08 Apr, 2014
40 commits
-
There's only one caller of set_page_dirty_balance() and that will call it
with page_mkwrite == 0.The page_mkwrite argument was unused since commit b827e496c893 "mm: close
page_mkwrite races".Signed-off-by: Miklos Szeredi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
A BUG_ON(!PageLocked) was triggered in mlock_vma_page() by Sasha Levin
fuzzing with trinity. The call site try_to_unmap_cluster() does not lock
the pages other than its check_page parameter (which is already locked).The BUG_ON in mlock_vma_page() is not documented and its purpose is
somewhat unclear, but apparently it serializes against page migration,
which could otherwise fail to transfer the PG_mlocked flag. This would
not be fatal, as the page would be eventually encountered again, but
NR_MLOCK accounting would become distorted nevertheless. This patch adds
a comment to the BUG_ON in mlock_vma_page() and munlock_vma_page() to that
effect.The call site try_to_unmap_cluster() is fixed so that for page !=
check_page, trylock_page() is attempted (to avoid possible deadlocks as we
already have check_page locked) and mlock_vma_page() is performed only
upon success. If the page lock cannot be obtained, the page is left
without PG_mlocked, which is again not a problem in the whole unevictable
memory design.Signed-off-by: Vlastimil Babka
Signed-off-by: Bob Liu
Reported-by: Sasha Levin
Cc: Wanpeng Li
Cc: Michel Lespinasse
Cc: KOSAKI Motohiro
Acked-by: Rik van Riel
Cc: David Rientjes
Cc: Mel Gorman
Cc: Hugh Dickins
Cc: Joonsoo Kim
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
On NUMA systems, a node may start thrashing cache or even swap anonymous
pages while there are still free pages on remote nodes.This is a result of commits 81c0a2bb515f ("mm: page_alloc: fair zone
allocator policy") and fff4068cba48 ("mm: page_alloc: revert NUMA aspect
of fair allocation policy").Before those changes, the allocator would first try all allowed zones,
including those on remote nodes, before waking any kswapds. But now,
the allocator fastpath doubles as the fairness pass, which in turn can
only consider the local node to prevent remote spilling based on
exhausted fairness batches alone. Remote nodes are only considered in
the slowpath, after the kswapds are woken up. But if remote nodes still
have free memory, kswapd should not be woken to rebalance the local node
or it may thrash cash or swap prematurely.Fix this by adding one more unfair pass over the zonelist that is
allowed to spill to remote nodes after the local fairness pass fails but
before entering the slowpath and waking the kswapds.This also gets rid of the GFP_THISNODE exemption from the fairness
protocol because the unfair pass is no longer tied to kswapd, which
GFP_THISNODE is not allowed to wake up.However, because remote spills can be more frequent now - we prefer them
over local kswapd reclaim - the allocation batches on remote nodes could
underflow more heavily. When resetting the batches, use
atomic_long_read() directly instead of zone_page_state() to calculate the
delta as the latter filters negative counter values.Signed-off-by: Johannes Weiner
Acked-by: Rik van Riel
Acked-by: Mel Gorman
Cc: [3.12+]Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
mem_cgroup_newpage_charge is used only for charging anonymous memory so
it is better to rename it to mem_cgroup_charge_anon.mem_cgroup_cache_charge is used for file backed memory so rename it to
mem_cgroup_charge_file.Signed-off-by: Michal Hocko
Cc: Johannes Weiner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Some callsites pass a memcg directly, some callsites pass an mm that
then has to be translated to a memcg. This makes for a terrible
function interface.Just push the mm-to-memcg translation into the respective callsites and
always pass a memcg to mem_cgroup_try_charge().[mhocko@suse.cz: add charge mm helper]
Signed-off-by: Johannes Weiner
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
__mem_cgroup_try_charge duplicates get_mem_cgroup_from_mm for charges
which came without a memcg. The only reason seems to be a tiny
optimization when css_tryget is not called if the charge can be consumed
from the stock. Nevertheless css_tryget is very cheap since it has been
reworked to use per-cpu counting so this optimization doesn't give us
anything these days.So let's drop the code duplication so that the code is more readable.
Signed-off-by: Michal Hocko
Signed-off-by: Johannes Weiner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Instead of returning NULL from try_get_mem_cgroup_from_mm() when the mm
owner is exiting, just return root_mem_cgroup. This makes sense for all
callsites and gets rid of some of them having to fallback manually.[fengguang.wu@intel.com: fix warnings]
Signed-off-by: Johannes Weiner
Signed-off-by: Fengguang Wu
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Users pass either a mm that has been established under task lock, or use
a verified current->mm, which means the task can't be exiting.Signed-off-by: Johannes Weiner
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Only page cache charges can happen without an mm context, so push this
special case out of the inner core and into the cache charge function.An ancient comment explains that the mm can also be NULL in case the
task is currently being migrated, but that is not actually true with the
current case, so just remove it.Signed-off-by: Johannes Weiner
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
mem_cgroup_charge_common() is used by both cache and anon pages, but
most of its body only applies to anon pages and the remainder is not
worth having in a separate function.Signed-off-by: Johannes Weiner
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It used to disable preemption and run sanity checks but now it's only
taking a number out of one percpu counter and putting it into another.
Do this directly in the callsite and save the indirection.Signed-off-by: Johannes Weiner
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
lock_page_cgroup() disables preemption, remove explicit preemption
disabling for code paths holding this lock.Signed-off-by: Johannes Weiner
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
I tried to use 'dump_page(page, __func__)' for debugging, but it triggers
warning:warning: passing argument 2 of `dump_page' discards `const' qualifier from pointer target type [enabled by default]
Let's convert 'reason' to 'const char *' in dump_page() and friends: we
shouldn't modify it anyway.Signed-off-by: Kirill A. Shutemov
Cc: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
vm_map_ram() has a fragmentation problem when it cannot purge a
chunk(ie, 4M address space) if there is a pinning object in that
addresss space. So it could consume all VMALLOC address space easily.We can fix the fragmentation problem by using vmap instead of
vm_map_ram() but vmap() is known to be slow compared to vm_map_ram().
Minchan said vm_map_ram is 5 times faster than vmap in his tests. So I
thought we should fix fragment problem of vm_map_ram because our
proprietary GPU driver has used it heavily.On second thought, it's not an easy because we should reuse freed space
for solving the problem and it could make more IPI and bitmap operation
for searching hole. It could mitigate API's goal which is very fast
mapping. And even fragmentation problem wouldn't show in 64 bit
machine.Another option is that the user should separate long-life and short-life
object and use vmap for long-life but vm_map_ram for short-life. If we
inform the user about the characteristic of vm_map_ram the user can
choose one according to the page lifetime.Let's add some notice messages to user.
[akpm@linux-foundation.org: tweak comment text]
Signed-off-by: Gioh Kim
Reviewed-by: Zhang Yanfei
Cc: Minchan Kim
Cc: Johannes Weiner
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Choi Gi-yong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add unlikely and likely hints to the function mempool_free. It lays out
the code in such a way that the common path is executed straighforward and
saves a cache line.Signed-off-by: Mikulas Patocka
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The conditions that control the isolation mode in
isolate_migratepages_range() do not change during the iteration, so
extract them out and only define the value once.This actually does have an effect, gcc doesn't optimize it itself because
of cc->sync.Signed-off-by: David Rientjes
Cc: Mel Gorman
Acked-by: Rik van Riel
Acked-by: Vlastimil Babka
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The res_counter_{charge,uncharge}_locked() variants are not used in the
kernel outside of the resource counter code itself, so remove the
interface.Signed-off-by: David Rientjes
Acked-by: Michal Hocko
Cc: Johannes Weiner
Cc: KAMEZAWA Hiroyuki
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: Tejun Heo
Cc: Mel Gorman
Cc: Oleg Nesterov
Cc: Rik van Riel
Cc: Jianguo Wu
Cc: Tim Hockin
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
PF_MEMPOLICY is an unnecessary optimization for CONFIG_SLAB users.
