27 Jul, 2011
1 commit
-
This allows us to move duplicated code in
(atomic_inc_not_zero() for now) toSigned-off-by: Arun Sharma
Reviewed-by: Eric Dumazet
Cc: Ingo Molnar
Cc: David Miller
Cc: Eric Dumazet
Acked-by: Mike Frysinger
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 May, 2011
1 commit
-
enums are problematic because they cannot be forward-declared:
akpm2:/home/akpm> cat t.c
enum foo;
static inline void bar(enum foo f)
{
}
akpm2:/home/akpm> gcc -c t.c
t.c:4: error: parameter 1 ('f') has incomplete typeSo move the enum's definition into a standalone header file which can be used
wherever its definition is needed.Cc: Ying Han
Cc: KAMEZAWA Hiroyuki
Cc: KOSAKI Motohiro
Cc: Minchan Kim
Cc: Daisuke Nishimura
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 May, 2011
2 commits
-
Currently, cpu hotplug updates pcp->stat_threshold, but memory hotplug
doesn't. There is no reason for this.[akpm@linux-foundation.org: fix CONFIG_SMP=n build]
Signed-off-by: KOSAKI Motohiro
Reviewed-by: KAMEZAWA Hiroyuki
Acked-by: Mel Gorman
Acked-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
commit 2ac390370a ("writeback: add
/sys/devices/system/node//vmstat") added vmstat entry. But
strangely it only show nr_written and nr_dirtied.# cat /sys/devices/system/node/node20/vmstat
nr_written 0
nr_dirtied 0Of course, It's not adequate. With this patch, the vmstat show all vm
stastics as /proc/vmstat.# cat /sys/devices/system/node/node0/vmstat
nr_free_pages 899224
nr_inactive_anon 201
nr_active_anon 17380
nr_inactive_file 31572
nr_active_file 28277
nr_unevictable 0
nr_mlock 0
nr_anon_pages 17321
nr_mapped 8640
nr_file_pages 60107
nr_dirty 33
nr_writeback 0
nr_slab_reclaimable 6850
nr_slab_unreclaimable 7604
nr_page_table_pages 3105
nr_kernel_stack 175
nr_unstable 0
nr_bounce 0
nr_vmscan_write 0
nr_writeback_temp 0
nr_isolated_anon 0
nr_isolated_file 0
nr_shmem 260
nr_dirtied 1050
nr_written 938
numa_hit 962872
numa_miss 0
numa_foreign 0
numa_interleave 8617
numa_local 962872
numa_other 0
nr_anon_transparent_hugepages 0[akpm@linux-foundation.org: no externs in .c files]
Signed-off-by: KOSAKI Motohiro
Cc: Michael Rubin
Cc: Wu Fengguang
Acked-by: David Rientjes
Cc: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Apr, 2011
1 commit
-
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
23 Mar, 2011
1 commit
-
Add a new __GFP_OTHER_NODE flag to tell the low level numa statistics in
zone_statistics() that an allocation is on behalf of another thread. This
way the local and remote counters can be still correct, even when
background daemons like khugepaged are changing memory mappings.This only affects the accounting, but I think it's worth doing that right
to avoid confusing users.I first tried to just pass down the right node, but this required a lot of
changes to pass down this parameter and at least one addition of a 10th
argument to a 9 argument function. Using the flag is a lot less
intrusive.Open: should be also used for migration?
[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
14 Jan, 2011
2 commits
-
reduce_pgdat_percpu_threshold() and restore_pgdat_percpu_threshold() exist
to adjust the per-cpu vmstat thresholds while kswapd is awake to avoid
errors due to counter drift. The functions duplicate some code so this
patch replaces them with a single set_pgdat_percpu_threshold() that takes
a callback function to calculate the desired threshold as a parameter.[akpm@linux-foundation.org: readability tweak]
[kosaki.motohiro@jp.fujitsu.com: set_pgdat_percpu_threshold(): don't use for_each_online_cpu]
Signed-off-by: Mel Gorman
Reviewed-by: Christoph Lameter
Reviewed-by: KAMEZAWA Hiroyuki
Signed-off-by: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Commit aa45484 ("calculate a better estimate of NR_FREE_PAGES when memory
is low") noted that watermarks were based on the vmstat NR_FREE_PAGES. To
avoid synchronization overhead, these counters are maintained on a per-cpu
basis and drained both periodically and when a threshold is above a
threshold. On large CPU systems, the difference between the estimate and
real value of NR_FREE_PAGES can be very high. The system can get into a
case where pages are allocated far below the min watermark potentially
causing livelock issues. The commit solved the problem by taking a better
reading of NR_FREE_PAGES when memory was low.Unfortately, as reported by Shaohua Li this accurate reading can consume a
large amount of CPU time on systems with many sockets due to cache line
bouncing. This patch takes a different approach. For large machines
where counter drift might be unsafe and while kswapd is awake, the per-cpu
thresholds for the target pgdat are reduced to limit the level of drift to
what should be a safe level. This incurs a performance penalty in heavy
memory pressure by a factor that depends on the workload and the machine
but the machine should function correctly without accidentally exhausting
all memory on a node. There is an additional cost when kswapd wakes and
sleeps but the event is not expected to be frequent - in Shaohua's test
case, there was one recorded sleep and wake event at least.To ensure that kswapd wakes up, a safe version of zone_watermark_ok() is
introduced that takes a more accurate reading of NR_FREE_PAGES when called
from wakeup_kswapd, when deciding whether it is really safe to go back to
sleep in sleeping_prematurely() and when deciding if a zone is really
balanced or not in balance_pgdat(). We are still using an expensive
function but limiting how often it is called.When the test case is reproduced, the time spent in the watermark
functions is reduced. The following report is on the percentage of time
spent cumulatively spent in the functions zone_nr_free_pages(),
zone_watermark_ok(), __zone_watermark_ok(), zone_watermark_ok_safe(),
zone_page_state_snapshot(), zone_page_state().vanilla 11.6615%
disable-threshold 0.2584%David said:
: We had to pull aa454840 "mm: page allocator: calculate a better estimate
: of NR_FREE_PAGES when memory is low and kswapd is awake" from 2.6.36
: internally because tests showed that it would cause the machine to stall
: as the result of heavy kswapd activity. I merged it back with this fix as
: it is pending in the -mm tree and it solves the issue we were seeing, so I
: definitely think this should be pushed to -stable (and I would seriously
: consider it for 2.6.37 inclusion even at this late date).Signed-off-by: Mel Gorman
Reported-by: Shaohua Li
Reviewed-by: Christoph Lameter
Tested-by: Nicolas Bareil
Cc: David Rientjes
Cc: Kyle McMartin
Cc: [2.6.37.1, 2.6.36.x]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Sep, 2010
1 commit
-
…low and kswapd is awake
Ordinarily watermark checks are based on the vmstat NR_FREE_PAGES as it is
cheaper than scanning a number of lists. To avoid synchronization
overhead, counter deltas are maintained on a per-cpu basis and drained
both periodically and when the delta is above a threshold. On large CPU
systems, the difference between the estimated and real value of
NR_FREE_PAGES can be very high. If NR_FREE_PAGES is much higher than
number of real free page in buddy, the VM can allocate pages below min
watermark, at worst reducing the real number of pages to zero. Even if
the OOM killer kills some victim for freeing memory, it may not free
memory if the exit path requires a new page resulting in livelock.This patch introduces a zone_page_state_snapshot() function (courtesy of
Christoph) that takes a slightly more accurate view of an arbitrary vmstat
counter. It is used to read NR_FREE_PAGES while kswapd is awake to avoid
the watermark being accidentally broken. The estimate is not perfect and
may result in cache line bounces but is expected to be lighter than the
IPI calls necessary to continually drain the per-cpu counters while kswapd
is awake.Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
25 May, 2010
2 commits
-
Ordinarily when a high-order allocation fails, direct reclaim is entered
to free pages to satisfy the allocation. With this patch, it is
determined if an allocation failed due to external fragmentation instead
of low memory and if so, the calling process will compact until a suitable
page is freed. Compaction by moving pages in memory is considerably
cheaper than paging out to disk and works where there are locked pages or
no swap. If compaction fails to free a page of a suitable size, then
reclaim will still occur.Direct compaction returns as soon as possible. As each block is
compacted, it is checked if a suitable page has been freed and if so, it
returns.[akpm@linux-foundation.org: Fix build errors]
[aarcange@redhat.com: fix count_vm_event preempt in memory compaction direct reclaim]
Signed-off-by: Mel Gorman
Acked-by: Rik van Riel
Reviewed-by: Minchan Kim
Cc: KOSAKI Motohiro
Cc: Christoph Lameter
Cc: KAMEZAWA Hiroyuki
Signed-off-by: Andrea Arcangeli
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch is the core of a mechanism which compacts memory in a zone by
relocating movable pages towards the end of the zone.A single compaction run involves a migration scanner and a free scanner.
