linux-toradex.git/mm/mempolicy.c, branch v2.6.33.19

numa: fix slab_node(MPOL_BIND)

2011-03-21T19:43:45+00:00

commit 800416f799e0723635ac2d720ad4449917a1481c upstream.

When a node contains only HighMem memory, slab_node(MPOL_BIND)
dereferences a NULL pointer.

[ This code seems to go back all the way to commit 19770b32609b: "mm:
  filter based on a nodemask as well as a gfp_mask".  Which was back in
  April 2008, and it got merged into 2.6.26.  - Linus ]

Signed-off-by: Eric Dumazet 
Cc: Mel Gorman 
Cc: Christoph Lameter 
Cc: Lee Schermerhorn 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

tmpfs: cleanup mpol_parse_str()

2010-04-01T23:01:32+00:00

commit 926f2ae04f183098cf9a30521776fb2759c8afeb upstream.

mpol_parse_str() made lots 'err' variable related bug.  Because it is ugly
and reviewing unfriendly.

This patch simplifies it.

Signed-off-by: KOSAKI Motohiro 
Cc: Ravikiran Thirumalai 
Cc: Christoph Lameter 
Cc: Mel Gorman 
Acked-by: Lee Schermerhorn 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

tmpfs: handle MPOL_LOCAL mount option properly

2010-04-01T23:01:31+00:00

commit 12821f5fb942e795f8009ece14bde868893bd811 upstream.

commit 71fe804b6d5 (mempolicy: use struct mempolicy pointer in
shmem_sb_info) added mpol=local mount option.  but its feature is broken
since it was born.  because such code always return 1 (i.e.  mount
failure).

This patch fixes it.

Signed-off-by: KOSAKI Motohiro 
Cc: Ravikiran Thirumalai 
Cc: Christoph Lameter 
Cc: Mel Gorman 
Acked-by: Lee Schermerhorn 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

tmpfs: mpol=bind:0 don't cause mount error.

2010-04-01T23:01:31+00:00

commit d69b2e63e9172afb4d07c305601b79a55509ac4c upstream.

Currently, following mount operation cause mount error.

% mount -t tmpfs -ompol=bind:0 none /tmp

Because commit 71fe804b6d5 (mempolicy: use struct mempolicy pointer in
shmem_sb_info) corrupted MPOL_BIND parse code.

This patch restore the needed one.

Signed-off-by: KOSAKI Motohiro 
Cc: Ravikiran Thirumalai 
Cc: Christoph Lameter 
Cc: Mel Gorman 
Acked-by: Lee Schermerhorn 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

tmpfs: fix oops on mounts with mpol=default

2010-04-01T23:01:30+00:00

commit 413b43deab8377819aba1dbad2abf0c15d59b491 upstream.

Fix an 'oops' when a tmpfs mount point is mounted with the mpol=default
mempolicy.

Upon remounting a tmpfs mount point with 'mpol=default' option, the mount
code crashed with a null pointer dereference.  The initial problem report
was on 2.6.27, but the problem exists in mainline 2.6.34-rc as well.  On
examining the code, we see that mpol_new returns NULL if default mempolicy
was requested.  This 'NULL' mempolicy is accessed to store the node mask
resulting in oops.

The following patch fixes it.

Signed-off-by: Ravikiran Thirumalai 
Signed-off-by: KOSAKI Motohiro 
Cc: Christoph Lameter 
Cc: Mel Gorman 
Acked-by: Lee Schermerhorn 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ksm: memory hotremove migration only

2009-12-15T16:53:20+00:00

The previous patch enables page migration of ksm pages, but that soon gets
into trouble: not surprising, since we're using the ksm page lock to lock
operations on its stable_node, but page migration switches the page whose
lock is to be used for that.  Another layer of locking would fix it, but
do we need that yet?

Do we actually need page migration of ksm pages?  Yes, memory hotremove
needs to offline sections of memory: and since we stopped allocating ksm
pages with GFP_HIGHUSER, they will tend to be GFP_HIGHUSER_MOVABLE
candidates for migration.

But KSM is currently unconscious of NUMA issues, happily merging pages
from different NUMA nodes: at present the rule must be, not to use
MADV_MERGEABLE where you care about NUMA.  So no, NUMA page migration of
ksm pages does not make sense yet.

So, to complete support for ksm swapping we need to make hotremove safe.
ksm_memory_callback() take ksm_thread_mutex when MEM_GOING_OFFLINE and
release it when MEM_OFFLINE or MEM_CANCEL_OFFLINE.  But if mapped pages
are freed before migration reaches them, stable_nodes may be left still
pointing to struct pages which have been removed from the system: the
stable_node needs to identify a page by pfn rather than page pointer, then
it can safely prune them when MEM_OFFLINE.

And make NUMA migration skip PageKsm pages where it skips PageReserved.
But it's only when we reach unmap_and_move() that the page lock is taken
and we can be sure that raised pagecount has prevented a PageAnon from
being upgraded: so add offlining arg to migrate_pages(), to migrate ksm
page when offlining (has sufficient locking) but reject it otherwise.

Signed-off-by: Hugh Dickins 
Cc: Izik Eidus 
Cc: Andrea Arcangeli 
Cc: Chris Wright 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb: derive huge pages nodes allowed from task mempolicy

2009-12-15T16:53:12+00:00

This patch derives a "nodes_allowed" node mask from the numa mempolicy of
the task modifying the number of persistent huge pages to control the
allocation, freeing and adjusting of surplus huge pages when the pool page
count is modified via the new sysctl or sysfs attribute
"nr_hugepages_mempolicy".  The nodes_allowed mask is derived as follows:

* For "default" [NULL] task mempolicy, a NULL nodemask_t pointer
  is produced.  This will cause the hugetlb subsystem to use
  node_online_map as the "nodes_allowed".  This preserves the
  behavior before this patch.
* For "preferred" mempolicy, including explicit local allocation,
  a nodemask with the single preferred node will be produced.
  "local" policy will NOT track any internode migrations of the
  task adjusting nr_hugepages.
* For "bind" and "interleave" policy, the mempolicy's nodemask
  will be used.
* Other than to inform the construction of the nodes_allowed node
  mask, the actual mempolicy mode is ignored.  That is, all modes
  behave like interleave over the resulting nodes_allowed mask
  with no "fallback".

See the updated documentation [next patch] for more information
about the implications of this patch.

Examples:

Starting with:

	Node 0 HugePages_Total:     0
	Node 1 HugePages_Total:     0
	Node 2 HugePages_Total:     0
	Node 3 HugePages_Total:     0

Default behavior [with or without this patch] balances persistent
hugepage allocation across nodes [with sufficient contiguous memory]:

	sysctl vm.nr_hugepages[_mempolicy]=32

yields:

	Node 0 HugePages_Total:     8
	Node 1 HugePages_Total:     8
	Node 2 HugePages_Total:     8
	Node 3 HugePages_Total:     8

Of course, we only have nr_hugepages_mempolicy with the patch,
but with default mempolicy, nr_hugepages_mempolicy behaves the
same as nr_hugepages.

Applying mempolicy--e.g., with numactl [using '-m' a.k.a.
'--membind' because it allows multiple nodes to be specified
and it's easy to type]--we can allocate huge pages on
individual nodes or sets of nodes.  So, starting from the
condition above, with 8 huge pages per node, add 8 more to
node 2 using:

	numactl -m 2 sysctl vm.nr_hugepages_mempolicy=40

This yields:

	Node 0 HugePages_Total:     8
	Node 1 HugePages_Total:     8
	Node 2 HugePages_Total:    16
	Node 3 HugePages_Total:     8

The incremental 8 huge pages were restricted to node 2 by the
specified mempolicy.

Similarly, we can use mempolicy to free persistent huge pages
from specified nodes:

	numactl -m 0,1 sysctl vm.nr_hugepages_mempolicy=32

yields:

	Node 0 HugePages_Total:     4
	Node 1 HugePages_Total:     4
	Node 2 HugePages_Total:    16
	Node 3 HugePages_Total:     8

The 8 huge pages freed were balanced over nodes 0 and 1.

[rientjes@google.com: accomodate reworked NODEMASK_ALLOC]
Signed-off-by: David Rientjes 
Signed-off-by: Lee Schermerhorn 
Acked-by: Mel Gorman 
Reviewed-by: Andi Kleen 
Cc: KAMEZAWA Hiroyuki 
Cc: Randy Dunlap 
Cc: Nishanth Aravamudan 
Cc: Adam Litke 
Cc: Andy Whitcroft 
Cc: Eric Whitney 
Cc: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move inc_zone_page_state(NR_ISOLATED) to just isolated place

2009-12-15T16:53:12+00:00

Christoph pointed out inc_zone_page_state(NR_ISOLATED) should be placed
in right after isolate_page().

This patch does it.

Reviewed-by: Christoph Lameter 
Signed-off-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

do_mbind(): fix memory leak

2009-10-29T14:39:29+00:00

If migrate_prep is failed, new variable is leaked.  This patch fixes it.

Signed-off-by: KOSAKI Motohiro 
Acked-by: Christoph Lameter 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mbind(): fix leak of never putback pages

2009-10-29T14:39:29+00:00

If mbind() receives an invalid address, do_mbind leaks a page.  The
following test program detects this leak.

This patch fixes it.

migrate_efault.c
=======================================
 #include 
 #include 
 #include 
 #include 
 #include 
 #include 
 #include 

static unsigned long pagesize;

static void* make_hole_mapping(void)
{

	void* addr;

	addr = mmap(NULL, pagesize*3, PROT_READ|PROT_WRITE,
		    MAP_ANON|MAP_PRIVATE, 0, 0);
	if (addr == MAP_FAILED)
		return NULL;

	/* make page populate */
	memset(addr, 0, pagesize*3);

	/* make memory hole */
	munmap(addr+pagesize, pagesize);

	return addr;
}

int main(int argc, char** argv)
{
	void* addr;
	int ch;
	int node;
	struct bitmask *nmask = numa_allocate_nodemask();
	int err;
	int node_set = 0;

	while ((ch = getopt(argc, argv, "n:")) != -1){
		switch (ch){
		case 'n':
			node = strtol(optarg, NULL, 0);
			numa_bitmask_setbit(nmask, node);
			node_set = 1;
			break;
		default:
			;
		}
	}
	argc -= optind;
	argv += optind;

	if (!node_set)
		numa_bitmask_setbit(nmask, 0);

	pagesize = getpagesize();

	addr = make_hole_mapping();

	err = mbind(addr, pagesize*3, MPOL_BIND, nmask->maskp, nmask->size, MPOL_MF_MOVE_ALL);
	if (err)
		perror("mbind ");

	return 0;
}
=======================================

Signed-off-by: KOSAKI Motohiro 
Acked-by: Christoph Lameter 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds