linux-toradex.git/fs/hugetlbfs, branch v3.19.1

mm: convert i_mmap_mutex to rwsem

2014-12-13T20:42:45+00:00

The i_mmap_mutex is a close cousin of the anon vma lock, both protecting
similar data, one for file backed pages and the other for anon memory.  To
this end, this lock can also be a rwsem.  In addition, there are some
important opportunities to share the lock when there are no tree
modifications.

This conversion is straightforward.  For now, all users take the write
lock.

[sfr@canb.auug.org.au: update fremap.c]
Signed-off-by: Davidlohr Bueso 
Reviewed-by: Rik van Riel 
Acked-by: "Kirill A. Shutemov" 
Acked-by: Hugh Dickins 
Cc: Oleg Nesterov 
Acked-by: Peter Zijlstra (Intel) 
Cc: Srikar Dronamraju 
Acked-by: Mel Gorman 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: use new helper functions around the i_mmap_mutex

2014-12-13T20:42:45+00:00

Convert all open coded mutex_lock/unlock calls to the
i_mmap_[lock/unlock]_write() helpers.

Signed-off-by: Davidlohr Bueso 
Acked-by: Rik van Riel 
Acked-by: "Kirill A. Shutemov" 
Acked-by: Hugh Dickins 
Cc: Oleg Nesterov 
Acked-by: Peter Zijlstra (Intel) 
Cc: Srikar Dronamraju 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/hugetlbfs/inode.c: remove null test before kfree

2014-06-04T23:54:11+00:00

Fix checkpatch warning:
WARNING: kfree(NULL) is safe this check is probably not required

Signed-off-by: Fabian Frederick 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/hugetlbfs/inode.c: use static const for dentry_operations

2014-06-04T23:54:11+00:00

...like other filesystems.

Signed-off-by: Fabian Frederick 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/hugetlbfs/inode.c: add static to hugetlbfs_i_mmap_mutex_key

2014-06-04T23:54:11+00:00

hugetlbfs_i_mmap_mutex_key is only used in inode.c

Signed-off-by: Fabian Frederick 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/hugetlbfs/inode.c: complete conversion to pr_foo()

2014-06-04T23:54:00+00:00

Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb: ensure hugepage access is denied if hugepages are not supported

2014-05-06T20:04:58+00:00

Currently, I am seeing the following when I `mount -t hugetlbfs /none
/dev/hugetlbfs`, and then simply do a `ls /dev/hugetlbfs`.  I think it's
related to the fact that hugetlbfs is properly not correctly setting
itself up in this state?:

  Unable to handle kernel paging request for data at address 0x00000031
  Faulting instruction address: 0xc000000000245710
  Oops: Kernel access of bad area, sig: 11 [#1]
  SMP NR_CPUS=2048 NUMA pSeries
  ....

In KVM guests on Power, in a guest not backed by hugepages, we see the
following:

  AnonHugePages:         0 kB
  HugePages_Total:       0
  HugePages_Free:        0
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:         64 kB

HPAGE_SHIFT == 0 in this configuration, which indicates that hugepages
are not supported at boot-time, but this is only checked in
hugetlb_init().  Extract the check to a helper function, and use it in a
few relevant places.

This does make hugetlbfs not supported (not registered at all) in this
environment.  I believe this is fine, as there are no valid hugepages
and that won't change at runtime.

[akpm@linux-foundation.org: use pr_info(), per Mel]
[akpm@linux-foundation.org: fix build when HPAGE_SHIFT is undefined]
Signed-off-by: Nishanth Aravamudan 
Reviewed-by: Aneesh Kumar K.V 
Acked-by: Mel Gorman 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, hugetlb: unify region structure handling

2014-04-03T23:20:59+00:00

Currently, to track reserved and allocated regions, we use two different
ways, depending on the mapping.  For MAP_SHARED, we use
address_mapping's private_list and, while for MAP_PRIVATE, we use a
resv_map.

Now, we are preparing to change a coarse grained lock which protect a
region structure to fine grained lock, and this difference hinder it.
So, before changing it, unify region structure handling, consistently
using a resv_map regardless of the kind of mapping.

