linux-toradex.git/arch/x86/include/asm/pgtable.h, branch v4.2.7

mm: clarify that the function operates on hugepage pte

2015-06-25T00:49:44+00:00

We have confusing functions to clear pmd, pmd_clear_* and pmd_clear.  Add
_huge_ to pmdp_clear functions so that we are clear that they operate on
hugepage pte.

We don't bother about other functions like pmdp_set_wrprotect,
pmdp_clear_flush_young, because they operate on PTE bits and hence
indicate they are operating on hugepage ptes

Signed-off-by: Aneesh Kumar K.V 
Acked-by: Kirill A. Shutemov 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Andrea Arcangeli 
Cc: Martin Schwidefsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86/mm: Teach is_new_memtype_allowed() about Write-Through type

2015-06-07T13:28:55+00:00

__ioremap_caller() calls reserve_memtype() and the passed down
@new_pcm contains the actual page cache type it reserved in the
success case.

is_new_memtype_allowed() verifies if converting to the new page
cache type is allowed when @pcm (the requested type) is
different from @new_pcm.

When WT is requested, the caller expects that writes are ordered
and uncached. Therefore, enhance is_new_memtype_allowed() to
disallow the following cases:

 - If the request is WT, mapping type cannot be WB
 - If the request is WT, mapping type cannot be WC

Signed-off-by: Toshi Kani 
Signed-off-by: Borislav Petkov 
Reviewed-by: Thomas Gleixner 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Elliott@hp.com
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Luis R. Rodriguez 
Cc: Peter Zijlstra 
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm 
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-7-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar

x86: expose number of page table levels on Kconfig level

2015-04-14T23:49:02+00:00

We would want to use number of page table level to define mm_struct.
Let's expose it as CONFIG_PGTABLE_LEVELS.

Signed-off-by: Kirill A. Shutemov 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Tested-by: Guenter Roeck 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86: pte_protnone() and pmd_protnone() must check entry is not present

2015-02-19T23:04:49+00:00

Since _PAGE_PROTNONE aliases _PAGE_GLOBAL it is only valid if
_PAGE_PRESENT is clear.  Make pte_protnone() and pmd_protnone() check
for this.

This fixes a 64-bit Xen PV guest regression introduced by 8a0516ed8b90
("mm: convert p[te|md]_numa users to p[te|md]_protnone_numa").  Any
userspace process would endlessly fault.

In a 64-bit PV guest, userspace page table entries have _PAGE_GLOBAL set
by the hypervisor.  This meant that any fault on a present userspace
entry (e.g., a write to a read-only mapping) would be misinterpreted as
a NUMA hinting fault and the fault would not be correctly handled,
resulting in the access endlessly faulting.

Signed-off-by: David Vrabel 
Acked-by: Mel Gorman 
Signed-off-by: Linus Torvalds

x86: mm: restore original pte_special check

2015-02-13T02:54:08+00:00

Commit b38af4721f59 ("x86,mm: fix pte_special versus pte_numa") adjusted
the pte_special check to take into account that a special pte had
SPECIAL and neither PRESENT nor PROTNONE.  Now that NUMA hinting PTEs
are no longer modifying _PAGE_PRESENT it should be safe to restore the
original pte_special behaviour.

Signed-off-by: Mel Gorman 
Cc: Aneesh Kumar K.V 
Cc: Benjamin Herrenschmidt 
Cc: Dave Jones 
Cc: Hugh Dickins 
Cc: Ingo Molnar 
Cc: Kirill Shutemov 
Cc: Linus Torvalds 
Cc: Paul Mackerras 
Cc: Rik van Riel 
Cc: Sasha Levin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove remaining references to NUMA hinting bits and helpers

2015-02-13T02:54:08+00:00

This patch removes the NUMA PTE bits and associated helpers.  As a
side-effect it increases the maximum possible swap space on x86-64.

One potential source of problems is races between the marking of PTEs
PROT_NONE, NUMA hinting faults and migration.  It must be guaranteed that
a PTE being protected is not faulted in parallel, seen as a pte_none and
corrupting memory.  The base case is safe but transhuge has problems in
the past due to an different migration mechanism and a dependance on page
lock to serialise migrations and warrants a closer look.

task_work hinting update			parallel fault
------------------------			--------------
change_pmd_range
  change_huge_pmd
    __pmd_trans_huge_lock
      pmdp_get_and_clear
						__handle_mm_fault
						pmd_none
						  do_huge_pmd_anonymous_page
						  read? pmd_lock blocks until hinting complete, fail !pmd_none test
						  write? __do_huge_pmd_anonymous_page acquires pmd_lock, checks pmd_none
      pmd_modify
      set_pmd_at

task_work hinting update			parallel migration
------------------------			------------------
change_pmd_range
  change_huge_pmd
    __pmd_trans_huge_lock
      pmdp_get_and_clear
						__handle_mm_fault
						  do_huge_pmd_numa_page
						    migrate_misplaced_transhuge_page
						    pmd_lock waits for updates to complete, recheck pmd_same
      pmd_modify
      set_pmd_at

Both of those are safe and the case where a transhuge page is inserted
during a protection update is unchanged.  The case where two processes try
migrating at the same time is unchanged by this series so should still be
ok.  I could not find a case where we are accidentally depending on the
PTE not being cleared and flushed.  If one is missed, it'll manifest as
corruption problems that start triggering shortly after this series is
merged and only happen when NUMA balancing is enabled.

Signed-off-by: Mel Gorman 
Tested-by: Sasha Levin 
Cc: Aneesh Kumar K.V 
Cc: Benjamin Herrenschmidt 
Cc: Dave Jones 
Cc: Hugh Dickins 
Cc: Ingo Molnar 
Cc: Kirill Shutemov 
Cc: Linus Torvalds 
Cc: Paul Mackerras 
Cc: Rik van Riel 
Cc: Mark Brown 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add p[te|md] protnone helpers for use by NUMA balancing

2015-02-13T02:54:08+00:00

This is a preparatory patch that introduces protnone helpers for automatic
NUMA balancing.

Signed-off-by: Mel Gorman 
Acked-by: Linus Torvalds 
Acked-by: Aneesh Kumar K.V 
Tested-by: Sasha Levin 
Cc: Benjamin Herrenschmidt 
Cc: Dave Jones 
Cc: Hugh Dickins 
Cc: Ingo Molnar 
Cc: Kirill Shutemov 
Cc: Paul Mackerras 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86: drop _PAGE_FILE and pte_file()-related helpers

2015-02-10T22:30:33+00:00

We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.

Signed-off-by: Kirill A. Shutemov 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patchbomb from Andrew)

2014-12-11T02:34:42+00:00

Merge first patchbomb from Andrew Morton:
 - a few minor cifs fixes
 - dma-debug upadtes
 - ocfs2
 - slab
 - about half of MM
 - procfs
 - kernel/exit.c
 - panic.c tweaks
 - printk upates
 - lib/ updates
 - checkpatch updates
 - fs/binfmt updates
 - the drivers/rtc tree
 - nilfs
 - kmod fixes
 - more kernel/exit.c
 - various other misc tweaks and fixes

* emailed patches from Andrew Morton : (190 commits)
  exit: pidns: fix/update the comments in zap_pid_ns_processes()
  exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting
  exit: exit_notify: re-use "dead" list to autoreap current
  exit: reparent: call forget_original_parent() under tasklist_lock
  exit: reparent: avoid find_new_reaper() if no children
  exit: reparent: introduce find_alive_thread()
  exit: reparent: introduce find_child_reaper()
  exit: reparent: document the ->has_child_subreaper checks
  exit: reparent: s/while_each_thread/for_each_thread/ in find_new_reaper()
  exit: reparent: fix the cross-namespace PR_SET_CHILD_SUBREAPER reparenting
  exit: reparent: fix the dead-parent PR_SET_CHILD_SUBREAPER reparenting
  exit: proc: don't try to flush /proc/tgid/task/tgid
  exit: release_task: fix the comment about group leader accounting
  exit: wait: drop tasklist_lock before psig->c* accounting
  exit: wait: don't use zombie->real_parent
  exit: wait: cleanup the ptrace_reparented() checks
  usermodehelper: kill the kmod_thread_locker logic
  usermodehelper: don't use CLONE_VFORK for ____call_usermodehelper()
  fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmp
  nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races
  ...

mm: fix huge zero page accounting in smaps report

2014-12-11T01:41:08+00:00

As a small zero page, huge zero page should not be accounted in smaps
report as normal page.

For small pages we rely on vm_normal_page() to filter out zero page, but
vm_normal_page() is not designed to handle pmds.  We only get here due
hackish cast pmd to pte in smaps_pte_range() -- pte and pmd format is not
necessary compatible on each and every architecture.

Let's add separate codepath to handle pmds.  follow_trans_huge_pmd() will
detect huge zero page for us.

We would need pmd_dirty() helper to do this properly.  The patch adds it
to THP-enabled architectures which don't yet have one.

[akpm@linux-foundation.org: use do_div to fix 32-bit build]
Signed-off-by: "Kirill A. Shutemov" 
Reported-by: Fengguang Wu 
Tested-by: Fengwei Yin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds