The use of mem= could leave part or all of the initrd outside of the
kernel linear map.  This will lead to an error when unpacking the initrd
and a probable failure to boot.  This patch catches that situation and
relocates the initrd to be fully within the linear map.
Signed-off-by: NMark Salter <msalter@redhat.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.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>

When booting an arm64 kernel w/initrd using UEFI/grub, use of mem= will
likely cut off part or all of the initrd.  This leaves it outside the
kernel linear map which leads to failure when unpacking.  The x86 code
has a similar need to relocate an initrd outside of mapped memory in
some cases.

The current x86 code uses early_memremap() to copy the original initrd
from unmapped to mapped RAM.  This patchset creates a generic
copy_from_early_mem() utility based on that x86 code and has arm64 and
x86 share it in their respective initrd relocation code.

This patch (of 3):

In some early boot circumstances, it may be necessary to copy from RAM
outside the kernel linear mapping to mapped RAM.  The need to relocate
an initrd is one example in the x86 code.  This patch creates a helper
function based on current x86 code.
Signed-off-by: NMark Salter <msalter@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.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 URL for libhugetlbfs has changed.  Also, put a stronger emphasis on
using libgugetlbfs for hugetlb regression testing.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The hugetlb selftests provide minimal coverage.  Have run script point
people at libhugetlbfs for better regression testing.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This manually reverts 7e50533d ("selftests: add hugetlbfstest").

The hugetlbfstest test depends on hugetlb pages being counted in a
task's rss.  This functionality is not in the kernel, so the test will
always fail.  Remove test to avoid confusion.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The compaction free scanner is looking for PageBuddy() pages and
skipping all others.  For large compound pages such as THP or hugetlbfs,
we can save a lot of iterations if we skip them at once using their
compound_order().  This is generally unsafe and we can read a bogus
value of order due to a race, but if we are careful, the only danger is
skipping too much.

When tested with stress-highalloc from mmtests on 4GB system with 1GB
hugetlbfs pages, the vmstat compact_free_scanned count decreased by at
least 15%.
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The compaction migrate scanner tries to skip THP pages by their order,
to reduce number of iterations for pages it cannot isolate.  The check
is only done if PageLRU() is true, which means it applies to THP pages,
but not e.g.  hugetlbfs pages or any other non-LRU compound pages, which
we have to iterate by base pages.

This limitation comes from the assumption that it's only safe to read
compound_order() when we have the zone's lru_lock and THP cannot be
split under us.  But the only danger (after filtering out order values
that are not below MAX_ORDER, to prevent overflows) is that we skip too
much or too little after reading a bogus compound_order() due to a rare
race.  This is the same reasoning as patch 99c0fd5e ("mm,
compaction: skip buddy pages by their order in the migrate scanner")
introduced for unsafely reading PageBuddy() order.

After this patch, all pages are tested for PageCompound() and we skip
them by compound_order().  The test is done after the test for
balloon_page_movable() as we don't want to assume if balloon pages (or
other pages with own isolation and migration implementation if a generic
API gets implemented) are compound or not.

When tested with stress-highalloc from mmtests on 4GB system with 1GB
hugetlbfs pages, the vmstat compact_migrate_scanned count decreased by
15%.

[kirill.shutemov@linux.intel.com: change PageTransHuge checks to PageCompound for different series was squashed here]
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: NMel Gorman <mgorman@suse.de>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Reseting the cached compaction scanner positions is now open-coded in
__reset_isolation_suitable() and compact_finished().  Encapsulate the
functionality in a new function reset_cached_positions().
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Handling the position where compaction free scanner should restart
(stored in cc->free_pfn) got more complex with commit e14c720e ("mm,
compaction: remember position within pageblock in free pages scanner").
Currently the position is updated in each loop iteration of
isolate_freepages(), although it should be enough to update it only when
breaking from the loop.  There's also an extra check outside the loop
updates the position in case we have met the migration scanner.

This can be simplified if we move the test for having isolated enough
from the for-loop header next to the test for contention, and
determining the restart position only in these cases.  We can reuse the
isolate_start_pfn variable for this instead of setting cc->free_pfn
directly.  Outside the loop, we can simply set cc->free_pfn to current
value of isolate_start_pfn without any extra check.

Also add a VM_BUG_ON to catch possible mistake in the future, in case we
later add a new condition that terminates isolate_freepages_block()
prematurely without also considering the condition in
isolate_freepages().
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: NMel Gorman <mgorman@suse.de>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Assorted compaction cleanups and optimizations.  The interesting patches
are 4 and 5.  In 4, skipping of compound pages in single iteration is
improved for migration scanner, so it works also for !PageLRU compound
pages such as hugetlbfs, slab etc.  Patch 5 introduces this kind of
skipping in the free scanner.  The trick is that we can read
compound_order() without any protection, if we are careful to filter out
values larger than MAX_ORDER.  The only danger is that we skip too much.
The same trick was already used for reading the freepage order in the
migrate scanner.

To demonstrate improvements of Patches 4 and 5 I've run stress-highalloc
from mmtests, set to simulate THP allocations (including __GFP_COMP) on
a 4GB system where 1GB was occupied by hugetlbfs pages.  I'll include
just the relevant stats:

                               Patch 3     Patch 4     Patch 5

Compaction stalls                 7523        7529        7515
Compaction success                 323         304         322
Compaction failures               7200        7224        7192
Page migrate success            247778      264395      240737
Page migrate failure             15358       33184       21621
Compaction pages isolated       906928      980192      909983
Compaction migrate scanned     2005277     1692805     1498800
Compaction free scanned       13255284    11539986     9011276
Compaction cost                    288         305         277

With 5 iterations per patch, the results are still noisy, but we can see
that Patch 4 does reduce migrate_scanned by 15% thanks to skipping the
hugetlbfs pages at once.  Interestingly, free_scanned is also reduced
and I have no idea why.  Patch 5 further reduces free_scanned as
expected, by 15%.  Other stats are unaffected modulo noise.

[1] https://lkml.org/lkml/2015/1/19/158

This patch (of 5):

Compaction should finish when the migration and free scanner meet, i.e.
they reach the same pageblock.  Currently however, the test in
compact_finished() simply just compares the exact pfns, which may yield
a false negative when the free scanner position is in the middle of a
pageblock and the migration scanner reaches the begining of the same
pageblock.

This hasn't been a problem until commit e14c720e ("mm, compaction:
remember position within pageblock in free pages scanner") allowed the
free scanner position to be in the middle of a pageblock between
invocations.  The hot-fix 1d5bfe1f ("mm, compaction: prevent
infinite loop in compact_zone") prevented the issue by adding a special
check in the migration scanner to satisfy the current detection of
scanners meeting.

However, the proper fix is to make the detection more robust.  This
patch introduces the compact_scanners_met() function that returns true
when the free scanner position is in the same or lower pageblock than
the migration scanner.  The special case in isolate_migratepages()
introduced by 1d5bfe1f is removed.
Suggested-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: NMel Gorman <mgorman@suse.de>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

add [pci|dma]_pool_zalloc coccinelle check.
replaces instances of [pci|dma]_pool_alloc() followed by memset(0)
with [pci|dma]_pool_zalloc().
Signed-off-by: NSean O. Stalley <sean.stalley@intel.com>
Acked-by: NJulia Lawall <julia.lawall@lip6.fr>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Gilles Muller <Gilles.Muller@lip6.fr>
Cc: Nicolas Palix <nicolas.palix@imag.fr>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a wrapper function for pci_pool_alloc() to get zeroed memory.
Signed-off-by: NSean O. Stalley <sean.stalley@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Gilles Muller <Gilles.Muller@lip6.fr>
Cc: Nicolas Palix <nicolas.palix@imag.fr>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a wrapper function for dma_pool_alloc() to get zeroed memory.
Signed-off-by: NSean O. Stalley <sean.stalley@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Gilles Muller <Gilles.Muller@lip6.fr>
Cc: Nicolas Palix <nicolas.palix@imag.fr>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently a call to dma_pool_alloc() with a ___GFP_ZERO flag returns a
non-zeroed memory region.

This patchset adds support for the __GFP_ZERO flag to dma_pool_alloc(),
adds 2 wrapper functions for allocing zeroed memory from a pool, and
provides a coccinelle script for finding & replacing instances of
dma_pool_alloc() followed by memset(0) with a single dma_pool_zalloc()
call.

There was some concern that this always calls memset() to zero, instead
of passing __GFP_ZERO into the page allocator.
[https://lkml.org/lkml/2015/7/15/881]

I ran a test on my system to get an idea of how often dma_pool_alloc()
calls into pool_alloc_page().

After Boot:	[   30.119863] alloc_calls:541, page_allocs:7
After an hour:	[ 3600.951031] alloc_calls:9566, page_allocs:12
After copying 1GB file onto a USB drive:
		[ 4260.657148] alloc_calls:17225, page_allocs:12

It doesn't look like dma_pool_alloc() calls down to the page allocator
very often (at least on my system).

This patch (of 4):

Currently the __GFP_ZERO flag is ignored by dma_pool_alloc().
Make dma_pool_alloc() zero the memory if this flag is set.
Signed-off-by: NSean O. Stalley <sean.stalley@intel.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Gilles Muller <Gilles.Muller@lip6.fr>
Cc: Nicolas Palix <nicolas.palix@imag.fr>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

reclaim_clean_pages_from_list() assumes that shrink_page_list() returns
number of pages removed from the candidate list.  But shrink_page_list()
puts back mlocked pages without passing it to caller and without
counting as nr_reclaimed.  This increases nr_isolated.

To fix this, this patch changes shrink_page_list() to pass unevictable
pages back to caller.  Caller will take care those pages.

Minchan said:

It fixes two issues.

1. With unevictable page, cma_alloc will be successful.

Exactly speaking, cma_alloc of current kernel will fail due to
unevictable pages.

2. fix leaking of NR_ISOLATED counter of vmstat

With it, too_many_isolated works.  Otherwise, it could make hang until
the process get SIGKILL.
Signed-off-by: NJaewon Kim <jaewon31.kim@samsung.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If transparent huge pages are enabled, we can isolate many more pages
than we actually need to scan, because we count both single and huge
pages equally in isolate_lru_pages().

Since commit 5bc7b8ac ("mm: thp: add split tail pages to shrink
page list in page reclaim"), we scan all the tail pages immediately
after a huge page split (see shrink_page_list()).  As a result, we can
reclaim up to SWAP_CLUSTER_MAX * HPAGE_PMD_NR (512 MB) in one run!

This is easy to catch on memcg reclaim with zswap enabled.  The latter
makes swapout instant so that if we happen to scan an unreferenced huge
page we will evict both its head and tail pages immediately, which is
likely to result in excessive reclaim.
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NMichal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__nocast does no good for vm_flags_t. It only produces useless sparse
warnings.

Let's drop it.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Bootmem isn't popular any more, but some architectures still use it, and
freeing to bootmem after calling free_all_bootmem_core() can end up
scribbling over random memory.  Instead, make sure the kernel generates
a warning in this case by ensuring the node_bootmem_map field is
non-NULL when are freeing or marking bootmem.

An instance of this bug was just fixed in the tile architecture ("tile:
use free_bootmem_late() for initrd") and catching this case more widely
seems like a good thing.
Signed-off-by: NChris Metcalf <cmetcalf@ezchip.com>
Acked-by: NMel Gorman <mgorman@suse.de>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Paul McQuade <paulmcquad@gmail.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Nowaday, set/unset_migratetype_isolate() is defined and used only in
mm/page_isolation, so let's limit the scope within the file.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This check was introduced as part of
   6f4576e3 ("mempolicy: apply page table walker on queue_pages_range()")

which got duplicated by
   48684a65 ("mm: pagewalk: fix misbehavior of walk_page_range for vma(VM_PFNMAP)")

by reintroducing it earlier on queue_page_test_walk()
Signed-off-by: NAristeu Rozanski <aris@redhat.com>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: NCyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When parsing SRAT, all memory ranges are added into numa_meminfo.  In
numa_init(), before entering numa_cleanup_meminfo(), all possible memory
ranges are in numa_meminfo.  And numa_cleanup_meminfo() removes all
ranges over max_pfn or empty.

But, this only works if the nodes are continuous.  Let's have a look at
the following example:

We have an SRAT like this:
SRAT: Node 0 PXM 0 [mem 0x00000000-0x5fffffff]
SRAT: Node 0 PXM 0 [mem 0x100000000-0x1ffffffffff]
SRAT: Node 1 PXM 1 [mem 0x20000000000-0x3ffffffffff]
SRAT: Node 4 PXM 2 [mem 0x40000000000-0x5ffffffffff] hotplug
SRAT: Node 5 PXM 3 [mem 0x60000000000-0x7ffffffffff] hotplug
SRAT: Node 2 PXM 4 [mem 0x80000000000-0x9ffffffffff] hotplug
SRAT: Node 3 PXM 5 [mem 0xa0000000000-0xbffffffffff] hotplug
SRAT: Node 6 PXM 6 [mem 0xc0000000000-0xdffffffffff] hotplug
SRAT: Node 7 PXM 7 [mem 0xe0000000000-0xfffffffffff] hotplug

On boot, only node 0,1,2,3 exist.

And the numa_meminfo will look like this:
numa_meminfo.nr_blks = 9
1. on node 0: [0, 60000000]
2. on node 0: [100000000, 20000000000]
3. on node 1: [20000000000, 40000000000]
4. on node 4: [40000000000, 60000000000]
5. on node 5: [60000000000, 80000000000]
6. on node 2: [80000000000, a0000000000]
7. on node 3: [a0000000000, a0800000000]
8. on node 6: [c0000000000, a0800000000]
9. on node 7: [e0000000000, a0800000000]

And numa_cleanup_meminfo() will merge 1 and 2, and remove 8,9 because the
end address is over max_pfn, which is a0800000000.  But 4 and 5 are not
removed because their end addresses are less then max_pfn.  But in fact,
node 4 and 5 don't exist.

In a word, numa_cleanup_meminfo() is not able to handle holes between nodes.

Since memory ranges in node 4 and 5 are in numa_meminfo, in
numa_register_memblks(), node 4 and 5 will be mistakenly set to online.

If you run lscpu, it will show:
NUMA node0 CPU(s):     0-14,128-142
NUMA node1 CPU(s):     15-29,143-157
NUMA node2 CPU(s):
NUMA node3 CPU(s):
NUMA node4 CPU(s):     62-76,190-204
NUMA node5 CPU(s):     78-92,206-220

In this patch, we use memblock_overlaps_region() to check if ranges in
numa_meminfo overlap with ranges in memory_block.  Since memory_block
contains all available memory at boot time, if they overlap, it means the
ranges exist.  If not, then remove them from numa_meminfo.

After this patch, lscpu will show:
NUMA node0 CPU(s):     0-14,128-142
NUMA node1 CPU(s):     15-29,143-157
NUMA node4 CPU(s):     62-76,190-204
NUMA node5 CPU(s):     78-92,206-220
Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memblock_overlaps_region() checks if the given memblock region
intersects a region in memblock.  If so, it returns the index of the
intersected region.

But its only caller is memblock_is_region_reserved(), and it returns 0
if false, non-zero if true.

Both of these should return bool.
Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that we have hole punching support for hugetlbfs, we can also
support the MADV_REMOVE interface to it.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is based on the shmem version, but it has diverged quite a bit.  We
have no swap to worry about, nor the new file sealing.  Add
synchronication via the fault mutex table to coordinate page faults,
fallocate allocation and fallocate hole punch.

What this allows us to do is move physical memory in and out of a
hugetlbfs file without having it mapped.  This also gives us the ability
to support MADV_REMOVE since it is currently implemented using
fallocate().  MADV_REMOVE lets madvise() remove pages from the middle of
a hugetlbfs file, which wasn't possible before.

hugetlbfs fallocate only operates on whole huge pages.

Based on code by Dave Hansen.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, there is only a single place where hugetlbfs pages are added
to the page cache.  The new fallocate code be adding a second one, so
break the functionality out into its own helper.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Areas hole punched by fallocate will not have entries in the
region/reserve map.  However, shared mappings with min_size subpool
reservations may still have reserved pages.  alloc_huge_page needs to
handle this special case and do the proper accounting.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In vma_has_reserves(), the current assumption is that reserves are
always present for shared mappings.  However, this will not be the case
with fallocate hole punch.  When punching a hole, the present page will
be deleted as well as the region/reserve map entry (and hence any
reservation).  vma_has_reserves is passed "chg" which indicates whether
or not a region/reserve map is present.  Use this to determine if
reserves are actually present or were removed via hole punch.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Modify truncate_hugepages() to take a range of pages (start, end)
instead of simply start.  If an end value of LLONG_MAX is passed, the
current "truncate" functionality is maintained.  Existing callers are
modified to pass LLONG_MAX as end of range.  By keying off end ==
LLONG_MAX, the routine behaves differently for truncate and hole punch.
Page removal is now synchronized with page allocation via faults by
using the fault mutex table.  The hole punch case can experience the
rare region_del error and must handle accordingly.

Add the routine hugetlb_fix_reserve_counts to fix up reserve counts in
the case where region_del returns an error.

Since the routine handles more than just the truncate case, it is
renamed to remove_inode_hugepages().  To be consistent, the routine
truncate_huge_page() is renamed remove_huge_page().

Downstream of remove_inode_hugepages(), the routine
hugetlb_unreserve_pages() is also modified to take a range of pages.
hugetlb_unreserve_pages is modified to detect an error from region_del and
pass it back to the caller.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fallocate hole punch will want to unmap a specific range of pages.
Modify the existing hugetlb_vmtruncate_list() routine to take a
start/end range.  If end is 0, this indicates all pages after start
should be unmapped.  This is the same as the existing truncate
functionality.  Modify existing callers to add 0 as end of range.

Since the routine will be used in hole punch as well as truncate
operations, it is more appropriately renamed to hugetlb_vmdelete_list().
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

hugetlb page faults are currently synchronized by the table of mutexes
(htlb_fault_mutex_table).  fallocate code will need to synchronize with
the page fault code when it allocates or deletes pages.  Expose
interfaces so that fallocate operations can be synchronized with page
faults.  Minor name changes to be more consistent with other global
hugetlb symbols.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fallocate hole punch will want to remove a specific range of pages.  The
existing region_truncate() routine deletes all region/reserve map
entries after a specified offset.  region_del() will provide this same
functionality if the end of region is specified as LONG_MAX.  Hence,
region_del() can replace region_truncate().

Unlike region_truncate(), region_del() can return an error in the rare
case where it can not allocate memory for a region descriptor.  This
ONLY happens in the case where an existing region must be split.
Current callers passing LONG_MAX as end of range will never experience
this error and do not need to deal with error handling.  Future callers
of region_del() (such as fallocate hole punch) will need to handle this
error.
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

hugetlbfs is used today by applications that want a high degree of
control over huge page usage.  Often, large hugetlbfs files are used to
map a large number huge pages into the application processes.  The
applications know when page ranges within these large files will no
longer be used, and ideally would like to release them back to the
subpool or global pools for other uses.  The fallocate() system call
provides an interface for preallocation and hole punching within files.
This patch set adds fallocate functionality to hugetlbfs.

fallocate hole punch will want to remove a specific range of pages.
When pages are removed, their associated entries in the region/reserve
map will also be removed.  This will break an assumption in the
region_chg/region_add calling sequence.  If a new region descriptor must
be allocated, it is done as part of the region_chg processing.  In this
way, region_add can not fail because it does not need to attempt an
allocation.

To prepare for fallocate hole punch, create a "cache" of descriptors
that can be used by region_add if necessary.  region_chg will ensure
there are sufficient entries in the cache.  It will be necessary to
track the number of in progress add operations to know a sufficient
number of descriptors reside in the cache.  A new routine region_abort
is added to adjust this in progress count when add operations are
aborted.  vma_abort_reservation is also added for callers creating
reservations with vma_needs_reservation/vma_commit_reservation.

[akpm@linux-foundation.org: fix typo in comment, use more cols]
Signed-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The pair of get/set_freepage_migratetype() functions are used to cache
pageblock migratetype for a page put on a pcplist, so that it does not
have to be retrieved again when the page is put on a free list (e.g.
when pcplists become full).  Historically it was also assumed that the
value is accurate for pages on freelists (as the functions' names
unfortunately suggest), but that cannot be guaranteed without affecting
various allocator fast paths.  It is in fact not needed and all such
uses have been removed.

The last remaining (but pointless) usage related to pages of freelists
is in move_freepages(), which this patch removes.

To prevent further confusion, rename the functions to
get/set_pcppage_migratetype() and expand their description.  Since all
the users are now in mm/page_alloc.c, move the functions there from the
shared header.
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Seungho Park <seungho1.park@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Acked-by: NMel Gorman <mgorman@techsingularity.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The __test_page_isolated_in_pageblock() is used to verify whether all
pages in pageblock were either successfully isolated, or are hwpoisoned.
Two of the possible state of pages, that are tested, are however bogus
and misleading.

Both tests rely on get_freepage_migratetype(page), which however has no
guarantees about pages on freelists.  Specifically, it doesn't guarantee
that the migratetype returned by the function actually matches the
migratetype of the freelist that the page is on.  Such guarantee is not
its purpose and would have negative impact on allocator performance.

The first test checks whether the freepage_migratetype equals
MIGRATE_ISOLATE, supposedly to catch races between page isolation and
allocator activity.  These races should be fixed nowadays with
51bb1a40 ("mm/page_alloc: add freepage on isolate pageblock to correct
buddy list") and related patches.  As explained above, the check
wouldn't be able to catch them reliably anyway.  For the same reason
false positives can happen, although they are harmless, as the
move_freepages() call would just move the page to the same freelist it's
already on.  So removing the test is not a bug fix, just cleanup.  After
this patch, we assume that all PageBuddy pages are on the correct
freelist and that the races were really fixed.  A truly reliable
verification in the form of e.g.  VM_BUG_ON() would be complicated and
is arguably not needed.

The second test (page_count(page) == 0 && get_freepage_migratetype(page)
== MIGRATE_ISOLATE) is probably supposed (the code comes from a big
memory isolation patch from 2007) to catch pages on MIGRATE_ISOLATE
pcplists.  However, pcplists don't contain MIGRATE_ISOLATE freepages
nowadays, those are freed directly to free lists, so the check is
obsolete.  Remove it as well.
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Seungho Park <seungho1.park@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Acked-by: NMel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

CMA reserved memory is not part of total reserved memory.  Currently
when we print the total reserve memory it considers cma as part of
reserve memory and do minus of totalcma_pages from reserved, which is
wrong.  In cases where total reserved is less than cma reserved we will
get negative values & while printing we print as unsigned and we will
get a very large value.

Below is the show mem output on X86 ubuntu based system where CMA
reserved is 100MB (25600 pages) & total reserved is ~40MB(10316 pages).
And reserve memory shows a large value because of this bug.

Before:
[  127.066430] 898908 pages RAM
[  127.066432] 671682 pages HighMem/MovableOnly
[  127.066434] 4294952012 pages reserved
[  127.066436] 25600 pages cma reserved

After:
[   44.663129] 898908 pages RAM
[   44.663130] 671682 pages HighMem/MovableOnly
[   44.663130] 10316 pages reserved
[   44.663131] 25600 pages cma reserved
Signed-off-by: NVishnu Pratap Singh <vishnu.ps@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Danesh Petigara <dpetigara@broadcom.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The only user is sock_update_memcg which is living in memcontrol.c so it
doesn't make much sense to pollute sock.h by this inline helper.  Move it
to memcontrol.c and open code it into its only caller.
Signed-off-by: NMichal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sk_prot->proto_cgroup is allowed to return NULL but sock_update_memcg
doesn't check for NULL.  The function relies on the mem_cgroup_is_root
check because we shouldn't get NULL otherwise because mem_cgroup_from_task
will always return !NULL.

All other callers are checking for NULL and we can safely replace
mem_cgroup_is_root() check by cg_proto != NULL which will be more
straightforward (proto_cgroup returns NULL for the root memcg already).
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Restructure it to lower nesting level and help the planned threadgroup
leader iteration changes.

This is pure reorganization.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Most of the exported functions in this header are not marked extern so
change the rest to follow the same style.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The only user is cgwb_bdi_init and that one depends on
CONFIG_CGROUP_WRITEBACK which in turn depends on CONFIG_MEMCG so it
doesn't make much sense to definte an empty stub for !CONFIG_MEMCG.
Moreover ERR_PTR(-EINVAL) is ugly and would lead to runtime crashes if
used in unguarded code paths.  Better fail during compilation.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>