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  1. 12 2月, 2015 2 次提交
    • A
      mm: gup: use get_user_pages_unlocked within get_user_pages_fast · a7b78075
      由 Andrea Arcangeli 提交于 
      This allows the get_user_pages_fast slow path to release the mmap_sem
before blocking.
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Reviewed-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a7b78075
    • N
      mm/hugetlb: reduce arch dependent code around follow_huge_* · 61f77eda
      由 Naoya Horiguchi 提交于 
      Currently we have many duplicates in definitions around
follow_huge_addr(), follow_huge_pmd(), and follow_huge_pud(), so this
patch tries to remove the m.  The basic idea is to put the default
implementation for these functions in mm/hugetlb.c as weak symbols
(regardless of CONFIG_ARCH_WANT_GENERAL_HUGETL B), and to implement
arch-specific code only when the arch needs it.

For follow_huge_addr(), only powerpc and ia64 have their own
implementation, and in all other architectures this function just returns
ERR_PTR(-EINVAL).  So this patch sets returning ERR_PTR(-EINVAL) as
default.

As for follow_huge_(pmd|pud)(), if (pmd|pud)_huge() is implemented to
always return 0 in your architecture (like in ia64 or sparc,) it's never
called (the callsite is optimized away) no matter how implemented it is.
So in such architectures, we don't need arch-specific implementation.

In some architecture (like mips, s390 and tile,) their current
arch-specific follow_huge_(pmd|pud)() are effectively identical with the
common code, so this patch lets these architecture use the common code.

One exception is metag, where pmd_huge() could return non-zero but it
expects follow_huge_pmd() to always return NULL.  This means that we need
arch-specific implementation which returns NULL.  This behavior looks
strange to me (because non-zero pmd_huge() implies that the architecture
supports PMD-based hugepage, so follow_huge_pmd() can/should return some
relevant value,) but that's beyond this cleanup patch, so let's keep it.

Justification of non-trivial changes:
- in s390, follow_huge_pmd() checks !MACHINE_HAS_HPAGE at first, and this
  patch removes the check. This is OK because we can assume MACHINE_HAS_HPAGE
  is true when follow_huge_pmd() can be called (note that pmd_huge() has
  the same check and always returns 0 for !MACHINE_HAS_HPAGE.)
- in s390 and mips, we use HPAGE_MASK instead of PMD_MASK as done in common
  code. This patch forces these archs use PMD_MASK, but it's OK because
  they are identical in both archs.
  In s390, both of HPAGE_SHIFT and PMD_SHIFT are 20.
  In mips, HPAGE_SHIFT is defined as (PAGE_SHIFT + PAGE_SHIFT - 3) and
  PMD_SHIFT is define as (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3), but
  PTE_ORDER is always 0, so these are identical.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      61f77eda
  3. 30 1月, 2015 1 次提交
    • L
      vm: add VM_FAULT_SIGSEGV handling support · 33692f27
      由 Linus Torvalds 提交于 
      The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.
Reported-and-tested-by: NTakashi Iwai <tiwai@suse.de>
Tested-by: NJan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      33692f27
  5. 08 1月, 2015 1 次提交
  7. 14 12月, 2014 1 次提交
    • J
      mm/debug-pagealloc: make debug-pagealloc boottime configurable · 031bc574
      由 Joonsoo Kim 提交于 
      Now, we have prepared to avoid using debug-pagealloc in boottime.  So
introduce new kernel-parameter to disable debug-pagealloc in boottime, and
makes related functions to be disabled in this case.

Only non-intuitive part is change of guard page functions.  Because guard
page is effective only if debug-pagealloc is enabled, turning off
according to debug-pagealloc is reasonable thing to do.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Jungsoo Son <jungsoo.son@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      031bc574
  9. 28 11月, 2014 1 次提交
  11. 21 11月, 2014 1 次提交
  13. 10 11月, 2014 1 次提交
    • T
      /dev/mem: Use more consistent data types · 4707a341
      由 Thierry Reding 提交于 
      The xlate_dev_{kmem,mem}_ptr() functions take either a physical address
or a kernel virtual address, so data types should be phys_addr_t and
void *. They both return a kernel virtual address which is only ever
used in calls to copy_{from,to}_user(), so make variables that store it
void * rather than char * for consistency.

Also only define a weak unxlate_dev_mem_ptr() function if architectures
haven't overridden them in the asm/io.h header file.
Signed-off-by: NThierry Reding <treding@nvidia.com>
      4707a341
  15. 03 11月, 2014 1 次提交
  17. 28 10月, 2014 1 次提交
  19. 27 10月, 2014 5 次提交
  21. 15 10月, 2014 1 次提交
  23. 30 9月, 2014 1 次提交
  25. 25 9月, 2014 2 次提交
  27. 14 9月, 2014 1 次提交
  29. 29 8月, 2014 1 次提交
  31. 26 8月, 2014 2 次提交
  33. 25 8月, 2014 3 次提交
  35. 01 8月, 2014 2 次提交
  37. 05 6月, 2014 1 次提交
  39. 20 5月, 2014 4 次提交
  41. 16 5月, 2014 1 次提交
  43. 22 4月, 2014 4 次提交
  45. 09 4月, 2014 1 次提交
  47. 08 4月, 2014 1 次提交
    • A
      mm: revert "thp: make MADV_HUGEPAGE check for mm->def_flags" · 1e1836e8
      由 Alex Thorlton 提交于 
      The main motivation behind this patch is to provide a way to disable THP
for jobs where the code cannot be modified, and using a malloc hook with
madvise is not an option (i.e.  statically allocated data).  This patch
allows us to do just that, without affecting other jobs running on the
system.

We need to do this sort of thing for jobs where THP hurts performance,
due to the possibility of increased remote memory accesses that can be
created by situations such as the following:

When you touch 1 byte of an untouched, contiguous 2MB chunk, a THP will
be handed out, and the THP will be stuck on whatever node the chunk was
originally referenced from.  If many remote nodes need to do work on
that same chunk, they'll be making remote accesses.

With THP disabled, 4K pages can be handed out to separate nodes as
they're needed, greatly reducing the amount of remote accesses to
memory.

This patch is based on some of my work combined with some
suggestions/patches given by Oleg Nesterov.  The main goal here is to
add a prctl switch to allow us to disable to THP on a per mm_struct
basis.

Here's a bit of test data with the new patch in place...

First with the flag unset:

  # perf stat -a ./prctl_wrapper_mmv3 0 ./thp_pthread -C 0 -m 0 -c 512 -b 256g
  Setting thp_disabled for this task...
  thp_disable: 0
  Set thp_disabled state to 0
  Process pid = 18027

                                                                                                                       PF/
                                  MAX        MIN                                  TOTCPU/      TOT_PF/   TOT_PF/     WSEC/
  TYPE:               CPUS       WALL       WALL        SYS     USER     TOTCPU       CPU     WALL_SEC   SYS_SEC       CPU   NODES
   512      1.120      0.060      0.000    0.110      0.110     0.000    28571428864 -9223372036854775808  55803572      23

   Performance counter stats for './prctl_wrapper_mmv3_hack 0 ./thp_pthread -C 0 -m 0 -c 512 -b 256g':

    273719072.841402 task-clock                #  641.026 CPUs utilized           [100.00%]
           1,008,986 context-switches          #    0.000 M/sec                   [100.00%]
               7,717 CPU-migrations            #    0.000 M/sec                   [100.00%]
           1,698,932 page-faults               #    0.000 M/sec
  355,222,544,890,379 cycles                   #    1.298 GHz                     [100.00%]
  536,445,412,234,588 stalled-cycles-frontend  #  151.02% frontend cycles idle    [100.00%]
  409,110,531,310,223 stalled-cycles-backend   #  115.17% backend  cycles idle    [100.00%]
  148,286,797,266,411 instructions             #    0.42  insns per cycle
                                               #    3.62  stalled cycles per insn [100.00%]
  27,061,793,159,503 branches                  #   98.867 M/sec                   [100.00%]
       1,188,655,196 branch-misses             #    0.00% of all branches

       427.001706337 seconds time elapsed

Now with the flag set:

  # perf stat -a ./prctl_wrapper_mmv3 1 ./thp_pthread -C 0 -m 0 -c 512 -b 256g
  Setting thp_disabled for this task...
  thp_disable: 1
  Set thp_disabled state to 1
  Process pid = 144957

                                                                                                                       PF/
                                  MAX        MIN                                  TOTCPU/      TOT_PF/   TOT_PF/     WSEC/
  TYPE:               CPUS       WALL       WALL        SYS     USER     TOTCPU       CPU     WALL_SEC   SYS_SEC       CPU   NODES
   512      0.620      0.260      0.250    0.320      0.570     0.001    51612901376 128000000000 100806448      23

   Performance counter stats for './prctl_wrapper_mmv3_hack 1 ./thp_pthread -C 0 -m 0 -c 512 -b 256g':

    138789390.540183 task-clock                #  641.959 CPUs utilized           [100.00%]
             534,205 context-switches          #    0.000 M/sec                   [100.00%]
               4,595 CPU-migrations            #    0.000 M/sec                   [100.00%]
          63,133,119 page-faults               #    0.000 M/sec
  147,977,747,269,768 cycles                   #    1.066 GHz                     [100.00%]
  200,524,196,493,108 stalled-cycles-frontend  #  135.51% frontend cycles idle    [100.00%]
  105,175,163,716,388 stalled-cycles-backend   #   71.07% backend  cycles idle    [100.00%]
  180,916,213,503,160 instructions             #    1.22  insns per cycle
                                               #    1.11  stalled cycles per insn [100.00%]
  26,999,511,005,868 branches                  #  194.536 M/sec                   [100.00%]
         714,066,351 branch-misses             #    0.00% of all branches

       216.196778807 seconds time elapsed

As with previous versions of the patch, We're getting about a 2x
performance increase here.  Here's a link to the test case I used, along
with the little wrapper to activate the flag:

  http://oss.sgi.com/projects/memtests/thp_pthread_mmprctlv3.tar.gz

This patch (of 3):

Revert commit 8e72033f and add in code to fix up any issues caused
by the revert.

The revert is necessary because hugepage_madvise would return -EINVAL
when VM_NOHUGEPAGE is set, which will break subsequent chunks of this
patch set.

Here's a snip of an e-mail from Gerald detailing the original purpose of
this code, and providing justification for the revert:

  "The intent of commit 8e72033f was to guard against any future
   programming errors that may result in an madvice(MADV_HUGEPAGE) on
   guest mappings, which would crash the kernel.

   Martin suggested adding the bit to arch/s390/mm/pgtable.c, if
   8e72033f was to be reverted, because that check will also prevent
   a kernel crash in the case described above, it will now send a
   SIGSEGV instead.

   This would now also allow to do the madvise on other parts, if
   needed, so it is a more flexible approach.  One could also say that
   it would have been better to do it this way right from the
   beginning..."
Signed-off-by: NAlex Thorlton <athorlton@sgi.com>
Suggested-by: NOleg Nesterov <oleg@redhat.com>
Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1e1836e8