Commit Graph

255 Commits

Author SHA1 Message Date
Sasha Levin
81d1b09c6b mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA
Trivially convert a few VM_BUG_ON calls to VM_BUG_ON_VMA to extract
more information when they trigger.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:57 -04:00
Andres Lagar-Cavilla
5712846808 kvm: Fix page ageing bugs
1. We were calling clear_flush_young_notify in unmap_one, but we are
within an mmu notifier invalidate range scope. The spte exists no more
(due to range_start) and the accessed bit info has already been
propagated (due to kvm_pfn_set_accessed). Simply call
clear_flush_young.

2. We clear_flush_young on a primary MMU PMD, but this may be mapped
as a collection of PTEs by the secondary MMU (e.g. during log-dirty).
This required expanding the interface of the clear_flush_young mmu
notifier, so a lot of code has been trivially touched.

3. In the absence of shadow_accessed_mask (e.g. EPT A bit), we emulate
the access bit by blowing the spte. This requires proper synchronizing
with MMU notifier consumers, like every other removal of spte's does.

Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24 14:07:58 +02:00
Johannes Weiner
0a31bc97c8 mm: memcontrol: rewrite uncharge API
The memcg uncharging code that is involved towards the end of a page's
lifetime - truncation, reclaim, swapout, migration - is impressively
complicated and fragile.

Because anonymous and file pages were always charged before they had their
page->mapping established, uncharges had to happen when the page type
could still be known from the context; as in unmap for anonymous, page
cache removal for file and shmem pages, and swap cache truncation for swap
pages.  However, these operations happen well before the page is actually
freed, and so a lot of synchronization is necessary:

- Charging, uncharging, page migration, and charge migration all need
  to take a per-page bit spinlock as they could race with uncharging.

- Swap cache truncation happens during both swap-in and swap-out, and
  possibly repeatedly before the page is actually freed.  This means
  that the memcg swapout code is called from many contexts that make
  no sense and it has to figure out the direction from page state to
  make sure memory and memory+swap are always correctly charged.

- On page migration, the old page might be unmapped but then reused,
  so memcg code has to prevent untimely uncharging in that case.
  Because this code - which should be a simple charge transfer - is so
  special-cased, it is not reusable for replace_page_cache().

But now that charged pages always have a page->mapping, introduce
mem_cgroup_uncharge(), which is called after the final put_page(), when we
know for sure that nobody is looking at the page anymore.

For page migration, introduce mem_cgroup_migrate(), which is called after
the migration is successful and the new page is fully rmapped.  Because
the old page is no longer uncharged after migration, prevent double
charges by decoupling the page's memcg association (PCG_USED and
pc->mem_cgroup) from the page holding an actual charge.  The new bits
PCG_MEM and PCG_MEMSW represent the respective charges and are transferred
to the new page during migration.

mem_cgroup_migrate() is suitable for replace_page_cache() as well,
which gets rid of mem_cgroup_replace_page_cache().  However, care
needs to be taken because both the source and the target page can
already be charged and on the LRU when fuse is splicing: grab the page
lock on the charge moving side to prevent changing pc->mem_cgroup of a
page under migration.  Also, the lruvecs of both pages change as we
uncharge the old and charge the new during migration, and putback may
race with us, so grab the lru lock and isolate the pages iff on LRU to
prevent races and ensure the pages are on the right lruvec afterward.

Swap accounting is massively simplified: because the page is no longer
uncharged as early as swap cache deletion, a new mem_cgroup_swapout() can
transfer the page's memory+swap charge (PCG_MEMSW) to the swap entry
before the final put_page() in page reclaim.

Finally, page_cgroup changes are now protected by whatever protection the
page itself offers: anonymous pages are charged under the page table lock,
whereas page cache insertions, swapin, and migration hold the page lock.
Uncharging happens under full exclusion with no outstanding references.
Charging and uncharging also ensure that the page is off-LRU, which
serializes against charge migration.  Remove the very costly page_cgroup
lock and set pc->flags non-atomically.

[mhocko@suse.cz: mem_cgroup_charge_statistics needs preempt_disable]
[vdavydov@parallels.com: fix flags definition]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Tested-by: Jet Chen <jet.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:17 -07:00
Johannes Weiner
00501b531c mm: memcontrol: rewrite charge API
These patches rework memcg charge lifetime to integrate more naturally
with the lifetime of user pages.  This drastically simplifies the code and
reduces charging and uncharging overhead.  The most expensive part of
charging and uncharging is the page_cgroup bit spinlock, which is removed
entirely after this series.

Here are the top-10 profile entries of a stress test that reads a 128G
sparse file on a freshly booted box, without even a dedicated cgroup (i.e.
 executing in the root memcg).  Before:

    15.36%              cat  [kernel.kallsyms]   [k] copy_user_generic_string
    13.31%              cat  [kernel.kallsyms]   [k] memset
    11.48%              cat  [kernel.kallsyms]   [k] do_mpage_readpage
     4.23%              cat  [kernel.kallsyms]   [k] get_page_from_freelist
     2.38%              cat  [kernel.kallsyms]   [k] put_page
     2.32%              cat  [kernel.kallsyms]   [k] __mem_cgroup_commit_charge
     2.18%          kswapd0  [kernel.kallsyms]   [k] __mem_cgroup_uncharge_common
     1.92%          kswapd0  [kernel.kallsyms]   [k] shrink_page_list
     1.86%              cat  [kernel.kallsyms]   [k] __radix_tree_lookup
     1.62%              cat  [kernel.kallsyms]   [k] __pagevec_lru_add_fn

After:

    15.67%           cat  [kernel.kallsyms]   [k] copy_user_generic_string
    13.48%           cat  [kernel.kallsyms]   [k] memset
    11.42%           cat  [kernel.kallsyms]   [k] do_mpage_readpage
     3.98%           cat  [kernel.kallsyms]   [k] get_page_from_freelist
     2.46%           cat  [kernel.kallsyms]   [k] put_page
     2.13%       kswapd0  [kernel.kallsyms]   [k] shrink_page_list
     1.88%           cat  [kernel.kallsyms]   [k] __radix_tree_lookup
     1.67%           cat  [kernel.kallsyms]   [k] __pagevec_lru_add_fn
     1.39%       kswapd0  [kernel.kallsyms]   [k] free_pcppages_bulk
     1.30%           cat  [kernel.kallsyms]   [k] kfree

As you can see, the memcg footprint has shrunk quite a bit.

   text    data     bss     dec     hex filename
  37970    9892     400   48262    bc86 mm/memcontrol.o.old
  35239    9892     400   45531    b1db mm/memcontrol.o

This patch (of 4):

The memcg charge API charges pages before they are rmapped - i.e.  have an
actual "type" - and so every callsite needs its own set of charge and
uncharge functions to know what type is being operated on.  Worse,
uncharge has to happen from a context that is still type-specific, rather
than at the end of the page's lifetime with exclusive access, and so
requires a lot of synchronization.

Rewrite the charge API to provide a generic set of try_charge(),
commit_charge() and cancel_charge() transaction operations, much like
what's currently done for swap-in:

  mem_cgroup_try_charge() attempts to reserve a charge, reclaiming
  pages from the memcg if necessary.

  mem_cgroup_commit_charge() commits the page to the charge once it
  has a valid page->mapping and PageAnon() reliably tells the type.

  mem_cgroup_cancel_charge() aborts the transaction.

This reduces the charge API and enables subsequent patches to
drastically simplify uncharging.

As pages need to be committed after rmap is established but before they
are added to the LRU, page_add_new_anon_rmap() must stop doing LRU
additions again.  Revive lru_cache_add_active_or_unevictable().

[hughd@google.com: fix shmem_unuse]
[hughd@google.com: Add comments on the private use of -EAGAIN]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-08 15:57:17 -07:00
Naoya Horiguchi
a0f7a756c2 mm/rmap.c: fix pgoff calculation to handle hugepage correctly
I triggered VM_BUG_ON() in vma_address() when I tried to migrate an
anonymous hugepage with mbind() in the kernel v3.16-rc3.  This is
because pgoff's calculation in rmap_walk_anon() fails to consider
compound_order() only to have an incorrect value.

This patch introduces page_to_pgoff(), which gets the page's offset in
PAGE_CACHE_SIZE.

Kirill pointed out that page cache tree should natively handle
hugepages, and in order to make hugetlbfs fit it, page->index of
hugetlbfs page should be in PAGE_CACHE_SIZE.  This is beyond this patch,
but page_to_pgoff() contains the point to be fixed in a single function.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-23 15:10:54 -07:00
Hugh Dickins
f72e7dcdd2 mm: let mm_find_pmd fix buggy race with THP fault
Trinity has reported:

    BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
    IP: __lock_acquire (kernel/locking/lockdep.c:3070 (discriminator 1))
    CPU: 6 PID: 16173 Comm: trinity-c364 Tainted: G        W
                            3.15.0-rc1-next-20140415-sasha-00020-gaa90d09 #398
    lock_acquire (arch/x86/include/asm/current.h:14
                  kernel/locking/lockdep.c:3602)
    _raw_spin_lock (include/linux/spinlock_api_smp.h:143
                    kernel/locking/spinlock.c:151)
    remove_migration_pte (mm/migrate.c:137)
    rmap_walk (mm/rmap.c:1628 mm/rmap.c:1699)
    remove_migration_ptes (mm/migrate.c:224)
    migrate_pages (mm/migrate.c:922 mm/migrate.c:960 mm/migrate.c:1126)
    migrate_misplaced_page (mm/migrate.c:1733)
    __handle_mm_fault (mm/memory.c:3762 mm/memory.c:3812 mm/memory.c:3925)
    handle_mm_fault (mm/memory.c:3948)
    __get_user_pages (mm/memory.c:1851)
    __mlock_vma_pages_range (mm/mlock.c:255)
    __mm_populate (mm/mlock.c:711)
    SyS_mlockall (include/linux/mm.h:1799 mm/mlock.c:817 mm/mlock.c:791)

I believe this comes about because, whereas collapsing and splitting THP
functions take anon_vma lock in write mode (which excludes concurrent
rmap walks), faulting THP functions (write protection and misplaced
NUMA) do not - and mostly they do not need to.

But they do use a pmdp_clear_flush(), set_pmd_at() sequence which, for
an instant (indeed, for a long instant, given the inter-CPU TLB flush in
there), leaves *pmd neither present not trans_huge.

Which can confuse a concurrent rmap walk, as when removing migration
ptes, seen in the dumped trace.  Although that rmap walk has a 4k page
to insert, anon_vmas containing THPs are in no way segregated from
4k-page anon_vmas, so the 4k-intent mm_find_pmd() does need to cope with
that instant when a trans_huge pmd is temporarily absent.

I don't think we need strengthen the locking at the THP end: it's easily
handled with an ACCESS_ONCE() before testing both conditions.

And since mm_find_pmd() had only one caller who wanted a THP rather than
a pmd, let's slightly repurpose it to fail when it hits a THP or
non-present pmd, and open code split_huge_page_address() again.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Jones <davej@redhat.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>
2014-06-23 16:47:44 -07:00
Linus Torvalds
3f17ea6dea Merge branch 'next' (accumulated 3.16 merge window patches) into master
Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...
2014-06-08 11:31:16 -07:00
Andrey Ryabinin
624483f3ea mm: rmap: fix use-after-free in __put_anon_vma
While working address sanitizer for kernel I've discovered
use-after-free bug in __put_anon_vma.

For the last anon_vma, anon_vma->root freed before child anon_vma.
Later in anon_vma_free(anon_vma) we are referencing to already freed
anon_vma->root to check rwsem.

This fixes it by freeing the child anon_vma before freeing
anon_vma->root.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 08:53:41 -07:00
Konstantin Khlebnikov
daa5ba768b mm/rmap.c: cleanup ttu_flags
Transform action part of ttu_flags into individiual bits.  These flags
aren't part of any uses-space visible api or even trace events.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.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>
2014-06-04 16:54:12 -07:00
Konstantin Khlebnikov
3d92860f97 mm/rmap.c: don't call mmu_notifier_invalidate_page() during munlock
In its munmap mode, try_to_unmap_one() searches other mlocked vmas, it
never unmaps pages.  There is no reason for invalidation because ptes are
left unchanged.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.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>
2014-06-04 16:54:12 -07:00
Jianyu Zhan
7ee07a44eb mm: fold mlocked_vma_newpage() into its only call site
In previous commit(mm: use the light version __mod_zone_page_state in
mlocked_vma_newpage()) a irq-unsafe __mod_zone_page_state is used.  And as
suggested by Andrew, to reduce the risks that new call sites incorrectly
using mlocked_vma_newpage() without knowing they are adding racing, this
patch folds mlocked_vma_newpage() into its only call site,
page_add_new_anon_rmap, to make it open-cocded for people to know what is
going on.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Hugh Dickins <hughd@google.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>
2014-06-04 16:54:07 -07:00
Jianyu Zhan
bea04b0732 mm: use the light version __mod_zone_page_state in mlocked_vma_newpage()
mlocked_vma_newpage() is called with pte lock held(a spinlock), which
implies preemtion disabled, and the vm stat counter is not modified from
interrupt context, so we need not use an irq-safe mod_zone_page_state()
here, using a light-weight version __mod_zone_page_state() would be OK.

This patch also documents __mod_zone_page_state() and some of its
callsites.  The comment above __mod_zone_page_state() is from Hugh
Dickins, and acked by Christoph.

Most credits to Hugh and Christoph for the clarification on the usage of
the __mod_zone_page_state().

[akpm@linux-foundation.org: coding-style fixes]
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:07 -07:00
Kirill A. Shutemov
ac7695012a mm/rmap.c: make page_referenced_one() and try_to_unmap_one() static
KSM was converted to use rmap_walk() and now nobody uses these functions
outside mm/rmap.c.

Let's covert them back to static.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:05 -07:00
Cyrill Gorcunov
b43790eedd mm: softdirty: don't forget to save file map softdiry bit on unmap
pte_file_mksoft_dirty operates with argument passed by a value and
returns modified result thus we need to assign @ptfile here, otherwise
itis a no-op which may lead to loss of the softdirty bit.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.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>
2014-06-04 16:53:56 -07:00
Hugh Dickins
7f39dda9d8 mm: fix sleeping function warning from __put_anon_vma
Trinity reports BUG:

  sleeping function called from invalid context at kernel/locking/rwsem.c:47
  in_atomic(): 0, irqs_disabled(): 0, pid: 5787, name: trinity-c27

__might_sleep < down_write < __put_anon_vma < page_get_anon_vma <
migrate_pages < compact_zone < compact_zone_order < try_to_compact_pages ..

Right, since conversion to mutex then rwsem, we should not put_anon_vma()
from inside an rcu_read_lock()ed section: fix the two places that did so.
And add might_sleep() to anon_vma_free(), as suggested by Peter Zijlstra.

Fixes: 88c22088bf ("mm: optimize page_lock_anon_vma() fast-path")
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:53:51 -07:00
Vlastimil Babka
57e68e9cd6 mm: try_to_unmap_cluster() should lock_page() before mlocking
A BUG_ON(!PageLocked) was triggered in mlock_vma_page() by Sasha Levin
fuzzing with trinity.  The call site try_to_unmap_cluster() does not lock
the pages other than its check_page parameter (which is already locked).

The BUG_ON in mlock_vma_page() is not documented and its purpose is
somewhat unclear, but apparently it serializes against page migration,
which could otherwise fail to transfer the PG_mlocked flag.  This would
not be fatal, as the page would be eventually encountered again, but
NR_MLOCK accounting would become distorted nevertheless.  This patch adds
a comment to the BUG_ON in mlock_vma_page() and munlock_vma_page() to that
effect.

The call site try_to_unmap_cluster() is fixed so that for page !=
check_page, trylock_page() is attempted (to avoid possible deadlocks as we
already have check_page locked) and mlock_vma_page() is performed only
upon success.  If the page lock cannot be obtained, the page is left
without PG_mlocked, which is again not a problem in the whole unevictable
memory design.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:57 -07:00
Linus Torvalds
1f8c538ed6 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Martin Schwidefsky:
 "There are two memory management related changes, the CMMA support for
  KVM to avoid swap-in of freed pages and the split page table lock for
  the PMD level.  These two come with common code changes in mm/.

  A fix for the long standing theoretical TLB flush problem, this one
  comes with a common code change in kernel/sched/.

  Another set of changes is Heikos uaccess work, included is the initial
  set of patches with more to come.

  And fixes and cleanups as usual"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (36 commits)
  s390/con3270: optionally disable auto update
  s390/mm: remove unecessary parameter from pgste_ipte_notify
  s390/mm: remove unnecessary parameter from gmap_do_ipte_notify
  s390/mm: fixing comment so that parameter name match
  s390/smp: limit number of cpus in possible cpu mask
  hypfs: Add clarification for "weight_min" attribute
  s390: update defconfigs
  s390/ptrace: add support for PTRACE_SINGLEBLOCK
  s390/perf: make print_debug_cf() static
  s390/topology: Remove call to update_cpu_masks()
  s390/compat: remove compat exec domain
  s390: select CONFIG_TTY for use of tty in unconditional keyboard driver
  s390/appldata_os: fix cpu array size calculation
  s390/checksum: remove memset() within csum_partial_copy_from_user()
  s390/uaccess: remove copy_from_user_real()
  s390/sclp_early: Return correct HSA block count also for zero
  s390: add some drivers/subsystems to the MAINTAINERS file
  s390: improve debug feature usage
  s390/airq: add support for irq ranges
  s390/mm: enable split page table lock for PMD level
  ...
2014-03-31 14:35:30 -07:00
Hugh Dickins
7e09e738af mm: fix swapops.h:131 bug if remap_file_pages raced migration
Add remove_linear_migration_ptes_from_nonlinear(), to fix an interesting
little include/linux/swapops.h:131 BUG_ON(!PageLocked) found by trinity:
indicating that remove_migration_ptes() failed to find one of the
migration entries that was temporarily inserted.

The problem comes from remap_file_pages()'s switch from vma_interval_tree
(good for inserting the migration entry) to i_mmap_nonlinear list (no good
for locating it again); but can only be a problem if the remap_file_pages()
range does not cover the whole of the vma (zap_pte() clears the range).

remove_migration_ptes() needs a file_nonlinear method to go down the
i_mmap_nonlinear list, applying linear location to look for migration
entries in those vmas too, just in case there was this race.

The file_nonlinear method does need rmap_walk_control.arg to do this;
but it never needed vma passed in - vma comes from its own iteration.

Reported-and-tested-by: Dave Jones <davej@redhat.com>
Reported-and-tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-20 22:09:09 -07:00
Konstantin Weitz
45961722f8 mm: add support for discard of unused ptes
In a virtualized environment and given an appropriate interface the guest
can mark pages as unused while they are free (for the s390 implementation
see git commit 45e576b1c3 "guest page hinting light"). For the host
the unused state is a property of the pte.

This patch adds the primitive 'pte_unused' and code to the host swap out
handler so that pages marked as unused by all mappers are not swapped out
but discarded instead, thus saving one IO for swap out and potentially
another one for swap in.

[ Martin Schwidefsky: patch reordering and simplification ]

Signed-off-by: Konstantin Weitz <konstantin.weitz@gmail.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-02-21 08:50:18 +01:00
Fengguang Wu
871beb8c31 mm/rmap: fix coccinelle warnings
mm/rmap.c:851:9-10: WARNING: return of 0/1 in function 'invalid_mkclean_vma' with return type bool

 Return statements in functions returning bool should use
 true/false instead of 1/0.

Generated by: coccinelle/misc/boolreturn.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:53 -08:00
Sasha Levin
309381feae mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE
Most of the VM_BUG_ON assertions are performed on a page.  Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.

I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.

This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.

[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:50 -08:00
Joonsoo Kim
9853a407b9 mm/rmap: use rmap_walk() in page_mkclean()
Now, we have an infrastructure in rmap_walk() to handle difference from
   variants of rmap traversing functions.

So, just use it in page_mkclean().

In this patch, I change following things.

1. remove some variants of rmap traversing functions.
    cf> page_mkclean_file
2. mechanical change to use rmap_walk() in page_mkclean().

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:46 -08:00
Joonsoo Kim
9f32624be9 mm/rmap: use rmap_walk() in page_referenced()
Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.

So, just use it in page_referenced().

In this patch, I change following things.

1. remove some variants of rmap traversing functions.
	cf> page_referenced_ksm, page_referenced_anon,
	page_referenced_file

2. introduce new struct page_referenced_arg and pass it to
   page_referenced_one(), main function of rmap_walk, in order to count
   reference, to store vm_flags and to check finish condition.

3. mechanical change to use rmap_walk() in page_referenced().

[liwanp@linux.vnet.ibm.com: fix BUG at rmap_walk]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:45 -08:00
Joonsoo Kim
e8351ac9bf mm/rmap: use rmap_walk() in try_to_munlock()
Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.

So, just use it in try_to_munlock().

In this patch, I change following things.

1. remove some variants of rmap traversing functions.
	cf> try_to_unmap_ksm, try_to_unmap_anon, try_to_unmap_file
2. mechanical change to use rmap_walk() in try_to_munlock().
3. copy and paste comments.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:45 -08:00
Joonsoo Kim
5262950642 mm/rmap: use rmap_walk() in try_to_unmap()
Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.

So, just use it in try_to_unmap().

In this patch, I change following things.

1. enable rmap_walk() if !CONFIG_MIGRATION.
2. mechanical change to use rmap_walk() in try_to_unmap().

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:45 -08:00