Pgdat has similar feature.  When a section has pgdat area, it must be the last
section for removing on the node.  So, if section A has pgdat and section B
has usemap for section A, Both sections can't be removed due to dependency
each other.

To solve this issue, this patch collects usemap on same section with pgdat.
If other sections doesn't have any dependency, this section will be able to be
removed finally.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

alloc_bootmem_section() can allocate specified section's area.  This is used
for usemap to keep same section with pgdat by later patch.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To free memmap easier, this patch aligns it to page size.  Bootmem allocater
may mix some objects in one pages.  It's not good for freeing memmap of memory
hot-remove.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch set is to free pages which is allocated by bootmem for
memory-hotremove.  Some structures of memory management are allocated by
bootmem.  ex) memmap, etc.

To remove memory physically, some of them must be freed according to
circumstance.  This patch set makes basis to free those pages, and free
memmaps.

Basic my idea is using remain members of struct page to remember information
of users of bootmem (section number or node id).  When the section is
removing, kernel can confirm it.  By this information, some issues can be
solved.

  1) When the memmap of removing section is allocated on other
     section by bootmem, it should/can be free.
  2) When the memmap of removing section is allocated on the
     same section, it shouldn't be freed. Because the section has to be
     logical memory offlined already and all pages must be isolated against
     page allocater. If it is freed, page allocator may use it which will
     be removed physically soon.
  3) When removing section has other section's memmap,
     kernel will be able to show easily which section should be removed
     before it for user. (Not implemented yet)
  4) When the above case 2), the page isolation will be able to check and skip
     memmap's page when logical memory offline (offline_pages()).
     Current page isolation code fails in this case because this page is
     just reserved page and it can't distinguish this pages can be
     removed or not. But, it will be able to do by this patch.
     (Not implemented yet.)
  5) The node information like pgdat has similar issues. But, this
     will be able to be solved too by this.
     (Not implemented yet, but, remembering node id in the pages.)

Fortunately, current bootmem allocator just keeps PageReserved flags,
and doesn't use any other members of page struct. The users of
bootmem doesn't use them too.

This patch:

This is to register information which is node or section's id.  Kernel can
distinguish which node/section uses the pages allcated by bootmem.  This is
basis for hot-remove sections or nodes.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Huge ptes have a special type on s390 and cannot be handled with the standard
pte functions in certain cases, e.g.  because of a different location of the
invalid bit.  This patch adds some new architecture- specific functions to
hugetlb common code, as a prerequisite for the s390 large page support.

This won't affect other architectures in functionality, but I need to add some
new dummy inline functions to the headers.
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A cow break on a hugetlbfs page with page_count > 1 will set a new pte with
set_huge_pte_at(), w/o any tlb flush operation.  The old pte will remain in
the tlb and subsequent write access to the page will result in a page fault
loop, for as long as it may take until the tlb is flushed from somewhere else.
 This patch introduces an architecture-specific huge_ptep_clear_flush()
function, which is called before the the set_huge_pte_at() in hugetlb_cow().

ATTENTION: This is just a nop on all architectures for now, the s390
implementation will come with our large page patch later.  Other architectures
should define their own huge_ptep_clear_flush() if needed.
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch replaces the mempolicy mode, mode_flags, and nodemask in the
shmem_sb_info struct with a struct mempolicy pointer, initialized to NULL.
This removes dependency on the details of mempolicy from shmem.c and hugetlbfs
inode.c and simplifies the interfaces.

mpol_parse_str() in mempolicy.c is changed to return, via a pointer to a
pointer arg, a struct mempolicy pointer on success.  For MPOL_DEFAULT, the
returned pointer is NULL.  Further, mpol_parse_str() now takes a 'no_context'
argument that causes the input nodemask to be stored in the w.user_nodemask of
the created mempolicy for use when the mempolicy is installed in a tmpfs inode
shared policy tree.  At that time, any cpuset contextualization is applied to
the original input nodemask.  This preserves the previous behavior where the
input nodemask was stored in the superblock.  We can think of the returned
mempolicy as "context free".

Because mpol_parse_str() is now calling mpol_new(), we can remove from
mpol_to_str() the semantic checks that mpol_new() already performs.

Add 'no_context' parameter to mpol_to_str() to specify that it should format
the nodemask in w.user_nodemask for 'bind' and 'interleave' policies.

Change mpol_shared_policy_init() to take a pointer to a "context free" struct
mempolicy and to create a new, "contextualized" mempolicy using the mode,
mode_flags and user_nodemask from the input mempolicy.

  Note: we know that the mempolicy passed to mpol_to_str() or
  mpol_shared_policy_init() from a tmpfs superblock is "context free".  This
  is currently the only instance thereof.  However, if we found more uses for
  this concept, and introduced any ambiguity as to whether a mempolicy was
  context free or not, we could add another internal mode flag to identify
  context free mempolicies.  Then, we could remove the 'no_context' argument
  from mpol_to_str().

Added shmem_get_sbmpol() to return a reference counted superblock mempolicy,
if one exists, to pass to mpol_shared_policy_init().  We must add the
reference under the sb stat_lock to prevent races with replacement of the mpol
by remount.  This reference is removed in mpol_shared_policy_init().

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: another build fix]
[akpm@linux-foundation.org: yet another build fix]
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For tmpfs/shmem shared policies, MPOL_DEFAULT is not necessarily equivalent to
"local allocation".  Because shared policies are at the same "scope" level
[see Documentation/vm/numa_memory_policy.txt], as vma policies MPOL_DEFAULT
means "fall back to current task policy".

This patch extends the memory policy string parsing function to display
"local" for MPOL_PREFERRED + MPOL_F_LOCAL.  This allows one to specify local
allocation as the default policy for shared memory areas via the tmpfs mpol
mount option, regardless of the current task's policy.

Also, "local" is now displayed for this policy.  This patch allows us to
accept the same input format as the display.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/shmem.c currently contains functions to parse and display memory policy
strings for the tmpfs 'mpol' mount option.  Move this to mm/mempolicy.c with
the rest of the mempolicy support.  With subsequent patches, we'll be able to
remove knowledge of the details [mode, flags, policy, ...] completely from
shmem.c

1) replace shmem_parse_mpol() in mm/shmem.c with mpol_parse_str() in
   mm/mempolicy.c.  Rework to use the policy_types[] array [used by
   mpol_to_str()] to look up mode by name.

2) use mpol_to_str() to format policy for shmem_show_mpol().  mpol_to_str()
   expects a pointer to a struct mempolicy, so temporarily construct one.
   This will be replaced with a reference to a struct mempolicy in the tmpfs
   superblock in a subsequent patch.

   NOTE 1: I changed mpol_to_str() to use a colon ':' rather than an equal
   sign '=' as the nodemask delimiter to match mpol_parse_str() and the
   tmpfs/shmem mpol mount option formatting that now uses mpol_to_str().  This
   is a user visible change to numa_maps, but then the addition of the mode
   flags already changed the display.  It makes sense to me to have the mounts
   and numa_maps display the policy in the same format.  However, if anyone
   objects strongly, I can pass the desired nodemask delimeter as an arg to
   mpol_to_str().

   Note 2: Like show_numa_map(), I don't check the return code from
   mpol_to_str().  I do use a longer buffer than the one provided by
   show_numa_map(), which seems to have sufficed so far.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mpol-to-str() formats memory policies into printable strings.  Currently this
is only used to display "numa_maps".  A subsequent patch will use
mpol_to_str() for formatting tmpfs [shmem] mpol mount options, allowing us to
remove essentially duplicate code in mm/shmem.c.  This patch cleans up
mpol_to_str() generally and in preparation for that patch.

1) show_numa_maps() is not checking the return code from mpol_to_str().
   There's not a lot we can do in this context if mpol_to_str() did return the
   error [insufficient space in buffer].  Proposed "solution": just check,
   under DEBUG_VM, that callers are providing sufficient buffer space for the
   policy, flags, and a few nodes.  This way, we'll get some display.
   show_numa_maps() is providing a 50-byte buffer, so it won't trip this
   check.  50-bytes should be sufficient unless one has a large number of
   nodes in a very sparse nodemask.

2) The display of the new mode flags ["static" & "relative"] was set up to
   display multiple flags, separated by a "bar" '|'.  However, this support is
   incomplete--e.g., need_bar was never incremented; and currently, these two
   flags are mutually exclusive.  So remove the "bar" support, for now, and
   only display one flag.

3) Use snprint() to format flags, so as not to overflow the buffer.  Not
   that it's ever happed, AFAIK.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that we're using "preferred local" policy for system default, we need to
make this as fast as possible.  Because of the variable size of the mempolicy
structure [based on size of nodemasks], the preferred_node may be in a
different cacheline from the mode.  This can result in accessing an extra
cacheline in the normal case of system default policy.  Suspect this is the
cause of an observed 2-3% slowdown in page fault testing relative to kernel
without this patch series.

To alleviate this, use an internal mode flag, MPOL_F_LOCAL in the mempolicy
flags member which is guaranteed [?] to be in the same cacheline as the mode
itself.

Verified that reworked mempolicy now performs slightly better on 25-rc8-mm1
for both anon and shmem segments with system default and vma [preferred local]
policy.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Here are a couple of "cleanups" for MPOL_PREFERRED behavior when
v.preferred_node < 0 -- i.e., "local allocation":

1)  [do_]get_mempolicy() calls the now renamed get_policy_nodemask()
    to fetch the nodemask associated with a policy.  Currently,
    get_policy_nodemask() returns the set of nodes with memory, when
    the policy 'mode' is 'PREFERRED, and the preferred_node is < 0.
    Change to return an empty nodemask, as this is what was specified
    to achieve "local allocation".

2)  When a task is moved into a [new] cpuset, mpol_rebind_policy() is
    called to adjust any task and vma policy nodes to be valid in the
    new cpuset.  However, when the policy is MPOL_PREFERRED, and the
    preferred_node is <0, no rebind is necessary.  The "local allocation"
    indication is valid in any cpuset.  Existing code will "do the right
    thing" because node_remap() will just return the argument node when
    it is outside of the valid range of node ids.  However, I think it is
    clearer and cleaner to skip the remap explicitly in this case.

3)  mpol_to_str() produces a printable, "human readable" string from a
    struct mempolicy.  For MPOL_PREFERRED with preferred_node <0,  show
    "local", as this indicates local allocation, as the task migrates
    among nodes.  Note that this matches the usage of "local allocation"
    in libnuma() and numactl.  Without this change, I believe that node_set()
    [via set_bit()] will set bit 31, resulting in a misleading display.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, when one specifies MPOL_DEFAULT via a NUMA memory policy API
[set_mempolicy(), mbind() and internal versions], the kernel simply installs a
NULL struct mempolicy pointer in the appropriate context: task policy, vma
policy, or shared policy.  This causes any use of that policy to "fall back"
to the next most specific policy scope.

The only use of MPOL_DEFAULT to mean "local allocation" is in the system
default policy.  This requires extra checks/cases for MPOL_DEFAULT in many
mempolicy.c functions.

There is another, "preferred" way to specify local allocation via the APIs.
That is using the MPOL_PREFERRED policy mode with an empty nodemask.
Internally, the empty nodemask gets converted to a preferred_node id of '-1'.
All internal usage of MPOL_PREFERRED will convert the '-1' to the id of the
node local to the cpu where the allocation occurs.

System default policy, except during boot, is hard-coded to "local
allocation".  By using the MPOL_PREFERRED mode with a negative value of
preferred node for system default policy, MPOL_DEFAULT will never occur in the
'policy' member of a struct mempolicy.  Thus, we can remove all checks for
MPOL_DEFAULT when converting policy to a node id/zonelist in the allocation
paths.

In slab_node() return local node id when policy pointer is NULL.  No need to
set a pol value to take the switch default.  Replace switch default with
BUG()--i.e., shouldn't happen.

With this patch MPOL_DEFAULT is only used in the APIs, including internal
calls to do_set_mempolicy() and in the display of policy in
/proc/<pid>/numa_maps.  It always means "fall back" to the the next most
specific policy scope.  This simplifies the description of memory policies
quite a bit, with no visible change in behavior.

get_mempolicy() continues to return MPOL_DEFAULT and an empty nodemask when
the requested policy [task or vma/shared] is NULL.  These are the values one
would supply via set_mempolicy() or mbind() to achieve that condition--default
behavior.