Signed-off-by: Joonsoo Kim 
Signed-off-by: Davidlohr Bueso 
Reviewed-by: Aneesh Kumar K.V 
Reviewed-by: Naoya Horiguchi 
Cc: David Gibson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cope with potentially long ->d_dname() output for shmem/hugetlb

2013-08-24T16:10:17+00:00

dynamic_dname() is both too much and too little for those - the
output may be well in excess of 64 bytes dynamic_dname() assumes
to be enough (thanks to ashmem feeding really long names to
shmem_file_setup()) and vsnprintf() is an overkill for those
guys.

Signed-off-by: Al Viro

hugetlb: fix lockdep splat caused by pmd sharing

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

Dave has reported the following lockdep splat:

  =================================
  [ INFO: inconsistent lock state ]
  3.11.0-rc1+ #9 Not tainted
  ---------------------------------
  inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
  kswapd0/49 [HC0[0]:SC0[0]:HE1:SE1] takes:
   (&mapping->i_mmap_mutex){+.+.?.}, at: [] page_referenced+0x87/0x5e3
  {RECLAIM_FS-ON-W} state was registered at:
     mark_held_locks+0x81/0xe7
     lockdep_trace_alloc+0x5e/0xbc
     __alloc_pages_nodemask+0x8b/0x9b6
     __get_free_pages+0x20/0x31
     get_zeroed_page+0x12/0x14
     __pmd_alloc+0x1c/0x6b
     huge_pmd_share+0x265/0x283
     huge_pte_alloc+0x5d/0x71
     hugetlb_fault+0x7c/0x64a
     handle_mm_fault+0x255/0x299
     __do_page_fault+0x142/0x55c
     do_page_fault+0xd/0x16
     error_code+0x6c/0x74
  irq event stamp: 3136917
  hardirqs last  enabled at (3136917):  _raw_spin_unlock_irq+0x27/0x50
  hardirqs last disabled at (3136916):  _raw_spin_lock_irq+0x15/0x78
  softirqs last  enabled at (3136180):  __do_softirq+0x137/0x30f
  softirqs last disabled at (3136175):  irq_exit+0xa8/0xaa
  other info that might help us debug this:
   Possible unsafe locking scenario:
         CPU0
         ----
    lock(&mapping->i_mmap_mutex);
    
      lock(&mapping->i_mmap_mutex);

  *** DEADLOCK ***
  no locks held by kswapd0/49.

  stack backtrace:
  CPU: 1 PID: 49 Comm: kswapd0 Not tainted 3.11.0-rc1+ #9
  Hardware name: Dell Inc.                 Precision WorkStation 490    /0DT031, BIOS A08 04/25/2008
  Call Trace:
    dump_stack+0x4b/0x79
    print_usage_bug+0x1d9/0x1e3
    mark_lock+0x1e0/0x261
    __lock_acquire+0x623/0x17f2
    lock_acquire+0x7d/0x195
    mutex_lock_nested+0x6c/0x3a7
    page_referenced+0x87/0x5e3
    shrink_page_list+0x3d9/0x947
    shrink_inactive_list+0x155/0x4cb
    shrink_lruvec+0x300/0x5ce
    shrink_zone+0x53/0x14e
    kswapd+0x517/0xa75
    kthread+0xa8/0xaa
    ret_from_kernel_thread+0x1b/0x28

which is a false positive caused by hugetlb pmd sharing code which
allocates a new pmd from withing mapping->i_mmap_mutex.  If this
allocation causes reclaim then the lockdep detector complains that we
might self-deadlock.

This is not correct though, because hugetlb pages are not reclaimable so
their mapping will be never touched from the reclaim path.

The patch tells lockup detector that hugetlb i_mmap_mutex is special by
assigning it a separate lockdep class so it won't report possible
deadlocks on unrelated mappings.

[peterz@infradead.org: comment for annotation]
Reported-by: Dave Jones 
Signed-off-by: Michal Hocko 
Cc: Peter Zijlstra 
Reviewed-by: Minchan Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds