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2539 commits

Author SHA1 Message Date
Helge Deller
72eb8c6747 unitialized return value in mm/mlock.c: __mlock_vma_pages_range()
Fix an unitialized return value when compiling on parisc (with CONFIG_UNEVICTABLE_LRU=y):
	mm/mlock.c: In function `__mlock_vma_pages_range':
	mm/mlock.c:165: warning: `ret' might be used uninitialized in this function

Signed-off-by: Helge Deller <deller@gmx.de>
[ It isn't ever really used uninitialized, since no caller should ever
  call this function with an empty range.  But the compiler is correct
  that from a local analysis standpoint that is impossible to see, and
  fixing the warning is appropriate.  ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-16 15:55:36 -08:00
KOSAKI Motohiro
748f1a2ed7 mm: remove unevictable's show_page_path
Hugh Dickins reported show_page_path() is buggy and unsafe because

 - lack dput() against d_find_alias()
 - don't concern vma->vm_mm->owner == NULL
 - lack lock_page()

it was only for debugging, so rather than trying to fix it, just remove
it now.

Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
CC: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-15 11:36:07 -08:00
KAMEZAWA Hiroyuki
33c5d3d645 memcg: bugfix for memory hotplug
The start pfn calculation in page_cgroup's memory hotplug notifier chain
is wrong.

Tested-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-12 17:17:17 -08:00
KOSAKI Motohiro
8891d6da17 mm: remove lru_add_drain_all() from the munlock path
lockdep warns about following message at boot time on one of my test
machine.  Then, schedule_on_each_cpu() sholdn't be called when the task
have mmap_sem.

Actually, lru_add_drain_all() exist to prevent the unevictalble pages
stay on reclaimable lru list.  but currenct unevictable code can rescue
unevictable pages although it stay on reclaimable list.

So removing is better.

In addition, this patch add lru_add_drain_all() to sys_mlock() and
sys_mlockall().  it isn't must.  but it reduce the failure of moving to
unevictable list.  its failure can rescue in vmscan later.  but reducing
is better.

Note, if above rescuing happend, the Mlocked and the Unevictable field
mismatching happend in /proc/meminfo.  but it doesn't cause any real
trouble.

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.28-rc2-mm1 #2
-------------------------------------------------------
lvm/1103 is trying to acquire lock:
 (&cpu_hotplug.lock){--..}, at: [<c0130789>] get_online_cpus+0x29/0x50

but task is already holding lock:
 (&mm->mmap_sem){----}, at: [<c01878ae>] sys_mlockall+0x4e/0xb0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&mm->mmap_sem){----}:
       [<c0153da2>] check_noncircular+0x82/0x110
       [<c0185e6a>] might_fault+0x4a/0xa0
       [<c0156161>] validate_chain+0xb11/0x1070
       [<c0185e6a>] might_fault+0x4a/0xa0
       [<c0156923>] __lock_acquire+0x263/0xa10
       [<c015714c>] lock_acquire+0x7c/0xb0			(*) grab mmap_sem
       [<c0185e6a>] might_fault+0x4a/0xa0
       [<c0185e9b>] might_fault+0x7b/0xa0
       [<c0185e6a>] might_fault+0x4a/0xa0
       [<c0294dd0>] copy_to_user+0x30/0x60
       [<c01ae3ec>] filldir+0x7c/0xd0
       [<c01e3a6a>] sysfs_readdir+0x11a/0x1f0			(*) grab sysfs_mutex
       [<c01ae370>] filldir+0x0/0xd0
       [<c01ae370>] filldir+0x0/0xd0
       [<c01ae4c6>] vfs_readdir+0x86/0xa0			(*) grab i_mutex
       [<c01ae75b>] sys_getdents+0x6b/0xc0
       [<c010355a>] syscall_call+0x7/0xb
       [<ffffffff>] 0xffffffff

-> #2 (sysfs_mutex){--..}:
       [<c0153da2>] check_noncircular+0x82/0x110
       [<c01e3d2c>] sysfs_addrm_start+0x2c/0xc0
       [<c0156161>] validate_chain+0xb11/0x1070
       [<c01e3d2c>] sysfs_addrm_start+0x2c/0xc0
       [<c0156923>] __lock_acquire+0x263/0xa10
       [<c015714c>] lock_acquire+0x7c/0xb0			(*) grab sysfs_mutex
       [<c01e3d2c>] sysfs_addrm_start+0x2c/0xc0
       [<c04f8b55>] mutex_lock_nested+0xa5/0x2f0
       [<c01e3d2c>] sysfs_addrm_start+0x2c/0xc0
       [<c01e3d2c>] sysfs_addrm_start+0x2c/0xc0
       [<c01e3d2c>] sysfs_addrm_start+0x2c/0xc0
       [<c01e422f>] create_dir+0x3f/0x90
       [<c01e42a9>] sysfs_create_dir+0x29/0x50
       [<c04faaf5>] _spin_unlock+0x25/0x40
       [<c028f21d>] kobject_add_internal+0xcd/0x1a0
       [<c028f37a>] kobject_set_name_vargs+0x3a/0x50
       [<c028f41d>] kobject_init_and_add+0x2d/0x40
       [<c019d4d2>] sysfs_slab_add+0xd2/0x180
       [<c019d580>] sysfs_add_func+0x0/0x70
       [<c019d5dc>] sysfs_add_func+0x5c/0x70			(*) grab slub_lock
       [<c01400f2>] run_workqueue+0x172/0x200
       [<c014008f>] run_workqueue+0x10f/0x200
       [<c0140bd0>] worker_thread+0x0/0xf0
       [<c0140c6c>] worker_thread+0x9c/0xf0
       [<c0143c80>] autoremove_wake_function+0x0/0x50
       [<c0140bd0>] worker_thread+0x0/0xf0
       [<c0143972>] kthread+0x42/0x70
       [<c0143930>] kthread+0x0/0x70
       [<c01042db>] kernel_thread_helper+0x7/0x1c
       [<ffffffff>] 0xffffffff

