linux.git/mm/rmap.c, branch v3.11

mm: save soft-dirty bits on file pages

2013-08-14T00:57:48+00:00

Andy reported that if file page get reclaimed we lose the soft-dirty bit
if it was there, so save _PAGE_BIT_SOFT_DIRTY bit when page address get
encoded into pte entry.  Thus when #pf happens on such non-present pte
we can restore it back.

Reported-by: Andy Lutomirski 
Signed-off-by: Cyrill Gorcunov 
Acked-by: Pavel Emelyanov 
Cc: Matt Mackall 
Cc: Xiao Guangrong 
Cc: Marcelo Tosatti 
Cc: KOSAKI Motohiro 
Cc: Stephen Rothwell 
Cc: Peter Zijlstra 
Cc: "Aneesh Kumar K.V" 
Cc: Minchan Kim 
Cc: Wanpeng Li 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: save soft-dirty bits on swapped pages

2013-08-14T00:57:47+00:00

Andy Lutomirski reported that if a page with _PAGE_SOFT_DIRTY bit set
get swapped out, the bit is getting lost and no longer available when
pte read back.

To resolve this we introduce _PTE_SWP_SOFT_DIRTY bit which is saved in
pte entry for the page being swapped out.  When such page is to be read
back from a swap cache we check for bit presence and if it's there we
clear it and restore the former _PAGE_SOFT_DIRTY bit back.

One of the problem was to find a place in pte entry where we can save
the _PTE_SWP_SOFT_DIRTY bit while page is in swap.  The _PAGE_PSE was
chosen for that, it doesn't intersect with swap entry format stored in
pte.

Reported-by: Andy Lutomirski 
Signed-off-by: Cyrill Gorcunov 
Acked-by: Pavel Emelyanov 
Cc: Matt Mackall 
Cc: Xiao Guangrong 
Cc: Marcelo Tosatti 
Cc: KOSAKI Motohiro 
Cc: Stephen Rothwell 
Cc: Peter Zijlstra 
Cc: "Aneesh Kumar K.V" 
Reviewed-by: Minchan Kim 
Reviewed-by: Wanpeng Li 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove unused VM_ macros and expand other in-place

2013-07-09T17:33:23+00:00

These VM_ macros aren't used very often and three of them
aren't used at all.

Expand the ones that are used in-place, and remove all the now unused
#define VM_ macros.

VM_READHINTMASK, VM_NormalReadHint and VM_ClearReadHint were added just
before 2.4 and appears have never been used.

Signed-off-by: Joe Perches 
Acked-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove lru parameter from __lru_cache_add and lru_cache_add_lru

2013-07-03T23:07:31+00:00

Similar to __pagevec_lru_add, this patch removes the LRU parameter from
__lru_cache_add and lru_cache_add_lru as the caller does not control the
exact LRU the page gets added to.  lru_cache_add_lru gets renamed to
lru_cache_add the name is silly without the lru parameter.  With the
parameter removed, it is required that the caller indicate if they want
the page added to the active or inactive list by setting or clearing
PageActive respectively.

[akpm@linux-foundation.org: Suggested the patch]
[gang.chen@asianux.com: fix used-unintialized warning]
Signed-off-by: Mel Gorman 
Signed-off-by: Chen Gang 
Cc: Jan Kara 
Cc: Rik van Riel 
Acked-by: Johannes Weiner 
Cc: Alexey Lyahkov 
Cc: Andrew Perepechko 
Cc: Robin Dong 
Cc: Theodore Tso 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Bernd Schubert 
Cc: David Howells 
Cc: Trond Myklebust 
Cc: Mel Gorman 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rmap: recompute pgoff for unmapping huge page

2013-04-29T22:54:28+00:00

We have to recompute pgoff if the given page is huge, since result based
on HPAGE_SIZE is not approapriate for scanning the vma interval tree, as
shown by commit 36e4f20af833 ("hugetlb: do not use vma_hugecache_offset()
for vma_prio_tree_foreach").

Signed-off-by: Hillf Danton 
Cc: Michal Hocko 
Cc: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: rename anon_vma_unlock() => anon_vma_unlock_write()

2013-02-24T01:50:17+00:00

The comment in commit 4fc3f1d66b1e ("mm/rmap, migration: Make
rmap_walk_anon() and try_to_unmap_anon() more scalable") says:

| 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.

But that commit renames only anon_vma_lock()

Signed-off-by: Konstantin Khlebnikov 
Cc: Ingo Molnar 
Reviewed-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

s390/mm: implement software dirty bits

2013-02-14T14:55:23+00:00

The s390 architecture is unique in respect to dirty page detection,
it uses the change bit in the per-page storage key to track page
modifications. All other architectures track dirty bits by means
of page table entries. This property of s390 has caused numerous
problems in the past, e.g. see git commit ef5d437f71afdf4a
"mm: fix XFS oops due to dirty pages without buffers on s390".

To avoid future issues in regard to per-page dirty bits convert
s390 to a fault based software dirty bit detection mechanism. All
user page table entries which are marked as clean will be hardware
read-only, even if the pte is supposed to be writable. A write by
the user process will trigger a protection fault which will cause
the user pte to be marked as dirty and the hardware read-only bit
is removed.

With this change the dirty bit in the storage key is irrelevant
for Linux as a host, but the storage key is still required for
KVM guests. The effect is that page_test_and_clear_dirty and the
related code can be removed. The referenced bit in the storage
key is still used by the page_test_and_clear_young primitive to
provide page age information.

For page cache pages of mappings with mapping_cap_account_dirty
there will not be any change in behavior as the dirty bit tracking
already uses read-only ptes to control the amount of dirty pages.
Only for swap cache pages and pages of mappings without
mapping_cap_account_dirty there can be additional protection faults.
To avoid an excessive number of additional faults the mk_pte
primitive checks for PageDirty if the pgprot value allows for writes
and pre-dirties the pte. That avoids all additional faults for
tmpfs and shmem pages until these pages are added to the swap cache.

Signed-off-by: Martin Schwidefsky

Merge tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma

2012-12-16T23:18:08+00:00

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
  ...

hwpoison, hugetlbfs: fix RSS-counter warning

2012-12-13T01:38:35+00:00

Memory error handling on hugepages can break a RSS counter, which emits a
message like "Bad rss-counter state mm:ffff88040abecac0 idx:1 val:-1".
This is because PageAnon returns true for hugepage (this behavior is
necessary for reverse mapping to work on hugetlbfs).

[akpm@linux-foundation.org: clean up code layout]
Signed-off-by: Naoya Horiguchi 
Cc: Andi Kleen 
Cc: Tony Luck 
Cc: Wu Fengguang 
Cc: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add comment on storage key dirty bit semantics

2012-12-12T01:22:23+00:00

Add comments that dirty bit in storage key gets set whenever page content
is changed.  Hopefully if someone will use this function, he'll have a
look at one of the two places where we comment on this.

Signed-off-by: Jan Kara 
Cc: Martin Schwidefsky 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds