linux.git/include/linux/gfp.h, branch v2.6.26-rc2

mm: fix misleading __GFP_REPEAT related comments

2008-04-29T15:05:58+00:00

The definition and use of __GFP_REPEAT, __GFP_NOFAIL and __GFP_NORETRY in the
core VM have somewhat differing comments as to their actual semantics.
Annoyingly, the flags definition has inline and header comments, which might
be interpreted as not being equivalent.  Just add references to the header
comments in the inline ones so they don't go out of sync in the future.  In
their use in __alloc_pages() clarify that the current implementation treats
low-order allocations and __GFP_REPEAT allocations as distinct cases.

To clarify, the flags' semantics are:

__GFP_NORETRY means try no harder than one run through __alloc_pages

__GFP_REPEAT means __GFP_NOFAIL

__GFP_NOFAIL means repeat forever

order <= PAGE_ALLOC_COSTLY_ORDER means __GFP_NOFAIL

Signed-off-by: Nishanth Aravamudan 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix broken gfp_zone with __GFP_THISNODE

2008-04-28T15:58:26+00:00

This hack, "base = MAX_NR_ZONES", at __GFP_THISNODE was used for old
zonliests.

Now, new zonelist[] have a list for __GFP_THISNODE and this hack is incorrect.
Should be removed.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Mel Gorman 
Cc: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: filter based on a nodemask as well as a gfp_mask

2008-04-28T15:58:19+00:00

The MPOL_BIND policy creates a zonelist that is used for allocations
controlled by that mempolicy.  As the per-node zonelist is already being
filtered based on a zone id, this patch adds a version of __alloc_pages() that
takes a nodemask for further filtering.  This eliminates the need for
MPOL_BIND to create a custom zonelist.

A positive benefit of this is that allocations using MPOL_BIND now use the
local node's distance-ordered zonelist instead of a custom node-id-ordered
zonelist.  I.e., pages will be allocated from the closest allowed node with
available memory.

[Lee.Schermerhorn@hp.com: Mempolicy: update stale documentation and comments]
[Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask]
[Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask rework]
Signed-off-by: Mel Gorman 
Acked-by: Christoph Lameter 
Signed-off-by: Lee Schermerhorn 
Cc: KAMEZAWA Hiroyuki 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: use two zonelist that are filtered by GFP mask

2008-04-28T15:58:18+00:00

Currently a node has two sets of zonelists, one for each zone type in the
system and a second set for GFP_THISNODE allocations.  Based on the zones
allowed by a gfp mask, one of these zonelists is selected.  All of these
zonelists consume memory and occupy cache lines.

This patch replaces the multiple zonelists per-node with two zonelists.  The
first contains all populated zones in the system, ordered by distance, for
fallback allocations when the target/preferred node has no free pages.  The
second contains all populated zones in the node suitable for GFP_THISNODE
allocations.

An iterator macro is introduced called for_each_zone_zonelist() that interates
through each zone allowed by the GFP flags in the selected zonelist.

Signed-off-by: Mel Gorman 
Acked-by: Christoph Lameter 
Signed-off-by: Lee Schermerhorn 
Cc: KAMEZAWA Hiroyuki 
Cc: Mel Gorman 
Cc: Christoph Lameter 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce node_zonelist() for accessing the zonelist for a GFP mask

2008-04-28T15:58:18+00:00

Introduce a node_zonelist() helper function.  It is used to lookup the
appropriate zonelist given a node and a GFP mask.  The patch on its own is a
cleanup but it helps clarify parts of the two-zonelist-per-node patchset.  If
necessary, it can be merged with the next patch in this set without problems.

Reviewed-by: Christoph Lameter 
Signed-off-by: Mel Gorman 
Signed-off-by: Lee Schermerhorn 
Cc: KAMEZAWA Hiroyuki 
Cc: Mel Gorman 
Cc: Christoph Lameter 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Remove set_migrateflags()

2008-04-28T15:58:17+00:00

Migrate flags must be set on slab creation as agreed upon when the antifrag
logic was reviewed.  Otherwise some slabs of a slabcache will end up in the
unmovable and others in the reclaimable section depending on which flag was
active when a new slab page was allocated.

This likely slid in somehow when antifrag was merged. Remove it.

The buffer_heads are always allocated with __GFP_RECLAIMABLE because the
SLAB_RECLAIM_ACCOUNT option is set.  The set_migrateflags() never had any
effect there.

Radix tree allocations are not directly reclaimable but they are allocated
with __GFP_RECLAIMABLE set on each allocation.  We now set
SLAB_RECLAIM_ACCOUNT on radix tree slab creation making sure that radix
tree slabs are consistently placed in the reclaimable section.  Radix tree
slabs will also be accounted as such.

There is then no user left of set_migratepages. So remove it.

Signed-off-by: Christoph Lameter 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

include/linux: Remove all users of FASTCALL() macro

2008-02-14T00:21:18+00:00

FASTCALL() is always expanded to empty, remove it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Page allocator: clean up pcp draining functions

2008-02-05T17:44:17+00:00

- Add comments explaing how drain_pages() works.

- Eliminate useless functions

- Rename drain_all_local_pages to drain_all_pages(). It does drain
  all pages not only those of the local processor.

- Eliminate useless interrupt off / on sequences. drain_pages()
  disables interrupts on its own. The execution thread is
  pinned to processor by the caller. So there is no need to
  disable interrupts.

- Put drain_all_pages() declaration in gfp.h and remove the
  declarations from suspend.h and from mm/memory_hotplug.c

- Make software suspend call drain_all_pages(). The draining
  of processor local pages is may not the right approach if
  software suspend wants to support SMP. If they call drain_all_pages
  then we can make drain_pages() static.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Christoph Lameter 
Acked-by: Mel Gorman 
Cc: "Rafael J. Wysocki" 
Cc: Daniel Walker 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Print out statistics in relation to fragmentation avoidance to /proc/pagetypeinfo

2007-10-16T16:43:00+00:00

This patch provides fragmentation avoidance statistics via /proc/pagetypeinfo.
 The information is collected only on request so there is no runtime overhead.
 The statistics are in three parts:

The first part prints information on the size of blocks that pages are
being grouped on and looks like

Page block order: 10
Pages per block:  1024

The second part is a more detailed version of /proc/buddyinfo and looks like

Free pages count per migrate type at order       0      1      2      3      4      5      6      7      8      9     10
Node    0, zone      DMA, type    Unmovable      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone      DMA, type  Reclaimable      1      0      0      0      0      0      0      0      0      0      0
Node    0, zone      DMA, type      Movable      0      0      0      0      0      0      0      0      0      0      0
Node    0, zone      DMA, type      Reserve      0      4      4      0      0      0      0      1      0      1      0
Node    0, zone   Normal, type    Unmovable    111      8      4      4      2      3      1      0      0      0      0
Node    0, zone   Normal, type  Reclaimable    293     89      8      0      0      0      0      0      0      0      0
Node    0, zone   Normal, type      Movable      1      6     13      9      7      6      3      0      0      0      0
Node    0, zone   Normal, type      Reserve      0      0      0      0      0      0      0      0      0      0      4

The third part looks like

Number of blocks type     Unmovable  Reclaimable      Movable      Reserve
Node 0, zone      DMA            0            1            2            1
Node 0, zone   Normal            3           17           94            4

To walk the zones within a node with interrupts disabled, walk_zones_in_node()
is introduced and shared between /proc/buddyinfo, /proc/zoneinfo and
/proc/pagetypeinfo to reduce code duplication.  It seems specific to what
vmstat.c requires but could be broken out as a general utility function in
mmzone.c if there were other other potential users.

Signed-off-by: Mel Gorman 
Acked-by: Andy Whitcroft 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Group short-lived and reclaimable kernel allocations

2007-10-16T16:43:00+00:00

This patch marks a number of allocations that are either short-lived such as
network buffers or are reclaimable such as inode allocations.  When something
like updatedb is called, long-lived and unmovable kernel allocations tend to
be spread throughout the address space which increases fragmentation.

This patch groups these allocations together as much as possible by adding a
new MIGRATE_TYPE.  The MIGRATE_RECLAIMABLE type is for allocations that can be
reclaimed on demand, but not moved.  i.e.  they can be migrated by deleting
them and re-reading the information from elsewhere.

Signed-off-by: Mel Gorman 
Cc: Andy Whitcroft 
Cc: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds