linux-stable.git/mm/sparse.c, branch v3.5.3

mm: setup pageblock_order before it's used by sparsemem

2012-08-15T14:52:45+00:00

commit ca57df79d4f64e1a4886606af4289d40636189c5 upstream.

On architectures with CONFIG_HUGETLB_PAGE_SIZE_VARIABLE set, such as
Itanium, pageblock_order is a variable with default value of 0.  It's set
to the right value by set_pageblock_order() in function
free_area_init_core().

But pageblock_order may be used by sparse_init() before free_area_init_core()
is called along path:
sparse_init()
    ->sparse_early_usemaps_alloc_node()
	->usemap_size()
	    ->SECTION_BLOCKFLAGS_BITS
		->((1UL << (PFN_SECTION_SHIFT - pageblock_order)) *
NR_PAGEBLOCK_BITS)

The uninitialized pageblock_size will cause memory wasting because
usemap_size() returns a much bigger value then it's really needed.

For example, on an Itanium platform,
sparse_init() pageblock_order=0 usemap_size=24576
free_area_init_core() before pageblock_order=0, usemap_size=24576
free_area_init_core() after pageblock_order=12, usemap_size=8

That means 24K memory has been wasted for each section, so fix it by calling
set_pageblock_order() from sparse_init().

Signed-off-by: Xishi Qiu 
Signed-off-by: Jiang Liu 
Cc: Tony Luck 
Cc: Yinghai Lu 
Cc: KAMEZAWA Hiroyuki 
Cc: Benjamin Herrenschmidt 
Cc: KOSAKI Motohiro 
Cc: David Rientjes 
Cc: Keping Chen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm: sparse: fix usemap allocation above node descriptor section

2012-07-11T23:04:49+00:00

After commit f5bf18fa22f8 ("bootmem/sparsemem: remove limit constraint
in alloc_bootmem_section"), usemap allocations may easily be placed
outside the optimal section that holds the node descriptor, even if
there is space available in that section.  This results in unnecessary
hotplug dependencies that need to have the node unplugged before the
section holding the usemap.

The reason is that the bootmem allocator doesn't guarantee a linear
search starting from the passed allocation goal but may start out at a
much higher address absent an upper limit.

Fix this by trying the allocation with the limit at the section end,
then retry without if that fails.  This keeps the fix from f5bf18fa22f8
of not panicking if the allocation does not fit in the section, but
still makes sure to try to stay within the section at first.

Signed-off-by: Yinghai Lu 
Signed-off-by: Johannes Weiner 
Cc: 	[3.3.x, 3.4.x]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: sparse: fix section usemap placement calculation

2012-07-11T23:04:49+00:00

Commit 238305bb4d41 ("mm: remove sparsemem allocation details from the
bootmem allocator") introduced a bug in the allocation goal calculation
that put section usemaps not in the same section as the node
descriptors, creating unnecessary hotplug dependencies between them:

  node 0 must be removed before remove section 16399
  node 1 must be removed before remove section 16399
  node 2 must be removed before remove section 16399
  node 3 must be removed before remove section 16399
  node 4 must be removed before remove section 16399
  node 5 must be removed before remove section 16399
  node 6 must be removed before remove section 16399

The reason is that it applies PAGE_SECTION_MASK to the physical address
of the node descriptor when finding a suitable place to put the usemap,
when this mask is actually intended to be used with PFNs.  Because the
PFN mask is wider, the target address will point beyond the wanted
section holding the node descriptor and the node must be offlined before
the section holding the usemap can go.

Fix this by extending the mask to address width before use.

Signed-off-by: Yinghai Lu 
Signed-off-by: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove sparsemem allocation details from the bootmem allocator

2012-05-29T23:22:22+00:00

alloc_bootmem_section() derives allocation area constraints from the
specified sparsemem section.  This is a bit specific for a generic memory
allocator like bootmem, though, so move it over to sparsemem.

As __alloc_bootmem_node_nopanic() already retries failed allocations with
relaxed area constraints, the fallback code in sparsemem.c can be removed
and the code becomes a bit more compact overall.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Johannes Weiner 
Acked-by: Tejun Heo 
Acked-by: David S. Miller 
Cc: Yinghai Lu 
Cc: Gavin Shan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bootmem/sparsemem: remove limit constraint in alloc_bootmem_section

2012-03-22T00:54:58+00:00

While testing AMS (Active Memory Sharing) / CMO (Cooperative Memory
Overcommit) on powerpc, we tripped the following:

  kernel BUG at mm/bootmem.c:483!
  cpu 0x0: Vector: 700 (Program Check) at [c000000000c03940]
      pc: c000000000a62bd8: .alloc_bootmem_core+0x90/0x39c
      lr: c000000000a64bcc: .sparse_early_usemaps_alloc_node+0x84/0x29c
      sp: c000000000c03bc0
     msr: 8000000000021032
    current = 0xc000000000b0cce0
    paca    = 0xc000000001d80000
      pid   = 0, comm = swapper
  kernel BUG at mm/bootmem.c:483!
  enter ? for help
  [c000000000c03c80] c000000000a64bcc
  .sparse_early_usemaps_alloc_node+0x84/0x29c
  [c000000000c03d50] c000000000a64f10 .sparse_init+0x12c/0x28c
  [c000000000c03e20] c000000000a474f4 .setup_arch+0x20c/0x294
  [c000000000c03ee0] c000000000a4079c .start_kernel+0xb4/0x460
  [c000000000c03f90] c000000000009670 .start_here_common+0x1c/0x2c

This is

        BUG_ON(limit && goal + size > limit);

and after some debugging, it seems that

	goal = 0x7ffff000000
	limit = 0x80000000000

and sparse_early_usemaps_alloc_node ->
sparse_early_usemaps_alloc_pgdat_section calls

	return alloc_bootmem_section(usemap_size() * count, section_nr);

This is on a system with 8TB available via the AMS pool, and as a quirk
of AMS in firmware, all of that memory shows up in node 0.  So, we end
up with an allocation that will fail the goal/limit constraints.

In theory, we could "fall-back" to alloc_bootmem_node() in
sparse_early_usemaps_alloc_node(), but since we actually have HOTREMOVE
defined, we'll BUG_ON() instead.  A simple solution appears to be to
unconditionally remove the limit condition in alloc_bootmem_section,
meaning allocations are allowed to cross section boundaries (necessary
for systems of this size).

Johannes Weiner pointed out that if alloc_bootmem_section() no longer
guarantees section-locality, we need check_usemap_section_nr() to print
possible cross-dependencies between node descriptors and the usemaps
allocated through it.  That makes the two loops in
sparse_early_usemaps_alloc_node() identical, so re-factor the code a
bit.

[akpm@linux-foundation.org: code simplification]
Signed-off-by: Nishanth Aravamudan 
Cc: Dave Hansen 
Cc: Anton Blanchard 
Cc: Paul Mackerras 
Cc: Ben Herrenschmidt 
Cc: Robert Jennings 
Acked-by: Johannes Weiner 
Acked-by: Mel Gorman 
Cc: 	[3.3.1]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: Map most files to use export.h instead of module.h

2011-10-31T13:20:12+00:00

The files changed within are only using the EXPORT_SYMBOL
macro variants.  They are not using core modular infrastructure
and hence don't need module.h but only the export.h header.

Signed-off-by: Paul Gortmaker

mm: make some struct page's const

2011-07-26T03:57:07+00:00

These uses are read-only and in a subsequent patch I have a const struct
page in my hand...

[akpm@linux-foundation.org: fix warnings in lowmem_page_address()]
Signed-off-by: Ian Campbell 
Cc: Rik van Riel 
Cc: Andrea Arcangeli 
Cc: Mel Gorman 
Cc: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

thp: remove PG_buddy

2011-01-14T01:32:43+00:00

PG_buddy can be converted to _mapcount == -2.  So the PG_compound_lock can
be added to page->flags without overflowing (because of the sparse section
bits increasing) with CONFIG_X86_PAE=y and CONFIG_X86_PAT=y.  This also
has to move the memory hotplug code from _mapcount to lru.next to avoid
any risk of clashes.  We can't use lru.next for PG_buddy removal, but
memory hotplug can use lru.next even more easily than the mapcount
instead.

Signed-off-by: Andrea Arcangeli 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sparsemem: on no vmemmap path put mem_map on node high too

2010-05-25T15:06:56+00:00

We need to put mem_map high when virtual memmap is not used.

before this patch
free mem pfn range on first node:
[    0.000000]  19 - 1f
[    0.000000]  28 40 - 80 95
[    0.000000]  702 740 - 1000 1000
[    0.000000]  347c - 347e
[    0.000000]  34e7 3500 - 3b80 3b8b
[    0.000000]  73b8b 73bc0 - 73c00 73c00
[    0.000000]  73ddd - 73e00
[    0.000000]  73fdd - 74000
[    0.000000]  741dd - 74200
[    0.000000]  743dd - 74400
[    0.000000]  745dd - 74600
[    0.000000]  747dd - 74800
[    0.000000]  749dd - 74a00
[    0.000000]  74bdd - 74c00
[    0.000000]  74ddd - 74e00
[    0.000000]  74fdd - 75000
[    0.000000]  751dd - 75200
[    0.000000]  753dd - 75400
[    0.000000]  755dd - 75600
[    0.000000]  757dd - 75800
[    0.000000]  759dd - 75a00
[    0.000000]  79bdd 79c00 - 7d540 7d550
[    0.000000]  7f745 - 7f750
[    0.000000]  10000b 100040 - 2080000 2080000
so only 79c00 - 7d540 are major free block under 4g...

after this patch, we will get
[    0.000000]  19 - 1f
[    0.000000]  28 40 - 80 95
[    0.000000]  702 740 - 1000 1000
[    0.000000]  347c - 347e
[    0.000000]  34e7 3500 - 3600 3600
[    0.000000]  37dd - 3800
[    0.000000]  39dd - 3a00
[    0.000000]  3bdd - 3c00
[    0.000000]  3ddd - 3e00
[    0.000000]  3fdd - 4000
[    0.000000]  41dd - 4200
[    0.000000]  43dd - 4400
[    0.000000]  45dd - 4600
[    0.000000]  47dd - 4800
[    0.000000]  49dd - 4a00
[    0.000000]  4bdd - 4c00
[    0.000000]  4ddd - 4e00
[    0.000000]  4fdd - 5000
[    0.000000]  51dd - 5200
[    0.000000]  53dd - 5400
[    0.000000]  95dd 9600 - 7d540 7d550
[    0.000000]  7f745 - 7f750
[    0.000000]  17000b 170040 - 2080000 2080000
we will have 9600 - 7d540 for major free block...

sparse-vmemmap path already used __alloc_bootmem_node_high()

Signed-off-by: Yinghai Lu 
Cc: Jiri Slaby 
Cc: "H. Peter Anvin" 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Christoph Lameter 
Cc: Greg Thelen 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds