When we create a sl[au]b cache, we allocate kmem_cache_node structures
for each online NUMA node.  To handle nodes taken online/offline, we
register memory hotplug notifier and allocate/free kmem_cache_node
corresponding to the node that changes its state for each kmem cache.

To synchronize between the two paths we hold the slab_mutex during both
the cache creationg/destruction path and while tuning per-node parts of
kmem caches in memory hotplug handler, but that's not quite right,
because it does not guarantee that a newly created cache will have all
kmem_cache_nodes initialized in case it races with memory hotplug.  For
instance, in case of slub:

    CPU0                            CPU1
    ----                            ----
    kmem_cache_create:              online_pages:
     __kmem_cache_create:            slab_memory_callback:
                                      slab_mem_going_online_callback:
                                       lock slab_mutex
                                       for each slab_caches list entry
                                           allocate kmem_cache node
                                       unlock slab_mutex
      lock slab_mutex
      init_kmem_cache_nodes:
       for_each_node_state(node, N_NORMAL_MEMORY)
           allocate kmem_cache node
      add kmem_cache to slab_caches list
      unlock slab_mutex
                                    online_pages (continued):
                                     node_states_set_node

As a result we'll get a kmem cache with not all kmem_cache_nodes
allocated.

To avoid issues like that we should hold get/put_online_mems() during
the whole kmem cache creation/destruction/shrink paths, just like we
deal with cpu hotplug.  This patch does the trick.

Note, that after it's applied, there is no need in taking the slab_mutex
for kmem_cache_shrink any more, so it is removed from there.
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kmem_cache_{create,destroy,shrink} need to get a stable value of
cpu/node online mask, because they init/destroy/access per-cpu/node
kmem_cache parts, which can be allocated or destroyed on cpu/mem
hotplug.  To protect against cpu hotplug, these functions use
{get,put}_online_cpus.  However, they do nothing to synchronize with
memory hotplug - taking the slab_mutex does not eliminate the
possibility of race as described in patch 2.

What we need there is something like get_online_cpus, but for memory.
We already have lock_memory_hotplug, which serves for the purpose, but
it's a bit of a hammer right now, because it's backed by a mutex.  As a
result, it imposes some limitations to locking order, which are not
desirable, and can't be used just like get_online_cpus.  That's why in
patch 1 I substitute it with get/put_online_mems, which work exactly
like get/put_online_cpus except they block not cpu, but memory hotplug.

[ v1 can be found at https://lkml.org/lkml/2014/4/6/68.  I NAK'ed it by
  myself, because it used an rw semaphore for get/put_online_mems,
  making them dead lock prune.  ]

This patch (of 2):

{un}lock_memory_hotplug, which is used to synchronize against memory
hotplug, is currently backed by a mutex, which makes it a bit of a
hammer - threads that only want to get a stable value of online nodes
mask won't be able to proceed concurrently.  Also, it imposes some
strong locking ordering rules on it, which narrows down the set of its
usage scenarios.

This patch introduces get/put_online_mems, which are the same as
get/put_online_cpus, but for memory hotplug, i.e.  executing a code
inside a get/put_online_mems section will guarantee a stable value of
online nodes, present pages, etc.

lock_memory_hotplug()/unlock_memory_hotplug() are removed altogether.
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is only used in slab and should not be used anywhere else so there is
no need in exporting it.
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pgdat->reclaim_nodes tracks if a remote node is allowed to be reclaimed
by zone_reclaim due to its distance.  As it is expected that
zone_reclaim_mode will be rarely enabled it is unreasonable for all
machines to take a penalty.  Fortunately, the zone_reclaim_mode() path
is already slow and it is the path that takes the hit.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When it was introduced, zone_reclaim_mode made sense as NUMA distances
punished and workloads were generally partitioned to fit into a NUMA
node.  NUMA machines are now common but few of the workloads are
NUMA-aware and it's routine to see major performance degradation due to
zone_reclaim_mode being enabled but relatively few can identify the
problem.

Those that require zone_reclaim_mode are likely to be able to detect
when it needs to be enabled and tune appropriately so lets have a
sensible default for the bulk of users.

This patch (of 2):

zone_reclaim_mode causes processes to prefer reclaiming memory from
local node instead of spilling over to other nodes.  This made sense
initially when NUMA machines were almost exclusively HPC and the
workload was partitioned into nodes.  The NUMA penalties were
sufficiently high to justify reclaiming the memory.  On current machines
and workloads it is often the case that zone_reclaim_mode destroys
performance but not all users know how to detect this.  Favour the
common case and disable it by default.  Users that are sophisticated
enough to know they need zone_reclaim_mode will detect it.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

HugeTLB is limited to allocating hugepages whose size are less than
MAX_ORDER order.  This is so because HugeTLB allocates hugepages via the
buddy allocator.  Gigantic pages (that is, pages whose size is greater
than MAX_ORDER order) have to be allocated at boottime.

However, boottime allocation has at least two serious problems.  First,
it doesn't support NUMA and second, gigantic pages allocated at boottime
can't be freed.

This commit solves both issues by adding support for allocating gigantic
pages during runtime.  It works just like regular sized hugepages,
meaning that the interface in sysfs is the same, it supports NUMA, and
gigantic pages can be freed.

For example, on x86_64 gigantic pages are 1GB big. To allocate two 1G
gigantic pages on node 1, one can do:

 # echo 2 > \
   /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages

And to free them all:

 # echo 0 > \
   /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages

The one problem with gigantic page allocation at runtime is that it
can't be serviced by the buddy allocator.  To overcome that problem,
this commit scans all zones from a node looking for a large enough
contiguous region.  When one is found, it's allocated by using CMA, that
is, we call alloc_contig_range() to do the actual allocation.  For
example, on x86_64 we scan all zones looking for a 1GB contiguous
region.  When one is found, it's allocated by alloc_contig_range().

One expected issue with that approach is that such gigantic contiguous
regions tend to vanish as runtime goes by.  The best way to avoid this
for now is to make gigantic page allocations very early during system
boot, say from a init script.  Other possible optimization include using
compaction, which is supported by CMA but is not explicitly used by this
commit.

It's also important to note the following:

 1. Gigantic pages allocated at boottime by the hugepages= command-line
    option can be freed at runtime just fine

 2. This commit adds support for gigantic pages only to x86_64. The
    reason is that I don't have access to nor experience with other archs.
    The code is arch indepedent though, so it should be simple to add
    support to different archs

 3. I didn't add support for hugepage overcommit, that is allocating
    a gigantic page on demand when
   /proc/sys/vm/nr_overcommit_hugepages > 0. The reason is that I don't
   think it's reasonable to do the hard and long work required for
   allocating a gigantic page at fault time. But it should be simple
   to add this if wanted

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Next commit will add new code which will want to call
for_each_node_mask_to_alloc() macro.  Move it, its buddy
for_each_node_mask_to_free() and their dependencies up in the file so the
new code can use them.  This is just code movement, no logic change.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NAndrea Arcangeli <aarcange@redhat.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reviewed-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Hugepages pages never get the PG_reserved bit set, so don't clear it.

However, note that if the bit gets mistakenly set free_pages_check() will
catch it.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NAndrea Arcangeli <aarcange@redhat.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reviewed-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The HugeTLB subsystem uses the buddy allocator to allocate hugepages
during runtime.  This means that hugepages allocation during runtime is
limited to MAX_ORDER order.  For archs supporting gigantic pages (that
is, page sizes greater than MAX_ORDER), this in turn means that those
pages can't be allocated at runtime.

HugeTLB supports gigantic page allocation during boottime, via the boot
allocator.  To this end the kernel provides the command-line options
hugepagesz= and hugepages=, which can be used to instruct the kernel to
allocate N gigantic pages during boot.

For example, x86_64 supports 2M and 1G hugepages, but only 2M hugepages
can be allocated and freed at runtime.  If one wants to allocate 1G
gigantic pages, this has to be done at boot via the hugepagesz= and
hugepages= command-line options.

Now, gigantic page allocation at boottime has two serious problems:

 1. Boottime allocation is not NUMA aware. On a NUMA machine the kernel
    evenly distributes boottime allocated hugepages among nodes.

    For example, suppose you have a four-node NUMA machine and want
    to allocate four 1G gigantic pages at boottime. The kernel will
    allocate one gigantic page per node.

