Commit Graph

866 Commits

Author SHA1 Message Date
Johannes Weiner
27329369c9 mm: page_alloc: exempt GFP_THISNODE allocations from zone fairness
Jan Stancek reports manual page migration encountering allocation
failures after some pages when there is still plenty of memory free, and
bisected the problem down to commit 81c0a2bb51 ("mm: page_alloc: fair
zone allocator policy").

The problem is that GFP_THISNODE obeys the zone fairness allocation
batches on one hand, but doesn't reset them and wake kswapd on the other
hand.  After a few of those allocations, the batches are exhausted and
the allocations fail.

Fixing this means either having GFP_THISNODE wake up kswapd, or
GFP_THISNODE not participating in zone fairness at all.  The latter
seems safer as an acute bugfix, we can clean up later.

Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@kernel.org>		[3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-04 07:55:50 -08:00
David Rientjes
668f9abbd4 mm: close PageTail race
Commit bf6bddf192 ("mm: introduce compaction and migration for
ballooned pages") introduces page_count(page) into memory compaction
which dereferences page->first_page if PageTail(page).

This results in a very rare NULL pointer dereference on the
aforementioned page_count(page).  Indeed, anything that does
compound_head(), including page_count() is susceptible to racing with
prep_compound_page() and seeing a NULL or dangling page->first_page
pointer.

This patch uses Andrea's implementation of compound_trans_head() that
deals with such a race and makes it the default compound_head()
implementation.  This includes a read memory barrier that ensures that
if PageTail(head) is true that we return a head page that is neither
NULL nor dangling.  The patch then adds a store memory barrier to
prep_compound_page() to ensure page->first_page is set.

This is the safest way to ensure we see the head page that we are
expecting, PageTail(page) is already in the unlikely() path and the
memory barriers are unfortunately required.

Hugetlbfs is the exception, we don't enforce a store memory barrier
during init since no race is possible.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Holger Kiehl <Holger.Kiehl@dwd.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-04 07:55:47 -08:00
Han Pingtian
42aa83cb67 mm: show message when updating min_free_kbytes in thp
min_free_kbytes may be raised during THP's initialization.  Sometimes,
this will change the value which was set by the user.  Showing this
message will clarify this confusion.

Only show this message when changing a value which was set by the user
according to Michal Hocko's suggestion.

Show the old value of min_free_kbytes according to Dave Hansen's
suggestion.  This will give user the chance to restore old value of
min_free_kbytes.

Signed-off-by: Han Pingtian <hanpt@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:52 -08:00
Han Pingtian
da8c757b08 mm: prevent setting of a value less than 0 to min_free_kbytes
If echo -1 > /proc/vm/sys/min_free_kbytes, the system will hang.  Changing
proc_dointvec() to proc_dointvec_minmax() in the
min_free_kbytes_sysctl_handler() can prevent this to happen.

mhocko said:

: You can still do echo $BIG_VALUE > /proc/vm/sys/min_free_kbytes and make
: your machine unusable but I agree that proc_dointvec_minmax is more
: suitable here as we already have:
:
: 	.proc_handler   = min_free_kbytes_sysctl_handler,
: 	.extra1         = &zero,
:
: It used to work properly but then 6fce56ec91 ("sysctl: Remove references
: to ctl_name and strategy from the generic sysctl table") has removed
: sysctl_intvec strategy and so extra1 is ignored.

Signed-off-by: Han Pingtian <hanpt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:52 -08:00
Sasha Levin
309381feae mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE
Most of the VM_BUG_ON assertions are performed on a page.  Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.

I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.

This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.

[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:50 -08:00
Dave Hansen
f0b791a34c mm: print more details for bad_page()
bad_page() is cool in that it prints out a bunch of data about the page.
But, I can never remember which page flags are good and which are bad,
or whether ->index or ->mapping is required to be NULL.

This patch allows bad/dump_page() callers to specify a string about why
they are dumping the page and adds explanation strings to a number of
places.  It also adds a 'bad_flags' argument to bad_page(), which it
then dumps out separately from the flags which are actually set.

This way, the messages will show specifically why the page was bad,
*specifically* which flags it is complaining about, if it was a page
flag combination which was the problem.

[akpm@linux-foundation.org: switch to pr_alert]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:50 -08:00
David Rientjes
aed0a0e32d mm, page_alloc: warn for non-blockable __GFP_NOFAIL allocation failure
__GFP_NOFAIL may return NULL when coupled with GFP_NOWAIT or GFP_ATOMIC.

Luckily, nothing currently does such craziness.  So instead of causing
such allocations to loop (potentially forever), we maintain the current
behavior and also warn about the new users of the deprecated flag.

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:49 -08:00
Vlastimil Babka
de6c60a6c1 mm: compaction: encapsulate defer reset logic
Currently there are several functions to manipulate the deferred
compaction state variables.  The remaining case where the variables are
touched directly is when a successful allocation occurs in direct
compaction, or is expected to be successful in the future by kswapd.
Here, the lowest order that is expected to fail is updated, and in the
case of successful allocation, the deferred status and counter is reset
completely.

Create a new function compaction_defer_reset() to encapsulate this
functionality and make it easier to understand the code.  No functional
change.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:48 -08:00
Santosh Shilimkar
6782832eba mm/page_alloc.c: use memblock apis for early memory allocations
Switch to memblock interfaces for early memory allocator instead of
bootmem allocator.  No functional change in beahvior than what it is in
current code from bootmem users points of view.

Archs already converted to NO_BOOTMEM now directly use memblock
interfaces instead of bootmem wrappers build on top of memblock.  And
the archs which still uses bootmem, these new apis just fallback to
exiting bootmem APIs.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:47 -08:00
Tang Chen
b2f3eebe7a x86, numa, acpi, memory-hotplug: make movable_node have higher priority
If users specify the original movablecore=nn@ss boot option, the kernel
will arrange [ss, ss+nn) as ZONE_MOVABLE.  The kernelcore=nn@ss boot
option is similar except it specifies ZONE_NORMAL ranges.

Now, if users specify "movable_node" in kernel commandline, the kernel
will arrange hotpluggable memory in SRAT as ZONE_MOVABLE.  And if users
do this, all the other movablecore=nn@ss and kernelcore=nn@ss options
should be ignored.

For those who don't want this, just specify nothing.  The kernel will
act as before.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Rafael J . Wysocki" <rjw@sisk.pl>
Cc: Chen Tang <imtangchen@gmail.com>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Liu Jiang <jiang.liu@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:45 -08:00
Mel Gorman
aec6a8889a mm, show_mem: remove SHOW_MEM_FILTER_PAGE_COUNT
Commit 4b59e6c473 ("mm, show_mem: suppress page counts in
non-blockable contexts") introduced SHOW_MEM_FILTER_PAGE_COUNT to
suppress PFN walks on large memory machines.  Commit c78e93630d ("mm:
do not walk all of system memory during show_mem") avoided a PFN walk in
the generic show_mem helper which removes the requirement for
SHOW_MEM_FILTER_PAGE_COUNT in that case.

This patch removes PFN walkers from the arch-specific implementations
that report on a per-node or per-zone granularity.  ARM and unicore32
still do a PFN walk as they report memory usage on each bank which is a
much finer granularity where the debugging information may still be of
use.  As the remaining arches doing PFN walks have relatively small
amounts of memory, this patch simply removes SHOW_MEM_FILTER_PAGE_COUNT.

[akpm@linux-foundation.org: fix parisc]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: James Bottomley <jejb@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:44 -08:00
Yasuaki Ishimatsu
943dca1a1f mm: get rid of unnecessary pageblock scanning in setup_zone_migrate_reserve
Yasuaki Ishimatsu reported memory hot-add spent more than 5 _hours_ on
9TB memory machine since onlining memory sections is too slow.  And we
found out setup_zone_migrate_reserve spent >90% of the time.

The problem is, setup_zone_migrate_reserve scans all pageblocks
unconditionally, but it is only necessary if the number of reserved
block was reduced (i.e.  memory hot remove).

Moreover, maximum MIGRATE_RESERVE per zone is currently 2.  It means
that the number of reserved pageblocks is almost always unchanged.

This patch adds zone->nr_migrate_reserve_block to maintain the number of
MIGRATE_RESERVE pageblocks and it reduces the overhead of
setup_zone_migrate_reserve dramatically.  The following table shows time
of onlining a memory section.

  Amount of memory     | 128GB | 192GB | 256GB|
  ---------------------------------------------
  linux-3.12           |  23.9 |  31.4 | 44.5 |
  This patch           |   8.3 |   8.3 |  8.6 |
  Mel's proposal patch |  10.9 |  19.2 | 31.3 |
  ---------------------------------------------
                                   (millisecond)

  128GB : 4 nodes and each node has 32GB of memory
  192GB : 6 nodes and each node has 32GB of memory
  256GB : 8 nodes and each node has 32GB of memory

  (*1) Mel proposed his idea by the following threads.
       https://lkml.org/lkml/2013/10/30/272

[akpm@linux-foundation.org: tweak comment]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reported-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Tested-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:43 -08:00
Johannes Weiner
fff4068cba mm: page_alloc: revert NUMA aspect of fair allocation policy
Commit 81c0a2bb51 ("mm: page_alloc: fair zone allocator policy") meant
to bring aging fairness among zones in system, but it was overzealous
and badly regressed basic workloads on NUMA systems.

Due to the way kswapd and page allocator interacts, we still want to
make sure that all zones in any given node are used equally for all
allocations to maximize memory utilization and prevent thrashing on the
highest zone in the node.

While the same principle applies to NUMA nodes - memory utilization is
obviously improved by spreading allocations throughout all nodes -
remote references can be costly and so many workloads prefer locality
over memory utilization.  The original change assumed that
zone_reclaim_mode would be a good enough predictor for that, but it
turned out to be as indicative as a coin flip.

Revert the NUMA aspect of the fairness until we can find a proper way to
make it configurable and agree on a sane default.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@kernel.org> # 3.12
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-20 12:19:18 -08:00
Mel Gorman
8798cee2f9 Revert "mm: page_alloc: exclude unreclaimable allocations from zone fairness policy"
This reverts commit 73f038b863.  The NUMA behaviour of this patch is
less than ideal.  An alternative approch is to interleave allocations
only within local zones which is implemented in the next patch.

Cc: stable@vger.kernel.org
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-20 12:19:18 -08:00
Johannes Weiner
73f038b863 mm: page_alloc: exclude unreclaimable allocations from zone fairness policy
Dave Hansen noted a regression in a microbenchmark that loops around
open() and close() on an 8-node NUMA machine and bisected it down to
commit 81c0a2bb51 ("mm: page_alloc: fair zone allocator policy").
That change forces the slab allocations of the file descriptor to spread
out to all 8 nodes, causing remote references in the page allocator and
slab.

The round-robin policy is only there to provide fairness among memory
allocations that are reclaimed involuntarily based on pressure in each
zone.  It does not make sense to apply it to unreclaimable kernel
allocations that are freed manually, in this case instantly after the
allocation, and incur the remote reference costs twice for no reason.

Only round-robin allocations that are usually freed through page reclaim
or slab shrinking.

Bisected by Dave Hansen.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-18 19:04:51 -08:00
Zhi Yong Wu
a1aeb65a4c mm/page_alloc.c: fix comment in zlc_setup()
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:11 +09:00
KOSAKI Motohiro
0cbef29a78 mm: __rmqueue_fallback() should respect pageblock type
When __rmqueue_fallback() doesn't find a free block with the required size
it splits a larger page and puts the rest of the page onto the free list.

But it has one serious mistake.  When putting back, __rmqueue_fallback()
always use start_migratetype if type is not CMA.  However,
__rmqueue_fallback() is only called when all of the start_migratetype
queue is empty.  That said, __rmqueue_fallback always puts back memory to
the wrong queue except try_to_steal_freepages() changed pageblock type
(i.e.  requested size is smaller than half of page block).  The end result
is that the antifragmentation framework increases fragmenation instead of
decreasing it.

Mel's original anti fragmentation does the right thing.  But commit
47118af076 ("mm: mmzone: MIGRATE_CMA migration type added") broke it.

This patch restores sane and old behavior.  It also removes an incorrect
comment which was introduced by commit fef903efcf ("mm/page_alloc.c:
restructure free-page stealing code and fix a bug").

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:10 +09:00
KOSAKI Motohiro
52c8f6a5ae mm: get rid of unnecessary overhead of trace_mm_page_alloc_extfrag()
In general, every tracepoint should be zero overhead if it is disabled.
However, trace_mm_page_alloc_extfrag() is one of exception.  It evaluate
"new_type == start_migratetype" even if tracepoint is disabled.

However, the code can be moved into tracepoint's TP_fast_assign() and
TP_fast_assign exist exactly such purpose.  This patch does it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:10 +09:00
KOSAKI Motohiro
5d0f3f72ef mm: fix page_group_by_mobility_disabled breakage
Currently, set_pageblock_migratetype() screws up MIGRATE_CMA and
MIGRATE_ISOLATE if page_group_by_mobility_disabled is true.  It rewrites
the argument to MIGRATE_UNMOVABLE and we lost these attribute.

The problem was introduced by commit 49255c619f ("page allocator: move
check for disabled anti-fragmentation out of fastpath").  So a 4 year
old issue may mean that nobody uses page_group_by_mobility_disabled.

But anyway, this patch fixes the problem.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:09 +09:00
Zhang Yanfei
bfc4f9d520 mm/page_alloc.c: remove unused marco LONG_ALIGN
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:07 +09:00
Qiang Huang
b9921ecdee mm: add a helper function to check may oom condition
Use helper function to check if we need to deal with oom condition.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:04 +09:00
Xishi Qiu
b38a872596 mm: use populated_zone() instead of if(zone->present_pages)
Use "if (zone->present_pages)" instead of "if (zone->present_pages)".
Simplify the code, no functional change.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:04 +09:00
Peter Zijlstra
90572890d2 mm: numa: Change page last {nid,pid} into {cpu,pid}
Change the per page last fault tracking to use cpu,pid instead of
nid,pid. This will allow us to try and lookup the alternate task more
easily. Note that even though it is the cpu that is store in the page
flags that the mpol_misplaced decision is still based on the node.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1381141781-10992-43-git-send-email-mgorman@suse.de
[ Fixed build failure on 32-bit systems. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09 14:47:45 +02:00
Mel Gorman
b795854b1f sched/numa: Set preferred NUMA node based on number of private faults
Ideally it would be possible to distinguish between NUMA hinting faults that
are private to a task and those that are shared. If treated identically
there is a risk that shared pages bounce between nodes depending on
the order they are referenced by tasks. Ultimately what is desirable is
that task private pages remain local to the task while shared pages are
interleaved between sharing tasks running on different nodes to give good
average performance. This is further complicated by THP as even
applications that partition their data may not be partitioning on a huge
page boundary.

To start with, this patch assumes that multi-threaded or multi-process
applications partition their data and that in general the private accesses
are more important for cpu->memory locality in the general case. Also,
no new infrastructure is required to treat private pages properly but
interleaving for shared pages requires additional infrastructure.

To detect private accesses the pid of the last accessing task is required
but the storage requirements are a high. This patch borrows heavily from
Ingo Molnar's patch "numa, mm, sched: Implement last-CPU+PID hash tracking"
to encode some bits from the last accessing task in the page flags as
well as the node information. Collisions will occur but it is better than
just depending on the node information. Node information is then used to
determine if a page needs to migrate. The PID information is used to detect
private/shared accesses. The preferred NUMA node is selected based on where
the maximum number of approximately private faults were measured. Shared
faults are not taken into consideration for a few reasons.

First, if there are many tasks sharing the page then they'll all move
towards the same node. The node will be compute overloaded and then
scheduled away later only to bounce back again. Alternatively the shared
tasks would just bounce around nodes because the fault information is
effectively noise. Either way accounting for shared faults the same as
private faults can result in lower performance overall.

The second reason is based on a hypothetical workload that has a small
number of very important, heavily accessed private pages but a large shared
array. The shared array would dominate the number of faults and be selected
as a preferred node even though it's the wrong decision.

The third reason is that multiple threads in a process will race each
other to fault the shared page making the fault information unreliable.

Signed-off-by: Mel Gorman <mgorman@suse.de>
[ Fix complication error when !NUMA_BALANCING. ]
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-30-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09 12:40:35 +02:00
Joonyoung Shim
7393dc45f6 revert "mm/memory-hotplug: fix lowmem count overflow when offline pages"
This reverts commit cea27eb2a2 ("mm/memory-hotplug: fix lowmem count
overflow when offline pages").

The fixed bug by commit cea27eb was fixed to another way by commit
3dcc0571cd ("mm: correctly update zone->managed_pages").  That commit
enhances memory_hotplug.c to adjust totalhigh_pages when hot-removing
memory, for details please refer to:

  http://marc.info/?l=linux-mm&m=136957578620221&w=2

As a result, commit cea27eb2a2 currently causes duplicated decreasing
of totalhigh_pages, thus the revert.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-30 14:31:01 -07:00
Wang Sheng-Hui
cf6fe94538 mm: correct the comment about the value for buddy _mapcount
Set _mapcount PAGE_BUDDY_MAPCOUNT_VALUE to make the page buddy.  Not the
magic number -2.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:58:06 -07:00
Lisa Du
6e543d5780 mm: vmscan: fix do_try_to_free_pages() livelock
This patch is based on KOSAKI's work and I add a little more description,
please refer https://lkml.org/lkml/2012/6/14/74.

Currently, I found system can enter a state that there are lots of free
pages in a zone but only order-0 and order-1 pages which means the zone is
heavily fragmented, then high order allocation could make direct reclaim
path's long stall(ex, 60 seconds) especially in no swap and no compaciton
enviroment.  This problem happened on v3.4, but it seems issue still lives
in current tree, the reason is do_try_to_free_pages enter live lock:

kswapd will go to sleep if the zones have been fully scanned and are still
not balanced.  As kswapd thinks there's little point trying all over again
to avoid infinite loop.  Instead it changes order from high-order to
0-order because kswapd think order-0 is the most important.  Look at
73ce02e9 in detail.  If watermarks are ok, kswapd will go back to sleep
and may leave zone->all_unreclaimable =3D 0.  It assume high-order users
can still perform direct reclaim if they wish.

Direct reclaim continue to reclaim for a high order which is not a
COSTLY_ORDER without oom-killer until kswapd turn on
zone->all_unreclaimble= .  This is because to avoid too early oom-kill.
So it means direct_reclaim depends on kswapd to break this loop.

In worst case, direct-reclaim may continue to page reclaim forever when
kswapd sleeps forever until someone like watchdog detect and finally kill
the process.  As described in:
http://thread.gmane.org/gmane.linux.kernel.mm/103737

We can't turn on zone->all_unreclaimable from direct reclaim path because
direct reclaim path don't take any lock and this way is racy.  Thus this
patch removes zone->all_unreclaimable field completely and recalculates
zone reclaimable state every time.

Note: we can't take the idea that direct-reclaim see zone->pages_scanned
directly and kswapd continue to use zone->all_unreclaimable.  Because, it
is racy.  commit 929bea7c71 (vmscan: all_unreclaimable() use
zone->all_unreclaimable as a name) describes the detail.

[akpm@linux-foundation.org: uninline zone_reclaimable_pages() and zone_reclaimable()]
Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Nick Piggin <npiggin@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: Neil Zhang <zhangwm@marvell.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Lisa Du <cldu@marvell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:58:01 -07:00
SeungHun Lee
3b11f0aaae mm: page_alloc: fix comment get_page_from_freelist
cpuset_zone_allowed is changed to cpuset_zone_allowed_softwall and the
comment is moved to __cpuset_node_allowed_softwall.  So fix this comment.

Signed-off-by: SeungHun Lee <waydi1@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:56 -07:00
Yinghai Lu
e76b63f80d memblock, numa: binary search node id
Current early_pfn_to_nid() on arch that support memblock go over
memblock.memory one by one, so will take too many try near the end.

We can use existing memblock_search to find the node id for given pfn,
that could save some time on bigger system that have many entries
memblock.memory array.

Here are the timing differences for several machines.  In each case with
the patch less time was spent in __early_pfn_to_nid().

                        3.11-rc5        with patch      difference (%)
                        --------        ----------      --------------
UV1: 256 nodes  9TB:     411.66          402.47         -9.19 (2.23%)
UV2: 255 nodes 16TB:    1141.02         1138.12         -2.90 (0.25%)
UV2:  64 nodes  2TB:     128.15          126.53         -1.62 (1.26%)
UV2:  32 nodes  2TB:     121.87          121.07         -0.80 (0.66%)
                        Time in seconds.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:51 -07:00
Naoya Horiguchi
c8721bbbdd mm: memory-hotplug: enable memory hotplug to handle hugepage
Until now we can't offline memory blocks which contain hugepages because a
hugepage is considered as an unmovable page.  But now with this patch
series, a hugepage has become movable, so by using hugepage migration we
can offline such memory blocks.

What's different from other users of hugepage migration is that we need to
decompose all the hugepages inside the target memory block into free buddy
pages after hugepage migration, because otherwise free hugepages remaining
in the memory block intervene the memory offlining.  For this reason we
introduce new functions dissolve_free_huge_page() and
dissolve_free_huge_pages().

Other than that, what this patch does is straightforwardly to add hugepage
migration code, that is, adding hugepage code to the functions which scan
over pfn and collect hugepages to be migrated, and adding a hugepage
allocation function to alloc_migrate_target().

As for larger hugepages (1GB for x86_64), it's not easy to do hotremove
over them because it's larger than memory block.  So we now simply leave
it to fail as it is.

[yongjun_wei@trendmicro.com.cn: remove duplicated include]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:48 -07:00
Xishi Qiu
8080fc038e mm: use zone_is_empty() instead of if(zone->spanned_pages)
Use "zone_is_empty()" instead of "if (zone->spanned_pages)".
Simplify the code, no functional change.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:38 -07:00
Christoph Lameter
2bb921e526 vmstat: create separate function to fold per cpu diffs into local counters
The main idea behind this patchset is to reduce the vmstat update overhead
by avoiding interrupt enable/disable and the use of per cpu atomics.

This patch (of 3):

It is better to have a separate folding function because
refresh_cpu_vm_stats() also does other things like expire pages in the
page allocator caches.

If we have a separate function then refresh_cpu_vm_stats() is only called
from the local cpu which allows additional optimizations.

The folding function is only called when a cpu is being downed and
therefore no other processor will be accessing the counters.  Also
simplifies synchronization.

[akpm@linux-foundation.org: fix UP build]
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:31 -07:00
Joonsoo Kim
e66f097257 mm, page_alloc: add unlikely macro to help compiler optimization
We rarely allocate a page with ALLOC_NO_WATERMARKS and it is used in slow
path.  For helping compiler optimization, add unlikely macro to
ALLOC_NO_WATERMARKS checking.

This patch doesn't have any effect now, because gcc already optimize this
properly.  But we cannot assume that gcc always does right and nobody
re-evaluate if gcc do proper optimization with their change, for example,
it is not optimized properly on v3.10.  So adding compiler hint here is
reasonable.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:29 -07:00
Johannes Weiner
81c0a2bb51 mm: page_alloc: fair zone allocator policy
Each zone that holds userspace pages of one workload must be aged at a
speed proportional to the zone size.  Otherwise, the time an individual
page gets to stay in memory depends on the zone it happened to be
allocated in.  Asymmetry in the zone aging creates rather unpredictable
aging behavior and results in the wrong pages being reclaimed, activated
etc.

But exactly this happens right now because of the way the page allocator
and kswapd interact.  The page allocator uses per-node lists of all zones
in the system, ordered by preference, when allocating a new page.  When
the first iteration does not yield any results, kswapd is woken up and the
allocator retries.  Due to the way kswapd reclaims zones below the high
watermark while a zone can be allocated from when it is above the low
watermark, the allocator may keep kswapd running while kswapd reclaim
ensures that the page allocator can keep allocating from the first zone in
the zonelist for extended periods of time.  Meanwhile the other zones
rarely see new allocations and thus get aged much slower in comparison.

The result is that the occasional page placed in lower zones gets
relatively more time in memory, even gets promoted to the active list
after its peers have long been evicted.  Meanwhile, the bulk of the
working set may be thrashing on the preferred zone even though there may
be significant amounts of memory available in the lower zones.

Even the most basic test -- repeatedly reading a file slightly bigger than
memory -- shows how broken the zone aging is.  In this scenario, no single
page should be able stay in memory long enough to get referenced twice and
activated, but activation happens in spades:

  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 0
      nr_inactive_file 0
      nr_active_file 8
      nr_inactive_file 1582
      nr_active_file 11994
  $ cat data data data data >/dev/null
  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 70
      nr_inactive_file 258753
      nr_active_file 443214
      nr_inactive_file 149793
      nr_active_file 12021

Fix this with a very simple round robin allocator.  Each zone is allowed a
batch of allocations that is proportional to the zone's size, after which
it is treated as full.  The batch counters are reset when all zones have
been tried and the allocator enters the slowpath and kicks off kswapd
reclaim.  Allocation and reclaim is now fairly spread out to all
available/allowable zones:

  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 0
      nr_inactive_file 174
      nr_active_file 4865
      nr_inactive_file 53
      nr_active_file 860
  $ cat data data data data >/dev/null
  $ grep active_file /proc/zoneinfo
      nr_inactive_file 0
      nr_active_file 0
      nr_inactive_file 666622
      nr_active_file 4988
      nr_inactive_file 190969
      nr_active_file 937

When zone_reclaim_mode is enabled, allocations will now spread out to all
zones on the local node, not just the first preferred zone (which on a 4G
node might be a tiny Normal zone).

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Paul Bolle <paul.bollee@gmail.com>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:23 -07:00
Johannes Weiner
e085dbc52f mm: page_alloc: rearrange watermark checking in get_page_from_freelist
Allocations that do not have to respect the watermarks are rare
high-priority events.  Reorder the code such that per-zone dirty limits
and future checks important only to regular page allocations are ignored
in these extraordinary situations.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Paul Bolle <paul.bollee@gmail.com>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:22 -07:00
Yinghai Lu
e2d0bd2b92 mm: kill one if loop in __free_pages_bootmem()
We should not check loop+1 with loop end in loop body.  Just duplicate two
lines code to avoid it.

