Hugepage invalidate involves invalidating multiple hpte entries.
Optimize the operation using H_BULK_REMOVE on lpar platforms.
On native, reduce the number of tlb flush.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We enable only if the we support 16MB page size.
Reviewed-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We find all the overlapping vma and mark them such that we don't allocate
hugepage in that range. Also we split existing huge page so that the
normal page hash can be invalidated and new page faulted in with new
protection bits.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

With THP we set pmd to none, before we do pte_clear. Hence we can't
walk page table to get the pte lock ptr and verify whether it is locked.
THP do take pte lock before calling pte_clear. So we don't change the locking
rules here. It is that we can't use page table walking to check whether
pte locks are held with THP.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

GCC is very likely to read the pagetables just once and cache them in
the local stack or in a register, but it is can also decide to re-read
the pagetables. The problem is that the pagetable in those places can
change from under gcc.

With THP/hugetlbfs the pmd (and pgd for hugetlbfs giga pages) can
change under gup_fast. The pages won't be freed untill we finish
gup fast because we have irq disabled and we free these pages via
rcu callback.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We need to have irqs disabled to handle all the possible parallel update for
linux page table without holding locks.

Events that we are intersted in while walking page tables are
1) Page fault
2) umap
3) THP split
4) THP collapse

A) local_irq_disabled:
------------------------
1) page fault:
A none to valid transition via page fault is not an issue because we
would either see a none or valid. If it is none, we would error out
the page table walk. We may need to use on stack values when checking for
type of page table elements, because if we do

if (!is_hugepd()) {
    if (!pmd_none() {
       if (pmd_bad() {

We could take that bad condition because the pmd got converted to a hugepd
after the !is_hugepd check via a hugetlb fault.

The right way would be to check for pmd_none higher up or use on stack value.

2) A valid to none conversion via unmap:
We can safely walk the upper level table, because we don't remove the the
page table entries until rcu grace period. So even if we followed a
wrong pointer we still have the pointer valid till the grace period.

A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and
 _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent
pte_clear we take _PAGE_BUSY.

3) THP split:
A valid transparent hugepage is converted to nomal page. Before we split we
do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING
So when walking page table we need to check for pmd_trans_splitting and
handle that. The pte returned should also need to be checked for
_PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save
the value of PTE on stack and check for the flag in the local pte value.
If we don't have the value set we can safely operate on the local pte value
and we atomicaly set _PAGE_BUSY.

4) THP collapse:
A normal page gets converted to hugepage. In the collapse path, we
mark the pmd none early (pmdp_clear_flush). With irq disabled, if we
are aleady walking page table we would see the pmd_none and won't continue.
If we see a valid PMD, we should still check for _PAGE_PRESENT before
setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The deposted PTE page in the second half of the PMD table is used to
track the state on hash PTEs. After updating the HPTE, we mark the
coresponding slot in the deposted PTE page valid.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Replace find_linux_pte with find_linux_pte_or_hugepte and explicitly
document why we don't need to handle transparent hugepages at callsites.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Reviewed-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We will use this in the later patch for handling THP pages
Reviewed-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We now have pmd entries covering 16MB range and the PMD table double its original size.
We use the second half of the PMD table to deposit the pgtable (PTE page).
The depoisted PTE page is further used to track the HPTE information. The information
include [ secondary group | 3 bit hidx | valid ]. We use one byte per each HPTE entry.
With 16MB hugepage and 64K HPTE we need 256 entries and with 4K HPTE we need
4096 entries. Both will fit in a 4K PTE page. On hugepage invalidate we need to walk
the PTE page and invalidate all valid HPTEs.

This patch implements necessary arch specific functions for THP support and also
hugepage invalidate logic. These PMD related functions are intentionally kept
similar to their PTE counter-part.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

THP code does PTE page allocation along with large page request and deposit them
for later use. This is to ensure that we won't have any failures when we split
hugepages to regular pages.

On powerpc we want to use the deposited PTE page for storing hash pte slot and
secondary bit information for the HPTEs. We use the second half
of the pmd table to save the deposted PTE page.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

If a hash bucket gets full, we "evict" a more/less random entry from it.
When we do that we don't invalidate the TLB (hpte_remove) because we assume
the old translation is still technically "valid". This implies that when
we are invalidating or updating pte, even if HPTE entry is not valid
we should do a tlb invalidate. With hugepages, we need to pass the correct
actual page size value for tlb invalidation.

This change update the patch 0608d692
"powerpc/mm: Always invalidate tlb on hpte invalidate and update" to handle
transparent hugepages correctly.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

There appears to be no good reason to keep this as 64bit only. It works
on 32bit also, and has checks so that it can work correctly with 32bit
binaries on 64bit hardware which is why I think this works.

I tested this on qemu using the virtex-ml507 machine type.

Before,

/bin2 # ./test & cat /proc/${!}/maps
00100000-00103000 r-xp 00000000 00:00 0          [vdso]
10000000-10007000 r-xp 00000000 00:01 454        /bin2/test
10017000-10018000 rw-p 00007000 00:01 454        /bin2/test
48000000-48020000 r-xp 00000000 00:01 224        /lib/ld-2.11.3.so
48021000-48023000 rw-p 00021000 00:01 224        /lib/ld-2.11.3.so
bfd03000-bfd24000 rw-p 00000000 00:00 0          [stack]
/bin2 # ./test & cat /proc/${!}/maps
00100000-00103000 r-xp 00000000 00:00 0          [vdso]
0fe6e000-0ffd8000 r-xp 00000000 00:01 214        /lib/libc-2.11.3.so
0ffd8000-0ffe8000 ---p 0016a000 00:01 214        /lib/libc-2.11.3.so
0ffe8000-0ffed000 rw-p 0016a000 00:01 214        /lib/libc-2.11.3.so
0ffed000-0fff0000 rw-p 00000000 00:00 0
10000000-10007000 r-xp 00000000 00:01 454        /bin2/test
10017000-10018000 rw-p 00007000 00:01 454        /bin2/test
48000000-48020000 r-xp 00000000 00:01 224        /lib/ld-2.11.3.so
48020000-48021000 rw-p 00000000 00:00 0
48021000-48023000 rw-p 00021000 00:01 224        /lib/ld-2.11.3.so
bf98a000-bf9ab000 rw-p 00000000 00:00 0          [stack]
/bin2 # ./test & cat /proc/${!}/maps
00100000-00103000 r-xp 00000000 00:00 0          [vdso]
0fe6e000-0ffd8000 r-xp 00000000 00:01 214        /lib/libc-2.11.3.so
0ffd8000-0ffe8000 ---p 0016a000 00:01 214        /lib/libc-2.11.3.so
0ffe8000-0ffed000 rw-p 0016a000 00:01 214        /lib/libc-2.11.3.so
0ffed000-0fff0000 rw-p 00000000 00:00 0
10000000-10007000 r-xp 00000000 00:01 454        /bin2/test
10017000-10018000 rw-p 00007000 00:01 454        /bin2/test
48000000-48020000 r-xp 00000000 00:01 224        /lib/ld-2.11.3.so
48020000-48021000 rw-p 00000000 00:00 0
48021000-48023000 rw-p 00021000 00:01 224        /lib/ld-2.11.3.so
bfa54000-bfa75000 rw-p 00000000 00:00 0          [stack]

After,

bash-4.1# ./test & cat /proc/${!}/maps
[7] 803
00100000-00103000 r-xp 00000000 00:00 0          [vdso]
10000000-10007000 r-xp 00000000 00:01 454        /bin2/test
10017000-10018000 rw-p 00007000 00:01 454        /bin2/test
b7eb0000-b7ed0000 r-xp 00000000 00:01 224        /lib/ld-2.11.3.so
b7ed1000-b7ed3000 rw-p 00021000 00:01 224        /lib/ld-2.11.3.so
bfbc0000-bfbe1000 rw-p 00000000 00:00 0          [stack]
bash-4.1# ./test & cat /proc/${!}/maps
[8] 805
00100000-00103000 r-xp 00000000 00:00 0          [vdso]
10000000-10007000 r-xp 00000000 00:01 454        /bin2/test
10017000-10018000 rw-p 00007000 00:01 454        /bin2/test
b7b03000-b7b23000 r-xp 00000000 00:01 224        /lib/ld-2.11.3.so
b7b24000-b7b26000 rw-p 00021000 00:01 224        /lib/ld-2.11.3.so
bfc27000-bfc48000 rw-p 00000000 00:00 0          [stack]
bash-4.1# ./test & cat /proc/${!}/maps
[9] 807
00100000-00103000 r-xp 00000000 00:00 0          [vdso]
10000000-10007000 r-xp 00000000 00:01 454        /bin2/test
10017000-10018000 rw-p 00007000 00:01 454        /bin2/test
b7f37000-b7f57000 r-xp 00000000 00:01 224        /lib/ld-2.11.3.so
b7f58000-b7f5a000 rw-p 00021000 00:01 224        /lib/ld-2.11.3.so
bff96000-bffb7000 rw-p 00000000 00:00 0          [stack]
Signed-off-by: NDaniel Walker <dwalker@fifo90.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This happens with threads that are offline due to CPU hotplug
(including threads that were never "plugged in" to begin with because
SMT is disabled).
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

If a hash bucket gets full, we "evict" a more/less random entry from it.
When we do that we don't invalidate the TLB (hpte_remove) because we assume
the old translation is still technically "valid". This implies that when
we are invalidating or updating pte, even if HPTE entry is not valid
we should do a tlb invalidate.

This was a regression introduced by b1022fbdSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This is the exception hooks for context tracking subsystem, including
data access, program check, single step, instruction breakpoint, machine check,
alignment, fp unavailable, altivec assist, unknown exception, whose handlers
might use RCU.

This patch corresponds to
[PATCH] x86: Exception hooks for userspace RCU extended QS
  commit 6ba3c97a

But after the exception handling moved to generic code, and some changes in
following two commits:
56dd9470
  context_tracking: Move exception handling to generic code
6c1e0256
  context_tracking: Restore correct previous context state on exception exit

it is able for exception hooks to use the generic code above instead of a
redundant arch implementation.
Signed-off-by: NLi Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Make sure that current->thread.reg exists before we deference it in
flush_hash_page.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Reported-by: NJohn J Miller <millerjo@us.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Encode the actual page correctly in tlbie/tlbiel. This make sure we handle
multiple page size segment correctly.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This gives hint about different base and actual page size combination
supported by the platform.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

As per ISA doc, we encode base and actual page size in the LP bits of
PTE. The number of bit used to encode the page sizes depend on actual
page size.  ISA doc lists this as

   PTE LP     actual page size
rrrr rrrz 	>=8KB
rrrr rrzz	>=16KB
rrrr rzzz 	>=32KB
rrrr zzzz 	>=64KB
rrrz zzzz 	>=128KB
rrzz zzzz 	>=256KB
rzzz zzzz	>=512KB
zzzz zzzz 	>=1MB

ISA doc also says
"The values of the “z” bits used to specify each size, along with all possible
values of “r” bits in the LP field, must result in LP values distinct from
other LP values for other sizes."

based on the above update hpte_decode to use the correct decoding for LP bits.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We look at both the segment base page size and actual page size and store
the pte-lp-encodings in an array per base page size.

We also update all relevant functions to take actual page size argument
so that we can use the correct PTE LP encoding in HPTE. This should also
get the basic Multiple Page Size per Segment (MPSS) support. This is needed
to enable THP on ppc64.

[Fixed PR KVM build --BenH]
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

In all these cases we are doing something similar to

HPTE_V_COMPARE(hpte_v, want_v) which ignores the HPTE_V_LARGE bit

With MPSS support we would need actual page size to set HPTE_V_LARGE
bit and that won't be available in most of these cases. Since we are ignoring
HPTE_V_LARGE bit, use the  avpn value instead. There should not be any change
in behaviour after this patch.
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We allocate one page for the last level of linux page table. With THP and
large page size of 16MB, that would mean we are wasting large part
of that page. To map 16MB area, we only need a PTE space of 2K with 64K
page size. This patch reduce the space wastage by sharing the page
allocated for the last level of linux page table with multiple pmd
entries. We call these smaller chunks PTE page fragments and allocated
page, PTE page.

In order to support systems which doesn't have 64K HPTE support, we also
add another 2K to PTE page fragment. The second half of the PTE fragments
is used for storing slot and secondary bit information of an HPTE. With this
we now have a 4K PTE fragment.

We use a simple approach to share the PTE page. On allocation, we bump the
PTE page refcount to 16 and share the PTE page with the next 16 pte alloc
request. This should help in the node locality of the PTE page fragment,
assuming that the immediate pte alloc request will mostly come from the
same NUMA node. We don't try to reuse the freed PTE page fragment. Hence
we could be waisting some space.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We will be switching PMD_SHIFT to 24 bits to facilitate THP impmenetation.
With PMD_SHIFT set to 24, we now have 16MB huge pages allocated at PGD level.
That means with 32 bit process we cannot allocate normal pages at
all, because we cover the entire address space with one pgd entry. Fix this
by switching to a new page table format for hugepages. With the new page table
format for 16GB and 16MB hugepages we won't allocate hugepage directory. Instead
we encode the PTE information directly at the directory level. This forces 16MB
hugepage at PMD level. This will also make the page take walk much simpler later
when we add the THP support.

With the new table format we have 4 cases for pgds and pmds:
(1) invalid (all zeroes)
(2) pointer to next table, as normal; bottom 6 bits == 0
(3) leaf pte for huge page, bottom two bits != 00
(4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Change the hugepage directory format so that we can have leaf ptes directly
at page directory avoiding the allocation of hugepage directory.

With the new table format we have 3 cases for pgds and pmds:
(1) invalid (all zeroes)
(2) pointer to next table, as normal; bottom 6 bits == 0
(4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table

Instead of storing shift value in hugepd pointer we use mmu_psize_def index
so that we can fit all the supported hugepage size in 4 bits
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

USE PTRS_PER_PTE to indicate the size of pte page. To support THP,
later patches will be changing PTRS_PER_PTE value.
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Correct build failure for powerpc/pseries builds with CONFIG_SMP not defined.

The function cpu_sibling_mask has no meaning (or definition) when CONFIG_SMP
is not defined. Additionally, the updating of NUMA affinity for a CPU in a UP
system doesn't really make sense.

This patch ifdef's out the code making the affinity updates for PRRN events to
fix the following build break.

arch/powerpc/mm/numa.c: In function ‘stage_topology_update’:
arch/powerpc/mm/numa.c:1535: error: implicit declaration of function ‘cpu_sibling_mask’
arch/powerpc/mm/numa.c:1535: warning: passing argument 3 of ‘cpumask_or’ makes pointer from integer without a cast
make[1]: *** [arch/powerpc/mm/numa.o] Error 1
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

After merging the cgroup tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:

arch/powerpc/mm/numa.c: In function 'arch_update_cpu_topology':
arch/powerpc/mm/numa.c:1465:2: error: implicit declaration of function 'kzalloc' [-Werror=implicit-function-declaration]
arch/powerpc/mm/numa.c:1465:10: error: assignment makes pointer from integer without a cast [-Werror]
arch/powerpc/mm/numa.c:1497:2: error: implicit declaration of function 'kfree' [-Werror=implicit-function-declaration]

Caused by commit 30c05350 ("powerpc/pseries: Use stop machine to
update cpu maps") from the powerpc tree interacting with (probably)
commit ff794dea ("cpuset: remove include of cgroup.h from cpuset.h")
from the cgroup tree.  Removing includes from header files is fraught
with danger ...

The former should have added an include of linux/slab.h to
arch/powerpc/mm/numa.c.

I have added the following merge fix patch for today (but it should be
applied to the powerpc tree ASAP).

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Mon, 29 Apr 2013 14:01:44 +1000
Subject: [PATCH] powerpc: numa.c: using kzalloc/kfree requires including
 slab.h

fixes these build errors:

arch/powerpc/mm/numa.c: In function 'arch_update_cpu_topology':
arch/powerpc/mm/numa.c:1465:2: error: implicit declaration of function 'kzalloc' [-Werror=implicit-function-declaration]
arch/powerpc/mm/numa.c:1465:10: error: assignment makes pointer from integer without a cast [-Werror]
arch/powerpc/mm/numa.c:1497:2: error: implicit declaration of function 'kfree' [-Werror=implicit-function-declaration]
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Update the powerpc slice_get_unmapped_area function to make use of
vm_unmapped_area() instead of implementing a brute force search.
Signed-off-by: NMichel Lespinasse <walken@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Tested-by: N"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

As all other architectures have been converted to use vm_unmapped_area(),
we are about to retire the free_area_cache.

This change simply removes the use of that cache in
slice_get_unmapped_area(), which will most certainly have a
performance cost. Next one will convert that function to use the
vm_unmapped_area() infrastructure and regain the performance.
Signed-off-by: NMichel Lespinasse <walken@google.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

[sfr@canb.auug.org.au: add missing semicolon]
Signed-off-by: NCody P Schafer <cody@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@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>

The sparse code, when asking the architecture to populate the vmemmap,
specifies the section range as a starting page and a number of pages.

This is an awkward interface, because none of the arch-specific code
actually thinks of the range in terms of 'struct page' units and always
translates it to bytes first.

In addition, later patches mix huge page and regular page backing for
the vmemmap.  For this, they need to call vmemmap_populate_basepages()
on sub-section ranges with PAGE_SIZE and PMD_SIZE in mind.  But these
are not necessarily multiples of the 'struct page' size and so this unit
is too coarse.

Just translate the section range into bytes once in the generic sparse
code, then pass byte ranges down the stack.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Bernhard Schmidt <Bernhard.Schmidt@lrz.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Tested-by: NDavid S. Miller <davem@davemloft.net>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use helper function free_highmem_page() to free highmem pages into
the buddy system.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: "Suzuki K. Poulose" <suzuki@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use common help functions to free reserved pages.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anatolij Gustschin <agust@denx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are instances in which we do not want topology updates to occur.
In order to allow this a /proc interface (/proc/powerpc/topology_updates)
is introduced so that topology updates can be enabled and disabled.

This patch also adds a prrn_is_enabled() call so that PRRN events are
handled in the kernel only if topology updating is enabled.
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The new PRRN firmware feature provides a more convenient and event-driven
interface than VPHN for notifying Linux of changes to the NUMA affinity of
platform resources. However, for practical reasons, it may not be feasible
for some customers to update to the latest firmware. For these customers,
the VPHN feature supported on previous firmware versions may still be the
best option.

The VPHN feature was previously disabled due to races with the load
balancing code when accessing the NUMA cpu maps, but the new stop_machine()
approach protects the NUMA cpu maps from these concurrent accesses. It
should be safe to re-enable this feature now.
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>