This patch updates Documentation to reflect this change.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After further discussion with Christoph Lameter, it has become clear that my
earlier attempts to clean up the mempolicy reference counting were a bit of
overkill in some areas, resulting in superflous ref/unref in what are usually
fast paths.  In other areas, further inspection reveals that I botched the
unref for interleave policies.

A separate patch, suitable for upstream/stable trees, fixes up the known
errors in the previous attempt to fix reference counting.

This patch reworks the memory policy referencing counting and, one hopes,
simplifies the code.  Maybe I'll get it right this time.

See the update to the numa_memory_policy.txt document for a discussion of
memory policy reference counting that motivates this patch.

Summary:

Lookup of mempolicy, based on (vma, address) need only add a reference for
shared policy, and we need only unref the policy when finished for shared
policies.  So, this patch backs out all of the unneeded extra reference
counting added by my previous attempt.  It then unrefs only shared policies
when we're finished with them, using the mpol_cond_put() [conditional put]
helper function introduced by this patch.

Note that shmem_swapin() calls read_swap_cache_async() with a dummy vma
containing just the policy.  read_swap_cache_async() can call alloc_page_vma()
multiple times, so we can't let alloc_page_vma() unref the shared policy in
this case.  To avoid this, we make a copy of any non-null shared policy and
remove the MPOL_F_SHARED flag from the copy.  This copy occurs before reading
a page [or multiple pages] from swap, so the overhead should not be an issue
here.

I introduced a new static inline function "mpol_cond_copy()" to copy the
shared policy to an on-stack policy and remove the flags that would require a
conditional free.  The current implementation of mpol_cond_copy() assumes that
the struct mempolicy contains no pointers to dynamically allocated structures
that must be duplicated or reference counted during copy.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As part of yet another rework of mempolicy reference counting, we want to be
able to identify shared policies efficiently, because they have an extra ref
taken on lookup that needs to be removed when we're finished using the policy.

  Note:  the extra ref is required because the policies are
  shared between tasks/processes and can be changed/freed
  by one task while another task is using them--e.g., for
  page allocation.

Building on David Rientjes mempolicy "mode flags" enhancement, this patch
indicates a "shared" policy by setting a new MPOL_F_SHARED flag in the flags
member of the struct mempolicy added by David.  MPOL_F_SHARED, and any future
"internal mode flags" are reserved from bit zero up, as they will never be
passed in the upper bits of the mode argument of a mempolicy API.

I set the MPOL_F_SHARED flag when the policy is installed in the shared policy
rb-tree.  Don't need/want to clear the flag when removing from the tree as the
mempolicy is freed [unref'd] internally to the sp_delete() function.  However,
a task could hold another reference on this mempolicy from a prior lookup.  We
need the MPOL_F_SHARED flag to stay put so that any tasks holding a ref will
unref, eventually freeing, the mempolicy.

A later patch in this series will introduce a function to conditionally unref
[mpol_free] a policy.  The MPOL_F_SHARED flag is one reason [currently the
only reason] to unref/free a policy via the conditional free.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The terms 'policy' and 'mode' are both used in various places to describe the
semantics of the value stored in the 'policy' member of struct mempolicy.
Furthermore, the term 'policy' is used to refer to that member, to the entire
struct mempolicy and to the more abstract concept of the tuple consisting of a
"mode" and an optional node or set of nodes.  Recently, we have added "mode
flags" that are passed in the upper bits of the 'mode' [or sometimes,
'policy'] member of the numa APIs.

I'd like to resolve this confusion, which perhaps only exists in my mind, by
renaming the 'policy' member to 'mode' throughout, and fixing up the
Documentation.  Man pages will be updated separately.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

get_vma_policy() is not handling fallback to task policy correctly when the
get_policy() vm_op returns NULL.  The NULL overwrites the 'pol' variable that
was holding the fallback task mempolicy.  So, it was falling back directly to
system default policy.

Fix get_vma_policy() to use only non-NULL policy returned from the vma
get_policy op.

shm_get_policy() was falling back to current task's mempolicy if the "backing
file system" [tmpfs vs hugetlbfs] does not support the get_policy vm_op and
the vma policy is null.  This is incorrect for show_numa_maps() which is
likely querying the numa_maps of some task other than current.  Remove this
fallback.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A read of /proc/<pid>/numa_maps holds the target task's mmap_sem for read
while examining each vma's mempolicy.  A vma's mempolicy can fall back to the
task's policy.  However, the task could be changing it's task policy and free
the one that the show_numa_maps() is examining.

To prevent this, grab the mmap_sem for write when updating task mempolicy.
Pointed out to me by Christoph Lameter and extracted and reworked from
Christoph's alternative mempol reference counting patch.

This is analogous to the way that do_mbind() and do_get_mempolicy() prevent
races between task's sharing an mm_struct [a.k.a.  threads] setting and
querying a mempolicy for a particular address.

Note: this is necessary, but not sufficient, to allow us to stop taking an
extra reference on "other task's mempolicy" in get_vma_policy.  Subsequent
patches will complete this update, allowing us to simplify the tests for
whether we need to unref a mempolicy at various points in the code.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch renames mpol_copy() to mpol_dup() because, well, that's what it
does.  Like, e.g., strdup() for strings, mpol_dup() takes a pointer to an
existing mempolicy, allocates a new one and copies the contents.

In a later patch, I want to use the name mpol_copy() to copy the contents from
one mempolicy to another like, e.g., strcpy() does for strings.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a change that was requested some time ago by Mel Gorman.  Makes sense
to me, so here it is.

Note: I retain the name "mpol_free_shared_policy()" because it actually does
free the shared_policy, which is NOT a reference counted object.  However, ...

The mempolicy object[s] referenced by the shared_policy are reference counted,
so mpol_put() is used to release the reference held by the shared_policy.  The
mempolicy might not be freed at this time, because some task attached to the
shared object associated with the shared policy may be in the process of
allocating a page based on the mempolicy.  In that case, the task performing
the allocation will hold a reference on the mempolicy, obtained via
mpol_shared_policy_lookup().  The mempolicy will be freed when all tasks
holding such a reference have called mpol_put() for the mempolicy.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Allocating huge pages directly from the buddy allocator is not guaranteed to
succeed.  Success depends on several factors (such as the amount of physical
memory available and the level of fragmentation).  With the addition of
dynamic hugetlb pool resizing, allocations can occur much more frequently.
For these reasons it is desirable to keep track of huge page allocation
successes and failures.

Add two new vmstat entries to track huge page allocations that succeed and
fail.  The presence of the two entries is contingent upon CONFIG_HUGETLB_PAGE
being enabled.

[akpm@linux-foundation.org: reduced ifdeffery]
Signed-off-by: NAdam Litke <agl@us.ibm.com>
Signed-off-by: NEric Munson <ebmunson@us.ibm.com>
Tested-by: NMel Gorman <mel@csn.ul.ie>
Reviewed-by: NAndy Whitcroft <apw@shadowen.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for
the user mappings.

This requires the get_xip_page API to be changed to an address based one.
Improve the API layering a little bit too, while we're here.

This is required in order to support XIP filesystems on memory that isn't
backed with struct page (but memory with struct page is still supported too).
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

vm_insert_mixed will insert either a raw pfn or a refcounted struct page into
the page tables, depending on whether vm_normal_page() will return the page or
not.  With the introduction of the new pte bit, this is now a too tricky for
drivers to be doing themselves.

filemap_xip uses this in a subsequent patch.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

s390 for one, cannot implement VM_MIXEDMAP with pfn_valid, due to their memory
model (which is more dynamic than most).  Instead, they had proposed to
implement it with an additional path through vm_normal_page(), using a bit in
the pte to determine whether or not the page should be refcounted:

vm_normal_page()
{
	...
        if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
                if (vma->vm_flags & VM_MIXEDMAP) {
#ifdef s390
			if (!mixedmap_refcount_pte(pte))
				return NULL;
#else
                        if (!pfn_valid(pfn))
                                return NULL;
#endif
                        goto out;
                }
	...
}

This is fine, however if we are allowed to use a bit in the pte to determine
refcountedness, we can use that to _completely_ replace all the vma based
schemes.  So instead of adding more cases to the already complex vma-based
scheme, we can have a clearly seperate and simple pte-based scheme (and get
slightly better code generation in the process):

vm_normal_page()
{
#ifdef s390
	if (!mixedmap_refcount_pte(pte))
		return NULL;
	return pte_page(pte);
#else
	...
#endif
}

And finally, we may rather make this concept usable by any architecture rather
than making it s390 only, so implement a new type of pte state for this.
Unfortunately the old vma based code must stay, because some architectures may
not be able to spare pte bits.  This makes vm_normal_page a little bit more
ugly than we would like, but the 2 cases are clearly seperate.

So introduce a pte_special pte state, and use it in mm/memory.c.  It is
currently a noop for all architectures, so this doesn't actually result in any
compiled code changes to mm/memory.o.

BTW:
I haven't put vm_normal_page() into arch code as-per an earlier suggestion.
The reason is that, regardless of where vm_normal_page is actually
implemented, the *abstraction* is still exactly the same. Also, while it
depends on whether the architecture has pte_special or not, that is the
only two possible cases, and it really isn't an arch specific function --
the role of the arch code should be to provide primitive functions and
accessors with which to build the core code; pte_special does that. We do
not want architectures to know or care about vm_normal_page itself, and
we definitely don't want them being able to invent something new there
out of sight of mm/ code. If we made vm_normal_page an arch function, then
we have to make vm_insert_mixed (next patch) an arch function too. So I
don't think moving it to arch code fundamentally improves any abstractions,
while it does practically make the code more difficult to follow, for both
mm and arch developers, and easier to misuse.

[akpm@linux-foundation.org: build fix]
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This series introduces some important infrastructure work.  The overall result
is that:

1. We now support XIP backed filesystems using memory that have no
   struct page allocated to them. And patches 6 and 7 actually implement
   this for s390.

   This is pretty important in a number of cases. As far as I understand,
   in the case of virtualisation (eg. s390), each guest may mount a
   readonly copy of the same filesystem (eg. the distro). Currently,
   guests need to allocate struct pages for this image. So if you have
   100 guests, you already need to allocate more memory for the struct
   pages than the size of the image. I think. (Carsten?)

   For other (eg. embedded) systems, you may have a very large non-
   volatile filesystem. If you have to have struct pages for this, then
   your RAM consumption will go up proportionally to fs size. Even
   though it is just a small proportion, the RAM can be much more costly
   eg in terms of power, so every KB less that Linux uses makes it more
   attractive to a lot of these guys.

2. VM_MIXEDMAP allows us to support mappings where you actually do want
   to refcount _some_ pages in the mapping, but not others, and support
   COW on arbitrary (non-linear) mappings. Jared needs this for his NVRAM
   filesystem in progress. Future iterations of this filesystem will
   most likely want to migrate pages between pagecache and XIP backing,
   which is where the requirement for mixed (some refcounted, some not)
   comes from.

3. pte_special also has a peripheral usage that I need for my lockless
   get_user_pages patch. That was shown to speed up "oltp" on db2 by
   10% on a 2 socket system, which is kind of significant because they
   scrounge for months to try to find 0.1% improvement on these
   workloads. I'm hoping we might finally be faster than AIX on
   pSeries with this :). My reference to lockless get_user_pages is not
   meant to justify this patchset (which doesn't include lockless gup),
   but just to show that pte_special is not some s390 specific thing that
   should be hidden in arch code or xip code: I definitely want to use it
   on at least x86 and powerpc as well.

This patch:

Introduce a new type of mapping, VM_MIXEDMAP.  This is unlike VM_PFNMAP in
that it can support COW mappings of arbitrary ranges including ranges without
struct page *and* ranges with a struct page that we actually want to refcount
(PFNMAP can only support COW in those cases where the un-COW-ed translations
are mapped linearly in the virtual address, and can only support non
refcounted ranges).

VM_MIXEDMAP achieves this by refcounting all pfn_valid pages, and not
refcounting !pfn_valid pages (which is not an option for VM_PFNMAP, because it
needs to avoid refcounting pfn_valid pages eg.  for /dev/mem mappings).
Signed-off-by: NJared Hulbert <jaredeh@gmail.com>
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Having separate page flags for the head and the tail of a compound page allows
the compiler to use bitops instead of operations on a word to check for a tail
page.  That is f.e.  important for virt_to_head_page() which is used in
various critical code paths (kfree for example):

Code for PageTail(page)

Before:

 mov    (%rdi),%rdx		page->flags
 mov    %rdx,%rax		3 bytes
 and    $0x12000,%eax		5 bytes
 cmp    $0x12000,%rax		6 bytes
 je     897 <kfree+0xa7>

After:

 mov    (%rdi),%rax
 test   $0x40,%ah			(3 bytes)
 jne    887 <kfree+0x97>

So we go from 14 bytes to 3 bytes and from 3 instructions to one.  From the
use of 2 registers we go to none.

We can only use page flags for this if we have page flags available.  This
patch introduces CONFIG_PAGEFLAGS_EXTENDED that is set if pageflags are not
scarce due to SPARSEMEM using page flags for its sectionid on 32 bit NUMA
platforms.

Additional page flag definitions can be added to the CONFIG_PAGEFLAGS_EXTENDED
section in page-flags.h if the functionality depends on PAGEFLAGS_EXTENDED or
if more page flag overlapping tricks are used for the !PAGEFLAGS_EXTENDED
fallback (the upcoming virtual compound patch may hook in here and Rik's/Lee's
additional page flags to solve the reclaim issues could also be added there
[hint...  hint...  where are these patchsets?]).

Avoiding the overlaying of Pg_reclaim also clears the way for possible use of
compound pages for the pagecache or on the LRU.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove aliases of PG_xxx.  We can easily drop those now and alias by
specifying the PG_xxx flag in the macro that generates the functions.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add caller information so that /proc/vmallocinfo shows where the allocation
request for a slice of vmalloc memory originated.

Results in output like this:

0xffffc20000000000-0xffffc20000801000 8392704 alloc_large_system_hash+0x127/0x246 pages=2048 vmalloc vpages
0xffffc20000801000-0xffffc20000806000   20480 alloc_large_system_hash+0x127/0x246 pages=4 vmalloc
0xffffc20000806000-0xffffc20000c07000 4198400 alloc_large_system_hash+0x127/0x246 pages=1024 vmalloc vpages
0xffffc20000c07000-0xffffc20000c0a000   12288 alloc_large_system_hash+0x127/0x246 pages=2 vmalloc
0xffffc20000c0a000-0xffffc20000c0c000    8192 acpi_os_map_memory+0x13/0x1c phys=cff68000 ioremap
0xffffc20000c0c000-0xffffc20000c0f000   12288 acpi_os_map_memory+0x13/0x1c phys=cff64000 ioremap
0xffffc20000c10000-0xffffc20000c15000   20480 acpi_os_map_memory+0x13/0x1c phys=cff65000 ioremap
0xffffc20000c16000-0xffffc20000c18000    8192 acpi_os_map_memory+0x13/0x1c phys=cff69000 ioremap
0xffffc20000c18000-0xffffc20000c1a000    8192 acpi_os_map_memory+0x13/0x1c phys=fed1f000 ioremap
0xffffc20000c1a000-0xffffc20000c1c000    8192 acpi_os_map_memory+0x13/0x1c phys=cff68000 ioremap
0xffffc20000c1c000-0xffffc20000c1e000    8192 acpi_os_map_memory+0x13/0x1c phys=cff68000 ioremap
0xffffc20000c1e000-0xffffc20000c20000    8192 acpi_os_map_memory+0x13/0x1c phys=cff68000 ioremap
0xffffc20000c20000-0xffffc20000c22000    8192 acpi_os_map_memory+0x13/0x1c phys=cff68000 ioremap
0xffffc20000c22000-0xffffc20000c24000    8192 acpi_os_map_memory+0x13/0x1c phys=cff68000 ioremap
0xffffc20000c24000-0xffffc20000c26000    8192 acpi_os_map_memory+0x13/0x1c phys=e0081000 ioremap
0xffffc20000c26000-0xffffc20000c28000    8192 acpi_os_map_memory+0x13/0x1c phys=e0080000 ioremap
0xffffc20000c28000-0xffffc20000c2d000   20480 alloc_large_system_hash+0x127/0x246 pages=4 vmalloc
0xffffc20000c2d000-0xffffc20000c31000   16384 tcp_init+0xd5/0x31c pages=3 vmalloc
0xffffc20000c31000-0xffffc20000c34000   12288 alloc_large_system_hash+0x127/0x246 pages=2 vmalloc
0xffffc20000c34000-0xffffc20000c36000    8192 init_vdso_vars+0xde/0x1f1
0xffffc20000c36000-0xffffc20000c38000    8192 pci_iomap+0x8a/0xb4 phys=d8e00000 ioremap
0xffffc20000c38000-0xffffc20000c3a000    8192 usb_hcd_pci_probe+0x139/0x295 [usbcore] phys=d8e00000 ioremap
0xffffc20000c3a000-0xffffc20000c3e000   16384 sys_swapon+0x509/0xa15 pages=3 vmalloc
0xffffc20000c40000-0xffffc20000c61000  135168 e1000_probe+0x1c4/0xa32 phys=d8a20000 ioremap
0xffffc20000c61000-0xffffc20000c6a000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc20000c6a000-0xffffc20000c73000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc20000c73000-0xffffc20000c7c000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc20000c7c000-0xffffc20000c7f000   12288 e1000e_setup_tx_resources+0x29/0xbe pages=2 vmalloc
0xffffc20000c80000-0xffffc20001481000 8392704 pci_mmcfg_arch_init+0x90/0x118 phys=e0000000 ioremap
0xffffc20001481000-0xffffc20001682000 2101248 alloc_large_system_hash+0x127/0x246 pages=512 vmalloc
0xffffc20001682000-0xffffc20001e83000 8392704 alloc_large_system_hash+0x127/0x246 pages=2048 vmalloc vpages
0xffffc20001e83000-0xffffc20002204000 3674112 alloc_large_system_hash+0x127/0x246 pages=896 vmalloc vpages
0xffffc20002204000-0xffffc2000220d000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc2000220d000-0xffffc20002216000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc20002216000-0xffffc2000221f000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc2000221f000-0xffffc20002228000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc20002228000-0xffffc20002231000   36864 _xfs_buf_map_pages+0x8e/0xc0 vmap
0xffffc20002231000-0xffffc20002234000   12288 e1000e_setup_rx_resources+0x35/0x122 pages=2 vmalloc
0xffffc20002240000-0xffffc20002261000  135168 e1000_probe+0x1c4/0xa32 phys=d8a60000 ioremap
0xffffc20002261000-0xffffc2000270c000 4894720 sys_swapon+0x509/0xa15 pages=1194 vmalloc vpages
0xffffffffa0000000-0xffffffffa0022000  139264 module_alloc+0x4f/0x55 pages=33 vmalloc
0xffffffffa0022000-0xffffffffa0029000   28672 module_alloc+0x4f/0x55 pages=6 vmalloc
0xffffffffa002b000-0xffffffffa0034000   36864 module_alloc+0x4f/0x55 pages=8 vmalloc
0xffffffffa0034000-0xffffffffa003d000   36864 module_alloc+0x4f/0x55 pages=8 vmalloc
0xffffffffa003d000-0xffffffffa0049000   49152 module_alloc+0x4f/0x55 pages=11 vmalloc
0xffffffffa0049000-0xffffffffa0050000   28672 module_alloc+0x4f/0x55 pages=6 vmalloc

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement a new proc file that allows the display of the currently allocated
vmalloc memory.

It allows to see the users of vmalloc.  That is important if vmalloc space is
scarce (i386 for example).

And it's going to be important for the compound page fallback to vmalloc.
Many of the current users can be switched to use compound pages with fallback.
 This means that the number of users of vmalloc is reduced and page tables no
longer necessary to access the memory.  /proc/vmallocinfo allows to review how
that reduction occurs.

If memory becomes fragmented and larger order allocations are no longer
possible then /proc/vmallocinfo allows to see which compound page allocations
fell back to virtual compound pages.  That is important for new users of
virtual compound pages.  Such as order 1 stack allocation etc that may
fallback to virtual compound pages in the future.

/proc/vmallocinfo permissions are made readable-only-by-root to avoid possible
information leakage.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: CONFIG_MMU=n build fix]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Clean up messy conditional calling of test_clear_page_writeback() from both
rotate_reclaimable_page() and end_page_writeback().

The only user of rotate_reclaimable_page() is end_page_writeback() so this is
OK.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>