That will help a bit when we have huge amount of pages on system with
16TiB memory.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:19 -07:00
Srivatsa S. Bhat
f92310c187 mm/page_alloc.c: fix the value of fallback_migratetype in alloc_extfrag tracepoint()
In the current code, the value of fallback_migratetype that is printed
using the mm_page_alloc_extfrag tracepoint, is the value of the
migratetype *after* it has been set to the preferred migratetype (if the
ownership was changed).  Obviously that wouldn't have been the original
intent.  (We already have a separate 'change_ownership' field to tell
whether the ownership of the pageblock was changed from the
fallback_migratetype to the preferred type.)

The intent of the fallback_migratetype field is to show the migratetype
from which we borrowed pages in order to satisfy the allocation request.
So fix the code to print that value correctly.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:19 -07:00
Srivatsa S. Bhat
fef903efcf mm/page_allo.c: restructure free-page stealing code and fix a bug
The free-page stealing code in __rmqueue_fallback() is somewhat hard to
follow, and has an incredible amount of subtlety hidden inside!

First off, there is a minor bug in the reporting of change-of-ownership of
pageblocks.  Under some conditions, we try to move upto
'pageblock_nr_pages' no.  of pages to the preferred allocation list.  But
we change the ownership of that pageblock to the preferred type only if we
manage to successfully move atleast half of that pageblock (or if
page_group_by_mobility_disabled is set).

However, the current code ignores the latter part and sets the
'migratetype' variable to the preferred type, irrespective of whether we
actually changed the pageblock migratetype of that block or not.  So, the
page_alloc_extfrag tracepoint can end up printing incorrect info (i.e.,
'change_ownership' might be shown as 1 when it must have been 0).

So fixing this involves moving the update of the 'migratetype' variable to
the right place.  But looking closer, we observe that the 'migratetype'
variable is used subsequently for checks such as "is_migrate_cma()".
Obviously the intent there is to check if the *fallback* type is
MIGRATE_CMA, but since we already set the 'migratetype' variable to
start_migratetype, we end up checking if the *preferred* type is
MIGRATE_CMA!!

To make things more interesting, this actually doesn't cause a bug in
practice, because we never change *anything* if the fallback type is CMA.

So, restructure the code in such a way that it is trivial to understand
what is going on, and also fix the above mentioned bug.  And while at it,
also add a comment explaining the subtlety behind the migratetype used in
the call to expand().

[akpm@linux-foundation.org: remove unneeded `inline', small coding-style fix]
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:19 -07:00
Pintu Kumar
b8af29418a mm/page_alloc.c: fix coding style and spelling
Fix all errors reported by checkpatch and some small spelling mistakes.

Signed-off-by: Pintu Kumar <pintu.k@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:18 -07:00
Chen Gang
15ca220e1a mm/page_alloc.c: use '__paginginit' instead of '__init'
set_pageblock_order() may be called when memory hotplug, so need use
'__paginginit' instead of '__init'.

The related warning:

  The function __meminit .free_area_init_node() references
  a function __init .set_pageblock_order().
  If .set_pageblock_order is only used by .free_area_init_node then
  annotate .set_pageblock_order with a matching annotation.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:13 -07:00
Jerry Zhou
a7e833182a mm: fix negative left shift count when PAGE_SHIFT > 20
When PAGE_SHIFT > 20, the result of "20 - PAGE_SHIFT" is negative. The
previous calculating here will generate an unexpected result. In
addition, if PAGE_SIZE >= 1MB, The memory size of "numentries" was
already integral multiple of 1MB.

Signed-off-by: Jerry Zhou <uulinux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:57:12 -07:00
Li Zhong
9cf510a58c Fix comment typo for init_cma_reserved_pageblock
It seems the "it's" should be "its" here.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2013-08-27 10:58:04 +02:00
Michal Hocko
5f12733e9d mm: honor min_free_kbytes set by user
min_free_kbytes is updated during memory hotplug (by
init_per_zone_wmark_min) currently which is right thing to do in most
cases but this could be unexpected if admin increased the value to
prevent from allocation failures and the new min_free_kbytes would be
decreased as a result of memory hotadd.

This patch saves the user defined value and allows updating
min_free_kbytes only if it is higher than the saved one.

