linux.git/mm/huge_memory.c, branch v2.6.39

mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups

2011-04-28T18:28:20+00:00

The huge_memory.c THP page fault was allowed to run if vm_ops was null
(which would succeed for /dev/zero MAP_PRIVATE, as the f_op->mmap wouldn't
setup a special vma->vm_ops and it would fallback to regular anonymous
memory) but other THP logics weren't fully activated for vmas with vm_file
not NULL (/dev/zero has a not NULL vma->vm_file).

So this removes the vm_file checks so that /dev/zero also can safely use
THP (the other albeit safer approach to fix this bug would have been to
prevent the THP initial page fault to run if vm_file was set).

After removing the vm_file checks, this also makes huge_memory.c stricter
in khugepaged for the DEBUG_VM=y case.  It doesn't replace the vm_file
check with a is_pfn_mapping check (but it keeps checking for VM_PFNMAP
under VM_BUG_ON) because for a is_cow_mapping() mapping VM_PFNMAP should
only be allowed to exist before the first page fault, and in turn when
vma->anon_vma is null (so preventing khugepaged registration).  So I tend
to think the previous comment saying if vm_file was set, VM_PFNMAP might
have been set and we could still be registered in khugepaged (despite
anon_vma was not NULL to be registered in khugepaged) was too paranoid.
The is_linear_pfn_mapping check is also I think superfluous (as described
by comment) but under DEBUG_VM it is safe to stay.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=33682

Signed-off-by: Andrea Arcangeli 
Reported-by: Caspar Zhang 
Acked-by: Mel Gorman 
Acked-by: Rik van Riel 
Cc: 		[2.6.38.x]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/thp: use conventional format for boolean attributes

2011-04-14T23:06:56+00:00

The conventional format for boolean attributes in sysfs is numeric ("0" or
"1" followed by new-line).  Any boolean attribute can then be read and
written using a generic function.  Using the strings "yes [no]", "[yes]
no" (read), "yes" and "no" (write) will frustrate this.

[akpm@linux-foundation.org: use kstrtoul()]
[akpm@linux-foundation.org: test_bit() doesn't return 1/0, per Neil]
Signed-off-by: Ben Hutchings 
Cc: Andrea Arcangeli 
Cc: Mel Gorman 
Cc: Johannes Weiner 
Cc: Rik van Riel 
Cc: Hugh Dickins 
Tested-by: David Rientjes 
Cc: NeilBrown 
Cc:  	[2.6.38.x]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add VM counters for transparent hugepages

2011-04-14T23:06:55+00:00

I found it difficult to make sense of transparent huge pages without
having any counters for its actions.  Add some counters to vmstat for
allocation of transparent hugepages and fallback to smaller pages.

Optional patch, but useful for development and understanding the system.

Contains improvements from Andrea Arcangeli and Johannes Weiner

[akpm@linux-foundation.org: coding-style fixes]
[hannes@cmpxchg.org: fix vmstat_text[] entries]
Signed-off-by: Andi Kleen 
Acked-by: Andrea Arcangeli 
Reviewed-by: KAMEZAWA Hiroyuki 
Signed-off-by: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: use __GFP_OTHER_NODE for transparent huge pages

2011-03-23T00:44:05+00:00

Pass __GFP_OTHER_NODE for transparent hugepages NUMA allocations done by the
hugepages daemon.  This way the low level accounting for local versus
remote pages works correctly.

Contains improvements from Andrea Arcangeli

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andi Kleen 
Cc: Andrea Arcangeli 
Reviewed-by: KAMEZAWA Hiroyuki 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp+memcg-numa: fix BUG at include/linux/mm.h:370!

2011-03-14T15:29:50+00:00

THP's collapse_huge_page() has an understandable but ugly difference
in when its huge page is allocated: inside if NUMA but outside if not.
It's hardly surprising that the memcg failure path forgot that, freeing
the page in the non-NUMA case, then hitting a VM_BUG_ON in get_page()
(or even worse, using the freed page).

Signed-off-by: Hugh Dickins 
Reviewed-by: Minchan Kim 
Signed-off-by: Linus Torvalds

mm: use correct numa policy node for transparent hugepages

2011-03-05T01:53:39+00:00

Pass down the correct node for a transparent hugepage allocation.  Most
callers continue to use the current node, however the hugepaged daemon
now uses the previous node of the first to be collapsed page instead.
This ensures that khugepaged does not mess up local memory for an
existing process which uses local policy.

The choice of node is somewhat primitive currently: it just uses the
node of the first page in the pmd range.  An alternative would be to
look at multiple pages and use the most popular node.  I used the
simplest variant for now which should work well enough for the case of
all pages being on the same node.

[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Andrea Arcangeli 
Signed-off-by: Andi Kleen 
Reviewed-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: preserve original node for transparent huge page copies

2011-03-05T01:53:39+00:00

This makes a difference for LOCAL policy, where the node cannot be
determined from the policy itself, but has to be gotten from the original
page.

Acked-by: Andrea Arcangeli 
Signed-off-by: Andi Kleen 
Reviewed-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: change alloc_pages_vma to pass down the policy node for local policy

2011-03-05T01:53:39+00:00

Currently alloc_pages_vma() always uses the local node as policy node for
the LOCAL policy.  Pass this node down as an argument instead.

No behaviour change from this patch, but will be needed for followons.

Acked-by: Andrea Arcangeli 
Signed-off-by: Andi Kleen 
Reviewed-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: prevent hugepages during args/env copying into the user stack

2011-02-15T23:21:11+00:00

Transparent hugepages can only be created if rmap is fully
functional. So we must prevent hugepages to be created while
is_vma_temporary_stack() is true.

This also optmizes away some harmless but unnecessary setting of
khugepaged_scan.address and it switches some BUG_ON to VM_BUG_ON.

Signed-off-by: Andrea Arcangeli 
Acked-by: Rik van Riel 
Signed-off-by: Linus Torvalds

memcg: fix leak of accounting at failure path of hugepage collapsing

2011-02-12T00:12:20+00:00

mem_cgroup_uncharge_page() should be called in all failure cases after
mem_cgroup_charge_newpage() is called in huge_memory.c::collapse_huge_page()

 [ 4209.076861] BUG: Bad page state in process khugepaged  pfn:1e9800
 [ 4209.077601] page:ffffea0006b14000 count:0 mapcount:0 mapping:          (null) index:0x2800
 [ 4209.078674] page flags: 0x40000000004000(head)
 [ 4209.079294] pc:ffff880214a30000 pc->flags:2146246697418756 pc->mem_cgroup:ffffc9000177a000
 [ 4209.082177] (/A)
 [ 4209.082500] Pid: 31, comm: khugepaged Not tainted 2.6.38-rc3-mm1 #1
 [ 4209.083412] Call Trace:
 [ 4209.083678]  [] ? bad_page+0xe4/0x140
 [ 4209.084240]  [] ? free_pages_prepare+0xd6/0x120
 [ 4209.084837]  [] ? rwsem_down_failed_common+0xbd/0x150
 [ 4209.085509]  [] ? __free_pages_ok+0x32/0xe0
 [ 4209.086110]  [] ? free_compound_page+0x1b/0x20
 [ 4209.086699]  [] ? __put_compound_page+0x1c/0x30
 [ 4209.087333]  [] ? put_compound_page+0x4d/0x200
 [ 4209.087935]  [] ? put_page+0x45/0x50
 [ 4209.097361]  [] ? khugepaged+0x9e9/0x1430
 [ 4209.098364]  [] ? autoremove_wake_function+0x0/0x40
 [ 4209.099121]  [] ? khugepaged+0x0/0x1430
 [ 4209.099780]  [] ? kthread+0x96/0xa0
 [ 4209.100452]  [] ? kernel_thread_helper+0x4/0x10
 [ 4209.101214]  [] ? kthread+0x0/0xa0
 [ 4209.101842]  [] ? kernel_thread_helper+0x0/0x10

Signed-off-by: KAMEZAWA Hiroyuki 
Acked-by: Daisuke Nishimura 
Reviewed-by: Johannes Weiner 
Cc: Andrea Arcangeli 
Reviewed-by: Minchan Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds