Commit Graph

4804 Commits

Author SHA1 Message Date
Stephen Wilson
5ddd36b9c5 mm: implement access_remote_vm
Provide an alternative to access_process_vm that allows the caller to obtain a
reference to the supplied mm_struct.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23 16:36:57 -04:00
Stephen Wilson
206cb63657 mm: factor out main logic of access_process_vm
Introduce an internal helper __access_remote_vm and base access_process_vm on
top of it.  This new method may be called with a NULL task_struct if page fault
accounting is not desired.  This code will be shared with a new address space
accessor that is independent of task_struct.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23 16:36:56 -04:00
Stephen Wilson
e7f22e207b mm: use mm_struct to resolve gate vma's in __get_user_pages
We now check if a requested user page overlaps a gate vma using the supplied mm
instead of the supplied task.  The given task is now used solely for accounting
purposes and may be NULL.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23 16:36:56 -04:00
Stephen Wilson
cae5d39032 mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm
Now that gate vma's are referenced with respect to a particular mm and not a
particular task it only makes sense to propagate the change to this predicate as
well.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: Michel Lespinasse <walken@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23 16:36:55 -04:00
Stephen Wilson
83b964bbf8 mm: arch: make in_gate_area take an mm_struct instead of a task_struct
Morally, the question of whether an address lies in a gate vma should be asked
with respect to an mm, not a particular task.  Moreover, dropping the dependency
on task_struct will help make existing and future operations on mm's more
flexible and convenient.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: Michel Lespinasse <walken@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23 16:36:54 -04:00
Stephen Wilson
31db58b3ab mm: arch: make get_gate_vma take an mm_struct instead of a task_struct
Morally, the presence of a gate vma is more an attribute of a particular mm than
a particular task.  Moreover, dropping the dependency on task_struct will help
make both existing and future operations on mm's more flexible and convenient.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: Michel Lespinasse <walken@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23 16:36:54 -04:00
Linus Torvalds
e16b396ce3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (47 commits)
  doc: CONFIG_UNEVICTABLE_LRU doesn't exist anymore
  Update cpuset info & webiste for cgroups
  dcdbas: force SMI to happen when expected
  arch/arm/Kconfig: remove one to many l's in the word.
  asm-generic/user.h: Fix spelling in comment
  drm: fix printk typo 'sracth'
  Remove one to many n's in a word
  Documentation/filesystems/romfs.txt: fixing link to genromfs
  drivers:scsi Change printk typo initate -> initiate
  serial, pch uart: Remove duplicate inclusion of linux/pci.h header
  fs/eventpoll.c: fix spelling
  mm: Fix out-of-date comments which refers non-existent functions
  drm: Fix printk typo 'failled'
  coh901318.c: Change initate to initiate.
  mbox-db5500.c Change initate to initiate.
  edac: correct i82975x error-info reported
  edac: correct i82975x mci initialisation
  edac: correct commented info
  fs: update comments to point correct document
  target: remove duplicate include of target/target_core_device.h from drivers/target/target_core_hba.c
  ...

Trivial conflict in fs/eventpoll.c (spelling vs addition)
2011-03-18 10:37:40 -07:00
Linus Torvalds
ec0afc9311 Merge branch 'kvm-updates/2.6.39' of git://git.kernel.org/pub/scm/virt/kvm/kvm
* 'kvm-updates/2.6.39' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (55 commits)
  KVM: unbreak userspace that does not sets tss address
  KVM: MMU: cleanup pte write path
  KVM: MMU: introduce a common function to get no-dirty-logged slot
  KVM: fix rcu usage in init_rmode_* functions
  KVM: fix kvmclock regression due to missing clock update
  KVM: emulator: Fix permission checking in io permission bitmap
  KVM: emulator: Fix io permission checking for 64bit guest
  KVM: SVM: Load %gs earlier if CONFIG_X86_32_LAZY_GS=n
  KVM: x86: Remove useless regs_page pointer from kvm_lapic
  KVM: improve comment on rcu use in irqfd_deassign
  KVM: MMU: remove unused macros
  KVM: MMU: cleanup page alloc and free
  KVM: MMU: do not record gfn in kvm_mmu_pte_write
  KVM: MMU: move mmu pages calculated out of mmu lock
  KVM: MMU: set spte accessed bit properly
  KVM: MMU: fix kvm_mmu_slot_remove_write_access dropping intermediate W bits
  KVM: Start lock documentation
  KVM: better readability of efer_reserved_bits
  KVM: Clear async page fault hash after switching to real mode
  KVM: VMX: Initialize vm86 TSS only once.
  ...
2011-03-17 18:40:35 -07:00
Andrea Arcangeli
ef2b4b95a6 mm: PageBuddy and mapcount robustness
Change the _mapcount value indicating PageBuddy from -2 to -128 for
more robusteness against page_mapcount() undeflows.

Use reset_page_mapcount instead of __ClearPageBuddy in bad_page to
ignore the previous retval of PageBuddy().

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-17 16:31:13 -07:00
Huang Ying
f58c9df78c mm: remove is_hwpoison_address
Unused.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-17 13:08:27 -03:00
Huang Ying
69ebb83e13 mm: make __get_user_pages return -EHWPOISON for HWPOISON page optionally
Make __get_user_pages return -EHWPOISON for HWPOISON page only if
FOLL_HWPOISON is specified.  With this patch, the interested callers
can distinguish HWPOISON pages from general FAULT pages, while other
callers will still get -EFAULT for all these pages, so the user space
interface need not to be changed.

This feature is needed by KVM, where UCR MCE should be relayed to
guest for HWPOISON page, while instruction emulation and MMIO will be
tried for general FAULT page.

The idea comes from Andrew Morton.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-03-17 13:08:27 -03:00
Huang Ying
0014bd990e mm: export __get_user_pages
In most cases, get_user_pages and get_user_pages_fast should be used
to pin user pages in memory.  But sometimes, some special flags except
FOLL_GET, FOLL_WRITE and FOLL_FORCE are needed, for example in
following patch, KVM needs FOLL_HWPOISON.  To support these users,
__get_user_pages is exported directly.

There are some symbol name conflicts in infiniband driver, fixed them too.

Signed-off-by: Huang Ying <ying.huang@intel.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Michel Lespinasse <walken@google.com>
CC: Roland Dreier <roland@kernel.org>
CC: Ralph Campbell <infinipath@qlogic.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-17 13:08:27 -03:00
Linus Torvalds
0f6e0e8448 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (33 commits)
  AppArmor: kill unused macros in lsm.c
  AppArmor: cleanup generated files correctly
  KEYS: Add an iovec version of KEYCTL_INSTANTIATE
  KEYS: Add a new keyctl op to reject a key with a specified error code
  KEYS: Add a key type op to permit the key description to be vetted
  KEYS: Add an RCU payload dereference macro
  AppArmor: Cleanup make file to remove cruft and make it easier to read
  SELinux: implement the new sb_remount LSM hook
  LSM: Pass -o remount options to the LSM
  SELinux: Compute SID for the newly created socket
  SELinux: Socket retains creator role and MLS attribute
  SELinux: Auto-generate security_is_socket_class
  TOMOYO: Fix memory leak upon file open.
  Revert "selinux: simplify ioctl checking"
  selinux: drop unused packet flow permissions
  selinux: Fix packet forwarding checks on postrouting
  selinux: Fix wrong checks for selinux_policycap_netpeer
  selinux: Fix check for xfrm selinux context algorithm
  ima: remove unnecessary call to ima_must_measure
  IMA: remove IMA imbalance checking
  ...
2011-03-16 09:15:43 -07:00
Linus Torvalds
181f977d13 Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (93 commits)
  x86, tlb, UV: Do small micro-optimization for native_flush_tlb_others()
  x86-64, NUMA: Don't call numa_set_distanc() for all possible node combinations during emulation
  x86-64, NUMA: Don't assume phys node 0 is always online in numa_emulation()
  x86-64, NUMA: Clean up initmem_init()
  x86-64, NUMA: Fix numa_emulation code with node0 without RAM
  x86-64, NUMA: Revert NUMA affine page table allocation
  x86: Work around old gas bug
  x86-64, NUMA: Better explain numa_distance handling
  x86-64, NUMA: Fix distance table handling
  mm: Move early_node_map[] reverse scan helpers under HAVE_MEMBLOCK
  x86-64, NUMA: Fix size of numa_distance array
  x86: Rename e820_table_* to pgt_buf_*
  bootmem: Move __alloc_memory_core_early() to nobootmem.c
  bootmem: Move contig_page_data definition to bootmem.c/nobootmem.c
  bootmem: Separate out CONFIG_NO_BOOTMEM code into nobootmem.c
  x86-64, NUMA: Seperate out numa_alloc_distance() from numa_set_distance()
  x86-64, NUMA: Add proper function comments to global functions
  x86-64, NUMA: Move NUMA emulation into numa_emulation.c
  x86-64, NUMA: Prepare numa_emulation() for moving NUMA emulation into a separate file
  x86-64, NUMA: Do not scan two times for setup_node_bootmem()
  ...

Fix up conflicts in arch/x86/kernel/smpboot.c
2011-03-15 19:49:10 -07:00
Linus Torvalds
422e6c4bc4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (57 commits)
  tidy the trailing symlinks traversal up
  Turn resolution of trailing symlinks iterative everywhere
  simplify link_path_walk() tail
  Make trailing symlink resolution in path_lookupat() iterative
  update nd->inode in __do_follow_link() instead of after do_follow_link()
  pull handling of one pathname component into a helper
  fs: allow AT_EMPTY_PATH in linkat(), limit that to CAP_DAC_READ_SEARCH
  Allow passing O_PATH descriptors via SCM_RIGHTS datagrams
  readlinkat(), fchownat() and fstatat() with empty relative pathnames
  Allow O_PATH for symlinks
  New kind of open files - "location only".
  ext4: Copy fs UUID to superblock
  ext3: Copy fs UUID to superblock.
  vfs: Export file system uuid via /proc/<pid>/mountinfo
  unistd.h: Add new syscalls numbers to asm-generic
  x86: Add new syscalls for x86_64
  x86: Add new syscalls for x86_32
  fs: Remove i_nlink check from file system link callback
  fs: Don't allow to create hardlink for deleted file
  vfs: Add open by file handle support
  ...
2011-03-15 15:48:13 -07:00
James Morris
a002951c97 Merge branch 'next' into for-linus 2011-03-16 09:41:17 +11:00
Ingo Molnar
8460b3e5bc Merge commit 'v2.6.38' into x86/mm
Conflicts:
	arch/x86/mm/numa_64.c

Merge reason: Resolve the conflict, update the branch to .38.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-15 08:29:44 +01:00
Linus Torvalds
52d3c03675 Revert "oom: oom_kill_process: fix the child_points logic"
This reverts the parent commit.  I hate doing that, but it's generating
some discussion ("half of it is right"), and since I am planning on
doing the 2.6.38 release later today we can punt it to stable if
required. Let's not rock the boat right now.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-14 15:17:07 -07:00
Oleg Nesterov
dc1b83ab08 oom: oom_kill_process: fix the child_points logic
oom_kill_process() starts with victim_points == 0.  This means that
(most likely) any child has more points and can be killed erroneously.

Also, "children has a different mm" doesn't match the reality, we should
check child->mm != t->mm.  This check is not exactly correct if t->mm ==
NULL but this doesn't really matter, oom_kill_task() will kill them
anyway.

Note: "Kill all processes sharing p->mm" in oom_kill_task() is wrong
too.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-14 13:38:35 -07:00
Hugh Dickins
2fbfac4e05 thp+memcg-numa: fix BUG at include/linux/mm.h:370!
THP's collapse_huge_page() has an understandable but ugly difference
in when its huge page is allocated: inside if NUMA but outside if not.
It's hardly surprising that the memcg failure path forgot that, freeing
the page in the non-NUMA case, then hitting a VM_BUG_ON in get_page()
(or even worse, using the freed page).

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-14 08:29:50 -07:00
Aneesh Kumar K.V
5fe0c23788 exportfs: Return the minimum required handle size
The exportfs encode handle function should return the minimum required
handle size. This helps user to find out the handle size by passing 0
handle size in the first step and then redoing to the call again with
the returned handle size value.

Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-14 09:15:28 -04:00
Andrea Arcangeli
2da28bfd96 thp: fix page_referenced to modify mapcount/vm_flags only if page is found
When vmscan.c calls page_referenced(), if an anon page was created
before a process forked, rmap will search for it in both of the
processes, even though one of them might have since broken COW.

If the child process mlocks the vma where the COWed page belongs to,
page_referenced() running on the page mapped by the parent would lead to
*vm_flags getting VM_LOCKED set erroneously (leading to the references
on the parent page being ignored and evicting the parent page too
early).

*mapcount would also be decremented by page_referenced_one even if the
page wasn't found by page_check_address.

This also lets pmdp_clear_flush_young_notify() go ahead on a
pmd_trans_splitting() pmd.

We hold the page_table_lock so __split_huge_page_map() must wait the
pmdp_clear_flush_young_notify() to complete before it can modify the
pmd.  The pmd is also still mapped in userland so the young bit may
materialize through a tlb miss before split_huge_page_map runs.

This will provide a more accurate page_referenced() behavior during
split_huge_page().

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel<riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-13 15:35:57 -07:00
James Morris
fe3fa43039 Merge branch 'master' of git://git.infradead.org/users/eparis/selinux into next 2011-03-08 11:38:10 +11:00
Andi Kleen
5c4b4be3b6 mm: use correct numa policy node for transparent hugepages
Pass down the correct node for a transparent hugepage allocation.  Most
callers continue to use the current node, however the hugepaged daemon
now uses the previous node of the first to be collapsed page instead.
This ensures that khugepaged does not mess up local memory for an
existing process which uses local policy.

The choice of node is somewhat primitive currently: it just uses the
node of the first page in the pmd range.  An alternative would be to
look at multiple pages and use the most popular node.  I used the
simplest variant for now which should work well enough for the case of
all pages being on the same node.

[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-04 17:53:39 -08:00
Andi Kleen
19ee151e14 mm: preserve original node for transparent huge page copies
This makes a difference for LOCAL policy, where the node cannot be
determined from the policy itself, but has to be gotten from the original
page.

Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-04 17:53:39 -08:00
Andi Kleen
2f5f9486f8 mm: change alloc_pages_vma to pass down the policy node for local policy
Currently alloc_pages_vma() always uses the local node as policy node for
the LOCAL policy.  Pass this node down as an argument instead.

No behaviour change from this patch, but will be needed for followons.

Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-04 17:53:39 -08:00
Justin P. Mattock
ae0e47f02a Remove one to many n's in a word
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-03-01 15:47:58 +01:00
Yinghai Lu
cc28989437 mm: Move early_node_map[] reverse scan helpers under HAVE_MEMBLOCK
Heiko found recent memblock change triggers these warnings on s390:

  mm/page_alloc.c:3623:22: warning: 'last_active_region_index_in_nid' defined but not used
  mm/page_alloc.c:3638:22: warning: 'previous_active_region_index_in_nid' defined but not used

Need to move those two function under HAVE_MEMBLOCK with its only
user, find_memory_core_early().

-tj: Minor updates to description.

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-02-26 13:05:43 +01:00
Hugh Dickins
e5598f8bf5 memcg: more mem_cgroup_uncharge() batching
It seems odd that truncate_inode_pages_range(), called not only when
truncating but also when evicting inodes, has mem_cgroup_uncharge_start
and _end() batching in its second loop to clear up a few leftovers, but
not in its first loop that does almost all the work: add them there too.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:37 -08:00
Andi Kleen
8eac563c1c thp: fix interleaving for transparent hugepages
The THP code didn't pass the correct interleaving shift to the memory
policy code.  Fix this here by adjusting for the order.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:37 -08:00
Namhyung Kim
29723fccc8 mm: fix dubious code in __count_immobile_pages()
When pfn_valid_within() failed 'iter' was incremented twice.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:37 -08:00
Mel Gorman
2876592f23 mm: vmscan: stop reclaim/compaction earlier due to insufficient progress if !__GFP_REPEAT
should_continue_reclaim() for reclaim/compaction allows scanning to
continue even if pages are not being reclaimed until the full list is
scanned.  In terms of allocation success, this makes sense but potentially
it introduces unwanted latency for high-order allocations such as
transparent hugepages and network jumbo frames that would prefer to fail
the allocation attempt and fallback to order-0 pages.  Worse, there is a
potential that the full LRU scan will clear all the young bits, distort
page aging information and potentially push pages into swap that would
have otherwise remained resident.

This patch will stop reclaim/compaction if no pages were reclaimed in the
last SWAP_CLUSTER_MAX pages that were considered.  For allocations such as
hugetlbfs that use __GFP_REPEAT and have fewer fallback options, the full
LRU list may still be scanned.

Order-0 allocation should not be affected because RECLAIM_MODE_COMPACTION
is not set so the following avoids the gfp_mask being examined:

        if (!(sc->reclaim_mode & RECLAIM_MODE_COMPACTION))
                return false;

A tool was developed based on ftrace that tracked the latency of
high-order allocations while transparent hugepage support was enabled and
three benchmarks were run.  The "fix-infinite" figures are 2.6.38-rc4 with
Johannes's patch "vmscan: fix zone shrinking exit when scan work is done"
applied.

  STREAM Highorder Allocation Latency Statistics
                 fix-infinite     break-early
  1 :: Count            10298           10229
  1 :: Min             0.4560          0.4640
  1 :: Mean            1.0589          1.0183
  1 :: Max            14.5990         11.7510
  1 :: Stddev          0.5208          0.4719
  2 :: Count                2               1
  2 :: Min             1.8610          3.7240
  2 :: Mean            3.4325          3.7240
  2 :: Max             5.0040          3.7240
  2 :: Stddev          1.5715          0.0000
  9 :: Count           111696          111694
  9 :: Min             0.5230          0.4110
  9 :: Mean           10.5831         10.5718
  9 :: Max            38.4480         43.2900
  9 :: Stddev          1.1147          1.1325

Mean time for order-1 allocations is reduced.  order-2 looks increased but
with so few allocations, it's not particularly significant.  THP mean
allocation latency is also reduced.  That said, allocation time varies so
significantly that the reductions are within noise.

Max allocation time is reduced by a significant amount for low-order
allocations but reduced for THP allocations which presumably are now
breaking before reclaim has done enough work.

  SysBench Highorder Allocation Latency Statistics
                 fix-infinite     break-early
  1 :: Count            15745           15677
  1 :: Min             0.4250          0.4550
  1 :: Mean            1.1023          1.0810
  1 :: Max            14.4590         10.8220
  1 :: Stddev          0.5117          0.5100
  2 :: Count                1               1
  2 :: Min             3.0040          2.1530
  2 :: Mean            3.0040          2.1530
  2 :: Max             3.0040          2.1530
  2 :: Stddev          0.0000          0.0000
  9 :: Count             2017            1931
  9 :: Min             0.4980          0.7480
  9 :: Mean           10.4717         10.3840
  9 :: Max            24.9460         26.2500
  9 :: Stddev          1.1726          1.1966

Again, mean time for order-1 allocations is reduced while order-2
allocations are too few to draw conclusions from.  The mean time for THP
allocations is also slightly reduced albeit the reductions are within
varianes.

Once again, our maximum allocation time is significantly reduced for
low-order allocations and slightly increased for THP allocations.

  Anon stream mmap reference Highorder Allocation Latency Statistics
  1 :: Count             1376            1790
  1 :: Min             0.4940          0.5010
  1 :: Mean            1.0289          0.9732
  1 :: Max             6.2670          4.2540
  1 :: Stddev          0.4142          0.2785
  2 :: Count                1               -
  2 :: Min             1.9060               -
  2 :: Mean            1.9060               -
  2 :: Max             1.9060               -
  2 :: Stddev          0.0000               -
  9 :: Count            11266           11257
  9 :: Min             0.4990          0.4940
  9 :: Mean        27250.4669      24256.1919
  9 :: Max      11439211.0000    6008885.0000
  9 :: Stddev     226427.4624     186298.1430

This benchmark creates one thread per CPU which references an amount of
anonymous memory 1.5 times the size of physical RAM.  This pounds swap
quite heavily and is intended to exercise THP a bit.

Mean allocation time for order-1 is reduced as before.  It's also reduced
for THP allocations but the variations here are pretty massive due to
swap.  As before, maximum allocation times are significantly reduced.

Overall, the patch reduces the mean and maximum allocation latencies for
the smaller high-order allocations.  This was with Slab configured so it
would be expected to be more significant with Slub which uses these size
allocations more aggressively.

The mean allocation times for THP allocations are also slightly reduced.
The maximum latency was slightly increased as predicted by the comments
due to reclaim/compaction breaking early.  However, workloads care more
about the latency of lower-order allocations than THP so it's an
acceptable trade-off.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:36 -08:00
Greg Thelen
a879bf582d mm: grab rcu read lock in move_pages()
The move_pages() usage of find_task_by_vpid() requires rcu_read_lock() to
prevent free_pid() from reclaiming the pid.

Without this patch, RCU warnings are printed in v2.6.38-rc4 move_pages()
with:

  CONFIG_LOCKUP_DETECTOR=y
  CONFIG_PREEMPT=y
  CONFIG_LOCKDEP=y
  CONFIG_PROVE_LOCKING=y
  CONFIG_PROVE_RCU=y

Previously, migrate_pages() went through a similar transformation
replacing usage of tasklist_lock with rcu read lock:

  commit 55cfaa3cbd
  Author: Zeng Zhaoming <zengzm.kernel@gmail.com>
  Date:   Thu Dec 2 14:31:13 2010 -0800

      mm/mempolicy.c: add rcu read lock to protect pid structure

  commit 1e50df39f6
  Author: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
  Date:   Thu Jan 13 15:46:14 2011 -0800

      mempolicy: remove tasklist_lock from migrate_pages

Signed-off-by: Greg Thelen <gthelen@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Zeng Zhaoming <zengzm.kernel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-25 15:07:36 -08:00
Miklos Szeredi
8074b26f67 mm: fix refcounting in swapon
Grab a reference to bdev before calling blkdev_get(), which expects
the refcount to be already incremented and either returns success or
decrements the refcount and returns an error.

The bug was introduced by e525fd89 (block: make blkdev_get/put()
handle exclusive access), which didn't take into account this behavior
of blkdev_get().

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-24 08:55:01 -08:00
Yinghai Lu
8bc1f91e1f bootmem: Move __alloc_memory_core_early() to nobootmem.c
Now that bootmem.c and nobootmem.c are separate, there's no reason to
define __alloc_memory_core_early(), which is used only by nobootmem,
inside #ifdef in page_alloc.c.  Move it to nobootmem.c and make it
static.

This patch doesn't introduce any behavior change.

-tj: Updated commit description.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-02-24 14:43:06 +01:00
Yinghai Lu
e782ab421b bootmem: Move contig_page_data definition to bootmem.c/nobootmem.c
Now that bootmem.c and nobootmem.c are separate, it's cleaner to
define contig_page_data in each file than in page_alloc.c with #ifdef.
Move it.

This patch doesn't introduce any behavior change.

-v2: According to Andrew, fixed the struct layout.
-tj: Updated commit description.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-02-24 14:43:06 +01:00
Yinghai Lu
0932587328 bootmem: Separate out CONFIG_NO_BOOTMEM code into nobootmem.c
mm/bootmem.c contained code paths for both bootmem and no bootmem
configurations.  They implement about the same set of APIs in
different ways and as a result bootmem.c contains massive amount of
#ifdef CONFIG_NO_BOOTMEM.

Separate out CONFIG_NO_BOOTMEM code into mm/nobootmem.c.  As the
common part is relatively small, duplicate them in nobootmem.c instead
of creating a common file or ifdef'ing in bootmem.c.

The followings are duplicated.

* {min|max}_low_pfn, max_pfn, saved_max_pfn
* free_bootmem_late()
* ___alloc_bootmem()
* __alloc_bootmem_low()

The followings are applicable only to nobootmem and moved verbatim.

* __free_pages_memory()
* free_all_memory_core_early()

The followings are not applicable to nobootmem and omitted in
nobootmem.c.

* reserve_bootmem_node()
* reserve_bootmem()

The rest split function bodies according to CONFIG_NO_BOOTMEM.

Makefile is updated so that only either bootmem.c or nobootmem.c is
built according to CONFIG_NO_BOOTMEM.

This patch doesn't introduce any behavior change.

-tj: Rewrote commit description.

Suggested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2011-02-24 14:43:05 +01:00
Hugh Dickins
a3e8cc643d mm: fix possible cause of a page_mapped BUG
Robert Swiecki reported a BUG_ON(page_mapped) from a fuzzer, punching
a hole with madvise(,, MADV_REMOVE).  That path is under mutex, and
cannot be explained by lack of serialization in unmap_mapping_range().

Reviewing the code, I found one place where vm_truncate_count handling
should have been updated, when I switched at the last minute from one
way of managing the restart_addr to another: mremap move changes the
virtual addresses, so it ought to adjust the restart_addr.

But rather than exporting the notion of restart_addr from memory.c, or
converting to restart_pgoff throughout, simply reset vm_truncate_count
to 0 to force a rescan if mremap move races with preempted truncation.

We have no confirmation that this fixes Robert's BUG,
but it is a fix that's worth making anyway.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-23 21:55:06 -08:00
Miklos Szeredi
2aa15890f3 mm: prevent concurrent unmap_mapping_range() on the same inode
Michael Leun reported that running parallel opens on a fuse filesystem
can trigger a "kernel BUG at mm/truncate.c:475"

Gurudas Pai reported the same bug on NFS.

The reason is, unmap_mapping_range() is not prepared for more than
one concurrent invocation per inode.  For example:

  thread1: going through a big range, stops in the middle of a vma and
     stores the restart address in vm_truncate_count.

  thread2: comes in with a small (e.g. single page) unmap request on
     the same vma, somewhere before restart_address, finds that the
     vma was already unmapped up to the restart address and happily
     returns without doing anything.

Another scenario would be two big unmap requests, both having to
restart the unmapping and each one setting vm_truncate_count to its
own value.  This could go on forever without any of them being able to
finish.

Truncate and hole punching already serialize with i_mutex.  Other
callers of unmap_mapping_range() do not, and it's difficult to get
i_mutex protection for all callers.  In particular ->d_revalidate(),
which calls invalidate_inode_pages2_range() in fuse, may be called
with or without i_mutex.

This patch adds a new mutex to 'struct address_space' to prevent
running multiple concurrent unmap_mapping_range() on the same mapping.

[ We'll hopefully get rid of all this with the upcoming mm
  preemptibility series by Peter Zijlstra, the "mm: Remove i_mmap_mutex
  lockbreak" patch in particular.  But that is for 2.6.39 ]

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reported-by: Michael Leun <lkml20101129@newton.leun.net>
Reported-by: Gurudas Pai <gurudas.pai@oracle.com>
Tested-by: Gurudas Pai <gurudas.pai@oracle.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-23 19:52:52 -08:00
Ryota Ozaki
a335b2e173 mm: Fix out-of-date comments which refers non-existent functions
do_file_page and do_no_page don't exist anymore, but some comments
still refers them. The patch fixes them by replacing them with
existing ones.

Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-02-17 16:54:39 +01:00
Andrea Arcangeli
a7d6e4ecdb thp: prevent hugepages during args/env copying into the user stack
Transparent hugepages can only be created if rmap is fully
functional. So we must prevent hugepages to be created while
is_vma_temporary_stack() is true.

This also optmizes away some harmless but unnecessary setting of
khugepaged_scan.address and it switches some BUG_ON to VM_BUG_ON.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-15 15:21:11 -08:00
Ingo Molnar
d2137d5af4 Merge branch 'linus' into x86/bootmem
Conflicts:
	arch/x86/mm/numa_64.c

Merge reason: fix the conflict, update to latest -rc and pick up this
              dependent fix from Yinghai:

  e6d2e2b2b1: memblock: don't adjust size in memblock_find_base()

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-02-14 11:55:18 +01:00
KAMEZAWA Hiroyuki
678ff896a3 memcg: fix leak of accounting at failure path of hugepage collapsing
mem_cgroup_uncharge_page() should be called in all failure cases after
mem_cgroup_charge_newpage() is called in huge_memory.c::collapse_huge_page()

 [ 4209.076861] BUG: Bad page state in process khugepaged  pfn:1e9800
 [ 4209.077601] page:ffffea0006b14000 count:0 mapcount:0 mapping:          (null) index:0x2800
 [ 4209.078674] page flags: 0x40000000004000(head)
 [ 4209.079294] pc:ffff880214a30000 pc->flags:2146246697418756 pc->mem_cgroup:ffffc9000177a000
 [ 4209.082177] (/A)
 [ 4209.082500] Pid: 31, comm: khugepaged Not tainted 2.6.38-rc3-mm1 #1
 [ 4209.083412] Call Trace:
 [ 4209.083678]  [<ffffffff810f4454>] ? bad_page+0xe4/0x140
 [ 4209.084240]  [<ffffffff810f53e6>] ? free_pages_prepare+0xd6/0x120
 [ 4209.084837]  [<ffffffff8155621d>] ? rwsem_down_failed_common+0xbd/0x150
 [ 4209.085509]  [<ffffffff810f5462>] ? __free_pages_ok+0x32/0xe0
 [ 4209.086110]  [<ffffffff810f552b>] ? free_compound_page+0x1b/0x20
 [ 4209.086699]  [<ffffffff810fad6c>] ? __put_compound_page+0x1c/0x30
 [ 4209.087333]  [<ffffffff810fae1d>] ? put_compound_page+0x4d/0x200
 [ 4209.087935]  [<ffffffff810fb015>] ? put_page+0x45/0x50
 [ 4209.097361]  [<ffffffff8113f779>] ? khugepaged+0x9e9/0x1430
 [ 4209.098364]  [<ffffffff8107c870>] ? autoremove_wake_function+0x0/0x40
 [ 4209.099121]  [<ffffffff8113ed90>] ? khugepaged+0x0/0x1430
 [ 4209.099780]  [<ffffffff8107c236>] ? kthread+0x96/0xa0
 [ 4209.100452]  [<ffffffff8100dda4>] ? kernel_thread_helper+0x4/0x10
 [ 4209.101214]  [<ffffffff8107c1a0>] ? kthread+0x0/0xa0
 [ 4209.101842]  [<ffffffff8100dda0>] ? kernel_thread_helper+0x0/0x10

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-11 16:12:20 -08:00
Johannes Weiner
f0fdc5e8e6 vmscan: fix zone shrinking exit when scan work is done
Commit 3e7d344970 ("mm: vmscan: reclaim order-0 and use compaction
instead of lumpy reclaim") introduced an indefinite loop in
shrink_zone().

It meant to break out of this loop when no pages had been reclaimed and
not a single page was even scanned.  The way it would detect the latter
is by taking a snapshot of sc->nr_scanned at the beginning of the
function and comparing it against the new sc->nr_scanned after the scan
loop.  But it would re-iterate without updating that snapshot, looping
forever if sc->nr_scanned changed at least once since shrink_zone() was
invoked.

This is not the sole condition that would exit that loop, but it
requires other processes to change the zone state, as the reclaimer that
is stuck obviously can not anymore.

This is only happening for higher-order allocations, where reclaim is
run back to back with compaction.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Michal Hocko <mhocko@suse.cz>
Tested-by: Kent Overstreet<kent.overstreet@gmail.com>
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-11 16:12:20 -08:00
Michel Lespinasse
419d8c96db mlock: do not munlock pages in __do_fault()
If the page is going to be written to, __do_page needs to break COW.

However, the old page (before breaking COW) was never mapped mapped into
the current pte (__do_fault is only called when the pte is not present),
so vmscan can't have marked the old page as PageMlocked due to being
mapped in __do_fault's VMA.  Therefore, __do_fault() does not need to
worry about clearing PageMlocked() on the old page.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-11 16:12:20 -08:00
Michel Lespinasse
e15f8c01af mlock: fix race when munlocking pages in do_wp_page()
vmscan can lazily find pages that are mapped within VM_LOCKED vmas, and
set the PageMlocked bit on these pages, transfering them onto the
unevictable list.  When do_wp_page() breaks COW within a VM_LOCKED vma,
it may need to clear PageMlocked on the old page and set it on the new
page instead.

This change fixes an issue where do_wp_page() was clearing PageMlocked
on the old page while the pte was still pointing to it (as well as
rmap).  Therefore, we were not protected against vmscan immediately
transfering the old page back onto the unevictable list.  This could
cause pages to get stranded there forever.

I propose to move the corresponding code to the end of do_wp_page(),
after the pte (and rmap) have been pointed to the new page.
Additionally, we can use munlock_vma_page() instead of
clear_page_mlock(), so that the old page stays mlocked if there are
still other VM_LOCKED vmas mapping it.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-11 16:12:20 -08:00
Yinghai Lu
e6d2e2b2b1 memblock: don't adjust size in memblock_find_base()
While applying patch to use memblock to find aperture for 64bit x86.
Ingo found system with 1g + force_iommu

> No AGP bridge found
> Node 0: aperture @ 38000000 size 32 MB
> Aperture pointing to e820 RAM. Ignoring.
> Your BIOS doesn't leave a aperture memory hole
> Please enable the IOMMU option in the BIOS setup
> This costs you 64 MB of RAM
> Cannot allocate aperture memory hole (0,65536K)

the corresponding code:

	addr = memblock_find_in_range(0, 1ULL<<32, aper_size, 512ULL<<20);
	if (addr == MEMBLOCK_ERROR || addr + aper_size > 0xffffffff) {
		printk(KERN_ERR
			"Cannot allocate aperture memory hole (%lx,%uK)\n",
				addr, aper_size>>10);
		return 0;
	}
	memblock_x86_reserve_range(addr, addr + aper_size, "aperture64")

fails because memblock core code align the size with 512M.  That could
make size way too big.

So don't align the size in that case.

actually __memblock_alloc_base, the another caller already align that
before calling that function.

BTW. x86 does not use __memblock_alloc_base...

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-11 16:12:20 -08:00
KAMEZAWA Hiroyuki
3751d60430 memcg: fix event counting breakage from recent THP update
Changes in e401f1761 ("memcg: modify accounting function for supporting
THP better") adds nr_pages to support multiple page size in
memory_cgroup_charge_statistics.

But counting the number of event nees abs(nr_pages) for increasing
counters.  This patch fixes event counting.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-02 16:03:19 -08:00
Johannes Weiner
8493ae439f memcg: never OOM when charging huge pages
Huge page coverage should obviously have less priority than the continued
execution of a process.

Never kill a process when charging it a huge page fails.  Instead, give up
after the first failed reclaim attempt and fall back to regular pages.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-02 16:03:19 -08:00
Johannes Weiner
19942822df memcg: prevent endless loop when charging huge pages to near-limit group
If reclaim after a failed charging was unsuccessful, the limits are
checked again, just in case they settled by means of other tasks.

This is all fine as long as every charge is of size PAGE_SIZE, because in
that case, being below the limit means having at least PAGE_SIZE bytes
available.

But with transparent huge pages, we may end up in an endless loop where
charging and reclaim fail, but we keep going because the limits are not
yet exceeded, although not allowing for a huge page.

Fix this up by explicitely checking for enough room, not just whether we
are within limits.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-02 16:03:19 -08:00