-> #1 (slub_lock){----}:
       [<c0153d2d>] check_noncircular+0xd/0x110
       [<c04f650f>] slab_cpuup_callback+0x11f/0x1d0
       [<c0156161>] validate_chain+0xb11/0x1070
       [<c04f650f>] slab_cpuup_callback+0x11f/0x1d0
       [<c015433d>] mark_lock+0x35d/0xd00
       [<c0156923>] __lock_acquire+0x263/0xa10
       [<c015714c>] lock_acquire+0x7c/0xb0
       [<c04f650f>] slab_cpuup_callback+0x11f/0x1d0
       [<c04f93a3>] down_read+0x43/0x80
       [<c04f650f>] slab_cpuup_callback+0x11f/0x1d0		(*) grab slub_lock
       [<c04f650f>] slab_cpuup_callback+0x11f/0x1d0
       [<c04fd9ac>] notifier_call_chain+0x3c/0x70
       [<c04f5454>] _cpu_up+0x84/0x110
       [<c04f552b>] cpu_up+0x4b/0x70				(*) grab cpu_hotplug.lock
       [<c06d1530>] kernel_init+0x0/0x170
       [<c06d15e5>] kernel_init+0xb5/0x170
       [<c06d1530>] kernel_init+0x0/0x170
       [<c01042db>] kernel_thread_helper+0x7/0x1c
       [<ffffffff>] 0xffffffff

-> #0 (&cpu_hotplug.lock){--..}:
       [<c0155bff>] validate_chain+0x5af/0x1070
       [<c040f7e0>] dev_status+0x0/0x50
       [<c0156923>] __lock_acquire+0x263/0xa10
       [<c015714c>] lock_acquire+0x7c/0xb0
       [<c0130789>] get_online_cpus+0x29/0x50
       [<c04f8b55>] mutex_lock_nested+0xa5/0x2f0
       [<c0130789>] get_online_cpus+0x29/0x50
       [<c0130789>] get_online_cpus+0x29/0x50
       [<c017bc30>] lru_add_drain_per_cpu+0x0/0x10
       [<c0130789>] get_online_cpus+0x29/0x50			(*) grab cpu_hotplug.lock
       [<c0140cf2>] schedule_on_each_cpu+0x32/0xe0
       [<c0187095>] __mlock_vma_pages_range+0x85/0x2c0
       [<c0156945>] __lock_acquire+0x285/0xa10
       [<c0188f09>] vma_merge+0xa9/0x1d0
       [<c0187450>] mlock_fixup+0x180/0x200
       [<c0187548>] do_mlockall+0x78/0x90			(*) grab mmap_sem
       [<c01878e1>] sys_mlockall+0x81/0xb0
       [<c010355a>] syscall_call+0x7/0xb
       [<ffffffff>] 0xffffffff

other info that might help us debug this:

1 lock held by lvm/1103:
 #0:  (&mm->mmap_sem){----}, at: [<c01878ae>] sys_mlockall+0x4e/0xb0

stack backtrace:
Pid: 1103, comm: lvm Not tainted 2.6.28-rc2-mm1 #2
Call Trace:
 [<c01555fc>] print_circular_bug_tail+0x7c/0xd0
 [<c0155bff>] validate_chain+0x5af/0x1070
 [<c040f7e0>] dev_status+0x0/0x50
 [<c0156923>] __lock_acquire+0x263/0xa10
 [<c015714c>] lock_acquire+0x7c/0xb0
 [<c0130789>] get_online_cpus+0x29/0x50
 [<c04f8b55>] mutex_lock_nested+0xa5/0x2f0
 [<c0130789>] get_online_cpus+0x29/0x50
 [<c0130789>] get_online_cpus+0x29/0x50
 [<c017bc30>] lru_add_drain_per_cpu+0x0/0x10
 [<c0130789>] get_online_cpus+0x29/0x50
 [<c0140cf2>] schedule_on_each_cpu+0x32/0xe0
 [<c0187095>] __mlock_vma_pages_range+0x85/0x2c0
 [<c0156945>] __lock_acquire+0x285/0xa10
 [<c0188f09>] vma_merge+0xa9/0x1d0
 [<c0187450>] mlock_fixup+0x180/0x200
 [<c0187548>] do_mlockall+0x78/0x90
 [<c01878e1>] sys_mlockall+0x81/0xb0
 [<c010355a>] syscall_call+0x7/0xb

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-12 17:17:16 -08:00
David Rientjes
e33c3b5e17 cpusets: update mems allowed in page allocator
If all allowable memory is unreclaimable, it is possible to loop forever
in the page allocator for ~__GFP_NORETRY allocations.

During this time, it is also possible for a task's cpuset to expand its
set of allowable nodes so that it now includes free memory.  The cached
copy of this set, current->mems_allowed, is stale, however, since there
has not been a subsequent call to cpuset_update_task_memory_state().

The cached copy of the set of allowable nodes is now updated in the page
allocator's slow path so the additional memory is available to
get_page_from_freelist().

[akpm@linux-foundation.org: add comment]
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Paul Menage <menage@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-12 17:17:16 -08:00
Adam Litke
7526674de0 hugetlb: make unmap_ref_private multi-size-aware
Oops.  Part of the hugetlb private reservation code was not fully
converted to use hstates.

When a huge page must be unmapped from VMAs due to a failed COW,
HPAGE_SIZE is used in the call to unmap_hugepage_range() regardless of
the page size being used.  This works if the VMA is using the default
huge page size.  Otherwise we might unmap too much, too little, or
trigger a BUG_ON.  Rare but serious -- fix it.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-12 17:17:16 -08:00
Denys Vlasenko
1c12718504 parisc: fix find_extend_vma() breakage
The STACK_GROWSUP case of stack expansion was missing a test for 'prev',
which got removed by commit cb8f488c33
("mmap.c: deinline a few functions") by mistake.

I found my original email in "sent" folder. The patch in that mail
does NOT remove !prev. That change had beed added by someone else.

Ok, I think we are not much interested in who did it, let's
fix it for good.

[ "It looks like this was caused by me fixing rejects.  That was the
  fancy include-lots-of-context-so-it-wont-apply patch." - akpm ]

Reported-and-bisected-by: Helge Deller <deller@gmx.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-12 10:37:48 -08:00
Jeremy Fitzhardinge
9b46333406 vmap: cope with vm_unmap_aliases before vmalloc_init()
Xen can end up calling vm_unmap_aliases() before vmalloc_init() has
been called.  In this case its safe to make it a simple no-op.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-07 10:05:59 +01:00
Linus Torvalds
9144f3821d Merge master.kernel.org:/home/rmk/linux-2.6-arm
* master.kernel.org:/home/rmk/linux-2.6-arm:
  [ARM] xsc3: fix xsc3_l2_inv_range
  [ARM] mm: fix page table initialization
  [ARM] fix naming of MODULE_START / MODULE_END
  ARM: OMAP: Fix define for twl4030 irqs
  ARM: OMAP: Fix get_irqnr_and_base to clear spurious interrupt bits
  ARM: OMAP: Fix debugfs_create_*'s error checking method for arm/plat-omap
  ARM: OMAP: Fix compiler warnings in gpmc.c
  [ARM] fix VFP+softfloat binaries
2008-11-06 15:56:29 -08:00
Gerald Schaefer
a70dcb969f memory hotplug: fix page_zone() calculation in test_pages_isolated()
My last bugfix here (adding zone->lock) introduced a new problem: Using
page_zone(pfn_to_page(pfn)) to get the zone after the for() loop is wrong.
 pfn will then be >= end_pfn, which may be in a different zone or not
present at all.  This may lead to an addressing exception in page_zone()
or spin_lock_irqsave().

Now I use __first_valid_page() again after the loop to find a valid page
for page_zone().

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: Nathan Fontenot <nfont@austin.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:19 -08:00
Qinghuang Feng
fbdd12676c mm/oom_kill.c: fix badness() kerneldoc
Paramter @mem has been removed since v2.6.26, now delete it's comment.

Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:19 -08:00
David Rientjes
b41ad14c30 vmemmap: warn about page_structs with remote distance
It's insufficient to simply compare node ids when warning about offnode
page_structs since it's possible to still have local affinity.

Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:19 -08:00
Christoph Lameter
0aedadf91a mm: move migrate_prep out from under mmap_sem
Move the migrate_prep outside the mmap_sem for the following system calls

1. sys_move_pages
2. sys_migrate_pages
3. sys_mbind()

It really does not matter when we flush the lru.  The system is free to
add pages onto the lru even during migration which will make the page
migration either skip the page (mbind, migrate_pages) or return a busy
state (move_pages).

Fixes this lockdep warning (and potential deadlock):

Some VM place has
      mmap_sem -> kevent_wq via lru_add_drain_all()

net/core/dev.c::dev_ioctl()  has
     rtnl_lock  ->  mmap_sem        (*) the ioctl has copy_from_user() and it can do page fault.

linkwatch_event has
     kevent_wq -> rtnl_lock

Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:18 -08:00
David Rientjes
b4416d2bea oom: do not dump task state for non thread group leaders
When /proc/sys/vm/oom_dump_tasks is enabled, it's only necessary to dump
task state information for thread group leaders.  The kernel log gets
quickly overwhelmed on machines with a massive number of threads by
dumping non-thread group leaders.

Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:18 -08:00
Andy Whitcroft
18229df5b6 hugetlb: pull gigantic page initialisation out of the default path
As we can determine exactly when a gigantic page is in use we can optimise
the common regular page cases by pulling out gigantic page initialisation
into its own function.  As gigantic pages are never released to buddy we
do not need a destructor.  This effectivly reverts the previous change to
the main buddy allocator.  It also adds a paranoid check to ensure we
never release gigantic pages from hugetlbfs to the main buddy.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>		[2.6.27.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:18 -08:00
Andy Whitcroft
69d177c2fc hugetlbfs: handle pages higher order than MAX_ORDER
When working with hugepages, hugetlbfs assumes that those hugepages are
smaller than MAX_ORDER.  Specifically it assumes that the mem_map is
contigious and uses that to optimise access to the elements of the mem_map
that represent the hugepage.  Gigantic pages (such as 16GB pages on
powerpc) by definition are of greater order than MAX_ORDER (larger than
MAX_ORDER_NR_PAGES in size).  This means that we can no longer make use of
the buddy alloctor guarentees for the contiguity of the mem_map, which
ensures that the mem_map is at least contigious for maximmally aligned
areas of MAX_ORDER_NR_PAGES pages.

This patch adds new mem_map accessors and iterator helpers which handle
any discontiguity at MAX_ORDER_NR_PAGES boundaries.  It then uses these to
implement gigantic page versions of copy_huge_page and clear_huge_page,
and to allow follow_hugetlb_page handle gigantic pages.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>		[2.6.27.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:18 -08:00
Russell King
ab4f2ee130 [ARM] fix naming of MODULE_START / MODULE_END
As of 73bdf0a60e, the kernel needs
to know where modules are located in the virtual address space.
On ARM, we located this region between MODULE_START and MODULE_END.
Unfortunately, everyone else calls it MODULES_VADDR and MODULES_END.
Update ARM to use the same naming, so is_vmalloc_or_module_addr()
can work properly.  Also update the comment on mm/vmalloc.c to
reflect that ARM also places modules in a separate region from the
vmalloc space.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-11-06 17:13:47 +00:00
Alan Cox
731572d39f nfsd: fix vm overcommit crash
Junjiro R.  Okajima reported a problem where knfsd crashes if you are
using it to export shmemfs objects and run strict overcommit.  In this
situation the current->mm based modifier to the overcommit goes through a
NULL pointer.

We could simply check for NULL and skip the modifier but we've caught
other real bugs in the past from mm being NULL here - cases where we did
need a valid mm set up (eg the exec bug about a year ago).

To preserve the checks and get the logic we want shuffle the checking
around and add a new helper to the vm_ security wrappers

Also fix a current->mm reference in nommu that should use the passed mm

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix build]
Reported-by: Junjiro R. Okajima <hooanon05@yahoo.co.jp>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-30 11:38:47 -07:00
Randy Dunlap
e99c97ade5 mm: fix kernel-doc function notation
Delete excess kernel-doc notation in mm/ subdirectory.
Actually this is a kernel-doc notation fix.

Warning(/var/linsrc/linux-2.6.27-git10//mm/vmalloc.c:902): Excess function parameter or struct member 'returns' description in 'vm_map_ram'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-30 11:38:46 -07:00
Nick Piggin
4e02ed4b4a fs: remove prepare_write/commit_write
Nothing uses prepare_write or commit_write. Remove them from the tree
completely.

[akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-30 11:38:45 -07:00
Linus Torvalds
88ed86fee6 Merge branch 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc
* 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc: (35 commits)
  proc: remove fs/proc/proc_misc.c
  proc: move /proc/vmcore creation to fs/proc/vmcore.c
  proc: move pagecount stuff to fs/proc/page.c
  proc: move all /proc/kcore stuff to fs/proc/kcore.c
  proc: move /proc/schedstat boilerplate to kernel/sched_stats.h
  proc: move /proc/modules boilerplate to kernel/module.c
  proc: move /proc/diskstats boilerplate to block/genhd.c
  proc: move /proc/zoneinfo boilerplate to mm/vmstat.c
  proc: move /proc/vmstat boilerplate to mm/vmstat.c
  proc: move /proc/pagetypeinfo boilerplate to mm/vmstat.c
  proc: move /proc/buddyinfo boilerplate to mm/vmstat.c
  proc: move /proc/vmallocinfo to mm/vmalloc.c
  proc: move /proc/slabinfo boilerplate to mm/slub.c, mm/slab.c
  proc: move /proc/slab_allocators boilerplate to mm/slab.c
  proc: move /proc/interrupts boilerplate code to fs/proc/interrupts.c
  proc: move /proc/stat to fs/proc/stat.c
  proc: move rest of /proc/partitions code to block/genhd.c
  proc: move /proc/cpuinfo code to fs/proc/cpuinfo.c
  proc: move /proc/devices code to fs/proc/devices.c
  proc: move rest of /proc/locks to fs/locks.c
  ...
2008-10-23 12:04:37 -07:00
KAMEZAWA Hiroyuki
94b6da5ab8 memcg: fix page_cgroup allocation
page_cgroup_init() is called from mem_cgroup_init(). But at this
point, we cannot call alloc_bootmem().
(and this caused panic at boot.)

This patch moves page_cgroup_init() to init/main.c.

Time table is following:
==
  parse_args(). # we can trust mem_cgroup_subsys.disabled bit after this.
  ....
  cgroup_init_early()  # "early" init of cgroup.
  ....
  setup_arch()         # memmap is allocated.
  ...
  page_cgroup_init();
  mem_init();   # we cannot call alloc_bootmem after this.
  ....
  cgroup_init() # mem_cgroup is initialized.
==

Before page_cgroup_init(), mem_map must be initialized. So,
I added page_cgroup_init() to init/main.c directly.

(*) maybe this is not very clean but
    - cgroup_init_early() is too early
    - in cgroup_init(), we have to use vmalloc instead of alloc_bootmem().
    use of vmalloc area in x86-32 is important and we should avoid very large
    vmalloc() in x86-32. So, we want to use alloc_bootmem() and added page_cgroup_init()
    directly to init/main.c

[akpm@linux-foundation.org: remove unneeded/bad mem_cgroup_subsys declaration]
[akpm@linux-foundation.org: fix build]
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-23 08:55:02 -07:00
Paul Mundt
4c8210427b mm: page_cgroup needs linux/vmalloc.h for vmalloc_node()/vfree().
mm/page_cgroup.c: In function 'init_section_page_cgroup':
mm/page_cgroup.c:111: error: implicit declaration of function 'vmalloc_node'
mm/page_cgroup.c:111: warning: assignment makes pointer from integer without a cast
mm/page_cgroup.c: In function '__free_page_cgroup':
mm/page_cgroup.c:140: error: implicit declaration of function 'vfree'

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-23 08:55:01 -07:00
Alexey Dobriyan
5c9fe6281b proc: move /proc/zoneinfo boilerplate to mm/vmstat.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
2008-10-23 17:35:04 +04:00
Alexey Dobriyan
b6aa44ab69 proc: move /proc/vmstat boilerplate to mm/vmstat.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
2008-10-23 17:12:51 +04:00
Alexey Dobriyan
74e2e8e8ce proc: move /proc/pagetypeinfo boilerplate to mm/vmstat.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-23 16:33:29 +04:00
Alexey Dobriyan
8f32f7e5ac proc: move /proc/buddyinfo boilerplate to mm/vmstat.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-23 16:12:04 +04:00
Alexey Dobriyan
5f6a6a9c4e proc: move /proc/vmallocinfo to mm/vmalloc.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
2008-10-23 15:48:28 +04:00
Alexey Dobriyan
7b3c3a50a3 proc: move /proc/slabinfo boilerplate to mm/slub.c, mm/slab.c
Lose dummy ->write hook in case of SLUB, it's possible now.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-10-23 15:20:06 +04:00
Alexey Dobriyan
a0ec95a8e6 proc: move /proc/slab_allocators boilerplate to mm/slab.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-10-23 15:17:27 +04:00
Alexey Dobriyan
e1759c215b proc: switch /proc/meminfo to seq_file
and move it to fs/proc/meminfo.c while I'm at it.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-23 13:52:40 +04:00
Huang Weiyi
a50c22eed5 mm: remove duplicated #include's
Removed duplicated #include <linux/vmalloc.h> in mm/vmalloc.c and
"internal.h" in mm/memory.c.

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 16:17:42 -07:00
Hugh Dickins
e798ba57e9 Export tiny shmem_file_setup for DRM-GEM
We're trying to keep the !CONFIG_SHMEM tiny-shmem.c (using ramfs without
swap) in synch with CONFIG_SHMEM shmem.c (and mpm is preparing patches
to combine them).  I was glad to see EXPORT_SYMBOL_GPL(shmem_file_setup)
go into shmem.c, but why not support DRM-GEM when !CONFIG_SHMEM too?
But caution says still depend on MMU, since !CONFIG_MMU is.. different.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 16:17:42 -07:00
Linus Torvalds
b9d7ccf56b Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86 ACPI: fix breakage of resume on 64-bit UP systems with SMP kernel
  Introduce is_vmalloc_or_module_addr() and use with DEBUG_VIRTUAL
2008-10-20 13:27:05 -07:00
Adrian Bunk
fdd2e5f88a make mm/rmap.c:anon_vma_cachep static
This patch makes the needlessly global anon_vma_cachep static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:40 -07:00
KAMEZAWA Hiroyuki
52d4b9ac0b memcg: allocate all page_cgroup at boot
Allocate all page_cgroup at boot and remove page_cgroup poitner from
struct page.  This patch adds an interface as

 struct page_cgroup *lookup_page_cgroup(struct page*)

All FLATMEM/DISCONTIGMEM/SPARSEMEM  and MEMORY_HOTPLUG is supported.

Remove page_cgroup pointer reduces the amount of memory by
 - 4 bytes per PAGE_SIZE.
 - 8 bytes per PAGE_SIZE
if memory controller is disabled. (even if configured.)

On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory.
On my x86-64 server with 48GB of memory, this saves 96MB of memory.
I think this reduction makes sense.

By pre-allocation, kmalloc/kfree in charge/uncharge are removed.
This means
  - we're not necessary to be afraid of kmalloc faiulre.
    (this can happen because of gfp_mask type.)
  - we can avoid calling kmalloc/kfree.
  - we can avoid allocating tons of small objects which can be fragmented.
  - we can know what amount of memory will be used for this extra-lru handling.

I added printk message as

	"allocated %ld bytes of page_cgroup"
        "please try cgroup_disable=memory option if you don't want"

maybe enough informative for users.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:39 -07:00
KAMEZAWA Hiroyuki
c05555b572 memcg: atomic ops for page_cgroup->flags
This patch makes page_cgroup->flags to be atomic_ops and define functions
(and macros) to access it.

Before trying to modify memory resource controller, this atomic operation
on flags is necessary.  Most of flags in this patch is for LRU and modfied
under mz->lru_lock but we'll add another flags which is not for LRU soon.
For example, we'll place LOCK bit on flags field.  We need atomic
operation to modify LRU bit without LOCK.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:39 -07:00
KAMEZAWA Hiroyuki
addb9efebb memcg: optimize per-cpu statistics
Some obvious optimization to memcg.

I found mem_cgroup_charge_statistics() is a little big (in object) and
does unnecessary address calclation.  This patch is for optimization to
reduce the size of this function.

And res_counter_charge() is 'likely' to succeed.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:39 -07:00
KAMEZAWA Hiroyuki
5b4e655e94 memcg: avoid accounting special pages
There are not-on-LRU pages which can be mapped and they are not worth to
be accounted.  (becasue we can't shrink them and need dirty codes to
handle specical case) We'd like to make use of usual objrmap/radix-tree's
protcol and don't want to account out-of-vm's control pages.

When special_mapping_fault() is called, page->mapping is tend to be NULL
and it's charged as Anonymous page.  insert_page() also handles some
special pages from drivers.

This patch is for avoiding to account special pages.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:38 -07:00
KAMEZAWA Hiroyuki
b7abea9630 memcg: make page->mapping NULL before uncharge
This patch tries to make page->mapping to be NULL before
mem_cgroup_uncharge_cache_page() is called.

"page->mapping == NULL" is a good check for "whether the page is still
radix-tree or not".  This patch also adds BUG_ON() to
mem_cgroup_uncharge_cache_page();

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:38 -07:00
KAMEZAWA Hiroyuki
073e587ec2 memcg: move charge swapin under lock
While page-cache's charge/uncharge is done under page_lock(), swap-cache
isn't.  (anonymous page is charged when it's newly allocated.)

This patch moves do_swap_page()'s charge() call under lock.  I don't see
any bad problem *now* but this fix will be good for future for avoiding
unnecessary racy state.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:38 -07:00
Brice Goglin
5e9a0f023b mm: extract do_pages_move() out of sys_move_pages()
To prepare the chunking, move the sys_move_pages() code that is used when
nodes!=NULL into do_pages_move().  And rename do_move_pages() into
do_move_page_to_node_array().

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:33 -07:00
Brice Goglin
2f007e74bb mm: don't vmalloc a huge page_to_node array for do_pages_stat()
do_pages_stat() does not need any page_to_node entry for real.  Just pass
the pointers to the user-space page address array and to the user-space
status array, and have do_pages_stat() traverse the former and fill the
latter directly.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:33 -07:00
Brice Goglin
e78bbfa826 mm: stop returning -ENOENT from sys_move_pages() if nothing got migrated
A patchset reworking sys_move_pages().  It removes the possibly large
vmalloc by using multiple chunks when migrating large buffers.  It also
dramatically increases the throughput for large buffers since the lookup
in new_page_node() is now limited to a single chunk, causing the quadratic
complexity to have a much slower impact.  There is no need to use any
radix-tree-like structure to improve this lookup.

sys_move_pages() duration on a 4-quadcore-opteron 2347HE (1.9Gz),
migrating between nodes #2 and #3:

	length		move_pages (us)		move_pages+patch (us)
	4kB		126			98
	40kB		198			168
	400kB		963			937
	4MB		12503			11930
	40MB		246867			11848

Patches #1 and #4 are the important ones:
1) stop returning -ENOENT from sys_move_pages() if nothing got migrated
2) don't vmalloc a huge page_to_node array for do_pages_stat()
3) extract do_pages_move() out of sys_move_pages()
4) rework do_pages_move() to work on page_sized chunks
5) move_pages: no need to set pp->page to ZERO_PAGE(0) by default

This patch:

There is no point in returning -ENOENT from sys_move_pages() if all pages
were already on the right node, while we return 0 if only 1 page was not.
Most application don't know where their pages are allocated, so it's not
an error to try to migrate them anyway.

Just return 0 and let the status array in user-space be checked if the
application needs details.

It will make the upcoming chunked-move_pages() support much easier.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:33 -07:00
Nathan Fontenot
de7f0cba96 memory hotplug: release memory regions in PAGES_PER_SECTION chunks
During hotplug memory remove, memory regions should be released on a
PAGES_PER_SECTION size chunks.  This mirrors the code in add_memory where
resources are requested on a PAGES_PER_SECTION size.

Attempting to release the entire memory region fails because there is not
a single resource for the total number of pages being removed.  Instead
the resources for the pages are split in PAGES_PER_SECTION size chunks as
requested during memory add.

Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:32 -07:00
Gerald Schaefer
1125b4e394 setup_per_zone_pages_min(): take zone->lock instead of zone->lru_lock
This replaces zone->lru_lock in setup_per_zone_pages_min() with zone->lock.
There seems to be no need for the lru_lock anymore, but there is a need for
zone->lock instead, because that function may call move_freepages() via
setup_zone_migrate_reserve().

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:32 -07:00
KOSAKI Motohiro
4b2e38ad70 hugepage: support ZERO_PAGE()
Presently hugepage doesn't use zero page at all because zero page is only
used for coredumping and hugepage can't core dump.

However we have now implemented hugepage coredumping.  Therefore we should
implement the zero page of hugepage.

Implementation note:

o Why do we only check VM_SHARED for zero page?
  normal page checked as ..

	static inline int use_zero_page(struct vm_area_struct *vma)
	{
	        if (vma->vm_flags & (VM_LOCKED | VM_SHARED))
	                return 0;

	        return !vma->vm_ops || !vma->vm_ops->fault;
	}

First, hugepages are never mlock()ed.  We aren't concerned with VM_LOCKED.

Second, hugetlbfs is a pseudo filesystem, not a real filesystem and it
doesn't have any file backing.  Thus ops->fault checking is meaningless.

o Why don't we use zero page if !pte.

!pte indicate {pud, pmd} doesn't exist or some error happened.  So we
shouldn't return zero page if any error occurred.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Kawai Hidehiro <hidehiro.kawai.ez@hitachi.com>
Cc: Mel Gorman <mel@skynet.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:32 -07:00
Yinghai Lu
d903ef9f38 mm: print out meminit for memmap
Improve debuggability of memory setup problems.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:32 -07:00
Harvey Harrison
2a4b3ded5c mm: hugetlb.c make functions static, use NULL rather than 0
mm/hugetlb.c:265:17: warning: symbol 'resv_map_alloc' was not declared. Should it be static?
mm/hugetlb.c:277:6: warning: symbol 'resv_map_release' was not declared. Should it be static?
mm/hugetlb.c:292:9: warning: Using plain integer as NULL pointer
mm/hugetlb.c:1750:5: warning: symbol 'unmap_ref_private' was not declared. Should it be static?

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:32 -07:00
Nick Piggin
db64fe0225 mm: rewrite vmap layer
Rewrite the vmap allocator to use rbtrees and lazy tlb flushing, and
provide a fast, scalable percpu frontend for small vmaps (requires a
slightly different API, though).

The biggest problem with vmap is actually vunmap.  Presently this requires
a global kernel TLB flush, which on most architectures is a broadcast IPI
to all CPUs to flush the cache.  This is all done under a global lock.  As
the number of CPUs increases, so will the number of vunmaps a scaled
workload will want to perform, and so will the cost of a global TLB flush.
 This gives terrible quadratic scalability characteristics.

Another problem is that the entire vmap subsystem works under a single
lock.  It is a rwlock, but it is actually taken for write in all the fast
paths, and the read locking would likely never be run concurrently anyway,
so it's just pointless.

This is a rewrite of vmap subsystem to solve those problems.  The existing
vmalloc API is implemented on top of the rewritten subsystem.

The TLB flushing problem is solved by using lazy TLB unmapping.  vmap
addresses do not have to be flushed immediately when they are vunmapped,
because the kernel will not reuse them again (would be a use-after-free)
until they are reallocated.  So the addresses aren't allocated again until
a subsequent TLB flush.  A single TLB flush then can flush multiple
vunmaps from each CPU.

XEN and PAT and such do not like deferred TLB flushing because they can't
always handle multiple aliasing virtual addresses to a physical address.
They now call vm_unmap_aliases() in order to flush any deferred mappings.
That call is very expensive (well, actually not a lot more expensive than
a single vunmap under the old scheme), however it should be OK if not
called too often.

The virtual memory extent information is stored in an rbtree rather than a
linked list to improve the algorithmic scalability.

There is a per-CPU allocator for small vmaps, which amortizes or avoids
global locking.

To use the per-CPU interface, the vm_map_ram / vm_unmap_ram interfaces
must be used in place of vmap and vunmap.  Vmalloc does not use these
interfaces at the moment, so it will not be quite so scalable (although it
will use lazy TLB flushing).

As a quick test of performance, I ran a test that loops in the kernel,
linearly mapping then touching then unmapping 4 pages.  Different numbers
of tests were run in parallel on an 4 core, 2 socket opteron.  Results are
in nanoseconds per map+touch+unmap.

threads           vanilla         vmap rewrite
1                 14700           2900
2                 33600           3000
4                 49500           2800
8                 70631           2900

So with a 8 cores, the rewritten version is already 25x faster.

In a slightly more realistic test (although with an older and less
scalable version of the patch), I ripped the not-very-good vunmap batching
code out of XFS, and implemented the large buffer mapping with vm_map_ram
and vm_unmap_ram...  along with a couple of other tricks, I was able to
speed up a large directory workload by 20x on a 64 CPU system.  I believe
vmap/vunmap is actually sped up a lot more than 20x on such a system, but
I'm running into other locks now.  vmap is pretty well blown off the
profiles.

Before:
1352059 total                                      0.1401
798784 _write_lock                              8320.6667 <- vmlist_lock
529313 default_idle                             1181.5022
 15242 smp_call_function                         15.8771  <- vmap tlb flushing
  2472 __get_vm_area_node                         1.9312  <- vmap
  1762 remove_vm_area                             4.5885  <- vunmap
   316 map_vm_area                                0.2297  <- vmap
   312 kfree                                      0.1950
   300 _spin_lock                                 3.1250
   252 sn_send_IPI_phys                           0.4375  <- tlb flushing
   238 vmap                                       0.8264  <- vmap
   216 find_lock_page                             0.5192
   196 find_next_bit                              0.3603
   136 sn2_send_IPI                               0.2024
   130 pio_phys_write_mmr                         2.0312
   118 unmap_kernel_range                         0.1229

After:
 78406 total                                      0.0081
 40053 default_idle                              89.4040
 33576 ia64_spinlock_contention                 349.7500
  1650 _spin_lock                                17.1875
   319 __reg_op                                   0.5538
   281 _atomic_dec_and_lock                       1.0977
   153 mutex_unlock                               1.5938
   123 iget_locked                                0.1671
   117 xfs_dir_lookup                             0.1662
   117 dput                                       0.1406
   114 xfs_iget_core                              0.0268
    92 xfs_da_hashname                            0.1917
    75 d_alloc                                    0.0670
    68 vmap_page_range                            0.0462 <- vmap
    58 kmem_cache_alloc                           0.0604
    57 memset                                     0.0540
    52 rb_next                                    0.1625
    50 __copy_user                                0.0208
    49 bitmap_find_free_region                    0.2188 <- vmap
    46 ia64_sn_udelay                             0.1106
    45 find_inode_fast                            0.1406
    42 memcmp                                     0.2188
    42 finish_task_switch                         0.1094
    42 __d_lookup                                 0.0410
    40 radix_tree_lookup_slot                     0.1250
    37 _spin_unlock_irqrestore                    0.3854
    36 xfs_bmapi                                  0.0050
    36 kmem_cache_free                            0.0256
    35 xfs_vn_getattr                             0.0322
    34 radix_tree_lookup                          0.1062
    33 __link_path_walk                           0.0035
    31 xfs_da_do_buf                              0.0091
    30 _xfs_buf_find                              0.0204
    28 find_get_page                              0.0875
    27 xfs_iread                                  0.0241
    27 __strncpy_from_user                        0.2812
    26 _xfs_buf_initialize                        0.0406
    24 _xfs_buf_lookup_pages                      0.0179
    24 vunmap_page_range                          0.0250 <- vunmap
    23 find_lock_page                             0.0799
    22 vm_map_ram                                 0.0087 <- vmap
    20 kfree                                      0.0125
    19 put_page                                   0.0330
    18 __kmalloc                                  0.0176
    17 xfs_da_node_lookup_int                     0.0086
    17 _read_lock                                 0.0885
    17 page_waitqueue                             0.0664

vmap has gone from being the top 5 on the profiles and flushing the crap
out of all TLBs, to using less than 1% of kernel time.

[akpm@linux-foundation.org: cleanups, section fix]
[akpm@linux-foundation.org: fix build on alpha]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:32 -07:00