Both scanners operate on pageblock-sized areas in the zone. The migration
scanner starts at the bottom of the zone and searches for all movable
pages within each area, isolating them onto a private list called
migratelist. The free scanner starts at the top of the zone and searches
for suitable areas and consumes the free pages within making them
available for the migration scanner. The pages isolated for migration are
then migrated to the newly isolated free pages.[aarcange@redhat.com: Fix unsafe optimisation]
[mel@csn.ul.ie: do not schedule work on other CPUs for compaction]
Signed-off-by: Mel Gorman
Acked-by: Rik van Riel
Reviewed-by: Minchan Kim
Cc: KOSAKI Motohiro
Cc: Christoph Lameter
Cc: KAMEZAWA Hiroyuki
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Jan, 2010
1 commit
-
Conflicts:
arch/powerpc/platforms/pseries/hvCall.S
include/linux/percpu.h
16 Dec, 2009
2 commits
-
If reclaim fails to make sufficient progress, the priority is raised.
Once the priority is higher, kswapd starts waiting on congestion.
However, if the zone is below the min watermark then kswapd needs to
continue working without delay as there is a danger of an increased rate
of GFP_ATOMIC allocation failure.This patch changes the conditions under which kswapd waits on congestion
by only going to sleep if the min watermarks are being met.[mel@csn.ul.ie: add stats to track how relevant the logic is]
[mel@csn.ul.ie: make kswapd only check its own zones and rename the relevant counters]
Signed-off-by: KOSAKI Motohiro
Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
After kswapd balances all zones in a pgdat, it goes to sleep. In the
event of no IO congestion, kswapd can go to sleep very shortly after the
high watermark was reached. If there are a constant stream of allocations
from parallel processes, it can mean that kswapd went to sleep too quickly
and the high watermark is not being maintained for sufficient length time.This patch makes kswapd go to sleep as a two-stage process. It first
tries to sleep for HZ/10. If it is woken up by another process or the
high watermark is no longer met, it's considered a premature sleep and
kswapd continues work. Otherwise it goes fully to sleep.This adds more counters to distinguish between fast and slow breaches of
watermarks. A "fast" premature sleep is one where the low watermark was
hit in a very short time after kswapd going to sleep. A "slow" premature
sleep indicates that the high watermark was breached after a very short
interval.Signed-off-by: Mel Gorman
Cc: Frans Pop
Cc: KOSAKI Motohiro
Cc: Rik van Riel
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Oct, 2009
1 commit
-
Now that the return from alloc_percpu is compatible with the address
of per-cpu vars, it makes sense to hand around the address of per-cpu
variables. To make this sane, we remove the per_cpu__ prefix we used
created to stop people accidentally using these vars directly.Now we have sparse, we can use that (next patch).
tj: * Updated to convert stuff which were missed by or added after the
original patch.* Kill per_cpu_var() macro.
Signed-off-by: Rusty Russell
Signed-off-by: Tejun Heo
Reviewed-by: Christoph Lameter
03 Oct, 2009
1 commit
-
Using per cpu atomics for the vm statistics reduces their overhead.
