linux.git/mm/vmstat.c, branch v2.6.21.7

[PATCH] optional ZONE_DMA: optional ZONE_DMA in the VM

2007-02-11T18:51:18+00:00

Make ZONE_DMA optional in core code.

- ifdef all code for ZONE_DMA and related definitions following the example
  for ZONE_DMA32 and ZONE_HIGHMEM.

- Without ZONE_DMA, ZONE_HIGHMEM and ZONE_DMA32 we get to a ZONES_SHIFT of
  0.

- Modify the VM statistics to work correctly without a DMA zone.

- Modify slab to not create DMA slabs if there is no ZONE_DMA.

[akpm@osdl.org: cleanup]
[jdike@addtoit.com: build fix]
[apw@shadowen.org: Simplify calculation of the number of bits we need for ZONES_SHIFT]
Signed-off-by: Christoph Lameter 
Cc: Andi Kleen 
Cc: "Luck, Tony" 
Cc: Kyle McMartin 
Cc: Matthew Wilcox 
Cc: James Bottomley 
Cc: Paul Mundt 
Signed-off-by: Andy Whitcroft 
Signed-off-by: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Drop get_zone_counts()

2007-02-11T18:51:18+00:00

Values are available via ZVC sums.

Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Drop __get_zone_counts()

2007-02-11T18:51:18+00:00

Values are readily available via ZVC per node and global sums.

Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Reorder ZVCs according to cacheline

2007-02-11T18:51:17+00:00

The global and per zone counter sums are in arrays of longs.  Reorder the ZVCs
so that the most frequently used ZVCs are put into the same cacheline.  That
way calculations of the global, node and per zone vm state touches only a
single cacheline.  This is mostly important for 64 bit systems were one 128
byte cacheline takes only 8 longs.

Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Use ZVC for free_pages

2007-02-11T18:51:17+00:00

This is again simplifies some of the VM counter calculations through the use
of the ZVC consolidated counters.

[michal.k.k.piotrowski@gmail.com: build fix]
Signed-off-by: Christoph Lameter 
Signed-off-by: Michal Piotrowski 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Use ZVC for inactive and active counts

2007-02-11T18:51:17+00:00

The determination of the dirty ratio to determine writeback behavior is
currently based on the number of total pages on the system.

However, not all pages in the system may be dirtied.  Thus the ratio is always
too low and can never reach 100%.  The ratio may be particularly skewed if
large hugepage allocations, slab allocations or device driver buffers make
large sections of memory not available anymore.  In that case we may get into
a situation in which f.e.  the background writeback ratio of 40% cannot be
reached anymore which leads to undesired writeback behavior.

This patchset fixes that issue by determining the ratio based on the actual
pages that may potentially be dirty.  These are the pages on the active and
the inactive list plus free pages.

The problem with those counts has so far been that it is expensive to
calculate these because counts from multiple nodes and multiple zones will
have to be summed up.  This patchset makes these counters ZVC counters.  This
means that a current sum per zone, per node and for the whole system is always
available via global variables and not expensive anymore to calculate.

The patchset results in some other good side effects:

- Removal of the various functions that sum up free, active and inactive
  page counts

- Cleanup of the functions that display information via the proc filesystem.

This patch:

The use of a ZVC for nr_inactive and nr_active allows a simplification of some
counter operations.  More ZVC functionality is used for sums etc in the
following patches.

[akpm@osdl.org: UP build fix]
Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] /proc/zoneinfo: fix vm stats display

2007-02-11T18:51:17+00:00

This early break prevents us from displaying info for the vm stats thresholds
if the zone doesn't have any pages in its per-cpu pagesets.

So my 800MB i386 box says:

Node 0, zone      DMA
  pages free     2365
        min      16
        low      20
        high     24
        active   0
        inactive 0
        scanned  0 (a: 0 i: 0)
        spanned  4096
        present  4044
    nr_anon_pages 0
    nr_mapped    1
    nr_file_pages 0
    nr_slab_reclaimable 0
    nr_slab_unreclaimable 0
    nr_page_table_pages 0
    nr_dirty     0
    nr_writeback 0
    nr_unstable  0
    nr_bounce    0
    nr_vmscan_write 0
        protection: (0, 868, 868)
  pagesets
  all_unreclaimable: 0
  prev_priority:     12
  start_pfn:         0
Node 0, zone   Normal
  pages free     199713
        min      934
        low      1167
        high     1401
        active   10215
        inactive 4507
        scanned  0 (a: 0 i: 0)
        spanned  225280
        present  222420
    nr_anon_pages 2685
    nr_mapped    1110
    nr_file_pages 12055
    nr_slab_reclaimable 2216
    nr_slab_unreclaimable 1527
    nr_page_table_pages 213
    nr_dirty     0
    nr_writeback 0
    nr_unstable  0
    nr_bounce    0
    nr_vmscan_write 0
        protection: (0, 0, 0)
  pagesets
    cpu: 0 pcp: 0
              count: 152
              high:  186
              batch: 31
    cpu: 0 pcp: 1
              count: 13
              high:  62
              batch: 15
  vm stats threshold: 16
    cpu: 1 pcp: 0
              count: 34
              high:  186
              batch: 31
    cpu: 1 pcp: 1
              count: 10
              high:  62
              batch: 15
  vm stats threshold: 16
  all_unreclaimable: 0
  prev_priority:     12
  start_pfn:         4096

Just nuke all that search-for-the-first-non-empty-pageset code.  Dunno why it
was there in the first place..

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

[PATCH] struct seq_operations and struct file_operations constification

2006-12-07T16:39:46+00:00

 - move some file_operations structs into the .rodata section

 - move static strings from policy_types[] array into the .rodata section

 - fix generic seq_operations usages, so that those structs may be defined
   as "const" as well

[akpm@osdl.org: couple of fixes]
Signed-off-by: Helge Deller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: cleanup indentation on switch for CPU operations

2006-12-07T16:39:23+00:00

These patches introduced new switch statements which are indented contrary
to the concensus in mm/*.c.  Fix them up to match that concensus.

    [PATCH] node local per-cpu-pages
    [PATCH] ZVC: Scale thresholds depending on the size of the system
    commit e7c8d5c9955a4d2e88e36b640563f5d6d5aba48a
    commit df9ecaba3f152d1ea79f2a5e0b87505e03f47590

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

[PATCH] vmscan: Fix temp_priority race

2006-10-28T18:30:50+00:00

The temp_priority field in zone is racy, as we can walk through a reclaim
path, and just before we copy it into prev_priority, it can be overwritten
(say with DEF_PRIORITY) by another reclaimer.

The same bug is contained in both try_to_free_pages and balance_pgdat, but
it is fixed slightly differently.  In balance_pgdat, we keep a separate
priority record per zone in a local array.  In try_to_free_pages there is
no need to do this, as the priority level is the same for all zones that we
reclaim from.

Impact of this bug is that temp_priority is copied into prev_priority, and
setting this artificially high causes reclaimers to set distress
artificially low.  They then fail to reclaim mapped pages, when they are,
in fact, under severe memory pressure (their priority may be as low as 0).
This causes the OOM killer to fire incorrectly.

From: Andrew Morton 

__zone_reclaim() isn't modifying zone->prev_priority.  But zone->prev_priority
is used in the decision whether or not to bring mapped pages onto the inactive
list.  Hence there's a risk here that __zone_reclaim() will fail because
zone->prev_priority ir large (ie: low urgency) and lots of mapped pages end up
stuck on the active list.

Fix that up by decreasing (ie making more urgent) zone->prev_priority as
__zone_reclaim() scans the zone's pages.

This bug perhaps explains why ZONE_RECLAIM_PRIORITY was created.  It should be
possible to remove that now, and to just start out at DEF_PRIORITY?

Cc: Nick Piggin 
Cc: Christoph Lameter 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds