set_recommended_min_free_kbytes() adjusts zone water marks to be suitable
for khugepaged. We avoid doing this if khugepaged is disabled, but don't
catch the case when khugepaged is failed to start.
Let's address this by checking khugepaged_thread instead of
khugepaged_enabled() in set_recommended_min_free_kbytes().
It's NULL if the kernel thread is stopped or failed to start.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We miss error-handling in few cases hugepage_init(). Let's fix that.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mempools keep elements in a reserved pool for contexts in which allocation
may not be possible. When an element is allocated from the reserved pool,
its memory contents is the same as when it was added to the reserved pool.
Because of this, elements lack any free poisoning to detect use-after-free
errors.
This patch adds free poisoning for elements backed by the slab allocator.
This is possible because the mempool layer knows the object size of each
element.
When an element is added to the reserved pool, it is poisoned with
POISON_FREE. When it is removed from the reserved pool, the contents are
checked for POISON_FREE. If there is a mismatch, a warning is emitted to
the kernel log.
This is only effective for configs with CONFIG_DEBUG_SLAB or
CONFIG_SLUB_DEBUG_ON.
[fabio.estevam@freescale.com: use '%zu' for printing 'size_t' variable]
[arnd@arndb.de: add missing include]
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All occurrences of mempools based on slab caches with object constructors
have been removed from the tree, so disallow creating them.
We can only dereference mem->ctor in mm/mempool.c without including
mm/slab.h in include/linux/mempool.h. So simply note the restriction,
just like the comment restricting usage of __GFP_ZERO, and warn on kernels
with CONFIG_DEBUG_VM() if such a mempool is allocated from.
We don't want to incur this check on every element allocation, so use
VM_BUG_ON().
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/
tree since it doesn't work reliably on non-scalar types.
This patch removes the rest of the usages of ACCESS_ONCE, and use the new
READ_ONCE API for the read accesses. This makes things cleaner, instead
of using separate/multiple sets of APIs.
Signed-off-by: Jason Low <jason.low2@hp.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 38c5ce936a ("mm/gup: Replace ACCESS_ONCE with READ_ONCE")
converted ACCESS_ONCE usage in gup_pmd_range() to READ_ONCE, since
ACCESS_ONCE doesn't work reliably on non-scalar types.
This patch also fixes the other ACCESS_ONCE usages in gup_pte_range()
and __get_user_pages_fast() in mm/gup.c
Signed-off-by: Jason Low <jason.low2@hp.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As suggested by Kirill the "goto"s in vma_to_resize aren't necessary, just
change them to explicit return.
Signed-off-by: Derek Che <crquan@ymail.com>
Suggested-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently I straced bash behavior in this dd zero pipe to read test, in
part of testing under vm.overcommit_memory=2 (OVERCOMMIT_NEVER mode):
# dd if=/dev/zero | read x
The bash sub shell is calling mremap to reallocate more and more memory
untill it finally failed -ENOMEM (I expect), or to be killed by system OOM
killer (which should not happen under OVERCOMMIT_NEVER mode); But the
mremap system call actually failed of -EFAULT, which is a surprise to me,
I think it's supposed to be -ENOMEM? then I wrote this piece of C code
testing confirmed it: https://gist.github.com/crquan/326bde37e1ddda8effe5
$ ./remap
allocated one page @0x7f686bf71000, (PAGE_SIZE: 4096)
grabbed 7680512000 bytes of memory (1875125 pages) @ 00007f6690993000.
mremap failed Bad address (14).
The -EFAULT comes from the branch of security_vm_enough_memory_mm failure,
underlyingly it calls __vm_enough_memory which returns only 0 for success
or -ENOMEM; So why vma_to_resize needs to return -EFAULT in this case?
this sounds like a mistake to me.
Some more digging into git history:
1) Before commit 119f657c7 ("RLIMIT_AS checking fix") in May 1 2005
(pre 2.6.12 days) it was returning -ENOMEM for this failure;
2) but commit 119f657c7 ("untangling do_mremap(), part 1") changed it
accidentally, to what ever is preserved in local ret, which happened to
be -EFAULT, in a previous assignment;
3) then in commit 54f5de709 code refactoring, it's explicitly returning
-EFAULT, should be wrong.
Signed-off-by: Derek Che <crquan@ymail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In original implementation of vm_map_ram made by Nick Piggin there were
two bitmaps: alloc_map and dirty_map. None of them were used as supposed
to be: finding a suitable free hole for next allocation in block.
vm_map_ram allocates space sequentially in block and on free call marks
pages as dirty, so freed space can't be reused anymore.
Actually it would be very interesting to know the real meaning of those
bitmaps, maybe implementation was incomplete, etc.
But long time ago Zhang Yanfei removed alloc_map by these two commits:
mm/vmalloc.c: remove dead code in vb_alloc
3fcd76e802
mm/vmalloc.c: remove alloc_map from vmap_block
b8e748b6c3
In this patch I replaced dirty_map with two range variables: dirty min and
max. These variables store minimum and maximum position of dirty space in
a block, since we need only to know the dirty range, not exact position of
dirty pages.
Why it was made? Several reasons: at first glance it seems that
vm_map_ram allocator concerns about fragmentation thus it uses bitmaps for
finding free hole, but it is not true. To avoid complexity seems it is
better to use something simple, like min or max range values. Secondly,
code also becomes simpler, without iteration over bitmap, just comparing
values in min and max macros. Thirdly, bitmap occupies up to 1024 bits
(4MB is a max size of a block). Here I replaced the whole bitmap with two
longs.
Finally vm_unmap_aliases should be slightly faster and the whole
vmap_block structure occupies less memory.
Signed-off-by: Roman Pen <r.peniaev@gmail.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Christoph Lameter <cl@linux.com>
Cc: Gioh Kim <gioh.kim@lge.com>
Cc: Rob Jones <rob.jones@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Previous implementation allocates new vmap block and repeats search of a
free block from the very beginning, iterating over the CPU free list.
Why it can be better??
1. Allocation can happen on one CPU, but search can be done on another CPU.
In worst case we preallocate amount of vmap blocks which is equal to
CPU number on the system.
2. In previous patch I added newly allocated block to the tail of free list
to avoid soon exhaustion of virtual space and give a chance to occupy
blocks which were allocated long time ago. Thus to find newly allocated
block all the search sequence should be repeated, seems it is not efficient.
In this patch newly allocated block is occupied right away, address of
virtual space is returned to the caller, so there is no any need to repeat
the search sequence, allocation job is done.
Signed-off-by: Roman Pen <r.peniaev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Christoph Lameter <cl@linux.com>
Cc: Gioh Kim <gioh.kim@lge.com>
Cc: Rob Jones <rob.jones@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently I came across high fragmentation of vm_map_ram allocator:
vmap_block has free space, but still new blocks continue to appear.
Further investigation showed that certain mapping/unmapping sequences
can exhaust vmalloc space. On small 32bit systems that's not a big
problem, cause purging will be called soon on a first allocation failure
(alloc_vmap_area), but on 64bit machines, e.g. x86_64 has 45 bits of
vmalloc space, that can be a disaster.
1) I came up with a simple allocation sequence, which exhausts virtual
space very quickly:
while (iters) {
/* Map/unmap big chunk */
vaddr = vm_map_ram(pages, 16, -1, PAGE_KERNEL);
vm_unmap_ram(vaddr, 16);
/* Map/unmap small chunks.
*
* -1 for hole, which should be left at the end of each block
* to keep it partially used, with some free space available */
for (i = 0; i < (VMAP_BBMAP_BITS - 16) / 8 - 1; i++) {
vaddr = vm_map_ram(pages, 8, -1, PAGE_KERNEL);
vm_unmap_ram(vaddr, 8);
}
}
The idea behind is simple:
1. We have to map a big chunk, e.g. 16 pages.
2. Then we have to occupy the remaining space with smaller chunks, i.e.
8 pages. At the end small hole should remain to keep block in free list,
but do not let big chunk to occupy remaining space.
3. Goto 1 - allocation request of 16 pages can't be completed (only 8 slots
are left free in the block in the #2 step), new block will be allocated,
all further requests will lay into newly allocated block.
To have some measurement numbers for all further tests I setup ftrace and
enabled 4 basic calls in a function profile:
echo vm_map_ram > /sys/kernel/debug/tracing/set_ftrace_filter;
echo alloc_vmap_area >> /sys/kernel/debug/tracing/set_ftrace_filter;
echo vm_unmap_ram >> /sys/kernel/debug/tracing/set_ftrace_filter;
echo free_vmap_block >> /sys/kernel/debug/tracing/set_ftrace_filter;
So for this scenario I got these results:
BEFORE (all new blocks are put to the head of a free list)
# cat /sys/kernel/debug/tracing/trace_stat/function0
Function Hit Time Avg s^2
-------- --- ---- --- ---
vm_map_ram 126000 30683.30 us 0.243 us 30819.36 us
vm_unmap_ram 126000 22003.24 us 0.174 us 340.886 us
alloc_vmap_area 1000 4132.065 us 4.132 us 0.903 us
AFTER (all new blocks are put to the tail of a free list)
# cat /sys/kernel/debug/tracing/trace_stat/function0
Function Hit Time Avg s^2
-------- --- ---- --- ---
vm_map_ram 126000 28713.13 us 0.227 us 24944.70 us
vm_unmap_ram 126000 20403.96 us 0.161 us 1429.872 us
alloc_vmap_area 993 3916.795 us 3.944 us 29.370 us
free_vmap_block 992 654.157 us 0.659 us 1.273 us
SUMMARY:
The most interesting numbers in those tables are numbers of block
allocations and deallocations: alloc_vmap_area and free_vmap_block
calls, which show that before the change blocks were not freed, and
virtual space and physical memory (vmap_block structure allocations,
etc) were consumed.
Average time which were spent in vm_map_ram/vm_unmap_ram became slightly
better. That can be explained with a reasonable amount of blocks in a
free list, which we need to iterate to find a suitable free block.
2) Another scenario is a random allocation:
while (iters) {
/* Randomly take number from a range [1..32/64] */
nr = rand(1, VMAP_MAX_ALLOC);
vaddr = vm_map_ram(pages, nr, -1, PAGE_KERNEL);
vm_unmap_ram(vaddr, nr);
}
I chose mersenne twister PRNG to generate persistent random state to
guarantee that both runs have the same random sequence. For each
vm_map_ram call random number from [1..32/64] was taken to represent
amount of pages which I do map.
I did 10'000 vm_map_ram calls and got these two tables:
BEFORE (all new blocks are put to the head of a free list)
# cat /sys/kernel/debug/tracing/trace_stat/function0
Function Hit Time Avg s^2
-------- --- ---- --- ---
vm_map_ram 10000 10170.01 us 1.017 us 993.609 us
vm_unmap_ram 10000 5321.823 us 0.532 us 59.789 us
alloc_vmap_area 420 2150.239 us 5.119 us 3.307 us
free_vmap_block 37 159.587 us 4.313 us 134.344 us
AFTER (all new blocks are put to the tail of a free list)
# cat /sys/kernel/debug/tracing/trace_stat/function0
Function Hit Time Avg s^2
-------- --- ---- --- ---
vm_map_ram 10000 7745.637 us 0.774 us 395.229 us
vm_unmap_ram 10000 5460.573 us 0.546 us 67.187 us
alloc_vmap_area 414 2201.650 us 5.317 us 5.591 us
free_vmap_block 412 574.421 us 1.394 us 15.138 us
SUMMARY:
'BEFORE' table shows, that 420 blocks were allocated and only 37 were
freed. Remained 383 blocks are still in a free list, consuming virtual
space and physical memory.
'AFTER' table shows, that 414 blocks were allocated and 412 were really
freed. 2 blocks remained in a free list.
So fragmentation was dramatically reduced. Why? Because when we put
newly allocated block to the head, all further requests will occupy new
block, regardless remained space in other blocks. In this scenario all
requests come randomly. Eventually remained free space will be less
than requested size, free list will be iterated and it is possible that
nothing will be found there - finally new block will be created. So
exhaustion in random scenario happens for the maximum possible
allocation size: 32 pages for 32-bit system and 64 pages for 64-bit
system.
Also average cost of vm_map_ram was reduced from 1.017 us to 0.774 us.
Again this can be explained by iteration through smaller list of free
blocks.
3) Next simple scenario is a sequential allocation, when the allocation
order is increased for each block. This scenario forces allocator to
reach maximum amount of partially free blocks in a free list:
while (iters) {
/* Populate free list with blocks with remaining space */
for (order = 0; order <= ilog2(VMAP_MAX_ALLOC); order++) {
nr = VMAP_BBMAP_BITS / (1 << order);
/* Leave a hole */
nr -= 1;
for (i = 0; i < nr; i++) {
vaddr = vm_map_ram(pages, (1 << order), -1, PAGE_KERNEL);
vm_unmap_ram(vaddr, (1 << order));
}
/* Completely occupy blocks from a free list */
for (order = 0; order <= ilog2(VMAP_MAX_ALLOC); order++) {
vaddr = vm_map_ram(pages, (1 << order), -1, PAGE_KERNEL);
vm_unmap_ram(vaddr, (1 << order));
}
}
Results which I got:
BEFORE (all new blocks are put to the head of a free list)
# cat /sys/kernel/debug/tracing/trace_stat/function0
Function Hit Time Avg s^2
-------- --- ---- --- ---
vm_map_ram 2032000 399545.2 us 0.196 us 467123.7 us
vm_unmap_ram 2032000 363225.7 us 0.178 us 111405.9 us
alloc_vmap_area 7001 30627.76 us 4.374 us 495.755 us
free_vmap_block 6993 7011.685 us 1.002 us 159.090 us
AFTER (all new blocks are put to the tail of a free list)
# cat /sys/kernel/debug/tracing/trace_stat/function0
Function Hit Time Avg s^2
-------- --- ---- --- ---
vm_map_ram 2032000 394259.7 us 0.194 us 589395.9 us
vm_unmap_ram 2032000 292500.7 us 0.143 us 94181.08 us
alloc_vmap_area 7000 31103.11 us 4.443 us 703.225 us
free_vmap_block 7000 6750.844 us 0.964 us 119.112 us
SUMMARY:
No surprises here, almost all numbers are the same.
Fixing this fragmentation problem I also did some improvements in a
allocation logic of a new vmap block: occupy block immediately and get
rid of extra search in a free list.
Also I replaced dirty bitmap with min/max dirty range values to make the
logic simpler and slightly faster, since two longs comparison costs
less, than loop thru bitmap.
This patchset raises several questions:
Q: Think the problem you comments is already known so that I wrote comments
about it as "it could consume lots of address space through fragmentation".
Could you tell me about your situation and reason why it should be avoided?
Gioh Kim
A: Indeed, there was a commit 364376383 which adds explicit comment about
fragmentation. But fragmentation which is described in this comment caused
by mixing of long-lived and short-lived objects, when a whole block is pinned
in memory because some page slots are still in use. But here I am talking
about blocks which are free, nobody uses them, and allocator keeps them alive
forever, continuously allocating new blocks.
Q: I think that if you put newly allocated block to the tail of a free
list, below example would results in enormous performance degradation.
new block: 1MB (256 pages)
while (iters--) {
vm_map_ram(3 or something else not dividable for 256) * 85
vm_unmap_ram(3) * 85
}
On every iteration, it needs newly allocated block and it is put to the
tail of a free list so finding it consumes large amount of time.
Joonsoo Kim
A: Second patch in current patchset gets rid of extra search in a free list,
so new block will be immediately occupied..
Also, the scenario above is impossible, cause vm_map_ram allocates virtual
range in orders, i.e. 2^n. I.e. passing 3 to vm_map_ram you will allocate
4 slots in a block and 256 slots (capacity of a block) of course dividable
on 4, so block will be completely occupied.
But there is a worst case which we can achieve: each free block has a hole
equal to order size.
The maximum size of allocation is 64 pages for 64-bit system
(if you try to map more, original alloc_vmap_area will be called).
So the maximum order is 6. That means that worst case, before allocator
makes a decision to allocate a new block, is to iterate 7 blocks:
HEAD
1st block - has 1 page slot free (order 0)
2nd block - has 2 page slots free (order 1)
3rd block - has 4 page slots free (order 2)
4th block - has 8 page slots free (order 3)
5th block - has 16 page slots free (order 4)
6th block - has 32 page slots free (order 5)
7th block - has 64 page slots free (order 6)
TAIL
So the worst scenario on 64-bit system is that each CPU queue can have 7
blocks in a free list.
This can happen only and only if you allocate blocks increasing the order.
(as I did in the function written in the comment of the first patch)
This is weird and rare case, but still it is possible. Afterwards you will
get 7 blocks in a list.
All further requests should be placed in a newly allocated block or some
free slots should be found in a free list.
Seems it does not look dramatically awful.
This patch (of 3):
If suitable block can't be found, new block is allocated and put into a
head of a free list, so on next iteration this new block will be found
first.
That's bad, because old blocks in a free list will not get a chance to be
fully used, thus fragmentation will grow.
Let's consider this simple example:
#1 We have one block in a free list which is partially used, and where only
one page is free:
HEAD |xxxxxxxxx-| TAIL
^
free space for 1 page, order 0
#2 New allocation request of order 1 (2 pages) comes, new block is allocated
since we do not have free space to complete this request. New block is put
into a head of a free list:
HEAD |----------|xxxxxxxxx-| TAIL
#3 Two pages were occupied in a new found block:
HEAD |xx--------|xxxxxxxxx-| TAIL
^
two pages mapped here
#4 New allocation request of order 0 (1 page) comes. Block, which was created
on #2 step, is located at the beginning of a free list, so it will be found
first:
HEAD |xxX-------|xxxxxxxxx-| TAIL
^ ^
page mapped here, but better to use this hole
It is obvious, that it is better to complete request of #4 step using the
old block, where free space is left, because in other case fragmentation
will be highly increased.
But fragmentation is not only the case. The worst thing is that I can
easily create scenario, when the whole vmalloc space is exhausted by
blocks, which are not used, but already dirty and have several free pages.
Let's consider this function which execution should be pinned to one CPU:
static void exhaust_virtual_space(struct page *pages[16], int iters)
{
/* Firstly we have to map a big chunk, e.g. 16 pages.
* Then we have to occupy the remaining space with smaller
* chunks, i.e. 8 pages. At the end small hole should remain.
* So at the end of our allocation sequence block looks like
* this:
* XX big chunk
* |XXxxxxxxx-| x small chunk
* - hole, which is enough for a small chunk,
* but is not enough for a big chunk
*/
while (iters--) {
int i;
void *vaddr;
/* Map/unmap big chunk */
vaddr = vm_map_ram(pages, 16, -1, PAGE_KERNEL);
vm_unmap_ram(vaddr, 16);
/* Map/unmap small chunks.
*
* -1 for hole, which should be left at the end of each block
* to keep it partially used, with some free space available */
for (i = 0; i < (VMAP_BBMAP_BITS - 16) / 8 - 1; i++) {
vaddr = vm_map_ram(pages, 8, -1, PAGE_KERNEL);
vm_unmap_ram(vaddr, 8);
}
}
}
On every iteration new block (1MB of vm area in my case) will be
allocated and then will be occupied, without attempt to resolve small
allocation request using previously allocated blocks in a free list.
In case of random allocation (size should be randomly taken from the
range [1..64] in 64-bit case or [1..32] in 32-bit case) situation is the
same: new blocks continue to appear if maximum possible allocation size
(32 or 64) passed to the allocator, because all remaining blocks in a
free list do not have enough free space to complete this allocation
request.
In summary if new blocks are put into the head of a free list eventually
virtual space will be exhausted.
In current patch I simply put newly allocated block to the tail of a
free list, thus reduce fragmentation, giving a chance to resolve
allocation request using older blocks with possible holes left.
Signed-off-by: Roman Pen <r.peniaev@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Christoph Lameter <cl@linux.com>
Cc: Gioh Kim <gioh.kim@lge.com>
Cc: Rob Jones <rob.jones@codethink.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make 'min_size=<value>' be an option when mounting a hugetlbfs. This
option takes the same value as the 'size' option. min_size can be
specified without specifying size. If both are specified, min_size must
be less that or equal to size else the mount will fail. If min_size is
specified, then at mount time an attempt is made to reserve min_size
pages. If the reservation fails, the mount fails. At umount time, the
reserved pages are released.
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The same routines that perform subpool maximum size accounting
hugepage_subpool_get/put_pages() are modified to also perform minimum size
accounting. When a delta value is passed to these routines, calculate how
global reservations must be adjusted to maintain the subpool minimum size.
The routines now return this global reserve count adjustment. This
global reserve count adjustment is then passed to the global accounting
routine hugetlb_acct_memory().
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hugetlbfs allocates huge pages from the global pool as needed. Even if
the global pool contains a sufficient number pages for the filesystem size
at mount time, those global pages could be grabbed for some other use. As
a result, filesystem huge page allocations may fail due to lack of pages.
Applications such as a database want to use huge pages for performance
reasons. hugetlbfs filesystem semantics with ownership and modes work
well to manage access to a pool of huge pages. However, the application
would like some reasonable assurance that allocations will not fail due to
a lack of huge pages. At application startup time, the application would
like to configure itself to use a specific number of huge pages. Before
starting, the application can check to make sure that enough huge pages
exist in the system global pools. However, there are no guarantees that
those pages will be available when needed by the application. What the
application wants is exclusive use of a subset of huge pages.
Add a new hugetlbfs mount option 'min_size=<value>' to indicate that the
specified number of pages will be available for use by the filesystem. At
mount time, this number of huge pages will be reserved for exclusive use
of the filesystem. If there is not a sufficient number of free pages, the
mount will fail. As pages are allocated to and freeed from the
filesystem, the number of reserved pages is adjusted so that the specified
minimum is maintained.
This patch (of 4):
Add a field to the subpool structure to indicate the minimimum number of
huge pages to always be used by this subpool. This minimum count includes
allocated pages as well as reserved pages. If the minimum number of pages
for the subpool have not been allocated, pages are reserved up to this
minimum. An additional field (rsv_hpages) is used to track the number of
pages reserved to meet this minimum size. The hstate pointer in the
subpool is convenient to have when reserving and unreserving the pages.
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the compaction is activated via /proc/sys/vm/compact_memory it would
better scan the whole zone. And some platforms, for instance ARM, have
the start_pfn of a zone at zero. Therefore the first try to compact via
/proc doesn't work. It needs to reset the compaction scanner position
first.
Signed-off-by: Gioh Kim <gioh.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memcg currently uses hardcoded GFP_TRANSHUGE gfp flags for all THP
charges. THP allocations, however, might be using different flags
depending on /sys/kernel/mm/transparent_hugepage/{,khugepaged/}defrag and
the current allocation context.
The primary difference is that defrag configured to "madvise" value will
clear __GFP_WAIT flag from the core gfp mask to make the allocation
lighter for all mappings which are not backed by VM_HUGEPAGE vmas. If
memcg charge path ignores this fact we will get light allocation but the a
potential memcg reclaim would kill the whole point of the configuration.
Fix the mismatch by providing the same gfp mask used for the allocation to
the charge functions. This is quite easy for all paths except for
hugepaged kernel thread with !CONFIG_NUMA which is doing a pre-allocation
long before the allocated page is used in collapse_huge_page via
khugepaged_alloc_page. To prevent from cluttering the whole code path
from khugepaged_do_scan we simply return the current flags as per
khugepaged_defrag() value which might have changed since the
preallocation. If somebody changed the value of the knob we would charge
differently but this shouldn't happen often and it is definitely not
critical because it would only lead to a reduced success rate of one-off
THP promotion.
[akpm@linux-foundation.org: fix weird code layout while we're there]
[rientjes@google.com: clean up around alloc_hugepage_gfpmask()]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
"deactivate_page" was created for file invalidation so it has too
specific logic for file-backed pages. So, let's change the name of the
function and date to a file-specific one and yield the generic name.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Wang, Yalin <Yalin.Wang@sonymobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, pages which are marked as unevictable are protected from
compaction, but not from other types of migration. The POSIX real time
extension explicitly states that mlock() will prevent a major page
fault, but the spirit of this is that mlock() should give a process the
ability to control sources of latency, including minor page faults.
However, the mlock manpage only explicitly says that a locked page will
not be written to swap and this can cause some confusion. The
compaction code today does not give a developer who wants to avoid swap
but wants to have large contiguous areas available any method to achieve
this state. This patch introduces a sysctl for controlling compaction
behavior with respect to the unevictable lru. Users who demand no page
faults after a page is present can set compact_unevictable_allowed to 0
and users who need the large contiguous areas can enable compaction on
locked memory by leaving the default value of 1.
To illustrate this problem I wrote a quick test program that mmaps a
large number of 1MB files filled with random data. These maps are
created locked and read only. Then every other mmap is unmapped and I
attempt to allocate huge pages to the static huge page pool. When the
compact_unevictable_allowed sysctl is 0, I cannot allocate hugepages
after fragmenting memory. When the value is set to 1, allocations
succeed.
Signed-off-by: Eric B Munson <emunson@akamai.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the page flag sanitization patchset, an invalid usage of
ClearPageReclaim() is detected in set_page_dirty(). This can be called
from __unmap_hugepage_range(), so let's check PageReclaim() before trying
to clear it to avoid the misuse.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the page flag sanitization patchset, an invalid usage of
ClearPageSwapCache() is detected in migration_page_copy().
migrate_page_copy() is shared by both normal and hugepage (both thp and
hugetlb) code path, so let's check PageSwapCache() and clear it if it's
set to avoid misuse of the invalid clear operation.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This cleanup patch moves all strings passed to action_result() into a
singl= e array action_page_type so that a reader can easily find which
kind of actio= n results are possible. And this patch also fixes the
odd lines to be printed out, like "unknown page state page" or "free
buddy, 2nd try page".
[akpm@linux-foundation.org: rename messages, per David]
[akpm@linux-foundation.org: s/DIRTY_UNEVICTABLE_LRU/CLEAN_UNEVICTABLE_LRU', per Andi]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Xie XiuQi" <xiexiuqi@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Low and high watermarks, as they defined in the TODO to the mem_cgroup
struct, have already been implemented by Johannes, so remove the stale
comment.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mem_cgroup_lookup() is a wrapper around mem_cgroup_from_id(), which
checks that id != 0 before issuing the function call. Today, there is
no point in this additional check apart from optimization, because there
is no css with id <= 0, so that css_from_id, called by
mem_cgroup_from_id, will return NULL for any id <= 0.
Since mem_cgroup_from_id is only called from mem_cgroup_lookup, let us
zap mem_cgroup_lookup, substituting calls to it with mem_cgroup_from_id
and moving the check if id > 0 to css_from_id.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge first patchbomb from Andrew Morton:
- arch/sh updates
- ocfs2 updates
- kernel/watchdog feature
- about half of mm/
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (122 commits)
Documentation: update arch list in the 'memtest' entry
Kconfig: memtest: update number of test patterns up to 17
arm: add support for memtest
arm64: add support for memtest
memtest: use phys_addr_t for physical addresses
mm: move memtest under mm
mm, hugetlb: abort __get_user_pages if current has been oom killed
mm, mempool: do not allow atomic resizing
memcg: print cgroup information when system panics due to panic_on_oom
mm: numa: remove migrate_ratelimited
mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE
mm: split ET_DYN ASLR from mmap ASLR
s390: redefine randomize_et_dyn for ELF_ET_DYN_BASE
mm: expose arch_mmap_rnd when available
s390: standardize mmap_rnd() usage
powerpc: standardize mmap_rnd() usage
mips: extract logic for mmap_rnd()
arm64: standardize mmap_rnd() usage
x86: standardize mmap_rnd() usage
arm: factor out mmap ASLR into mmap_rnd
...
Since memtest might be used by other architectures pass input parameters
as phys_addr_t instead of long to prevent overflow.
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memtest is a simple feature which fills the memory with a given set of
patterns and validates memory contents, if bad memory regions is detected
it reserves them via memblock API. Since memblock API is widely used by
other architectures this feature can be enabled outside of x86 world.
This patch set promotes memtest to live under generic mm umbrella and
enables memtest feature for arm/arm64.
It was reported that this patch set was useful for tracking down an issue
with some errant DMA on an arm64 platform.
This patch (of 6):
There is nothing platform dependent in the core memtest code, so other
platforms might benefit from this feature too.
[linux@roeck-us.net: MEMTEST depends on MEMBLOCK]
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If __get_user_pages() is faulting a significant number of hugetlb pages,
usually as the result of mmap(MAP_LOCKED), it can potentially allocate a
very large amount of memory.
If the process has been oom killed, this will cause a lot of memory to
potentially deplete memory reserves.
In the same way that commit 4779280d1e ("mm: make get_user_pages()
interruptible") aborted for pending SIGKILLs when faulting non-hugetlb
memory, based on the premise of commit 462e00cc71 ("oom: stop
allocating user memory if TIF_MEMDIE is set"), hugetlb page faults now
terminate when the process has been oom killed.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Greg Thelen <gthelen@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allocating a large number of elements in atomic context could quickly
deplete memory reserves, so just disallow atomic resizing entirely.
Nothing currently uses mempool_resize() with anything other than
GFP_KERNEL, so convert existing callers to drop the gfp_mask.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Steffen Maier <maier@linux.vnet.ibm.com> [zfcp]
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If kernel panics due to oom, caused by a cgroup reaching its limit, when
'compulsory panic_on_oom' is enabled, then we will only see that the OOM
happened because of "compulsory panic_on_oom is enabled" but this doesn't
tell the difference between mempolicy and memcg. And dumping system wide
information is plain wrong and more confusing. This patch provides the
information of the cgroup whose limit triggerred panic
Signed-off-by: Balasubramani Vivekanandan <balasubramani_vivekanandan@mentor.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This code is dead since commit 9e645ab6d0 ("sched/numa: Continue PTE
scanning even if migrate rate limited") so remove it.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When !MMU, it will report warning. The related warning with allmodconfig
under c6x:
CC mm/memcontrol.o
mm/memcontrol.c:2802:12: warning: 'mem_cgroup_move_account' defined but not used [-Wunused-function]
static int mem_cgroup_move_account(struct page *page,
^
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change vunmap_pmd_range() and vunmap_pud_range() to tear down huge KVA
mappings when they are set. pud_clear_huge() and pmd_clear_huge() return
zero when no-operation is performed, i.e. huge page mapping was not used.
These changes are only enabled when CONFIG_HAVE_ARCH_HUGE_VMAP is defined
on the architecture.
[akpm@linux-foundation.org: use consistent code layout]
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Robert Elliott <Elliott@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ioremap() and its related interfaces are used to create I/O mappings to
memory-mapped I/O devices. The mapping sizes of the traditional I/O
devices are relatively small. Non-volatile memory (NVM), however, has
many GB and is going to have TB soon. It is not very efficient to create
large I/O mappings with 4KB.
This patchset extends the ioremap() interfaces to transparently create I/O
mappings with huge pages whenever possible. ioremap() continues to use
4KB mappings when a huge page does not fit into a requested range. There
is no change necessary to the drivers using ioremap(). A requested
physical address must be aligned by a huge page size (1GB or 2MB on x86)
for using huge page mapping, though. The kernel huge I/O mapping will
improve performance of NVM and other devices with large memory, and reduce
the time to create their mappings as well.
On x86, MTRRs can override PAT memory types with a 4KB granularity. When
using a huge page, MTRRs can override the memory type of the huge page,
which may lead a performance penalty. The processor can also behave in an
undefined manner if a huge page is mapped to a memory range that MTRRs
have mapped with multiple different memory types. Therefore, the mapping
code falls back to use a smaller page size toward 4KB when a mapping range
is covered by non-WB type of MTRRs. The WB type of MTRRs has no affect on
the PAT memory types.
The patchset introduces HAVE_ARCH_HUGE_VMAP, which indicates that the arch
supports huge KVA mappings for ioremap(). User may specify a new kernel
option "nohugeiomap" to disable the huge I/O mapping capability of
ioremap() when necessary.
Patch 1-4 change common files to support huge I/O mappings. There is no
change in the functinalities unless HAVE_ARCH_HUGE_VMAP is defined on the
architecture of the system.
Patch 5-6 implement the HAVE_ARCH_HUGE_VMAP funcs on x86, and set
HAVE_ARCH_HUGE_VMAP on x86.
This patch (of 6):
__get_vm_area_node() takes unsigned long size, which is a 64-bit value on
a 64-bit kernel. However, fls(size) simply ignores the upper 32-bit.
Change to use fls_long() to handle the size properly.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Robert Elliott <Elliott@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 077fcf116c ("mm/thp: allocate transparent hugepages on local
node") restructured alloc_hugepage_vma() with the intent of only
allocating transparent hugepages locally when there was not an effective
interleave mempolicy.
alloc_pages_exact_node() does not limit the allocation to the single node,
however, but rather prefers it. This is because __GFP_THISNODE is not set
which would cause the node-local nodemask to be passed. Without it, only
a nodemask that prefers the local node is passed.
Fix this by passing __GFP_THISNODE and falling back to small pages when
the allocation fails.
Commit 9f1b868a13 ("mm: thp: khugepaged: add policy for finding target
node") suffers from a similar problem for khugepaged, which is also fixed.
Fixes: 077fcf116c ("mm/thp: allocate transparent hugepages on local node")
Fixes: 9f1b868a13 ("mm: thp: khugepaged: add policy for finding target node")
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Jarno Rajahalme <jrajahalme@nicira.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
NOTE: this is not about __GFP_THISNODE, this is only about GFP_THISNODE.
GFP_THISNODE is a secret combination of gfp bits that have different
behavior than expected. It is a combination of __GFP_THISNODE,
__GFP_NORETRY, and __GFP_NOWARN and is special-cased in the page
allocator slowpath to fail without trying reclaim even though it may be
used in combination with __GFP_WAIT.
An example of the problem this creates: commit e97ca8e5b8 ("mm: fix
GFP_THISNODE callers and clarify") fixed up many users of GFP_THISNODE
that really just wanted __GFP_THISNODE. The problem doesn't end there,
however, because even it was a no-op for alloc_misplaced_dst_page(),
which also sets __GFP_NORETRY and __GFP_NOWARN, and
migrate_misplaced_transhuge_page(), where __GFP_NORETRY and __GFP_NOWAIT
is set in GFP_TRANSHUGE. Converting GFP_THISNODE to __GFP_THISNODE is a
no-op in these cases since the page allocator special-cases
__GFP_THISNODE && __GFP_NORETRY && __GFP_NOWARN.
It's time to just remove GFP_THISNODE entirely. We leave __GFP_THISNODE
to restrict an allocation to a local node, but remove GFP_THISNODE and
its obscurity. Instead, we require that a caller clear __GFP_WAIT if it
wants to avoid reclaim.
This allows the aforementioned functions to actually reclaim as they
should. It also enables any future callers that want to do
__GFP_THISNODE but also __GFP_NORETRY && __GFP_NOWARN to reclaim. The
rule is simple: if you don't want to reclaim, then don't set __GFP_WAIT.
Aside: ovs_flow_stats_update() really wants to avoid reclaim as well, so
it is unchanged.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Jarno Rajahalme <jrajahalme@nicira.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
migrate_to_node() is intended to migrate a page from one source node to
a target node.
Today, migrate_to_node() could end up migrating to any node, not only
the target node. This is because the page migration allocator,
new_node_page() does not pass __GFP_THISNODE to
alloc_pages_exact_node(). This causes the target node to be preferred
but allows fallback to any other node in order of affinity.
Prevent this by allocating with __GFP_THISNODE. If memory is not
available, -ENOMEM will be returned as appropriate.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The limit equals 32 and is imposed by the number of entries in the
fs_poolid_map and shared_fs_poolid_map. Nowadays it is insufficient,
because with containers on board a Linux host can have hundreds of
active fs mounts.
These maps were introduced by commit 49a9ab815a ("mm: cleancache:
lazy initialization to allow tmem backends to build/run as modules") in
order to allow compiling cleancache drivers as modules. Real pool ids
are stored in these maps while super_block->cleancache_poolid points to
an entry in the map, so that on cleancache registration we can walk over
all (if there are <= 32 of them, of course) cleancache-enabled super
blocks and assign real pool ids.
Actually, there is absolutely no need in these maps, because we can
iterate over all super blocks immediately using iterate_supers. This is
not racy, because cleancache_init_ops is called from mount_fs with
super_block->s_umount held for writing, while iterate_supers takes this
semaphore for reading, so if we call iterate_supers after setting
cleancache_ops, all super blocks that had been created before
cleancache_register_ops was called will be assigned pool ids by the
action function of iterate_supers while all newer super blocks will
receive it in cleancache_init_fs.
This patch therefore removes the maps and hence the artificial limit on
the number of cleancache enabled filesystems.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, cleancache_register_ops returns the previous value of
cleancache_ops to allow chaining. However, chaining, as it is
implemented now, is extremely dangerous due to possible pool id
collisions. Suppose, a new cleancache driver is registered after the
previous one assigned an id to a super block. If the new driver assigns
the same id to another super block, which is perfectly possible, we will
have two different filesystems using the same id. No matter if the new
driver implements chaining or not, we are likely to get data corruption
with such a configuration eventually.
This patch therefore disables the ability to override cleancache_ops
altogether as potentially dangerous. If there is already cleancache
driver registered, all further calls to cleancache_register_ops will
return EBUSY. Since no user of cleancache implements chaining, we only
need to make minor changes to the code outside the cleancache core.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use super_block->s_uuid instead. Every shared filesystem using cleancache
must now initialize super_block->s_uuid before calling
cleancache_init_shared_fs. The only one on the tree, ocfs2, already meets
this requirement.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The do_wp_page function is extremely long. Extract the logic for
handling a page belonging to a shared vma into a function of its own.
This helps the readability of the code, without doing any functional
change in it.
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Haggai Eran <haggaie@mellanox.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Michel Lespinasse <walken@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In some cases, do_wp_page had to copy the page suffering a write fault
to a new location. If the function logic decided that to do this, it
was done by jumping with a "goto" operation to the relevant code block.
This made the code really hard to understand. It is also against the
kernel coding style guidelines.
This patch extracts the page copy and page table update logic to a
separate function. It also clean up the naming, from "gotten" to
"wp_page_copy", and adds few comments.
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Haggai Eran <haggaie@mellanox.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Michel Lespinasse <walken@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When do_wp_page is ending, in several cases it needs to unlock the pages
and ptls it was accessing.
Currently, this logic was "called" by using a goto jump. This makes
following the control flow of the function harder. Readability was
further hampered by the unlock case containing large amount of logic
needed only in one of the 3 cases.
Using goto for cleanup is generally allowed. However, moving the
trivial unlocking flows to the relevant call sites allow deeper
refactoring in the next patch.
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Haggai Eran <haggaie@mellanox.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Michel Lespinasse <walken@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently do_wp_page contains 265 code lines. It also contains 9 goto
statements, of which 5 are targeting labels which are not cleanup
related. This makes the function extremely difficult to understand.
The following patches are an attempt at breaking the function to its
basic components, and making it easier to understand.
The patches are straight forward function extractions from do_wp_page.
As we extract functions, we remove unneeded parameters and simplify the
code as much as possible. However, the functionality is supposed to
remain completely unchanged. The patches also attempt to document the
functionality of each extracted function. In patch 2, we split the
unlock logic to the contain logic relevant to specific needs of each use
case, instead of having huge number of conditional decisions in a single
unlock flow.
This patch (of 4):
When do_wp_page is ending, in several cases it needs to reuse the existing
page. This is achieved by making the page table writable, and possibly
updating the page-cache state.
Currently, this logic was "called" by using a goto jump. This makes
following the control flow of the function harder. It is also against the
coding style guidelines for using goto.
As the code can easily be refactored into a specialized function, refactor
it out and simplify the code flow in do_wp_page.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Haggai Eran <haggaie@mellanox.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Michel Lespinasse <walken@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It seems nobody needs this.
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes show_mem() much less verbose on huge machines. Instead of huge
and almost useless dump of counters for each per-zone per-cpu lists this
patch prints the sum of these counters for each zone (free_pcp) and size
of per-cpu list for current cpu (local_pcp).
The filter flag SHOW_MEM_PERCPU_LISTS reverts to the old verbose mode.
[akpm@linux-foundation.org: update show_free_areas comment]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch replaces cancel_dirty_page() with a helper function
account_page_cleaned() which only updates counters. It's called from
truncate_complete_page() and from try_to_free_buffers() (hack for ext3).
Page is locked in both cases, page-lock protects against concurrent
dirtiers: see commit 2d6d7f9828 ("mm: protect set_page_dirty() from
ongoing truncation").
Delete_from_page_cache() shouldn't be called for dirty pages, they must
be handled by caller (either written or truncated). This patch treats
final dirty accounting fixup at the end of __delete_from_page_cache() as
a debug check and adds WARN_ON_ONCE() around it. If something removes
dirty pages without proper handling that might be a bug and unwritten
data might be lost.
Hugetlbfs has no dirty pages accounting, ClearPageDirty() is enough
here.
cancel_dirty_page() in nfs_wb_page_cancel() is redundant. This is
helper for nfs_invalidate_page() and it's called only in case complete
invalidation.
The mess was started in v2.6.20 after commits 46d2277c79 ("Clean up
and make try_to_free_buffers() not race with dirty pages") and
3e67c0987d ("truncate: clear page dirtiness before running
try_to_free_buffers()") first was reverted right in v2.6.20 in commit
ecdfc9787f ("Resurrect 'try_to_free_buffers()' VM hackery"), second in
v2.6.25 commit a2b345642f ("Fix dirty page accounting leak with ext3
data=journal").
Custom fixes were introduced between these points. NFS in v2.6.23, commit
1b3b4a1a2d ("NFS: Fix a write request leak in nfs_invalidate_page()").
Kludge in __delete_from_page_cache() in v2.6.24, commit 3a6927906f ("Do
dirty page accounting when removing a page from the page cache"). Since
v2.6.25 all of them are redundant.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch improves THP collapse rates, by allowing zero pages.
Currently THP can collapse 4kB pages into a THP when there are up to
khugepaged_max_ptes_none pte_none ptes in a 2MB range. This patch counts
pte none and mapped zero pages with the same variable.
The patch was tested with a program that allocates 800MB of
memory, and performs interleaved reads and writes, in a pattern
that causes some 2MB areas to first see read accesses, resulting
in the zero pfn being mapped there.
To simulate memory fragmentation at allocation time, I modified
do_huge_pmd_anonymous_page to return VM_FAULT_FALLBACK for read faults.
Without the patch, only %50 of the program was collapsed into THP and the
percentage did not increase over time.
With this patch after 10 minutes of waiting khugepaged had collapsed %99
of the program's memory.
[aarcange@redhat.com: fix bogus BUG()]
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kirill A. Shutemov
David Rientjes
Jason Low
Derek
Roman Pen
Mike Kravetz
Gioh Kim
Michal Hocko
Minchan Kim
Eric B Munson
Naoya Horiguchi
Vladimir Davydov
Yaowei Bai
Linus Torvalds
Vladimir Murzin
Balasubramani Vivekanandan
Mel Gorman
Chen Gang
Toshi Kani
Sasha Levin
Shachar Raindel
Konstantin Khlebnikov
Konstantin Khlebnikov
Ebru Akagunduz