    On the other hand, we do have users who want to be able to specify
    which NUMA node gigantic pages should allocated from. So that they
    can place virtual machines on a specific NUMA node.

 2. Gigantic pages allocated at boottime can't be freed

At this point it's important to observe that regular hugepages allocated
at runtime don't have those problems.  This is so because HugeTLB
interface for runtime allocation in sysfs supports NUMA and runtime
allocated pages can be freed just fine via the buddy allocator.

This series adds support for allocating gigantic pages at runtime.  It
does so by allocating gigantic pages via CMA instead of the buddy
allocator.  Releasing gigantic pages is also supported via CMA.  As this
series builds on top of the existing HugeTLB interface, it makes gigantic
page allocation and releasing just like regular sized hugepages.  This
also means that NUMA support just works.

For example, to allocate two 1G gigantic pages on node 1, one can do:

 # echo 2 > \
   /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages

And, to release all gigantic pages on the same node:

 # echo 0 > \
   /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages

Please, refer to patch 5/5 for full technical details.

Finally, please note that this series is a follow up for a previous series
that tried to extend the command-line options set to be NUMA aware:

 http://marc.info/?l=linux-mm&m=139593335312191&w=2

During the discussion of that series it was agreed that having runtime
allocation support for gigantic pages was a better solution.

This patch (of 5):

This function is going to be used by non-init code in a future
commit.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix a coccinelle error regarding usage of IS_ERR and PTR_ERR instead of
PTR_ERR_OR_ZERO.
Signed-off-by: NDuan Jiong <duanj.fnst@cn.fujitsu.com>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Seems we all agree that information about SECTION, e.g. section size,
sections per memory block should be kept as kernel internals, and not
exposed to userspace.

This patch updates Documentation/memory-hotplug.txt to refer to memory
blocks instead of memory sections where appropriate and added a
paragraph to explain that memory blocks are made of memory sections.
The documentation update is mostly provided by Nathan.

Also, as end_phys_index in code is actually not the end section id, but
the end memory block id, which should always be the same as phys_index.
So it is removed here.
Signed-off-by: NLi Zhong <zhong@linux.vnet.ibm.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I recently added a patch to let folks pass a "reason" string dump_page()
which gets dumped out along with the page's data.  This essentially
saves the bug-reader a trip in to the source to figure out why we
BUG_ON()'d.

The new VM_BUG_ON_PAGE() passes in NULL for "reason".  It seems like we
might as well pass the BUG_ON() condition if we have it.  This will
bloat kernels a bit with ~160 new strings, but this is all under a
debugging option anyway.

	page:ffffea0008560280 count:1 mapcount:0 mapping:(null) index:0x0
	page flags: 0xbfffc0000000001(locked)
	page dumped because: VM_BUG_ON_PAGE(PageLocked(page))
	------------[ cut here ]------------
	kernel BUG at /home/davehans/linux.git/mm/filemap.c:464!
	invalid opcode: 0000 [#1] SMP
	CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0+ #251
	Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
	...

[akpm@linux-foundation.org: include stringify.h]
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NDavidlohr Bueso <davidlohr@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Per-memcg swappiness and oom killing can currently not be tweaked on a
memcg that is part of a hierarchy, but not the root of that hierarchy.
Users have complained that they can't configure this when they turned on
hierarchy mode.  In fact, with hierarchy mode becoming the default, this
restriction disables the tunables entirely.

But there is no good reason for this restriction.  The settings for
swappiness and OOM killing are taken from whatever memcg whose limit
triggered reclaim and OOM invocation, regardless of its position in the
hierarchy tree.

Allow setting swappiness on any group.  The knob on the root memcg
already reads the global VM swappiness, make it writable as well.

Allow disabling the OOM killer on any non-root memcg.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.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>

Memory obtained via mempool_alloc is not always zeroed even when
called with __GFP_ZERO. Add a note and VM_BUG_ON statement to make
that clear.

[akpm@linux-foundation.org: use VM_WARN_ON_ONCE]
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

WARN_ON() and WARN_ON_ONCE(), dependent on CONFIG_DEBUG_VM

Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It was using a mix of pr_foo() and printk(KERN_ERR ...).

Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It doesn't make sense to have two assert checks for each invariant: one
for printing and one for BUG().

Let's trigger BUG() if we print error message.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

dma_generic_alloc_coherent() firstly attempts to allocate by
dma_alloc_from_contiguous() if CONFIG_DMA_CMA is enabled.  But the
memory region allocated by it may not fit within the device's DMA mask.
This change makes it fall back to usual alloc_pages_node() allocation
for such cases.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, "cma=" kernel parameter is used to specify the size of CMA,
but we can't specify where it is located.  We want to locate CMA below
4GB for devices only supporting 32-bit addressing on 64-bit systems
without iommu.

This enables to specify the placement of CMA by extending "cma=" kernel
parameter.

Examples:
 1. locate 64MB CMA below 4GB by "cma=64M@0-4G"
 2. locate 64MB CMA exact at 512MB by "cma=64M@512M"

Note that the DMA contiguous memory allocator on x86 assumes that
page_address() works for the pages to allocate.  So this change requires
to limit end address of contiguous memory area upto max_pfn_mapped to
prevent from locating it on highmem area by the argument of
dma_contiguous_reserve().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This introduces memblock_alloc_range() which allocates memblock from the
specified range of physical address.  I would like to use this function
to specify the location of CMA.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds support for the DMA Contiguous Memory Allocator for
intel-iommu.  This change enables dma_alloc_coherent() to allocate big
contiguous memory.

It is achieved in the same way as nommu_dma_ops currently does, i.e.
trying to allocate memory by dma_alloc_from_contiguous() and
alloc_pages() is used as a fallback.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The DMA Contiguous Memory Allocator support on x86 is disabled when
swiotlb config option is enabled.  So DMA CMA is always disabled on
x86_64 because swiotlb is always enabled.  This attempts to support for
DMA CMA with enabling swiotlb config option.

The contiguous memory allocator on x86 is integrated in the function
dma_generic_alloc_coherent() which is .alloc callback in nommu_dma_ops
for dma_alloc_coherent().

x86_swiotlb_alloc_coherent() which is .alloc callback in swiotlb_dma_ops
tries to allocate with dma_generic_alloc_coherent() firstly and then
swiotlb_alloc_coherent() is called as a fallback.

The main part of supporting DMA CMA with swiotlb is that changing
x86_swiotlb_free_coherent() which is .free callback in swiotlb_dma_ops
for dma_free_coherent() so that it can distinguish memory allocated by
dma_generic_alloc_coherent() from one allocated by
swiotlb_alloc_coherent() and release it with dma_generic_free_coherent()
which can handle contiguous memory.  This change requires making
is_swiotlb_buffer() global function.

This also needs to change .free callback in the dma_map_ops for amd_gart
and sta2x11, because these dma_ops are also using
dma_generic_alloc_coherent().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patchset enhances the DMA Contiguous Memory Allocator on x86.

Currently the DMA CMA is only supported with pci-nommu dma_map_ops and
furthermore it can't be enabled on x86_64.  But I would like to allocate
big contiguous memory with dma_alloc_coherent() and tell it to the device
that requires it, regardless of which dma mapping implementation is
actually used in the system.

So this makes it work with swiotlb and intel-iommu dma_map_ops, too.  And
this also extends "cma=" kernel parameter to specify placement constraint
by the physical address range of memory allocations.  For example, CMA
allocates memory below 4GB by "cma=64M@0-4G", it is required for the
devices only supporting 32-bit addressing on 64-bit systems without iommu.

This patch (of 5):

Calling dma_alloc_coherent() with __GFP_ZERO must return zeroed memory.

But when the contiguous memory allocator (CMA) is enabled on x86 and the
memory region is allocated by dma_alloc_from_contiguous(), it doesn't
return zeroed memory.  Because dma_generic_alloc_coherent() forgot to fill
the memory region with zero if it was allocated by
dma_alloc_from_contiguous()

Most implementations of dma_alloc_coherent() return zeroed memory
regardless of whether __GFP_ZERO is specified.  So this fixes it by
unconditionally zeroing the allocated memory region.

Alternatively, we could fix dma_alloc_from_contiguous() to return zeroed
out memory and remove memset() from all caller of it.  But we can't simply
remove the memset on arm because __dma_clear_buffer() is used there for
ensuring cache flushing and it is used in many places.  Of course we can
do redundant memset in dma_alloc_from_contiguous(), but I think this patch
is less impact for fixing this problem.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For single threaded workloads, we can avoid flushing and iterating through
the entire list of tasks, making the whole function a lot faster,
requiring only a single atomic read for the mm_users.
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Suggested-by: NOleg Nesterov <oleg@redhat.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce a CONFIG_DEBUG_VM_VMACACHE option to enable counting the cache
hit rate -- exported in /proc/vmstat.

Any updates to the caching scheme needs this kind of data, thus it can
save some work re-implementing the counting all the time.
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Prior to this change, we would decide whether to force scan a LRU during
reclaim if that LRU itself was too small for the current priority.
However, this can lead to the file LRU getting force scanned even if
there are a lot of anonymous pages we can reclaim, leading to hot file
pages getting needlessly reclaimed.

To address this, we instead only force scan when none of the reclaimable
LRUs are big enough.

Gives huge improvements with zswap.  For example, when doing -j20 kernel
build in a 500MB container with zswap enabled, runtime (in seconds) is
greatly reduced:

x without this change
+ with this change
    N           Min           Max        Median           Avg        Stddev
x   5       700.997       790.076       763.928        754.05      39.59493
+   5       141.634       197.899       155.706         161.9     21.270224
Difference at 95.0% confidence
        -592.15 +/- 46.3521
        -78.5293% +/- 6.14709%
        (Student's t, pooled s = 31.7819)

Should also give some improvements in regular (non-zswap) swap cases.

Yes, hughd found significant speedup using regular swap, with several
memcgs under pressure; and it should also be effective in the non-memcg
case, whenever one or another zone LRU is forced too small.
Signed-off-by: NSuleiman Souhlal <suleiman@google.com>
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: NRik van Riel <riel@redhat.com>
Acked-by: NRafael Aquini <aquini@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Luigi Semenzato <semenzato@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

clear_refs_write() is called earlier than clear_soft_dirty() and it is
more natural to clear VM_SOFTDIRTY (which belongs to VMA entry but not
PTEs) that early instead of clearing it a way deeper inside call chain.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pte_file_mksoft_dirty operates with argument passed by a value and
returns modified result thus we need to assign @ptfile here, otherwise
itis a no-op which may lead to loss of the softdirty bit.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Hugh reported:

 | I noticed your soft_dirty work in install_file_pte(): which looked
 | good at first, until I realized that it's propagating the soft_dirty
 | of a pte it's about to zap completely, to the unrelated entry it's
 | about to insert in its place.  Which seems very odd to me.

Indeed this code ends up being nop in result -- pte_file_mksoft_dirty()
operates with pte_t argument and returns new pte_t which were never used
after.  After looking more I think what we need is to soft-dirtify all
newely remapped file pages because it should look like a new mapping for
memory tracker.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Reported-by: NHugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently to allocate a page that should be charged to kmemcg (e.g.
threadinfo), we pass __GFP_KMEMCG flag to the page allocator.  The page
allocated is then to be freed by free_memcg_kmem_pages.  Apart from
looking asymmetrical, this also requires intrusion to the general
allocation path.  So let's introduce separate functions that will
alloc/free pages charged to kmemcg.

The new functions are called alloc_kmem_pages and free_kmem_pages.  They
should be used when the caller actually would like to use kmalloc, but
has to fall back to the page allocator for the allocation is large.
They only differ from alloc_pages and free_pages in that besides
allocating or freeing pages they also charge them to the kmem resource
counter of the current memory cgroup.

[sfr@canb.auug.org.au: export kmalloc_order() to modules]
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Acked-by: NGreg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have only a few places where we actually want to charge kmem so
instead of intruding into the general page allocation path with
__GFP_KMEMCG it's better to explictly charge kmem there.  All kmem
charges will be easier to follow that way.

This is a step towards removing __GFP_KMEMCG.  It removes __GFP_KMEMCG
from memcg caches' allocflags.  Instead it makes slab allocation path
call memcg_charge_kmem directly getting memcg to charge from the cache's
memcg params.

This also eliminates any possibility of misaccounting an allocation
going from one memcg's cache to another memcg, because now we always
charge slabs against the memcg the cache belongs to.  That's why this
patch removes the big comment to memcg_kmem_get_cache.
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Acked-by: NGreg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There used to be only one path out of __slab_alloc(), and ALLOC_SLOWPATH
got bumped in that exit path.  Now there are two, and a bunch of gotos.
ALLOC_SLOWPATH can now get set more than once during a single call to
__slab_alloc() which is pretty bogus.  Here's the sequence:

1. Enter __slab_alloc(), fall through all the way to the
   stat(s, ALLOC_SLOWPATH);
2. hit 'if (!freelist)', and bump DEACTIVATE_BYPASS, jump to
   new_slab (goto #1)
3. Hit 'if (c->partial)', bump CPU_PARTIAL_ALLOC, goto redo
   (goto #2)
4. Fall through in the same path we did before all the way to
   stat(s, ALLOC_SLOWPATH)
5. bump ALLOC_REFILL stat, then return

Doing this is obviously bogus.  It keeps us from being able to
accurately compare ALLOC_SLOWPATH vs.  ALLOC_FASTPATH.  It also means
that the total number of allocs always exceeds the total number of
frees.

This patch moves stat(s, ALLOC_SLOWPATH) to be called from the same
place that __slab_alloc() is.  This makes it much less likely that
ALLOC_SLOWPATH will get botched again in the spaghetti-code inside
__slab_alloc().
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When the slab or slub allocators cannot allocate additional slab pages,
they emit diagnostic information to the kernel log such as current
number of slabs, number of objects, active objects, etc.  This is always
coupled with a page allocation failure warning since it is controlled by
!__GFP_NOWARN.

Suppress this out of memory warning if the allocator is configured
without debug supported.  The page allocation failure warning will
indicate it is a failed slab allocation, the order, and the gfp mask, so
this is only useful to diagnose allocator issues.

Since CONFIG_SLUB_DEBUG is already enabled by default for the slub
allocator, there is no functional change with this patch.  If debug is
disabled, however, the warnings are now suppressed.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Acked-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Inspired by Joe Perches suggestion in ntfs logging clean-up.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Joe Perches <joe@perches.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

All printk(KERN_foo converted to pr_foo()

Default printk converted to pr_warn()

Coalesce format fragments
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Joe Perches <joe@perches.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On system with 2TiB ram, current x86_64 have 128M as section size, and
one memory_block only include one section.  So will have 16400 entries
under /sys/devices/system/memory/.

Current code try to use block id to find block pointer in /sys for any
section, and reuse that block pointer.  that finding will take some time
even after commit 7c243c71 ("mm: speedup in __early_pfn_to_nid")
that will skip the search in that case during booting up.

So solution could be increase block size just like SGI UV system did.
(harded code to 2g).

This patch is trying to probe the block size to make it match mmio remap
size.  for example, Intel Nehalem later system will have memory range [0,
TOML), [4g, TOMH].  If the memory hole is 2g and total is 128g, TOM will
be 2g, and TOM2 will be 130g.

We could use 2g as block size instead of default 128M.  That will reduce
number of entries in /sys/devices/system/memory/

On system 6TiB system will reduce boot time by 35 seconds.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

_PAGE_NUMA is currently an alias of _PROT_PROTNONE to trap NUMA hinting
faults on x86.  Care is taken such that _PAGE_NUMA is used only in
situations where the VMA flags distinguish between NUMA hinting faults
and prot_none faults.  This decision was x86-specific and conceptually
it is difficult requiring special casing to distinguish between PROTNONE
and NUMA ptes based on context.

Fundamentally, we only need the _PAGE_NUMA bit to tell the difference
between an entry that is really unmapped and a page that is protected
for NUMA hinting faults as if the PTE is not present then a fault will
be trapped.

Swap PTEs on x86-64 use the bits after _PAGE_GLOBAL for the offset.
This patch shrinks the maximum possible swap size and uses the bit to
uniquely distinguish between NUMA hinting ptes and swap ptes.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

32-bit support for NUMA is an oddity on its own but with automatic NUMA
balancing on top there is a reasonable risk that the CPUPID information
cannot be stored in the page flags.  This patch removes support for
automatic NUMA support on 32-bit x86.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>