Commit Graph

260 Commits

Author SHA1 Message Date
Linus Torvalds d652e1eb8e Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler changes from Ingo Molnar:
 "Main changes:

   - scheduler side full-dynticks (user-space execution is undisturbed
     and receives no timer IRQs) preparation changes that convert the
     cputime accounting code to be full-dynticks ready, from Frederic
     Weisbecker.

   - Initial sched.h split-up changes, by Clark Williams

   - select_idle_sibling() performance improvement by Mike Galbraith:

        " 1 tbench pair (worst case) in a 10 core + SMT package:

          pre   15.22 MB/sec 1 procs
          post 252.01 MB/sec 1 procs "

  - sched_rr_get_interval() ABI fix/change.  We think this detail is not
    used by apps (so it's not an ABI in practice), but lets keep it
    under observation.

  - misc RT scheduling cleanups, optimizations"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  sched/rt: Add <linux/sched/rt.h> header to <linux/init_task.h>
  cputime: Remove irqsave from seqlock readers
  sched, powerpc: Fix sched.h split-up build failure
  cputime: Restore CPU_ACCOUNTING config defaults for PPC64
  sched/rt: Move rt specific bits into new header file
  sched/rt: Add a tuning knob to allow changing SCHED_RR timeslice
  sched: Move sched.h sysctl bits into separate header
  sched: Fix signedness bug in yield_to()
  sched: Fix select_idle_sibling() bouncing cow syndrome
  sched/rt: Further simplify pick_rt_task()
  sched/rt: Do not account zero delta_exec in update_curr_rt()
  cputime: Safely read cputime of full dynticks CPUs
  kvm: Prepare to add generic guest entry/exit callbacks
  cputime: Use accessors to read task cputime stats
  cputime: Allow dynamic switch between tick/virtual based cputime accounting
  cputime: Generic on-demand virtual cputime accounting
  cputime: Move default nsecs_to_cputime() to jiffies based cputime file
  cputime: Librarize per nsecs resolution cputime definitions
  cputime: Avoid multiplication overflow on utime scaling
  context_tracking: Export context state for generic vtime
  ...

Fix up conflict in kernel/context_tracking.c due to comment additions.
2013-02-19 18:19:48 -08:00
Clark Williams cf4aebc292 sched: Move sched.h sysctl bits into separate header
Move the sysctl-related bits from include/linux/sched.h into
a new file: include/linux/sched/sysctl.h. Then update source
files requiring access to those bits by including the new
header file.

Signed-off-by: Clark Williams <williams@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20130207094659.06dced96@riff.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-07 20:50:54 +01:00
Yuanhan Liu 631b0cfdbd mm: fix wrong comments about anon_vma lock
We use rwsem since commit 5a505085f0 ("mm/rmap: Convert the struct
anon_vma::mutex to an rwsem").  And most of comments are converted to
the new rwsem lock; while just 2 more missed from:

	 $ git grep 'anon_vma->mutex'

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.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>
2013-02-05 20:38:48 +11:00
Jiri Kosina 572043c90d mm: mmap: annotate vm_lock_anon_vma locking properly for lockdep
Commit 5a505085f0 ("mm/rmap: Convert the struct anon_vma::mutex to an
rwsem") turned anon_vma mutex to rwsem.

However, the properly annotated nested locking in mm_take_all_locks()
has been converted from

	mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem);

to

	down_write(&anon_vma->root->rwsem);

which is incomplete, and causes the false positive report from lockdep
below.

Annotate the fact that mmap_sem is used as an outter lock to serialize
taking of all the anon_vma rwsems at once no matter the order, using the
down_write_nest_lock() primitive.

This patch fixes this lockdep report:

 =============================================
 [ INFO: possible recursive locking detected ]
 3.8.0-rc2-00036-g5f73896 #171 Not tainted
 ---------------------------------------------
 qemu-kvm/2315 is trying to acquire lock:
  (&anon_vma->rwsem){+.+...}, at: mm_take_all_locks+0x149/0x1b0

 but task is already holding lock:
  (&anon_vma->rwsem){+.+...}, at: mm_take_all_locks+0x149/0x1b0

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&anon_vma->rwsem);
   lock(&anon_vma->rwsem);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 4 locks held by qemu-kvm/2315:
  #0:  (&mm->mmap_sem){++++++}, at: do_mmu_notifier_register+0xfc/0x170
  #1:  (mm_all_locks_mutex){+.+...}, at: mm_take_all_locks+0x36/0x1b0
  #2:  (&mapping->i_mmap_mutex){+.+...}, at: mm_take_all_locks+0xc9/0x1b0
  #3:  (&anon_vma->rwsem){+.+...}, at: mm_take_all_locks+0x149/0x1b0

 stack backtrace:
 Pid: 2315, comm: qemu-kvm Not tainted 3.8.0-rc2-00036-g5f73896 #171
 Call Trace:
   print_deadlock_bug+0xf2/0x100
   validate_chain+0x4f6/0x720
   __lock_acquire+0x359/0x580
   lock_acquire+0x121/0x190
   down_write+0x3f/0x70
   mm_take_all_locks+0x149/0x1b0
   do_mmu_notifier_register+0x68/0x170
   mmu_notifier_register+0xe/0x10
   kvm_create_vm+0x22b/0x330 [kvm]
   kvm_dev_ioctl+0xf8/0x1a0 [kvm]
   do_vfs_ioctl+0x9d/0x350
   sys_ioctl+0x91/0xb0
   system_call_fastpath+0x16/0x1b

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-11 14:54:55 -08:00
Linus Torvalds 3d59eebc5e Automatic NUMA Balancing V11
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Merge tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma

Pull Automatic NUMA Balancing bare-bones from Mel Gorman:
 "There are three implementations for NUMA balancing, this tree
  (balancenuma), numacore which has been developed in tip/master and
  autonuma which is in aa.git.

  In almost all respects balancenuma is the dumbest of the three because
  its main impact is on the VM side with no attempt to be smart about
  scheduling.  In the interest of getting the ball rolling, it would be
  desirable to see this much merged for 3.8 with the view to building
  scheduler smarts on top and adapting the VM where required for 3.9.

  The most recent set of comparisons available from different people are

    mel:    https://lkml.org/lkml/2012/12/9/108
    mingo:  https://lkml.org/lkml/2012/12/7/331
    tglx:   https://lkml.org/lkml/2012/12/10/437
    srikar: https://lkml.org/lkml/2012/12/10/397

  The results are a mixed bag.  In my own tests, balancenuma does
  reasonably well.  It's dumb as rocks and does not regress against
  mainline.  On the other hand, Ingo's tests shows that balancenuma is
  incapable of converging for this workloads driven by perf which is bad
  but is potentially explained by the lack of scheduler smarts.  Thomas'
  results show balancenuma improves on mainline but falls far short of
  numacore or autonuma.  Srikar's results indicate we all suffer on a
  large machine with imbalanced node sizes.

  My own testing showed that recent numacore results have improved
  dramatically, particularly in the last week but not universally.
  We've butted heads heavily on system CPU usage and high levels of
  migration even when it shows that overall performance is better.
  There are also cases where it regresses.  Of interest is that for
  specjbb in some configurations it will regress for lower numbers of
  warehouses and show gains for higher numbers which is not reported by
  the tool by default and sometimes missed in treports.  Recently I
  reported for numacore that the JVM was crashing with
  NullPointerExceptions but currently it's unclear what the source of
  this problem is.  Initially I thought it was in how numacore batch
  handles PTEs but I'm no longer think this is the case.  It's possible
  numacore is just able to trigger it due to higher rates of migration.

  These reports were quite late in the cycle so I/we would like to start
  with this tree as it contains much of the code we can agree on and has
  not changed significantly over the last 2-3 weeks."

* tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits)
  mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable
  mm/rmap: Convert the struct anon_vma::mutex to an rwsem
  mm: migrate: Account a transhuge page properly when rate limiting
  mm: numa: Account for failed allocations and isolations as migration failures
  mm: numa: Add THP migration for the NUMA working set scanning fault case build fix
  mm: numa: Add THP migration for the NUMA working set scanning fault case.
  mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node
  mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG
  mm: sched: numa: Control enabling and disabling of NUMA balancing
  mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate
  mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely task<->node relationships
  mm: numa: migrate: Set last_nid on newly allocated page
  mm: numa: split_huge_page: Transfer last_nid on tail page
  mm: numa: Introduce last_nid to the page frame
  sched: numa: Slowly increase the scanning period as NUMA faults are handled
  mm: numa: Rate limit setting of pte_numa if node is saturated
  mm: numa: Rate limit the amount of memory that is migrated between nodes
  mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting
  mm: numa: Migrate pages handled during a pmd_numa hinting fault
  mm: numa: Migrate on reference policy
  ...
2012-12-16 15:18:08 -08:00
Michel Lespinasse 4128997b5f mm: protect against concurrent vma expansion
expand_stack() runs with a shared mmap_sem lock.  Because of this, there
could be multiple concurrent stack expansions in the same mm, which may
cause problems in the vma gap update code.

I propose to solve this by taking the mm->page_table_lock around such vma
expansions, in order to avoid the concurrency issue.  We only have to
worry about concurrent expand_stack() calls here, since we hold a shared
mmap_sem lock and all vma modificaitons other than expand_stack() are done
under an exclusive mmap_sem lock.

I previously tried to achieve the same effect by making sure all growable
vmas in a given mm would share the same anon_vma, which we already lock
here.  However this turned out to be difficult - all of the schemes I
tried for refcounting the growable anon_vma and clearing turned out ugly.
So, I'm now proposing only the minimal fix.

The overhead of taking the page table lock during stack expansion is
expected to be small: glibc doesn't use expandable stacks for the threads
it creates, so having multiple growable stacks is actually uncommon and we
don't expect the page table lock to get bounced between threads.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 17:38:35 -08:00
Joonsoo Kim 2897b4d29d mm: WARN_ON_ONCE if f_op->mmap() change vma's start address
During reviewing the source code, I found a comment which mention that
after f_op->mmap(), vma's start address can be changed.  I didn't verify
that it is really possible, because there are so many f_op->mmap()
implementation.  But if there are some mmap() which change vma's start
address, it is possible error situation, because we already prepare prev
vma, rb_link and rb_parent and these are related to original address.

So add WARN_ON_ONCE for finding that this situtation really happens.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-12 17:38:33 -08:00
Linus Torvalds 608ff1a210 Merge branch 'akpm' (Andrew's patchbomb)
Merge misc updates from Andrew Morton:
 "About half of most of MM.  Going very early this time due to
  uncertainty over the coreautounifiednumasched things.  I'll send the
  other half of most of MM tomorrow.  The rest of MM awaits a slab merge
  from Pekka."

* emailed patches from Andrew Morton: (71 commits)
  memory_hotplug: ensure every online node has NORMAL memory
  memory_hotplug: handle empty zone when online_movable/online_kernel
  mm, memory-hotplug: dynamic configure movable memory and portion memory
  drivers/base/node.c: cleanup node_state_attr[]
  bootmem: fix wrong call parameter for free_bootmem()
  avr32, kconfig: remove HAVE_ARCH_BOOTMEM
  mm: cma: remove watermark hacks
  mm: cma: skip watermarks check for already isolated blocks in split_free_page()
  mm, oom: fix race when specifying a thread as the oom origin
  mm, oom: change type of oom_score_adj to short
  mm: cleanup register_node()
  mm, mempolicy: remove duplicate code
  mm/vmscan.c: try_to_freeze() returns boolean
  mm: introduce putback_movable_pages()
  virtio_balloon: introduce migration primitives to balloon pages
  mm: introduce compaction and migration for ballooned pages
  mm: introduce a common interface for balloon pages mobility
  mm: redefine address_space.assoc_mapping
  mm: adjust address_space_operations.migratepage() return code
  arch/sparc/kernel/sys_sparc_64.c: s/COLOUR/COLOR/
  ...
2012-12-11 18:05:37 -08:00
Michel Lespinasse db4fbfb952 mm: vm_unmapped_area() lookup function
Implement vm_unmapped_area() using the rb_subtree_gap and highest_vm_end
information to look up for suitable virtual address space gaps.

struct vm_unmapped_area_info is used to define the desired allocation
request:
 - lowest or highest possible address matching the remaining constraints
 - desired gap length
 - low/high address limits that the gap must fit into
 - alignment mask and offset

Also update the generic arch_get_unmapped_area[_topdown] functions to make
use of vm_unmapped_area() instead of implementing a brute force search.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:25 -08:00
Michel Lespinasse 5a0768f641 mm: check rb_subtree_gap correctness
When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is correctly
set for every vma and that mm->highest_vm_end is also correct.

Also add an explicit 'bug' variable to track if browse_rb() detected any
invalid condition.

[akpm@linux-foundation.org: repair innovative coding-style inventions]
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:25 -08:00
Michel Lespinasse d37371870c mm: augment vma rbtree with rb_subtree_gap
Define vma->rb_subtree_gap as the largest gap between any vma in the
subtree rooted at that vma, and their predecessor.  Or, for a recursive
definition, vma->rb_subtree_gap is the max of:

 - vma->vm_start - vma->vm_prev->vm_end
 - rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and
   vma->rb.rb_right

This will allow get_unmapped_area_* to find a free area of the right
size in O(log(N)) time, instead of potentially having to do a linear
walk across all the VMAs.

Also define mm->highest_vm_end as the vm_end field of the highest vma,
so that we can easily check if the following gap is suitable.

This does have the potential to make unmapping VMAs more expensive,
especially for processes with very large numbers of VMAs, where the VMA
rbtree can grow quite deep.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:25 -08:00
Andi Kleen 42d7395feb mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB
There was some desire in large applications using MAP_HUGETLB or
SHM_HUGETLB to use 1GB huge pages on some mappings, and stay with 2MB on
others.  This is useful together with NUMA policy: use 2MB interleaving
on some mappings, but 1GB on local mappings.

This patch extends the IPC/SHM syscall interfaces slightly to allow
specifying the page size.

It borrows some upper bits in the existing flag arguments and allows
encoding the log of the desired page size in addition to the *_HUGETLB
flag.  When 0 is specified the default size is used, this makes the
change fully compatible.

Extending the internal hugetlb code to handle this is straight forward.
Instead of a single mount it just keeps an array of them and selects the
right mount based on the specified page size.  When no page size is
specified it uses the mount of the default page size.

The change is not visible in /proc/mounts because internal mounts don't
appear there.  It also has very little overhead: the additional mounts
just consume a super block, but not more memory when not used.

I also exported the new flags to the user headers (they were previously
under __KERNEL__).  Right now only symbols for x86 and some other
architecture for 1GB and 2MB are defined.  The interface should already
work for all other architectures though.  Only architectures that define
multiple hugetlb sizes actually need it (that is currently x86, tile,
powerpc).  However tile and powerpc have user configurable hugetlb
sizes, so it's not easy to add defines.  A program on those
architectures would need to query sysfs and use the appropiate log2.

[akpm@linux-foundation.org: cleanups]
[rientjes@google.com: fix build]
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
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>
2012-12-11 17:22:25 -08:00
Ingo Molnar 4fc3f1d66b mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable
rmap_walk_anon() and try_to_unmap_anon() appears to be too
careful about locking the anon vma: while it needs protection
against anon vma list modifications, it does not need exclusive
access to the list itself.

Transforming this exclusive lock to a read-locked rwsem removes
a global lock from the hot path of page-migration intense
threaded workloads which can cause pathological performance like
this:

    96.43%        process 0  [kernel.kallsyms]  [k] perf_trace_sched_switch
                  |
                  --- perf_trace_sched_switch
                      __schedule
                      schedule
                      schedule_preempt_disabled
                      __mutex_lock_common.isra.6
                      __mutex_lock_slowpath
                      mutex_lock
                     |
                     |--50.61%-- rmap_walk
                     |          move_to_new_page
                     |          migrate_pages
                     |          migrate_misplaced_page
                     |          __do_numa_page.isra.69
                     |          handle_pte_fault
                     |          handle_mm_fault
                     |          __do_page_fault
                     |          do_page_fault
                     |          page_fault
                     |          __memset_sse2
                     |          |
                     |           --100.00%-- worker_thread
                     |                     |
                     |                      --100.00%-- start_thread
                     |
                      --49.39%-- page_lock_anon_vma
                                try_to_unmap_anon
                                try_to_unmap
                                migrate_pages
                                migrate_misplaced_page
                                __do_numa_page.isra.69
                                handle_pte_fault
                                handle_mm_fault
                                __do_page_fault
                                do_page_fault
                                page_fault
                                __memset_sse2
                                |
                                 --100.00%-- worker_thread
                                           start_thread

With this change applied the profile is now nicely flat
and there's no anon-vma related scheduling/blocking.

Rename anon_vma_[un]lock() => anon_vma_[un]lock_write(),
to make it clearer that it's an exclusive write-lock in
that case - suggested by Rik van Riel.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-11 14:43:00 +00:00
Ingo Molnar 5a505085f0 mm/rmap: Convert the struct anon_vma::mutex to an rwsem
Convert the struct anon_vma::mutex to an rwsem, which will help
in solving a page-migration scalability problem. (Addressed in
a separate patch.)

The conversion is simple and straightforward: in every case
where we mutex_lock()ed we'll now down_write().

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
2012-12-11 14:43:00 +00:00
Greg Kroah-Hartman 98c4514ff6 Merge 3.7-rc6 into char-misc-next 2012-11-16 18:21:36 -08:00
Michel Lespinasse 63c3b902e5 mm: add anon_vma_lock to validate_mm()
Iterating over the vma->anon_vma_chain without anon_vma_lock may cause
NULL ptr deref in anon_vma_interval_tree_verify(), because the node in the
chain might have been removed.

  BUG: unable to handle kernel paging request at fffffffffffffff0
  IP: [<ffffffff8122c29c>] anon_vma_interval_tree_verify+0xc/0xa0
  PGD 4e28067 PUD 4e29067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
  CPU 0
  Pid: 9050, comm: trinity-child64 Tainted: G        W    3.7.0-rc2-next-20121025-sasha-00001-g673f98e-dirty #77
  RIP: 0010: anon_vma_interval_tree_verify+0xc/0xa0
  Process trinity-child64 (pid: 9050, threadinfo ffff880045f80000, task ffff880048eb0000)
  Call Trace:
    validate_mm+0x58/0x1e0
    vma_adjust+0x635/0x6b0
    __split_vma.isra.22+0x161/0x220
    split_vma+0x24/0x30
    sys_madvise+0x5da/0x7b0
    tracesys+0xe1/0xe6
  RIP  anon_vma_interval_tree_verify+0xc/0xa0
  CR2: fffffffffffffff0

Figured out by Bob Liu.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-11-16 14:33:03 -08:00
K. Y. Srinivasan 997071bcb3 mm: export a function to get vm committed memory
It will be useful to be able to access global memory commitment from
device drivers.  On the Hyper-V platform, the host has a policy engine to
balance the available physical memory amongst all competing virtual
machines hosted on a given node.  This policy engine is driven by a number
of metrics including the memory commitment reported by the guests.  The
balloon driver for Linux on Hyper-V will use this function to retrieve
guest memory commitment.  This function is also used in Xen self
ballooning code.

[akpm@linux-foundation.org: coding-style tweak]
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-15 15:41:22 -08:00
Michel Lespinasse 38a76013ad mm: avoid taking rmap locks in move_ptes()
During mremap(), the destination VMA is generally placed after the
original vma in rmap traversal order: in move_vma(), we always have
new_pgoff >= vma->vm_pgoff, and as a result new_vma->vm_pgoff >=
vma->vm_pgoff unless vma_merge() merged the new vma with an adjacent one.

When the destination VMA is placed after the original in rmap traversal
order, we can avoid taking the rmap locks in move_ptes().

Essentially, this reintroduces the optimization that had been disabled in
"mm anon rmap: remove anon_vma_moveto_tail".  The difference is that we
don't try to impose the rmap traversal order; instead we just rely on
things being in the desired order in the common case and fall back to
taking locks in the uncommon case.  Also we skip the i_mmap_mutex in
addition to the anon_vma lock: in both cases, the vmas are traversed in
increasing vm_pgoff order with ties resolved in tree insertion order.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:42 +09:00
Michel Lespinasse 523d4e2008 mm anon rmap: in mremap, set the new vma's position before anon_vma_clone()
anon_vma_clone() expects new_vma->vm_{start,end,pgoff} to be correctly set
so that the new vma can be indexed on the anon interval tree.

copy_vma() was failing to do that, which broke mremap().

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:42 +09:00
Michel Lespinasse ed8ea81501 mm: add CONFIG_DEBUG_VM_RB build option
Add a CONFIG_DEBUG_VM_RB build option for the previously existing
DEBUG_MM_RB code.  Now that Andi Kleen modified it to avoid using
recursive algorithms, we can expose it a bit more.

Also extend this code to validate_mm() after stack expansion, and to check
that the vma's start and last pgoffs have not changed since the nodes were
inserted on the anon vma interval tree (as it is important that the nodes
be reindexed after each such update).

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:42 +09:00
Michel Lespinasse bf181b9f9d mm anon rmap: replace same_anon_vma linked list with an interval tree.
When a large VMA (anon or private file mapping) is first touched, which
will populate its anon_vma field, and then split into many regions through
the use of mprotect(), the original anon_vma ends up linking all of the
vmas on a linked list.  This can cause rmap to become inefficient, as we
have to walk potentially thousands of irrelevent vmas before finding the
one a given anon page might fall into.

By replacing the same_anon_vma linked list with an interval tree (where
each avc's interval is determined by its vma's start and last pgoffs), we
can make rmap efficient for this use case again.

While the change is large, all of its pieces are fairly simple.

Most places that were walking the same_anon_vma list were looking for a
known pgoff, so they can just use the anon_vma_interval_tree_foreach()
interval tree iterator instead.  The exception here is ksm, where the
page's index is not known.  It would probably be possible to rework ksm so
that the index would be known, but for now I have decided to keep things
simple and just walk the entirety of the interval tree there.

When updating vma's that already have an anon_vma assigned, we must take
care to re-index the corresponding avc's on their interval tree.  This is
done through the use of anon_vma_interval_tree_pre_update_vma() and
anon_vma_interval_tree_post_update_vma(), which remove the avc's from
their interval tree before the update and re-insert them after the update.
 The anon_vma stays locked during the update, so there is no chance that
rmap would miss the vmas that are being updated.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:41 +09:00
Michel Lespinasse 108d6642ad mm anon rmap: remove anon_vma_moveto_tail
mremap() had a clever optimization where move_ptes() did not take the
anon_vma lock to avoid a race with anon rmap users such as page migration.
 Instead, the avc's were ordered in such a way that the origin vma was
always visited by rmap before the destination.  This ordering and the use
of page table locks rmap usage safe.  However, we want to replace the use
of linked lists in anon rmap with an interval tree, and this will make it
harder to impose such ordering as the interval tree will always be sorted
by the avc->vma->vm_pgoff value.  For now, let's replace the
anon_vma_moveto_tail() ordering function with proper anon_vma locking in
move_ptes().  Once we have the anon interval tree in place, we will
re-introduce an optimization to avoid taking these locks in the most
common cases.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:41 +09:00
Michel Lespinasse 6b2dbba8b6 mm: replace vma prio_tree with an interval tree
Implement an interval tree as a replacement for the VMA prio_tree.  The
algorithms are similar to lib/interval_tree.c; however that code can't be
directly reused as the interval endpoints are not explicitly stored in the
VMA.  So instead, the common algorithm is moved into a template and the
details (node type, how to get interval endpoints from the node, etc) are
filled in using the C preprocessor.

Once the interval tree functions are available, using them as a
replacement to the VMA prio tree is a relatively simple, mechanical job.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:39 +09:00
Michel Lespinasse ca42b26ab2 mm: fix potential anon_vma locking issue in mprotect()
Fix an anon_vma locking issue in the following situation:

- vma has no anon_vma
- next has an anon_vma
- vma is being shrunk / next is being expanded, due to an mprotect call

We need to take next's anon_vma lock to avoid races with rmap users (such
as page migration) while next is being expanded.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:28 +09:00
Hugh Dickins 6597d78339 mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links()
People get confused by find_vma_prepare(), because it doesn't care about
what it returns in its output args, when its callers won't be interested.

Clarify by passing in end-of-range address too, and returning failure if
any existing vma overlaps the new range: instead of returning an ambiguous
vma which most callers then must check.  find_vma_links() is a clearer
name.

This does revert 2.6.27's dfe195fb79 ("mm: fix uninitialized variables
for find_vma_prepare callers"), but it looks like gcc 4.3.0 was one of
those releases too eager to shout about uninitialized variables: only
copy_vma() warns with 4.5.1 and 4.7.1, which a BUG on error silences.

[hughd@google.com: fix warning, remove BUG()]
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:20 +09:00
Konstantin Khlebnikov 314e51b985 mm: kill vma flag VM_RESERVED and mm->reserved_vm counter
A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:

 | effect                 | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump      | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock           | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP

This patch removes reserved_vm counter from mm_struct.  Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.

Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.

remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.

[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:19 +09:00
Konstantin Khlebnikov e9714acf8c mm: kill vma flag VM_EXECUTABLE and mm->num_exe_file_vmas
Currently the kernel sets mm->exe_file during sys_execve() and then tracks
number of vmas with VM_EXECUTABLE flag in mm->num_exe_file_vmas, as soon
as this counter drops to zero kernel resets mm->exe_file to NULL.  Plus it
resets mm->exe_file at last mmput() when mm->mm_users drops to zero.

VMA with VM_EXECUTABLE flag appears after mapping file with flag
MAP_EXECUTABLE, such vmas can appears only at sys_execve() or after vma
splitting, because sys_mmap ignores this flag.  Usually binfmt module sets
mm->exe_file and mmaps executable vmas with this file, they hold
mm->exe_file while task is running.

comment from v2.6.25-6245-g925d1c4 ("procfs task exe symlink"),
where all this stuff was introduced:

> The kernel implements readlink of /proc/pid/exe by getting the file from
> the first executable VMA.  Then the path to the file is reconstructed and
> reported as the result.
>
> Because of the VMA walk the code is slightly different on nommu systems.
> This patch avoids separate /proc/pid/exe code on nommu systems.  Instead of
> walking the VMAs to find the first executable file-backed VMA we store a
> reference to the exec'd file in the mm_struct.
>
> That reference would prevent the filesystem holding the executable file
> from being unmounted even after unmapping the VMAs.  So we track the number
> of VM_EXECUTABLE VMAs and drop the new reference when the last one is
> unmapped.  This avoids pinning the mounted filesystem.

exe_file's vma accounting is hooked into every file mmap/unmmap and vma
split/merge just to fix some hypothetical pinning fs from umounting by mm,
which already unmapped all its executable files, but still alive.

Seems like currently nobody depends on this behaviour.  We can try to
remove this logic and keep mm->exe_file until final mmput().

mm->exe_file is still protected with mm->mmap_sem, because we want to
change it via new sys_prctl(PR_SET_MM_EXE_FILE).  Also via this syscall
task can change its mm->exe_file and unpin mountpoint explicitly.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:18 +09:00
Konstantin Khlebnikov 0b173bc4da mm: kill vma flag VM_CAN_NONLINEAR
Move actual pte filling for non-linear file mappings into the new special
vma operation: ->remap_pages().

Filesystems must implement this method to get non-linear mapping support,
if it uses filemap_fault() then generic_file_remap_pages() can be used.

Now device drivers can implement this method and obtain nonlinear vma support.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>	#arch/tile
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:17 +09:00
Konstantin Khlebnikov 4b6e1e3702 mm: kill vma flag VM_INSERTPAGE
Merge VM_INSERTPAGE into VM_MIXEDMAP.  VM_MIXEDMAP VMA can mix pure-pfn
ptes, special ptes and normal ptes.

Now copy_page_range() always copies VM_MIXEDMAP VMA on fork like
VM_PFNMAP.  If driver populates whole VMA at mmap() it probably not
expects page-faults.

This patch removes special check from vma_wants_writenotify() which
disables pages write tracking for VMA populated via vm_instert_page().
BDI below mapped file should not use dirty-accounting, moreover
do_wp_page() can handle this.

vm_insert_page() still marks vma after first usage.  Usually it is called
from f_op->mmap() handler under mm->mmap_sem write-lock, so it able to
change vma->vm_flags.  Caller must set VM_MIXEDMAP at mmap time if it
wants to call this function from other places, for example from page-fault
handler.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:17 +09:00
Al Viro cb0942b812 make get_file() return its argument
simplifies a bunch of callers...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26 21:10:25 -04:00
Linus Torvalds 7ca63ee1b0 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "This tree contains misc fixlets: a perf script python binding fix, a
  uprobes fix and a syscall tracing fix."

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Add missing files to build the python binding
  uprobes: Fix mmap_region()'s mm->mm_rb corruption if uprobe_mmap() fails
  tracing/syscalls: Fix perf syscall tracing when syscall_nr == -1
2012-08-23 21:48:41 -07:00
Hugh Dickins f9aed62a2b mm: change nr_ptes BUG_ON to WARN_ON
Occasionally an isolated BUG_ON(mm->nr_ptes) gets reported, indicating
that not all the page tables allocated could be found and freed when
exit_mmap() tore down the user address space.

There's usually nothing we can say about it, beyond that it's probably a
sign of some bad memory or memory corruption; though it might still
indicate a bug in vma or page table management (and did recently reveal a
race in THP, fixed a few months ago).

But one overdue change we can make is from BUG_ON to WARN_ON.

It's fairly likely that the system will crash shortly afterwards in some
other way (for example, the BUG_ON(page_mapped(page)) in
__delete_from_page_cache(), once an inode mapped into the lost page tables
gets evicted); but might tell us more before that.

Change the BUG_ON(page_mapped) to WARN_ON too?  Later perhaps: I'm less
eager, since that one has several times led to fixes.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-08-21 16:45:02 -07:00
Oleg Nesterov c7a3a88c93 uprobes: Fix mmap_region()'s mm->mm_rb corruption if uprobe_mmap() fails
This patch fixes:

  https://bugzilla.redhat.com/show_bug.cgi?id=843640

If mmap_region()->uprobe_mmap() fails, unmap_and_free_vma path
does unmap_region() but does not remove the soon-to-be-freed vma
from rb tree. Actually there are more problems but this is how
William noticed this bug.

Perhaps we could do do_munmap() + return in this case, but in
fact it is simply wrong to abort if uprobe_mmap() fails. Until
at least we move the !UPROBE_COPY_INSN code from
install_breakpoint() to uprobe_register().

For example, uprobe_mmap()->install_breakpoint() can fail if the
probed insn is not supported (remember, uprobe_register()
succeeds if nobody mmaps inode/offset), mmap() should not fail
in this case.

dup_mmap()->uprobe_mmap() is wrong too by the same reason,
fork() can race with uprobe_register() and fail for no reason if
it wins the race and does install_breakpoint() first.

And, if nothing else, both mmap_region() and dup_mmap() return
success if uprobe_mmap() fails. Change them to ignore the error
code from uprobe_mmap().

Reported-and-tested-by: William Cohen <wcohen@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # v3.5
Cc: Anton Arapov <anton@redhat.com>
Cc: William Cohen <wcohen@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120819171042.GB26957@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-08-21 11:48:12 +02:00
Linus Torvalds ac694dbdbc Merge branch 'akpm' (Andrew's patch-bomb)
Merge Andrew's second set of patches:
 - MM
 - a few random fixes
 - a couple of RTC leftovers

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (120 commits)
  rtc/rtc-88pm80x: remove unneed devm_kfree
  rtc/rtc-88pm80x: assign ret only when rtc_register_driver fails
  mm: hugetlbfs: close race during teardown of hugetlbfs shared page tables
  tmpfs: distribute interleave better across nodes
  mm: remove redundant initialization
  mm: warn if pg_data_t isn't initialized with zero
  mips: zero out pg_data_t when it's allocated
  memcg: gix memory accounting scalability in shrink_page_list
  mm/sparse: remove index_init_lock
  mm/sparse: more checks on mem_section number
  mm/sparse: optimize sparse_index_alloc
  memcg: add mem_cgroup_from_css() helper
  memcg: further prevent OOM with too many dirty pages
  memcg: prevent OOM with too many dirty pages
  mm: mmu_notifier: fix freed page still mapped in secondary MMU
  mm: memcg: only check anon swapin page charges for swap cache
  mm: memcg: only check swap cache pages for repeated charging
  mm: memcg: split swapin charge function into private and public part
  mm: memcg: remove needless !mm fixup to init_mm when charging
  mm: memcg: remove unneeded shmem charge type
  ...
2012-07-31 19:25:39 -07:00
Huang Shijie 44de9d0cad mm: account the total_vm in the vm_stat_account()
vm_stat_account() accounts the shared_vm, stack_vm and reserved_vm now.
But we can also account for total_vm in the vm_stat_account() which makes
the code tidy.

Even for mprotect_fixup(), we can get the right result in the end.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31 18:42:39 -07:00
Oleg Nesterov 89133786f9 uprobes: Remove insert_vm_struct()->uprobe_mmap()
Remove insert_vm_struct()->uprobe_mmap(). It is not needed, nobody
except arch/ia64/kernel/perfmon.c uses insert_vm_struct(vma)
with vma->vm_file != NULL.

And it is wrong. Again, get_user_pages() can not succeed before
vma_link(vma) makes is visible to find_vma(). And even if this
worked, we must not insert the new bp before this mapping is
visible to vma_prio_tree_foreach() for uprobe_unregister().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120729182238.GA20349@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-07-30 11:27:22 +02:00
Oleg Nesterov 6dab3cc078 uprobes: Remove copy_vma()->uprobe_mmap()
Remove copy_vma()->uprobe_mmap(new_vma), it is absolutely wrong.

This new_vma was just initialized to represent the new unmapped
area, [vm_start, vm_end) was returned by get_unmapped_area() in
the caller.

This means that uprobe_mmap()->get_user_pages() will fail for
sure, simply because find_vma() can never succeed. And I
verified that sys_mremap()->mremap_to() indeed always fails with
the wrong ENOMEM code if [addr, addr+old_len] is probed.

And why this uprobe_mmap() was added? I believe the intent was
wrong. Note that the caller is going to do move_page_tables(),
all registered uprobes are already faulted in, we only change
the virtual addresses.

NOTE: However, somehow we need to close the race with
uprobe_register() which relies on map_info->vaddr. This needs
another fix I'll try to do later. Probably we need uprobe_mmap()
in move_vma() but we can not do this right now, this can confuse
uprobes_state.counter (which I still hope we are going to kill).

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120729182236.GA20342@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-07-30 11:27:22 +02:00
Linus Torvalds 1193755ac6 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs changes from Al Viro.
 "A lot of misc stuff.  The obvious groups:
   * Miklos' atomic_open series; kills the damn abuse of
     ->d_revalidate() by NFS, which was the major stumbling block for
     all work in that area.
   * ripping security_file_mmap() and dealing with deadlocks in the
     area; sanitizing the neighborhood of vm_mmap()/vm_munmap() in
     general.
   * ->encode_fh() switched to saner API; insane fake dentry in
     mm/cleancache.c gone.
   * assorted annotations in fs (endianness, __user)
   * parts of Artem's ->s_dirty work (jff2 and reiserfs parts)
   * ->update_time() work from Josef.
   * other bits and pieces all over the place.

  Normally it would've been in two or three pull requests, but
  signal.git stuff had eaten a lot of time during this cycle ;-/"

Fix up trivial conflicts in Documentation/filesystems/vfs.txt (the
'truncate_range' inode method was removed by the VM changes, the VFS
update adds an 'update_time()' method), and in fs/btrfs/ulist.[ch] (due
to sparse fix added twice, with other changes nearby).

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (95 commits)
  nfs: don't open in ->d_revalidate
  vfs: retry last component if opening stale dentry
  vfs: nameidata_to_filp(): don't throw away file on error
  vfs: nameidata_to_filp(): inline __dentry_open()
  vfs: do_dentry_open(): don't put filp
  vfs: split __dentry_open()
  vfs: do_last() common post lookup
  vfs: do_last(): add audit_inode before open
  vfs: do_last(): only return EISDIR for O_CREAT
  vfs: do_last(): check LOOKUP_DIRECTORY
  vfs: do_last(): make ENOENT exit RCU safe
  vfs: make follow_link check RCU safe
  vfs: do_last(): use inode variable
  vfs: do_last(): inline walk_component()
  vfs: do_last(): make exit RCU safe
  vfs: split do_lookup()
  Btrfs: move over to use ->update_time
  fs: introduce inode operation ->update_time
  reiserfs: get rid of resierfs_sync_super
  reiserfs: mark the superblock as dirty a bit later
  ...
2012-06-01 10:34:35 -07:00
Al Viro 17d1587f55 unexport do_munmap()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:18 -04:00
Al Viro eb36c5873b new helper: vm_mmap_pgoff()
take it to mm/util.c, convert vm_mmap() to use of that one and
take it to mm/util.c as well, convert both sys_mmap_pgoff() to
use of vm_mmap_pgoff()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:18 -04:00
Al Viro dc982501d9 kill do_mmap() completely
just pull into vm_mmap()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:17 -04:00
Al Viro e3fc629d7b switch aio and shm to do_mmap_pgoff(), make do_mmap() static
after all, 0 bytes and 0 pages is the same thing...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:17 -04:00
Al Viro 9ac4ed4bd0 move security_mmap_addr() to saner place
it really should be done by get_unmapped_area(); that cuts down on
the amount of callers considerably and it's the right place for
that stuff anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:16 -04:00
Al Viro 8b3ec6814c take security_mmap_file() outside of ->mmap_sem
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 10:37:01 -04:00
Al Viro e5467859f7 split ->file_mmap() into ->mmap_addr()/->mmap_file()
... i.e. file-dependent and address-dependent checks.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-31 13:11:54 -04:00
Al Viro cf74d14c4f unexport do_mmap()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-30 21:04:57 -04:00
Rajman Mekaco 841e31e5cc mm/mmap.c: find_vma(): remove unnecessary if(mm) check
The "if (mm)" check is not required in find_vma, as the kernel code
calls find_vma only when it is absolutely sure that the mm_struct arg to
it is non-NULL.

Remove the if(mm) check and adding the a WARN_ONCE(!mm) for now.  This
will serve the purpose of mandating that the execution
context(user-mode/kernel-mode) be known before find_vma is called.  Also
fixed 2 checkpatch.pl errors in the declaration of the rb_node and
vma_tmp local variables.

I was browsing through the internet and read a discussion at
https://lkml.org/lkml/2012/3/27/342 which discusses removal of the
validation check within find_vma.  Since no-one responded, I decided to
send this patch with Andrew's suggestions.

[akpm@linux-foundation.org: add remove-me comment]
Signed-off-by: Rajman Mekaco <rajman.mekaco@gmail.com>
Cc: Kautuk Consul <consul.kautuk@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:19 -07:00
Linus Torvalds 654443e20d Merge branch 'perf-uprobes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull user-space probe instrumentation from Ingo Molnar:
 "The uprobes code originates from SystemTap and has been used for years
  in Fedora and RHEL kernels.  This version is much rewritten, reviews
  from PeterZ, Oleg and myself shaped the end result.

  This tree includes uprobes support in 'perf probe' - but SystemTap
  (and other tools) can take advantage of user probe points as well.

  Sample usage of uprobes via perf, for example to profile malloc()
  calls without modifying user-space binaries.

  First boot a new kernel with CONFIG_UPROBE_EVENT=y enabled.

  If you don't know which function you want to probe you can pick one
  from 'perf top' or can get a list all functions that can be probed
  within libc (binaries can be specified as well):

	$ perf probe -F -x /lib/libc.so.6

  To probe libc's malloc():

	$ perf probe -x /lib64/libc.so.6 malloc
	Added new event:
	probe_libc:malloc    (on 0x7eac0)

  You can now use it in all perf tools, such as:

	perf record -e probe_libc:malloc -aR sleep 1

  Make use of it to create a call graph (as the flat profile is going to
  look very boring):

	$ perf record -e probe_libc:malloc -gR make
	[ perf record: Woken up 173 times to write data ]
	[ perf record: Captured and wrote 44.190 MB perf.data (~1930712

	$ perf report | less

	  32.03%            git  libc-2.15.so   [.] malloc
	                    |
	                    --- malloc

	  29.49%            cc1  libc-2.15.so   [.] malloc
	                    |
	                    --- malloc
	                       |
	                       |--0.95%-- 0x208eb1000000000
	                       |
	                       |--0.63%-- htab_traverse_noresize

	  11.04%             as  libc-2.15.so   [.] malloc
	                     |
	                     --- malloc
	                        |

	   7.15%             ld  libc-2.15.so   [.] malloc
	                     |
	                     --- malloc
	                        |

	   5.07%             sh  libc-2.15.so   [.] malloc
	                     |
	                     --- malloc
	                        |
	   4.99%  python-config  libc-2.15.so   [.] malloc
	          |
	          --- malloc
	             |
	   4.54%           make  libc-2.15.so   [.] malloc
	                   |
	                   --- malloc
	                      |
	                      |--7.34%-- glob
	                      |          |
	                      |          |--93.18%-- 0x41588f
	                      |          |
	                      |           --6.82%-- glob
	                      |                     0x41588f

	   ...

  Or:

	$ perf report -g flat | less

	# Overhead        Command  Shared Object      Symbol
	# ........  .............  .............  ..........
	#
	  32.03%            git  libc-2.15.so   [.] malloc
	          27.19%
	              malloc

	  29.49%            cc1  libc-2.15.so   [.] malloc
	          24.77%
	              malloc

	  11.04%             as  libc-2.15.so   [.] malloc
	          11.02%
	              malloc

	   7.15%             ld  libc-2.15.so   [.] malloc
	           6.57%
	              malloc

	 ...

  The core uprobes design is fairly straightforward: uprobes probe
  points register themselves at (inode:offset) addresses of
  libraries/binaries, after which all existing (or new) vmas that map
  that address will have a software breakpoint injected at that address.
  vmas are COW-ed to preserve original content.  The probe points are
  kept in an rbtree.

  If user-space executes the probed inode:offset instruction address
  then an event is generated which can be recovered from the regular
  perf event channels and mmap-ed ring-buffer.

  Multiple probes at the same address are supported, they create a
  dynamic callback list of event consumers.

  The basic model is further complicated by the XOL speedup: the
  original instruction that is probed is copied (in an architecture
  specific fashion) and executed out of line when the probe triggers.
  The XOL area is a single vma per process, with a fixed number of
  entries (which limits probe execution parallelism).

  The API: uprobes are installed/removed via
  /sys/kernel/debug/tracing/uprobe_events, the API is integrated to
  align with the kprobes interface as much as possible, but is separate
  to it.

  Injecting a probe point is privileged operation, which can be relaxed
  by setting perf_paranoid to -1.

  You can use multiple probes as well and mix them with kprobes and
  regular PMU events or tracepoints, when instrumenting a task."

Fix up trivial conflicts in mm/memory.c due to previous cleanup of
unmap_single_vma().

* 'perf-uprobes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  perf probe: Detect probe target when m/x options are absent
  perf probe: Provide perf interface for uprobes
  tracing: Fix kconfig warning due to a typo
  tracing: Provide trace events interface for uprobes
  tracing: Extract out common code for kprobes/uprobes trace events
  tracing: Modify is_delete, is_return from int to bool
  uprobes/core: Decrement uprobe count before the pages are unmapped
  uprobes/core: Make background page replacement logic account for rss_stat counters
  uprobes/core: Optimize probe hits with the help of a counter
  uprobes/core: Allocate XOL slots for uprobes use
  uprobes/core: Handle breakpoint and singlestep exceptions
  uprobes/core: Rename bkpt to swbp
  uprobes/core: Make order of function parameters consistent across functions
  uprobes/core: Make macro names consistent
  uprobes: Update copyright notices
  uprobes/core: Move insn to arch specific structure
  uprobes/core: Remove uprobe_opcode_sz
  uprobes/core: Make instruction tables volatile
  uprobes: Move to kernel/events/
  uprobes/core: Clean up, refactor and improve the code
  ...
2012-05-24 11:39:34 -07:00
Ingo Molnar 9cba26e66d Merge branch 'perf/uprobes' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/uprobes 2012-05-14 14:43:40 +02:00
Linus Torvalds 4f74d2c8e8 vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces
The VM accounting makes no sense at this level, and half of the callers
didn't ever actually use the end result.  The only time we want to
unaccount the memory is when we actually remove the vma, so do the
accounting at that point instead.

This simplifies the interfaces (no need to pass down that silly page
counter to functions that really don't care), and also makes it much
more obvious what is actually going on: we do vm_[un]acct_memory() when
adding or removing the vma, not on random page walking.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-06 14:05:17 -07:00