23 Nov, 2013
1 commit
-
Pull SLAB changes from Pekka Enberg:
"The patches from Joonsoo Kim switch mm/slab.c to use 'struct page' for
slab internals similar to mm/slub.c. This reduces memory usage and
improves performance:https://lkml.org/lkml/2013/10/16/155
Rest of the changes are bug fixes from various people"
* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (21 commits)
mm, slub: fix the typo in mm/slub.c
mm, slub: fix the typo in include/linux/slub_def.h
slub: Handle NULL parameter in kmem_cache_flags
slab: replace non-existing 'struct freelist *' with 'void *'
slab: fix to calm down kmemleak warning
slub: proper kmemleak tracking if CONFIG_SLUB_DEBUG disabled
slab: rename slab_bufctl to slab_freelist
slab: remove useless statement for checking pfmemalloc
slab: use struct page for slab management
slab: replace free and inuse in struct slab with newly introduced active
slab: remove SLAB_LIMIT
slab: remove kmem_bufctl_t
slab: change the management method of free objects of the slab
slab: use __GFP_COMP flag for allocating slab pages
slab: use well-defined macro, virt_to_slab()
slab: overloading the RCU head over the LRU for RCU free
slab: remove cachep in struct slab_rcu
slab: remove nodeid in struct slab
slab: remove colouroff in struct slab
slab: change return type of kmem_getpages() to struct page
...
22 Nov, 2013
1 commit
-
I don't know what went wrong, mis-merge or something, but ->pmd_huge_pte
placed in wrong union within struct page.In original patch[1] it's placed to union with ->lru and ->slab, but in
commit e009bb30c8df ("mm: implement split page table lock for PMD
level") it's in union with ->index and ->freelist.That union seems also unused for pages with table tables and safe to
re-use, but it's not what I've tested.Let's move it to original place. It fixes indentation at least. :)
[1] https://lkml.org/lkml/2013/10/7/288
Signed-off-by: Kirill A. Shutemov
Reviewed-by: Naoya Horiguchi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Nov, 2013
5 commits
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Use kernel/bounds.c to convert build-time spinlock_t size check into a
preprocessor symbol and apply that to properly separate the page::ptl
situation.Signed-off-by: Peter Zijlstra
Signed-off-by: Kirill A. Shutemov
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
If split page table lock is in use, we embed the lock into struct page
of table's page. We have to disable split lock, if spinlock_t is too
big be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC
enabled.This patch add support for dynamic allocation of split page table lock
if we can't embed it to struct page.page->ptl is unsigned long now and we use it as spinlock_t if
sizeof(spinlock_t) ptl.Signed-off-by: Kirill A. Shutemov
Reviewed-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The basic idea is the same as with PTE level: the lock is embedded into
struct page of table's page.We can't use mm->pmd_huge_pte to store pgtables for THP, since we don't
take mm->page_table_lock anymore. Let's reuse page->lru of table's page
for that.pgtable_pmd_page_ctor() returns true, if initialization is successful
and false otherwise. Current implementation never fails, but assumption
that constructor can fail will help to port it to -rt where spinlock_t
is rather huge and cannot be embedded into struct page -- dynamic
allocation is required.Signed-off-by: Naoya Horiguchi
Signed-off-by: Kirill A. Shutemov
Tested-by: Alex Thorlton
Cc: Ingo Molnar
Cc: "Eric W . Biederman"
Cc: "Paul E . McKenney"
Cc: Al Viro
Cc: Andi Kleen
Cc: Andrea Arcangeli
Cc: Dave Hansen
Cc: Dave Jones
Cc: David Howells
Cc: Frederic Weisbecker
Cc: Johannes Weiner
Cc: Kees Cook
Cc: Mel Gorman
Cc: Michael Kerrisk
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Rik van Riel
Cc: Robin Holt
Cc: Sedat Dilek
Cc: Srikar Dronamraju
Cc: Thomas Gleixner
Cc: Hugh Dickins
Reviewed-by: Steven Rostedt
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
With split page table lock for PMD level we can't hold mm->page_table_lock
while updating nr_ptes.Let's convert it to atomic_long_t to avoid races.
Signed-off-by: Kirill A. Shutemov
Tested-by: Alex Thorlton
Cc: Ingo Molnar
Cc: Naoya Horiguchi
Cc: "Eric W . Biederman"
Cc: "Paul E . McKenney"
Cc: Al Viro
Cc: Andi Kleen
Cc: Andrea Arcangeli
Cc: Dave Hansen
Cc: Dave Jones
Cc: David Howells
Cc: Frederic Weisbecker
Cc: Johannes Weiner
Cc: Kees Cook
Cc: Mel Gorman
Cc: Michael Kerrisk
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Rik van Riel
Cc: Robin Holt
Cc: Sedat Dilek
Cc: Srikar Dronamraju
Cc: Thomas Gleixner
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We're going to introduce split page table lock for PMD level. Let's
rename existing split ptlock for PTE level to avoid confusion.Signed-off-by: Kirill A. Shutemov
Tested-by: Alex Thorlton
Cc: Ingo Molnar
Cc: Naoya Horiguchi
Cc: "Eric W . Biederman"
Cc: "Paul E . McKenney"
Cc: Al Viro
Cc: Andi Kleen
Cc: Andrea Arcangeli
Cc: Dave Hansen
Cc: Dave Jones
Cc: David Howells
Cc: Frederic Weisbecker
Cc: Johannes Weiner
Cc: Kees Cook
Cc: Mel Gorman
Cc: Michael Kerrisk
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Rik van Riel
Cc: Robin Holt
Cc: Sedat Dilek
Cc: Srikar Dronamraju
Cc: Thomas Gleixner
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Oct, 2013
2 commits
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Now, there are a few field in struct slab, so we can overload these
over struct page. This will save some memory and reduce cache footprint.After this change, slabp_cache and slab_size no longer related to
a struct slab, so rename them as freelist_cache and freelist_size.These changes are just mechanical ones and there is no functional change.
Acked-by: Andi Kleen
Acked-by: Christoph Lameter
Signed-off-by: Joonsoo Kim
Signed-off-by: Pekka Enberg -
With build-time size checking, we can overload the RCU head over the LRU
of struct page to free pages of a slab in rcu context. This really help to
implement to overload the struct slab over the struct page and this
eventually reduce memory usage and cache footprint of the SLAB.Acked-by: Andi Kleen
Acked-by: Christoph Lameter
Signed-off-by: Joonsoo Kim
Signed-off-by: Pekka Enberg
09 Oct, 2013
4 commits
-
With scan rate adaptions based on whether the workload has properly
converged or not there should be no need for the scan period reset
hammer. Get rid of it.Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel
Cc: Andrea Arcangeli
Cc: Johannes Weiner
Cc: Srikar Dronamraju
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1381141781-10992-60-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar -
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
Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel
Cc: Andrea Arcangeli
Cc: Johannes Weiner
Cc: Srikar Dronamraju
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 -
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
[ Fix complication error when !NUMA_BALANCING. ]
Reviewed-by: Rik van Riel
Cc: Andrea Arcangeli
Cc: Johannes Weiner
Cc: Srikar Dronamraju
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1381141781-10992-30-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar -
PTE scanning and NUMA hinting fault handling is expensive so commit
5bca2303 ("mm: sched: numa: Delay PTE scanning until a task is scheduled
on a new node") deferred the PTE scan until a task had been scheduled on
another node. The problem is that in the purely shared memory case that
this may never happen and no NUMA hinting fault information will be
captured. We are not ruling out the possibility that something better
can be done here but for now, this patch needs to be reverted and depend
entirely on the scan_delay to avoid punishing short-lived processes.Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel
Cc: Andrea Arcangeli
Cc: Johannes Weiner
Cc: Srikar Dronamraju
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1381141781-10992-16-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar
14 Sep, 2013
1 commit
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Pull aio changes from Ben LaHaise:
"First off, sorry for this pull request being late in the merge window.
Al had raised a couple of concerns about 2 items in the series below.
I addressed the first issue (the race introduced by Gu's use of
mm_populate()), but he has not provided any further details on how he
wants to rework the anon_inode.c changes (which were sent out months
ago but have yet to be commented on).The bulk of the changes have been sitting in the -next tree for a few
months, with all the issues raised being addressed"* git://git.kvack.org/~bcrl/aio-next: (22 commits)
aio: rcu_read_lock protection for new rcu_dereference calls
aio: fix race in ring buffer page lookup introduced by page migration support
aio: fix rcu sparse warnings introduced by ioctx table lookup patch
aio: remove unnecessary debugging from aio_free_ring()
aio: table lookup: verify ctx pointer
staging/lustre: kiocb->ki_left is removed
aio: fix error handling and rcu usage in "convert the ioctx list to table lookup v3"
aio: be defensive to ensure request batching is non-zero instead of BUG_ON()
aio: convert the ioctx list to table lookup v3
aio: double aio_max_nr in calculations
aio: Kill ki_dtor
aio: Kill ki_users
aio: Kill unneeded kiocb members
aio: Kill aio_rw_vect_retry()
aio: Don't use ctx->tail unnecessarily
aio: io_cancel() no longer returns the io_event
aio: percpu ioctx refcount
aio: percpu reqs_available
aio: reqs_active -> reqs_available
aio: fix build when migration is disabled
...
23 Aug, 2013
1 commit
-
This is the updated version of df54d6fa5427 ("x86 get_unmapped_area():
use proper mmap base for bottom-up direction") that only randomizes the
mmap base address once.Signed-off-by: Radu Caragea
Reported-and-tested-by: Jeff Shorey
Cc: Andrew Morton
Cc: Michel Lespinasse
Cc: Oleg Nesterov
Cc: Rik van Riel
Cc: Ingo Molnar
Cc: Adrian Sendroiu
Cc: Greg KH
Cc: Kamal Mostafa
Signed-off-by: Linus Torvalds
31 Jul, 2013
1 commit
-
On Wed, Jun 12, 2013 at 11:14:40AM -0700, Kent Overstreet wrote:
> On Mon, Apr 15, 2013 at 02:40:55PM +0300, Octavian Purdila wrote:
> > When using a large number of threads performing AIO operations the
> > IOCTX list may get a significant number of entries which will cause
> > significant overhead. For example, when running this fio script:
> >
> > rw=randrw; size=256k ;directory=/mnt/fio; ioengine=libaio; iodepth=1
> > blocksize=1024; numjobs=512; thread; loops=100
> >
> > on an EXT2 filesystem mounted on top of a ramdisk we can observe up to
> > 30% CPU time spent by lookup_ioctx:
> >
> > 32.51% [guest.kernel] [g] lookup_ioctx
> > 9.19% [guest.kernel] [g] __lock_acquire.isra.28
> > 4.40% [guest.kernel] [g] lock_release
> > 4.19% [guest.kernel] [g] sched_clock_local
> > 3.86% [guest.kernel] [g] local_clock
> > 3.68% [guest.kernel] [g] native_sched_clock
> > 3.08% [guest.kernel] [g] sched_clock_cpu
> > 2.64% [guest.kernel] [g] lock_release_holdtime.part.11
> > 2.60% [guest.kernel] [g] memcpy
> > 2.33% [guest.kernel] [g] lock_acquired
> > 2.25% [guest.kernel] [g] lock_acquire
> > 1.84% [guest.kernel] [g] do_io_submit
> >
> > This patchs converts the ioctx list to a radix tree. For a performance
> > comparison the above FIO script was run on a 2 sockets 8 core
> > machine. This are the results (average and %rsd of 10 runs) for the
> > original list based implementation and for the radix tree based
> > implementation:
> >
> > cores 1 2 4 8 16 32
> > list 109376 ms 69119 ms 35682 ms 22671 ms 19724 ms 16408 ms
> > %rsd 0.69% 1.15% 1.17% 1.21% 1.71% 1.43%
> > radix 73651 ms 41748 ms 23028 ms 16766 ms 15232 ms 13787 ms
> > %rsd 1.19% 0.98% 0.69% 1.13% 0.72% 0.75%
> > % of radix
> > relative 66.12% 65.59% 66.63% 72.31% 77.26% 83.66%
> > to list
> >
> > To consider the impact of the patch on the typical case of having
> > only one ctx per process the following FIO script was run:
> >
> > rw=randrw; size=100m ;directory=/mnt/fio; ioengine=libaio; iodepth=1
> > blocksize=1024; numjobs=1; thread; loops=100
> >
> > on the same system and the results are the following:
> >
> > list 58892 ms
> > %rsd 0.91%
> > radix 59404 ms
> > %rsd 0.81%
> > % of radix
> > relative 100.87%
> > to list
>
> So, I was just doing some benchmarking/profiling to get ready to send
> out the aio patches I've got for 3.11 - and it looks like your patch is
> causing a ~1.5% throughput regression in my testing :/
...I've got an alternate approach for fixing this wart in lookup_ioctx()...
Instead of using an rbtree, just use the reserved id in the ring buffer
header to index an array pointing the ioctx. It's not finished yet, and
it needs to be tidied up, but is most of the way there.-ben
--
"Thought is the essence of where you are now."
--
kmo> And, a rework of Ben's code, but this was entirely his idea
kmo> -Kentbcrl> And fix the code to use the right mm_struct in kill_ioctx(), actually
free memory.Signed-off-by: Benjamin LaHaise
11 Jul, 2013
1 commit
-
Since all architectures have been converted to use vm_unmapped_area(),
there is no remaining use for the free_area_cache.Signed-off-by: Michel Lespinasse
Acked-by: Rik van Riel
Cc: "James E.J. Bottomley"
Cc: "Luck, Tony"
Cc: Benjamin Herrenschmidt
Cc: David Howells
Cc: Helge Deller
Cc: Ivan Kokshaysky
Cc: Matt Turner
Cc: Paul Mackerras
Cc: Richard Henderson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Feb, 2013
3 commits
-
page->_last_nid fits into page->flags on 64-bit. The unlikely 32-bit
NUMA configuration with NUMA Balancing will still need an extra page
field. As Peter notes "Completely dropping 32bit support for
CONFIG_NUMA_BALANCING would simplify things, but it would also remove
the warning if we grow enough 64bit only page-flags to push the last-cpu
out."[mgorman@suse.de: minor modifications]
Signed-off-by: Mel Gorman
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Ingo Molnar
Cc: Simon Jeons
Cc: Wanpeng Li
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This is a preparation patch for moving page->_last_nid into page->flags
that moves page flag layout information to a separate header. This
patch is necessary because otherwise there would be a circular
dependency between mm_types.h and mm.h.Signed-off-by: Mel Gorman
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Ingo Molnar
Cc: Simon Jeons
Cc: Wanpeng Li
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
s/me/be/ and clarify the comment a bit when we're changing it anyway.
Signed-off-by: Mel Gorman
Suggested-by: Simon Jeons
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Ingo Molnar
Cc: Wanpeng Li
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Dec, 2012
1 commit
-
Pull SLAB changes from Pekka Enberg:
"This contains preparational work from Christoph Lameter and Glauber
Costa for SLAB memcg and cleanups and improvements from Ezequiel
Garcia and Joonsoo Kim.Please note that the SLOB cleanup commit from Arnd Bergmann already
appears in your tree but I had also merged it myself which is why it
shows up in the shortlog."* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
mm/sl[aou]b: Common alignment code
slab: Use the new create_boot_cache function to simplify bootstrap
slub: Use statically allocated kmem_cache boot structure for bootstrap
mm, sl[au]b: create common functions for boot slab creation
slab: Simplify bootstrap
slub: Use correct cpu_slab on dead cpu
mm: fix slab.c kernel-doc warnings
mm/slob: use min_t() to compare ARCH_SLAB_MINALIGN
slab: Ignore internal flags in cache creation
mm/slob: Use free_page instead of put_page for page-size kmalloc allocations
mm/sl[aou]b: Move common kmem_cache_size() to slab.h
mm/slob: Use object_size field in kmem_cache_size()
mm/slob: Drop usage of page->private for storing page-sized allocations
slub: Commonize slab_cache field in struct page
sl[au]b: Process slabinfo_show in common code
mm/sl[au]b: Move print_slabinfo_header to slab_common.c
mm/sl[au]b: Move slabinfo processing to slab_common.c
slub: remove one code path and reduce lock contention in __slab_free()
17 Dec, 2012
1 commit
-
Pull Automatic NUMA Balancing bare-bones from Mel Gorman:
"There are three implementations for NUMA balancing, this tree
(balancenuma), numacore which has been developed in tip/master and
autonuma which is in aa.git.In almost all respects balancenuma is the dumbest of the three because
its main impact is on the VM side with no attempt to be smart about
scheduling. In the interest of getting the ball rolling, it would be
desirable to see this much merged for 3.8 with the view to building
scheduler smarts on top and adapting the VM where required for 3.9.The most recent set of comparisons available from different people are
mel: https://lkml.org/lkml/2012/12/9/108
mingo: https://lkml.org/lkml/2012/12/7/331
tglx: https://lkml.org/lkml/2012/12/10/437
srikar: https://lkml.org/lkml/2012/12/10/397The results are a mixed bag. In my own tests, balancenuma does
reasonably well. It's dumb as rocks and does not regress against
mainline. On the other hand, Ingo's tests shows that balancenuma is
incapable of converging for this workloads driven by perf which is bad
but is potentially explained by the lack of scheduler smarts. Thomas'
results show balancenuma improves on mainline but falls far short of
numacore or autonuma. Srikar's results indicate we all suffer on a
large machine with imbalanced node sizes.My own testing showed that recent numacore results have improved
dramatically, particularly in the last week but not universally.
We've butted heads heavily on system CPU usage and high levels of
migration even when it shows that overall performance is better.
There are also cases where it regresses. Of interest is that for
specjbb in some configurations it will regress for lower numbers of
warehouses and show gains for higher numbers which is not reported by
the tool by default and sometimes missed in treports. Recently I
reported for numacore that the JVM was crashing with
NullPointerExceptions but currently it's unclear what the source of
this problem is. Initially I thought it was in how numacore batch
handles PTEs but I'm no longer think this is the case. It's possible
numacore is just able to trigger it due to higher rates of migration.These reports were quite late in the cycle so I/we would like to start
with this tree as it contains much of the code we can agree on and has
not changed significantly over the last 2-3 weeks."* tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits)
mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable
mm/rmap: Convert the struct anon_vma::mutex to an rwsem
mm: migrate: Account a transhuge page properly when rate limiting
mm: numa: Account for failed allocations and isolations as migration failures
mm: numa: Add THP migration for the NUMA working set scanning fault case build fix
mm: numa: Add THP migration for the NUMA working set scanning fault case.
mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node
mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG
mm: sched: numa: Control enabling and disabling of NUMA balancing
mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate
mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely tasknode relationships
mm: numa: migrate: Set last_nid on newly allocated page
mm: numa: split_huge_page: Transfer last_nid on tail page
mm: numa: Introduce last_nid to the page frame
sched: numa: Slowly increase the scanning period as NUMA faults are handled
mm: numa: Rate limit setting of pte_numa if node is saturated
mm: numa: Rate limit the amount of memory that is migrated between nodes
mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting
mm: numa: Migrate pages handled during a pmd_numa hinting fault
mm: numa: Migrate on reference policy
...
12 Dec, 2012
2 commits
-
The kernel walks the VMA rbtree in various places, including the page
fault path. However, the vm_rb node spanned two cache lines, on 64 bit
systems with 64 byte cache lines (most x86 systems).Rearrange vm_area_struct a little, so all the information we need to do a
VMA tree walk is in the first cache line.[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Michel Lespinasse
Signed-off-by: Rik van Riel
Cc: Hugh Dickins
Cc: Russell King
Cc: Ralf Baechle
Cc: Paul Mundt
Cc: "David S. Miller"
Cc: Chris Metcalf
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: "H. Peter Anvin"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Define vma->rb_subtree_gap as the largest gap between any vma in the
subtree rooted at that vma, and their predecessor. Or, for a recursive
definition, vma->rb_subtree_gap is the max of:- vma->vm_start - vma->vm_prev->vm_end
- rb_subtree_gap fields of the vmas pointed by vma->rb.rb_left and
vma->rb.rb_rightThis will allow get_unmapped_area_* to find a free area of the right
size in O(log(N)) time, instead of potentially having to do a linear
walk across all the VMAs.Also define mm->highest_vm_end as the vm_end field of the highest vma,
so that we can easily check if the following gap is suitable.This does have the potential to make unmapping VMAs more expensive,
especially for processes with very large numbers of VMAs, where the VMA
rbtree can grow quite deep.Signed-off-by: Michel Lespinasse
Reviewed-by: Rik van Riel
Cc: Hugh Dickins
Cc: Russell King
Cc: Ralf Baechle
Cc: Paul Mundt
Cc: "David S. Miller"
Cc: Chris Metcalf
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: "H. Peter Anvin"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Dec, 2012
5 commits
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Due to the fact that migrations are driven by the CPU a task is running
on there is no point tracking NUMA faults until one task runs on a new
node. This patch tracks the first node used by an address space. Until
it changes, PTE scanning is disabled and no NUMA hinting faults are
trapped. This should help workloads that are short-lived, do not care
about NUMA placement or have bound themselves to a single node.This takes advantage of the logic in "mm: sched: numa: Implement slow
start for working set sampling" to delay when the checks are made. This
will take advantage of processes that set their CPU and node bindings
early in their lifetime. It will also potentially allow any initial load
balancing to take place.Signed-off-by: Mel Gorman
-
The PTE scanning rate and fault rates are two of the biggest sources of
system CPU overhead with automatic NUMA placement. Ideally a proper policy
would detect if a workload was properly placed, schedule and adjust the
PTE scanning rate accordingly. We do not track the necessary information
to do that but we at least know if we migrated or not.This patch scans slower if a page was not migrated as the result of a
NUMA hinting fault up to sysctl_numa_balancing_scan_period_max which is
now higher than the previous default. Once every minute it will reset
the scanner in case of phase changes.This is hilariously crude and the numbers are arbitrary. Workloads will
converge quite slowly in comparison to what a proper policy should be able
to do. On the plus side, we will chew up less CPU for workloads that have
no need for automatic balancing.Signed-off-by: Mel Gorman
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This patch introduces a last_nid field to the page struct. This is used
to build a two-stage filter in the next patch that is aimed at
mitigating a problem whereby pages migrate to the wrong node when
referenced by a process that was running off its home node.Signed-off-by: Mel Gorman
-
Previously, to probe the working set of a task, we'd use
a very simple and crude method: mark all of its address
space PROT_NONE.That method has various (obvious) disadvantages:
- it samples the working set at dissimilar rates,
giving some tasks a sampling quality advantage
over others.- creates performance problems for tasks with very
large working sets- over-samples processes with large address spaces but
which only very rarely executeImprove that method by keeping a rotating offset into the
address space that marks the current position of the scan,
and advance it by a constant rate (in a CPU cycles execution
proportional manner). If the offset reaches the last mapped
address of the mm then it then it starts over at the first
address.The per-task nature of the working set sampling functionality in this tree
allows such constant rate, per task, execution-weight proportional sampling
of the working set, with an adaptive sampling interval/frequency that
goes from once per 100ms up to just once per 8 seconds. The current
sampling volume is 256 MB per interval.As tasks mature and converge their working set, so does the
sampling rate slow down to just a trickle, 256 MB per 8
seconds of CPU time executed.This, beyond being adaptive, also rate-limits rarely
executing systems and does not over-sample on overloaded
systems.[ In AutoNUMA speak, this patch deals with the effective sampling
rate of the 'hinting page fault'. AutoNUMA's scanning is
currently rate-limited, but it is also fundamentally
single-threaded, executing in the knuma_scand kernel thread,
so the limit in AutoNUMA is global and does not scale up with
the number of CPUs, nor does it scan tasks in an execution
proportional manner.So the idea of rate-limiting the scanning was first implemented
in the AutoNUMA tree via a global rate limit. This patch goes
beyond that by implementing an execution rate proportional
working set sampling rate that is not implemented via a single
global scanning daemon. ][ Dan Carpenter pointed out a possible NULL pointer dereference in the
first version of this patch. ]Based-on-idea-by: Andrea Arcangeli
Bug-Found-By: Dan Carpenter
Signed-off-by: Peter Zijlstra
Cc: Linus Torvalds
Cc: Andrew Morton
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Rik van Riel
[ Wrote changelog and fixed bug. ]
Signed-off-by: Ingo Molnar
Signed-off-by: Mel Gorman
Reviewed-by: Rik van Riel -
NOTE: This patch is based on "sched, numa, mm: Add fault driven
placement and migration policy" but as it throws away all the policy
to just leave a basic foundation I had to drop the signed-offs-by.This patch creates a bare-bones method for setting PTEs pte_numa in the
context of the scheduler that when faulted later will be faulted onto the
node the CPU is running on. In itself this does nothing useful but any
placement policy will fundamentally depend on receiving hints on placement
from fault context and doing something intelligent about it.Signed-off-by: Mel Gorman
Acked-by: Rik van Riel
24 Oct, 2012
1 commit
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Right now, slab and slub have fields in struct page to derive which
cache a page belongs to, but they do it slightly differently.slab uses a field called slab_cache, that lives in the third double
word. slub, uses a field called "slab", living outside of the
doublewords area.Ideally, we could use the same field for this. Since slub heavily makes
use of the doubleword region, there isn't really much room to move
slub's slab_cache field around. Since slab does not have such strict
placement restrictions, we can move it outside the doubleword area.The naming used by slab, "slab_cache", is less confusing, and it is
preferred over slub's generic "slab".Signed-off-by: Glauber Costa
Acked-by: Christoph Lameter
CC: David Rientjes
Signed-off-by: Pekka Enberg
09 Oct, 2012
3 commits
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Implement an interval tree as a replacement for the VMA prio_tree. The
algorithms are similar to lib/interval_tree.c; however that code can't be
directly reused as the interval endpoints are not explicitly stored in the
VMA. So instead, the common algorithm is moved into a template and the
details (node type, how to get interval endpoints from the node, etc) are
filled in using the C preprocessor.Once the interval tree functions are available, using them as a
replacement to the VMA prio tree is a relatively simple, mechanical job.Signed-off-by: Michel Lespinasse
Cc: Rik van Riel
Cc: Hillf Danton
Cc: Peter Zijlstra
Cc: Catalin Marinas
Cc: Andrea Arcangeli
Cc: David Woodhouse
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:| effect | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAPThis patch removes reserved_vm counter from mm_struct. Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.
remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: Konstantin Khlebnikov
Cc: Alexander Viro
Cc: Carsten Otte
Cc: Chris Metcalf
Cc: Cyrill Gorcunov
Cc: Eric Paris
Cc: H. Peter Anvin
Cc: Hugh Dickins
Cc: Ingo Molnar
Cc: James Morris
Cc: Jason Baron
Cc: Kentaro Takeda
Cc: Matt Helsley
Cc: Nick Piggin
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Robert Richter
Cc: Suresh Siddha
Cc: Tetsuo Handa
Cc: Venkatesh Pallipadi
Acked-by: Linus Torvalds
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently the kernel sets mm->exe_file during sys_execve() and then tracks
number of vmas with VM_EXECUTABLE flag in mm->num_exe_file_vmas, as soon
as this counter drops to zero kernel resets mm->exe_file to NULL. Plus it
resets mm->exe_file at last mmput() when mm->mm_users drops to zero.VMA with VM_EXECUTABLE flag appears after mapping file with flag
MAP_EXECUTABLE, such vmas can appears only at sys_execve() or after vma
splitting, because sys_mmap ignores this flag. Usually binfmt module sets
mm->exe_file and mmaps executable vmas with this file, they hold
mm->exe_file while task is running.comment from v2.6.25-6245-g925d1c4 ("procfs task exe symlink"),
where all this stuff was introduced:> The kernel implements readlink of /proc/pid/exe by getting the file from
> the first executable VMA. Then the path to the file is reconstructed and
> reported as the result.
>
> Because of the VMA walk the code is slightly different on nommu systems.
> This patch avoids separate /proc/pid/exe code on nommu systems. Instead of
> walking the VMAs to find the first executable file-backed VMA we store a
> reference to the exec'd file in the mm_struct.
>
> That reference would prevent the filesystem holding the executable file
> from being unmounted even after unmapping the VMAs. So we track the number
> of VM_EXECUTABLE VMAs and drop the new reference when the last one is
> unmapped. This avoids pinning the mounted filesystem.exe_file's vma accounting is hooked into every file mmap/unmmap and vma
split/merge just to fix some hypothetical pinning fs from umounting by mm,
which already unmapped all its executable files, but still alive.Seems like currently nobody depends on this behaviour. We can try to
remove this logic and keep mm->exe_file until final mmput().mm->exe_file is still protected with mm->mmap_sem, because we want to
change it via new sys_prctl(PR_SET_MM_EXE_FILE). Also via this syscall
task can change its mm->exe_file and unpin mountpoint explicitly.Signed-off-by: Konstantin Khlebnikov
Cc: Alexander Viro
Cc: Carsten Otte
Cc: Chris Metcalf
Cc: Cyrill Gorcunov
Cc: Eric Paris
Cc: H. Peter Anvin
Cc: Hugh Dickins
Cc: Ingo Molnar
Cc: James Morris
Cc: Jason Baron
Cc: Kentaro Takeda
Cc: Matt Helsley
Cc: Nick Piggin
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Robert Richter
Cc: Suresh Siddha
Cc: Tetsuo Handa
Cc: Venkatesh Pallipadi
Acked-by: Linus Torvalds
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Aug, 2012
2 commits
-
__GFP_MEMALLOC will allow the allocation to disregard the watermarks, much
like PF_MEMALLOC. It allows one to pass along the memalloc state in
object related allocation flags as opposed to task related flags, such as
sk->sk_allocation. This removes the need for ALLOC_PFMEMALLOC as callers
using __GFP_MEMALLOC can get the ALLOC_NO_WATERMARK flag which is now
enough to identify allocations related to page reclaim.Signed-off-by: Peter Zijlstra
Signed-off-by: Mel Gorman
Cc: David Miller
Cc: Neil Brown
Cc: Mike Christie
Cc: Eric B Munson
Cc: Eric Dumazet
Cc: Sebastian Andrzej Siewior
Cc: Mel Gorman
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When a user or administrator requires swap for their application, they
create a swap partition and file, format it with mkswap and activate it
with swapon. Swap over the network is considered as an option in diskless
systems. The two likely scenarios are when blade servers are used as part
of a cluster where the form factor or maintenance costs do not allow the
use of disks and thin clients.The Linux Terminal Server Project recommends the use of the Network Block
Device (NBD) for swap according to the manual at
https://sourceforge.net/projects/ltsp/files/Docs-Admin-Guide/LTSPManual.pdf/download
There is also documentation and tutorials on how to setup swap over NBD at
places like https://help.ubuntu.com/community/UbuntuLTSP/EnableNBDSWAP The
nbd-client also documents the use of NBD as swap. Despite this, the fact
is that a machine using NBD for swap can deadlock within minutes if swap
is used intensively. This patch series addresses the problem.The core issue is that network block devices do not use mempools like
normal block devices do. As the host cannot control where they receive
packets from, they cannot reliably work out in advance how much memory
they might need. Some years ago, Peter Zijlstra developed a series of
patches that supported swap over an NFS that at least one distribution is
carrying within their kernels. This patch series borrows very heavily
from Peter's work to support swapping over NBD as a pre-requisite to
supporting swap-over-NFS. The bulk of the complexity is concerned with
preserving memory that is allocated from the PFMEMALLOC reserves for use
by the network layer which is needed for both NBD and NFS.Patch 1 adds knowledge of the PFMEMALLOC reserves to SLAB and SLUB to
preserve access to pages allocated under low memory situations
to callers that are freeing memory.Patch 2 optimises the SLUB fast path to avoid pfmemalloc checks
Patch 3 introduces __GFP_MEMALLOC to allow access to the PFMEMALLOC
reserves without setting PFMEMALLOC.Patch 4 opens the possibility for softirqs to use PFMEMALLOC reserves
for later use by network packet processing.Patch 5 only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was required
Patch 6 ignores memory policies when ALLOC_NO_WATERMARKS is set.
Patches 7-12 allows network processing to use PFMEMALLOC reserves when
the socket has been marked as being used by the VM to clean pages. If
packets are received and stored in pages that were allocated under
low-memory situations and are unrelated to the VM, the packets
are dropped.Patch 11 reintroduces __skb_alloc_page which the networking
folk may object to but is needed in some cases to propogate
pfmemalloc from a newly allocated page to an skb. If there is a
strong objection, this patch can be dropped with the impact being
that swap-over-network will be slower in some cases but it should
not fail.Patch 13 is a micro-optimisation to avoid a function call in the
common case.Patch 14 tags NBD sockets as being SOCK_MEMALLOC so they can use
PFMEMALLOC if necessary.Patch 15 notes that it is still possible for the PFMEMALLOC reserve
to be depleted. To prevent this, direct reclaimers get throttled on
a waitqueue if 50% of the PFMEMALLOC reserves are depleted. It is
expected that kswapd and the direct reclaimers already running
will clean enough pages for the low watermark to be reached and
the throttled processes are woken up.Patch 16 adds a statistic to track how often processes get throttled
Some basic performance testing was run using kernel builds, netperf on
loopback for UDP and TCP, hackbench (pipes and sockets), iozone and
sysbench. Each of them were expected to use the sl*b allocators
reasonably heavily but there did not appear to be significant performance
variances.For testing swap-over-NBD, a machine was booted with 2G of RAM with a
swapfile backed by NBD. 8*NUM_CPU processes were started that create
anonymous memory mappings and read them linearly in a loop. The total
size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under
memory pressure.Without the patches and using SLUB, the machine locks up within minutes
and runs to completion with them applied. With SLAB, the story is
different as an unpatched kernel run to completion. However, the patched
kernel completed the test 45% faster.MICRO
3.5.0-rc2 3.5.0-rc2
vanilla swapnbd
Unrecognised test vmscan-anon-mmap-write
MMTests Statistics: duration
Sys Time Running Test (seconds) 197.80 173.07
User+Sys Time Running Test (seconds) 206.96 182.03
Total Elapsed Time (seconds) 3240.70 1762.09This patch: mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages
Allocations of pages below the min watermark run a risk of the machine
hanging due to a lack of memory. To prevent this, only callers who have
PF_MEMALLOC or TIF_MEMDIE set and are not processing an interrupt are
allowed to allocate with ALLOC_NO_WATERMARKS. Once they are allocated to
a slab though, nothing prevents other callers consuming free objects
within those slabs. This patch limits access to slab pages that were
alloced from the PFMEMALLOC reserves.When this patch is applied, pages allocated from below the low watermark
are returned with page->pfmemalloc set and it is up to the caller to
determine how the page should be protected. SLAB restricts access to any
page with page->pfmemalloc set to callers which are known to able to
access the PFMEMALLOC reserve. If one is not available, an attempt is
made to allocate a new page rather than use a reserve. SLUB is a bit more
relaxed in that it only records if the current per-CPU page was allocated
from PFMEMALLOC reserve and uses another partial slab if the caller does
not have the necessary GFP or process flags. This was found to be
sufficient in tests to avoid hangs due to SLUB generally maintaining
smaller lists than SLAB.In low-memory conditions it does mean that !PFMEMALLOC allocators can fail
a slab allocation even though free objects are available because they are
being preserved for callers that are freeing pages.[a.p.zijlstra@chello.nl: Original implementation]
[sebastian@breakpoint.cc: Correct order of page flag clearing]
Signed-off-by: Mel Gorman
Cc: David Miller
Cc: Neil Brown
Cc: Peter Zijlstra
Cc: Mike Christie
Cc: Eric B Munson
Cc: Eric Dumazet
Cc: Sebastian Andrzej Siewior
Cc: Mel Gorman
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
31 Jul, 2012
1 commit
-
Pull SLAB changes from Pekka Enberg:
"Most of the changes included are from Christoph Lameter's "common
slab" patch series that unifies common parts of SLUB, SLAB, and SLOB
allocators. The unification is needed for Glauber Costa's "kmem
memcg" work that will hopefully appear for v3.7.The rest of the changes are fixes and speedups by various people."
* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (32 commits)
mm: Fix build warning in kmem_cache_create()
slob: Fix early boot kernel crash
mm, slub: ensure irqs are enabled for kmemcheck
mm, sl[aou]b: Move kmem_cache_create mutex handling to common code
mm, sl[aou]b: Use a common mutex definition
mm, sl[aou]b: Common definition for boot state of the slab allocators
mm, sl[aou]b: Extract common code for kmem_cache_create()
slub: remove invalid reference to list iterator variable
mm: Fix signal SIGFPE in slabinfo.c.
slab: move FULL state transition to an initcall
slab: Fix a typo in commit 8c138b "slab: Get rid of obj_size macro"
mm, slab: Build fix for recent kmem_cache changes
slab: rename gfpflags to allocflags
slub: refactoring unfreeze_partials()
slub: use __cmpxchg_double_slab() at interrupt disabled place
slab/mempolicy: always use local policy from interrupt context
slab: Get rid of obj_size macro
mm, sl[aou]b: Extract common fields from struct kmem_cache
slab: Remove some accessors
slab: Use page struct fields instead of casting
...
21 Jun, 2012
1 commit
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On arches that do not support this_cpu_cmpxchg_double() slab_lock is used
to do atomic cmpxchg() on double word which contains page->_count. The
page count can be changed from get_page() or put_page() without taking
slab_lock. That corrupts page counter.Fix it by moving page->_count out of cmpxchg_double data. So that slub
does no change it while updating slub meta-data in struct page.[akpm@linux-foundation.org: use standard comment layout, tweak comment text]
Reported-by: Amey Bhide
Signed-off-by: Pravin B Shelar
Acked-by: Christoph Lameter
Cc: Pekka Enberg
Cc: Andrea Arcangeli
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Jun, 2012
2 commits
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Add fields to the page struct so that it is properly documented that
slab overlays the lru fields.This cleans up some casts in slab.
Reviewed-by: Glauber Costa
Reviewed-by: Joonsoo Kim
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg -
Define the fields used by slob in mm_types.h and use struct page instead
of struct slob_page in slob. This cleans up numerous of typecasts in slob.c and
makes readers aware of slob's use of page struct fields.[Also cleans up some bitrot in slob.c. The page struct field layout
in slob.c is an old layout and does not match the one in mm_types.h]Reviewed-by: Glauber Costa
Acked-by: David Rientjes
Reviewed-by: Joonsoo Kim
Signed-off-by: Christoph Lameter
Signed-off-by: Pekka Enberg
30 May, 2012
1 commit
-
The swap token code no longer fits in with the current VM model. It
does not play well with cgroups or the better NUMA placement code in
development, since we have only one swap token globally.It also has the potential to mess with scalability of the system, by
increasing the number of non-reclaimable pages on the active and
inactive anon LRU lists.Last but not least, the swap token code has been broken for a year
without complaints, as reported by Konstantin Khlebnikov. This suggests
we no longer have much use for it.The days of sub-1G memory systems with heavy use of swap are over. If
we ever need thrashing reducing code in the future, we will have to
implement something that does scale.Signed-off-by: Rik van Riel
Cc: Konstantin Khlebnikov
Acked-by: Johannes Weiner
Cc: Mel Gorman
Cc: Hugh Dickins
Acked-by: Bob Picco
Acked-by: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