And in the case of x86 we are guaranteed that they will never race even
in the lax form used for vm statistics.Acked-by: Tejun Heo
Signed-off-by: Christoph Lameter
Signed-off-by: Tejun Heo
22 Sep, 2009
2 commits
-
global_lru_pages() / zone_lru_pages() can be used in two ways:
- to estimate max reclaimable pages in determine_dirtyable_memory()
- to calculate the slab scan ratioWhen swap is full or not present, the anon lru lists are not reclaimable
and also won't be scanned. So the anon pages shall not be counted in both
usage scenarios. Also rename to _reclaimable_pages: now they are counting
the possibly reclaimable lru pages.It can greatly (and correctly) increase the slab scan rate under high
memory pressure (when most file pages have been reclaimed and swap is
full/absent), thus reduce false OOM kills.Acked-by: Peter Zijlstra
Reviewed-by: Rik van Riel
Reviewed-by: Christoph Lameter
Reviewed-by: Minchan Kim
Cc: KOSAKI Motohiro
Signed-off-by: Wu Fengguang
Acked-by: Johannes Weiner
Reviewed-by: Minchan Kim
Reviewed-by: Jesse Barnes
Cc: David Howells
Cc: "Li, Ming Chun"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
__add_zone_page_state() and __sub_zone_page_state() are unused.
Signed-off-by: KOSAKI Motohiro
Cc: Wu Fengguang
Cc: Rik van Riel
Cc: Minchan Kim
Cc: Christoph Lameter
Cc: KAMEZAWA Hiroyuki
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Jun, 2009
2 commits
-
On NUMA machines, the administrator can configure zone_reclaim_mode that
is a more targetted form of direct reclaim. On machines with large NUMA
distances for example, a zone_reclaim_mode defaults to 1 meaning that
clean unmapped pages will be reclaimed if the zone watermarks are not
being met.There is a heuristic that determines if the scan is worthwhile but it is
possible that the heuristic will fail and the CPU gets tied up scanning
uselessly. Detecting the situation requires some guesswork and
experimentation so this patch adds a counter "zreclaim_failed" to
/proc/vmstat. If during high CPU utilisation this counter is increasing
rapidly, then the resolution to the problem may be to set
/proc/sys/vm/zone_reclaim_mode to 0.[akpm@linux-foundation.org: name things consistently]
Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel
Cc: Christoph Lameter
Reviewed-by: KOSAKI Motohiro
Cc: Wu Fengguang
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently, nobody wants to turn UNEVICTABLE_LRU off. Thus this
configurability is unnecessary.Signed-off-by: KOSAKI Motohiro
Cc: Johannes Weiner
Cc: Andi Kleen
Acked-by: Minchan Kim
Cc: David Woodhouse
Cc: Matt Mackall
Cc: Rik van Riel
Cc: Lee Schermerhorn
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Oct, 2008
4 commits
-
Signed-off-by: Alexey Dobriyan
Acked-by: Christoph Lameter -
Signed-off-by: Alexey Dobriyan
Acked-by: Christoph Lameter -
Signed-off-by: Alexey Dobriyan
-
Signed-off-by: Alexey Dobriyan
20 Oct, 2008
4 commits
-
Allow free of mlock()ed pages. This shouldn't happen, but during
developement, it occasionally did.This patch allows us to survive that condition, while keeping the
statistics and events correct for debug.Signed-off-by: Lee Schermerhorn
Signed-off-by: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add NR_MLOCK zone page state, which provides a (conservative) count of
mlocked pages (actually, the number of mlocked pages moved off the LRU).Reworked by lts to fit in with the modified mlock page support in the
Reclaim Scalability series.[kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo]
[lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics]
Signed-off-by: Nick Piggin
Signed-off-by: Lee Schermerhorn
Signed-off-by: Rik van Riel
Signed-off-by: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix to unevictable-lru-page-statistics.patch
Add unevictable lru infrastructure vm events to the statistics patch.
Rename the "NORECL_" and "noreclaim_" symbols and text strings to
"UNEVICTABLE_" and "unevictable_", respectively.Currently, both the infrastructure and the mlocked pages event are
added by a single patch later in the series. This makes it difficult
to add or rework the incremental patches. The events actually "belong"
with the stats, so pull them up to here.Also, restore the event counting to putback_lru_page(). This was removed
from previous patch in series where it was "misplaced". The actual events
weren't defined that early.Signed-off-by: Lee Schermerhorn
Cc: Rik van Riel
Reviewed-by: KOSAKI Motohiro
Cc: KAMEZAWA Hiroyuki
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Split the LRU lists in two, one set for pages that are backed by real file
systems ("file") and one for pages that are backed by memory and swap
("anon"). The latter includes tmpfs.The advantage of doing this is that the VM will not have to scan over lots
of anonymous pages (which we generally do not want to swap out), just to
find the page cache pages that it should evict.This patch has the infrastructure and a basic policy to balance how much
we scan the anon lists and how much we scan the file lists. The big
policy changes are in separate patches.[lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset]
[kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru]
[kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page]
[hugh@veritas.com: memcg swapbacked pages active]
[hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED]
[akpm@linux-foundation.org: fix /proc/vmstat units]
[nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration]
[kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo]
[kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()]
Signed-off-by: Rik van Riel
Signed-off-by: Lee Schermerhorn
Signed-off-by: KOSAKI Motohiro
Signed-off-by: Hugh Dickins
Signed-off-by: Daisuke Nishimura
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Jul, 2008
1 commit
-
This patch adds proper extern declarations for five variables in
include/linux/vmstat.hSigned-off-by: Adrian Bunk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Apr, 2008
2 commits
-
Allocating huge pages directly from the buddy allocator is not guaranteed to
succeed. Success depends on several factors (such as the amount of physical
memory available and the level of fragmentation). With the addition of
dynamic hugetlb pool resizing, allocations can occur much more frequently.
For these reasons it is desirable to keep track of huge page allocation
successes and failures.Add two new vmstat entries to track huge page allocations that succeed and
fail. The presence of the two entries is contingent upon CONFIG_HUGETLB_PAGE
being enabled.[akpm@linux-foundation.org: reduced ifdeffery]
Signed-off-by: Adam Litke
Signed-off-by: Eric Munson
Tested-by: Mel Gorman
Reviewed-by: Andy Whitcroft
Cc: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
On NUMA, zone_statistics() is used to record events like numa hit, miss and
foreign. It assumes that the first zone in a zonelist is the preferred zone.
When multiple zonelists are replaced by one that is filtered, this is no
longer the case.This patch records what the preferred zone is rather than assuming the first
zone in the zonelist is it. This simplifies the reading of later patches in
this set.Signed-off-by: Mel Gorman
Signed-off-by: Lee Schermerhorn
Cc: KAMEZAWA Hiroyuki
Cc: Mel Gorman
Reviewed-by: Christoph Lameter
Cc: Hugh Dickins
Cc: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Mar, 2008
1 commit
-
This removes code duplication and makes __dec_zone_page_state look like
__inc_zone_page_state.Signed-off-by: Uwe Kleine-König
Acked-by: Christoph Lameter
Signed-off-by: Linus Torvalds
18 Jul, 2007
1 commit
-
The following 8 patches against 2.6.20-mm2 create a zone called ZONE_MOVABLE
that is only usable by allocations that specify both __GFP_HIGHMEM and
__GFP_MOVABLE. This has the effect of keeping all non-movable pages within a
single memory partition while allowing movable allocations to be satisfied
from either partition. The patches may be applied with the list-based
anti-fragmentation patches that groups pages together based on mobility.The size of the zone is determined by a kernelcore= parameter specified at
boot-time. This specifies how much memory is usable by non-movable
allocations and the remainder is used for ZONE_MOVABLE. Any range of pages
within ZONE_MOVABLE can be released by migrating the pages or by reclaiming.When selecting a zone to take pages from for ZONE_MOVABLE, there are two
things to consider. First, only memory from the highest populated zone is
used for ZONE_MOVABLE. On the x86, this is probably going to be ZONE_HIGHMEM
but it would be ZONE_DMA on ppc64 or possibly ZONE_DMA32 on x86_64. Second,
the amount of memory usable by the kernel will be spread evenly throughout
NUMA nodes where possible. If the nodes are not of equal size, the amount of
memory usable by the kernel on some nodes may be greater than others.By default, the zone is not as useful for hugetlb allocations because they are
pinned and non-migratable (currently at least). A sysctl is provided that
allows huge pages to be allocated from that zone. This means that the huge
page pool can be resized to the size of ZONE_MOVABLE during the lifetime of
the system assuming that pages are not mlocked. Despite huge pages being
non-movable, we do not introduce additional external fragmentation of note as
huge pages are always the largest contiguous block we care about.Credit goes to Andy Whitcroft for catching a large variety of problems during
review of the patches.This patch creates an additional zone, ZONE_MOVABLE. This zone is only usable
by allocations which specify both __GFP_HIGHMEM and __GFP_MOVABLE. Hot-added
memory continues to be placed in their existing destination as there is no
mechanism to redirect them to a specific zone.[y-goto@jp.fujitsu.com: Fix section mismatch of memory hotplug related code]
[akpm@linux-foundation.org: various fixes]
Signed-off-by: Mel Gorman
Cc: Andy Whitcroft
Signed-off-by: Yasunori Goto
Cc: William Lee Irwin III
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 May, 2007
1 commit
-
vmstat is currently using the cache reaper to periodically bring the
statistics up to date. The cache reaper does only exists in SLUB as a way to
provide compatibility with SLAB. This patch removes the vmstat calls from the
slab allocators and provides its own handling.The advantage is also that we can use a different frequency for the updates.
Refreshing vm stats is a pretty fast job so we can run this every second and
stagger this by only one tick. This will lead to some overlap in large
systems. F.e a system running at 250 HZ with 1024 processors will have 4 vm
updates occurring at once.However, the vm stats update only accesses per node information. It is only
necessary to stagger the vm statistics updates per processor in each node. Vm
counter updates occurring on distant nodes will not cause cacheline
contention.We could implement an alternate approach that runs the first processor on each
node at the second and then each of the other processor on a node on a
subsequent tick. That may be useful to keep a large amount of the second free
of timer activity. Maybe the timer folks will have some feedback on this one?[jirislaby@gmail.com: add missing break]
Cc: Arjan van de Ven
Signed-off-by: Christoph Lameter
Signed-off-by: Jiri Slaby
Cc: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Feb, 2007
4 commits
-
- Prevent things like this:
block/ll_rw_blk.c: In function 'submit_bio':
block/ll_rw_blk.c:3222: warning: unused variable 'count'inlines are very, very preferable to macros.
- remove unused get_cpu_vm_events() macro
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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 -
nr_free_pages is now a simple access to a global variable. Make it a macro
instead of a function.The nr_free_pages now requires vmstat.h to be included. There is one
occurrence in power management where we need to add the include. Directly
refrer to global_page_state() there to clarify why the #include was added.[akpm@osdl.org: arm build fix]
[akpm@osdl.org: sparc64 build fix]
Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
23 Dec, 2006
2 commits
-
fix vm_events_fold_cpu() build breakage
2.6.20-rc1 does not build properly if CONFIG_VM_EVENT_COUNTERS is set
and CONFIG_HOTPLUG is unset:CC init/version.o
LD init/built-in.o
LD .tmp_vmlinux1
mm/built-in.o: In function `page_alloc_cpu_notify':
page_alloc.c:(.text+0x56eb): undefined reference to `vm_events_fold_cpu'
make: *** [.tmp_vmlinux1] Error 1[akpm@osdl.org: cleanup]
Signed-off-by: Magnus Damm
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The VM event counters, enabled by CONFIG_VM_EVENT_COUNTERS, which provides
VM event counters in /proc/vmstat, has become more essential to
non-EMBEDDED kernel configurations than they were in the past. Comments in
the code and the Kconfig configuration explanation were stale, downplaying
their role excessively.Refresh those comments to correctly reflect the current role of VM event
counters.Signed-off-by: Paul Jackson
Acked-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