A warning is printed when the new value is ignored.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 10:33:25 -07:00
Zhang Yanfei
345606d429 mm/page_alloc.c: remove unlikely() from the current_order test
In __rmqueue_fallback(), current_order loops down from MAX_ORDER - 1 to
the order passed.  MAX_ORDER is typically 11 and pageblock_order is
typically 9 on x86.  Integer division truncates, so pageblock_order / 2
is 4.  For the first eight iterations, it's guaranteed that
current_order >= pageblock_order / 2 if it even gets that far!

So just remove the unlikely(), it's completely bogus.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 10:33:22 -07:00
Zhang Yanfei
bc732f1d55 mm/page_alloc.c: remove zone_type argument of build_zonelists_node
The callers of build_zonelists_node always pass MAX_NR_ZONES -1 as the
zone_type argument, so we can directly use the value in
build_zonelists_node and remove zone_type argument.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 10:33:22 -07:00
Zhang Yanfei
7960aedde8 mm: remove duplicated call of get_pfn_range_for_nid
When calculating pages in a node, for each zone in that node, we will
have

  zone_spanned_pages_in_node
    --> get_pfn_range_for_nid
  zone_absent_pages_in_node
    --> get_pfn_range_for_nid

That is to say, we call the get_pfn_range_for_nid to get start_pfn and
end_pfn of the node for MAX_NR_ZONES * 2 times.  And this is totally
unnecessary if we call the get_pfn_range_for_nid before
zone_*_pages_in_node add two extra arguments node_start_pfn and
node_end_pfn for zone_*_pages_in_node, then we can remove the
get_pfn_range_in_node in zone_*_pages_in_node.

[akpm@linux-foundation.org: make definitions more readable]
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 10:33:20 -07:00
Jiang Liu
7ee3d4e8cd mm: introduce helper function mem_init_print_info() to simplify mem_init()
Introduce helper function mem_init_print_info() to simplify mem_init()
across different architectures, which also unifies the format and
information printed.

Function mem_init_print_info() calculates memory statistics information
without walking each page, so it should be a little faster on some
architectures.

Also introduce another helper get_num_physpages() to kill the global
variable num_physpages.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:07:35 -07:00
Jiang Liu
cdd91a7704 mm: report available pages as "MemTotal" for each NUMA node
As reported by https://bugzilla.kernel.org/show_bug.cgi?id=53501,
"MemTotal" from /proc/meminfo means memory pages managed by the buddy
system (managed_pages), but "MemTotal" from /sys/.../node/nodex/meminfo
means physical pages present (present_pages) within the NUMA node.
There's a difference between managed_pages and present_pages due to
bootmem allocator and reserved pages.

And Documentation/filesystems/proc.txt says
    MemTotal: Total usable ram (i.e. physical ram minus a few reserved
              bits and the kernel binary code)

So change /sys/.../node/nodex/meminfo to report available pages within
the node as "MemTotal".

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Reported-by: <sworddragon2@aol.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:07:34 -07:00
Jiang Liu
3dcc0571cd mm: correctly update zone->managed_pages
Enhance adjust_managed_page_count() to adjust totalhigh_pages for
highmem pages.  And change code which directly adjusts totalram_pages to
use adjust_managed_page_count() because it adjusts totalram_pages,
totalhigh_pages and zone->managed_pages altogether in a safe way.

Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
driver bacause adjust_managed_page_count() has already adjusted
totalhigh_pages.

This patch also fixes two bugs:

1) enhances virtio_balloon driver to adjust totalhigh_pages when
   reserve/unreserve pages.
2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
   memory.

We still need to deal with modifications of totalram_pages in file
arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.

[akpm@linux-foundation.org: remove ifdef, per Wanpeng Li, virtio_balloon.c cleanup, per Sergei]
[akpm@linux-foundation.org: export adjust_managed_page_count() to modules, for drivers/virtio/virtio_balloon.c]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:07:33 -07:00
Jiang Liu
170a5a7eb2 mm: make __free_pages_bootmem() only available at boot time
In order to simpilify management of totalram_pages and
zone->managed_pages, make __free_pages_bootmem() only available at boot
time.  With this change applied, __free_pages_bootmem() will only be
used by bootmem.c and nobootmem.c at boot time, so mark it as __init.
Other callers of __free_pages_bootmem() have been converted to use
free_reserved_page(), which handles totalram_pages and
zone->managed_pages in a safer way.

This patch also fix a bug in free_pagetable() for x86_64, which should
increase zone->managed_pages instead of zone->present_pages when freeing
reserved pages.

And now we have managed_pages_count_lock to protect totalram_pages and
zone->managed_pages, so remove the redundant ppb_lock lock in
put_page_bootmem().  This greatly simplifies the locking rules.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:07:33 -07:00