There's no significant performance degradation to checking
current->mempolicy rather than current->flags & PF_MEMPOLICY in the
allocation path, especially since this is considered unlikely().Running TCP_RR with netperf-2.4.5 through localhost on 16 cpu machine with
64GB of memory and without a mempolicy:threads before after
16 1249409 1244487
32 1281786 1246783
48 1239175 1239138
64 1244642 1241841
80 1244346 1248918
96 1266436 1254316
112 1307398 1312135
128 1327607 1326502Per-process flags are a scarce resource so we should free them up whenever
possible and make them available. We'll be using it shortly for memcg oom
reserves.Signed-off-by: David Rientjes
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: KAMEZAWA Hiroyuki
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: Tejun Heo
Cc: Mel Gorman
Cc: Oleg Nesterov
Cc: Rik van Riel
Cc: Jianguo Wu
Cc: Tim Hockin
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
slab_node() is actually a mempolicy function, so rename it to
mempolicy_slab_node() to make it clearer that it used for processes with
mempolicies.At the same time, cleanup its code by saving numa_mem_id() in a local
variable (since we require a node with memory, not just any node) and
remove an obsolete comment that assumes the mempolicy is actually passed
into the function.Signed-off-by: David Rientjes
Acked-by: Christoph Lameter
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: KAMEZAWA Hiroyuki
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: Tejun Heo
Cc: Mel Gorman
Cc: Oleg Nesterov
Cc: Rik van Riel
Cc: Jianguo Wu
Cc: Tim Hockin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
copy_flags() does not use the clone_flags formal and can be collapsed
into copy_process() for cleaner code.Signed-off-by: David Rientjes
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: KAMEZAWA Hiroyuki
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: Tejun Heo
Cc: Mel Gorman
Cc: Oleg Nesterov
Cc: Rik van Riel
Cc: Jianguo Wu
Cc: Tim Hockin
Cc: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
To increase compiler portability there is which
provides convenience macros for various gcc constructs. Eg: __weak for
__attribute__((weak)). I've replaced all instances of gcc attributes with
the right macro in the memory management (/mm) subsystem.[akpm@linux-foundation.org: while-we're-there consistency tweaks]
Signed-off-by: Gideon Israel Dsouza
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch is a continuation of efforts trying to optimize find_vma(),
avoiding potentially expensive rbtree walks to locate a vma upon faults.
The original approach (https://lkml.org/lkml/2013/11/1/410), where the
largest vma was also cached, ended up being too specific and random,
thus further comparison with other approaches were needed. There are
two things to consider when dealing with this, the cache hit rate and
the latency of find_vma(). Improving the hit-rate does not necessarily
translate in finding the vma any faster, as the overhead of any fancy
caching schemes can be too high to consider.We currently cache the last used vma for the whole address space, which
provides a nice optimization, reducing the total cycles in find_vma() by
up to 250%, for workloads with good locality. On the other hand, this
simple scheme is pretty much useless for workloads with poor locality.
Analyzing ebizzy runs shows that, no matter how many threads are
running, the mmap_cache hit rate is less than 2%, and in many situations
below 1%.The proposed approach is to replace this scheme with a small per-thread
cache, maximizing hit rates at a very low maintenance cost.
Invalidations are performed by simply bumping up a 32-bit sequence
number. The only expensive operation is in the rare case of a seq
number overflow, where all caches that share the same address space are
flushed. Upon a miss, the proposed replacement policy is based on the
page number that contains the virtual address in question. Concretely,
the following results are seen on an 80 core, 8 socket x86-64 box:1) System bootup: Most programs are single threaded, so the per-thread
scheme does improve ~50% hit rate by just adding a few more slots to
the cache.+----------------+----------+------------------+
| caching scheme | hit-rate | cycles (billion) |
+----------------+----------+------------------+
| baseline | 50.61% | 19.90 |
| patched | 73.45% | 13.58 |
+----------------+----------+------------------+2) Kernel build: This one is already pretty good with the current
approach as we're dealing with good locality.+----------------+----------+------------------+
| caching scheme | hit-rate | cycles (billion) |
+----------------+----------+------------------+
| baseline | 75.28% | 11.03 |
| patched | 88.09% | 9.31 |
+----------------+----------+------------------+3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload.
+----------------+----------+------------------+
| caching scheme | hit-rate | cycles (billion) |
+----------------+----------+------------------+
| baseline | 70.66% | 17.14 |
| patched | 91.15% | 12.57 |
+----------------+----------+------------------+4) Ebizzy: There's a fair amount of variation from run to run, but this
approach always shows nearly perfect hit rates, while baseline is just
about non-existent. The amounts of cycles can fluctuate between
anywhere from ~60 to ~116 for the baseline scheme, but this approach
reduces it considerably. For instance, with 80 threads:+----------------+----------+------------------+
| caching scheme | hit-rate | cycles (billion) |
+----------------+----------+------------------+
| baseline | 1.06% | 91.54 |
| patched | 99.97% | 14.18 |
+----------------+----------+------------------+[akpm@linux-foundation.org: fix nommu build, per Davidlohr]
[akpm@linux-foundation.org: document vmacache_valid() logic]
[akpm@linux-foundation.org: attempt to untangle header files]
[akpm@linux-foundation.org: add vmacache_find() BUG_ON]
[hughd@google.com: add vmacache_valid_mm() (from Oleg)]
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: adjust and enhance comments]
Signed-off-by: Davidlohr Bueso
Reviewed-by: Rik van Riel
Acked-by: Linus Torvalds
Reviewed-by: Michel Lespinasse
Cc: Oleg Nesterov
Tested-by: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In shmem/tmpfs, we also use the generic filemap_map_pages, seems the
additional checking is not worth a separate version of map_pages for it.Signed-off-by: Ning Qu
Acked-by: Hugh Dickins
Cc: "Kirill A. Shutemov"
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Dave Hansen
Cc: Dave Chinner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Let's allow people to tweak faultaround at runtime.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kirill A. Shutemov
Cc: Linus Torvalds
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Andi Kleen
Cc: Matthew Wilcox
Cc: Dave Hansen
Cc: Alexander Viro
Cc: Dave Chinner
Cc: Ning Qu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Minor cleanups:
- 'size' variable is now in bytes, not pages;
- use round_up(): it should be easier to read.Signed-off-by: Kirill A. Shutemov
Cc: Linus Torvalds
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Andi Kleen
Cc: Matthew Wilcox
Cc: Dave Hansen
Cc: Alexander Viro
Cc: Dave Chinner
Cc: Ning Qu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
filemap_map_pages() is generic implementation of ->map_pages() for
filesystems who uses page cache.It should be safe to use filemap_map_pages() for ->map_pages() if
filesystem use filemap_fault() for ->fault().Signed-off-by: Kirill A. Shutemov
Acked-by: Linus Torvalds
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Andi Kleen
Cc: Matthew Wilcox
Cc: Dave Hansen
Cc: Alexander Viro
Cc: Dave Chinner
Cc: Ning Qu
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Here's new version of faultaround patchset. It took a while to tune it
and collect performance data.First patch adds new callback ->map_pages to vm_operations_struct.
->map_pages() is called when VM asks to map easy accessible pages.
Filesystem should find and map pages associated with offsets from
"pgoff" till "max_pgoff". ->map_pages() is called with page table
locked and must not block. If it's not possible to reach a page without
blocking, filesystem should skip it. Filesystem should use do_set_pte()
to setup page table entry. Pointer to entry associated with offset
"pgoff" is passed in "pte" field in vm_fault structure. Pointers to
entries for other offsets should be calculated relative to "pte".Currently VM use ->map_pages only on read page fault path. We try to
map FAULT_AROUND_PAGES a time. FAULT_AROUND_PAGES is 16 for now.
Performance data for different FAULT_AROUND_ORDER is below.TODO:
- implement ->map_pages() for shmem/tmpfs;
- modify get_user_pages() to be able to use ->map_pages() and implement
mmap(MAP_POPULATE|MAP_NONBLOCK) on top.=========================================================================
Tested on 4-socket machine (120 threads) with 128GiB of RAM.Few real-world workloads. The sweet spot for FAULT_AROUND_ORDER here is
somewhere between 3 and 5. Let's say 4 :)Linux build (make -j60)
FAULT_AROUND_ORDER Baseline 1 3 4 5 7 9
minor-faults 283,301,572 247,151,987 212,215,789 204,772,882 199,568,944 194,703,779 193,381,485
time, seconds 151.227629483 153.920996480 151.356125472 150.863792049 150.879207877 151.150764954 151.450962358
Linux rebuild (make -j60)
FAULT_AROUND_ORDER Baseline 1 3 4 5 7 9
minor-faults 5,396,854 4,148,444 2,855,286 2,577,282 2,361,957 2,169,573 2,112,643
time, seconds 27.404543757 27.559725591 27.030057426 26.855045126 26.678618635 26.974523490 26.761320095
Git test suite (make -j60 test)
FAULT_AROUND_ORDER Baseline 1 3 4 5 7 9
minor-faults 129,591,823 99,200,751 66,106,718 57,606,410 51,510,808 45,776,813 44,085,515
time, seconds 66.087215026 64.784546905 64.401156567 65.282708668 66.034016829 66.793780811 67.237810413Two synthetic tests: access every word in file in sequential/random order.
It doesn't improve much after FAULT_AROUND_ORDER == 4.Sequential access 16GiB file
FAULT_AROUND_ORDER Baseline 1 3 4 5 7 9
1 thread
minor-faults 4,195,437 2,098,275 525,068 262,251 131,170 32,856 8,282
time, seconds 7.250461742 6.461711074 5.493859139 5.488488147 5.707213983 5.898510832 5.109232856
8 threads
minor-faults 33,557,540 16,892,728 4,515,848 2,366,999 1,423,382 442,732 142,339
time, seconds 16.649304881 9.312555263 6.612490639 6.394316732 6.669827501 6.75078944 6.371900528
32 threads
minor-faults 134,228,222 67,526,810 17,725,386 9,716,537 4,763,731 1,668,921 537,200
time, seconds 49.164430543 29.712060103 12.938649729 10.175151004 11.840094583 9.594081325 9.928461797
60 threads
minor-faults 251,687,988 126,146,952 32,919,406 18,208,804 10,458,947 2,733,907 928,217
time, seconds 86.260656897 49.626551828 22.335007632 17.608243696 16.523119035 16.339489186 16.326390902
120 threads
minor-faults 503,352,863 252,939,677 67,039,168 35,191,827 19,170,091 4,688,357 1,471,862
time, seconds 124.589206333 79.757867787 39.508707872 32.167281632 29.972989292 28.729834575 28.042251622
Random access 1GiB file
1 thread
minor-faults 262,636 132,743 34,369 17,299 8,527 3,451 1,222
time, seconds 15.351890914 16.613802482 16.569227308 15.179220992 16.557356122 16.578247824 15.365266994
8 threads
minor-faults 2,098,948 1,061,871 273,690 154,501 87,110 25,663 7,384
time, seconds 15.040026343 15.096933500 14.474757288 14.289129964 14.411537468 14.296316837 14.395635804
32 threads
minor-faults 8,390,734 4,231,023 1,054,432 528,847 269,242 97,746 26,881
time, seconds 20.430433109 21.585235358 22.115062928 14.872878951 14.880856305 14.883370649 14.821261690
60 threads
minor-faults 15,733,258 7,892,809 1,973,393 988,266 594,789 164,994 51,691
time, seconds 26.577302548 25.692397770 18.728863715 20.153026398 21.619101933 17.745086260 17.613215273
120 threads
minor-faults 31,471,111 15,816,616 3,959,209 1,978,685 1,008,299 264,635 96,010
time, seconds 41.835322703 40.459786095 36.085306105 35.313894834 35.814445675 36.552633793 34.289210594Touch only one page in page table in 16GiB file
FAULT_AROUND_ORDER Baseline 1 3 4 5 7 9
1 thread
minor-faults 8,372 8,324 8,270 8,260 8,249 8,239 8,237
time, seconds 0.039892712 0.045369149 0.051846126 0.063681685 0.079095975 0.17652406 0.541213386
8 threads
minor-faults 65,731 65,681 65,628 65,620 65,608 65,599 65,596
time, seconds 0.124159196 0.488600638 0.156854426 0.191901957 0.242631486 0.543569456 1.677303984
32 threads
minor-faults 262,388 262,341 262,285 262,276 262,266 262,257 263,183
time, seconds 0.452421421 0.488600638 0.565020946 0.648229739 0.789850823 1.651584361 5.000361559
60 threads
minor-faults 491,822 491,792 491,723 491,711 491,701 491,691 491,825
time, seconds 0.763288616 0.869620515 0.980727360 1.161732354 1.466915814 3.04041448 9.308612938
120 threads
minor-faults 983,466 983,655 983,366 983,372 983,363 984,083 984,164
time, seconds 1.595846553 1.667902182 2.008959376 2.425380942 2.941368804 5.977807890 18.401846125This patch (of 2):
Introduce new vm_ops callback ->map_pages() and uses it for mapping easy
accessible pages around fault address.On read page fault, if filesystem provides ->map_pages(), we try to map up
to FAULT_AROUND_PAGES pages around page fault address in hope to reduce
number of minor page faults.We call ->map_pages first and use ->fault() as fallback if page by the
offset is not ready to be mapped (cold page cache or something).Signed-off-by: Kirill A. Shutemov
Acked-by: Linus Torvalds
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Andi Kleen
Cc: Matthew Wilcox
Cc: Dave Hansen
Cc: Alexander Viro
Cc: Dave Chinner
Cc: Ning Qu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
"mm: introduce vm_ops->map_pages()" wants to export a do_set_pte() from core
kernel. Rename lguest's do_set_pte() to something more lguest-specific.Cc: "Kirill A. Shutemov"
Cc: Rusty Russell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
After this patch 'page-types' can walk over a file's mappings and
analyze populated page cache pages mostly without disturbing its state.It maps chunk of file, marks VMA as MADV_RANDOM to turn off readahead,
pokes VMA via mincore() to determine cached pages, triggers page-fault
only for them, and finally gathers information via pagemap/kpageflags.
Before unmap it marks VMA as MADV_SEQUENTIAL for ignoring reference
bits.usage: page-types -f
If is directory it will analyse all files in all subdirectories.
Symlinks are not followed as well as mount points. Hardlinks aren't
handled, they'll be dumped as many times as they are found. Recursive
walk brings all dentries into dcache and populates page cache of
block-devices aka 'Buffers'.Probably it's worth to add ioctl for dumping file page cache as array of
PFNs as a replacement for this hackish juggling with
mmap/madvise/mincore/pagemap. Also recursive walk could be replaced
with dumping cached inodes via some ioctl or debugfs interface followed
by openning them via open_by_handle_at, this would fix hardlinks
handling and unneeded population of dcache and buffers. This interface
might be used as data source for constructing readahead plans and for
background optimizations of actively used files.collateral changes:
+ fix 64-bit LFS: define _FILE_OFFSET_BITS instead of _LARGEFILE64_SOURCE
+ replace lseek + read with single pread
+ make show_page_range() reusable after flushusage example:
~/src/linux/tools/vm$ sudo ./page-types -L -f page-types
foffset offset flags
page-types Inode: 2229277 Size: 89065 (22 pages)
Modify: Tue Feb 25 12:00:59 2014 (162 seconds ago)
Access: Tue Feb 25 12:01:00 2014 (161 seconds ago)
0 3cbf3b __RU_lA____M________________________
1 38946a __RU_lA____M________________________
2 1a3cec __RU_lA____M________________________
3 1a8321 __RU_lA____M________________________
4 3af7cc __RU_lA____M________________________
5 1ed532 __RU_lA_____________________________
6 2e436a __RU_lA_____________________________
7 29a35e ___U_lA_____________________________
8 2de86e ___U_lA_____________________________
9 3bdfb4 ___U_lA_____________________________
10 3cd8a3 ___U_lA_____________________________
11 2afa50 ___U_lA_____________________________
12 2534c2 ___U_lA_____________________________
13 1b7a40 ___U_lA_____________________________
14 17b0be ___U_lA_____________________________
15 392b0c ___U_lA_____________________________
16 3ba46a __RU_lA_____________________________
17 397dc8 ___U_lA_____________________________
18 1f2a36 ___U_lA_____________________________
19 21fd30 __RU_lA_____________________________
20 2c35ba __RU_l______________________________
21 20f181 __RU_l______________________________flags page-count MB symbolic-flags long-symbolic-flags
0x000000000000002c 2 0 __RU_l______________________________ referenced,uptodate,lru
0x0000000000000068 11 0 ___U_lA_____________________________ uptodate,lru,active
0x000000000000006c 4 0 __RU_lA_____________________________ referenced,uptodate,lru,active
0x000000000000086c 5 0 __RU_lA____M________________________ referenced,uptodate,lru,active,mmap
total 22 0~/src/linux/tools/vm$ sudo ./page-types -f /
flags page-count MB symbolic-flags long-symbolic-flags
0x0000000000000028 21761 85 ___U_l______________________________ uptodate,lru
0x000000000000002c 127279 497 __RU_l______________________________ referenced,uptodate,lru
0x0000000000000068 74160 289 ___U_lA_____________________________ uptodate,lru,active
0x000000000000006c 84469 329 __RU_lA_____________________________ referenced,uptodate,lru,active
0x000000000000007c 1 0 __RUDlA_____________________________ referenced,uptodate,dirty,lru,active
0x0000000000000228 370 1 ___U_l___I__________________________ uptodate,lru,reclaim
0x0000000000000828 49 0 ___U_l_____M________________________ uptodate,lru,mmap
0x000000000000082c 126 0 __RU_l_____M________________________ referenced,uptodate,lru,mmap
0x0000000000000868 137 0 ___U_lA____M________________________ uptodate,lru,active,mmap
0x000000000000086c 12890 50 __RU_lA____M________________________ referenced,uptodate,lru,active,mmap
total 321242 1254Signed-off-by: Konstantin Khlebnikov
Cc: Arnaldo Carvalho de Melo
Cc: Fengguang Wu
Cc: Borislav Petkov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There's no reason to enable split page table lock if don't have page
tables.It also triggers build error at least on ARM since we don't define
pmd_page() for !MMU.In file included from arch/arm/kernel/asm-offsets.c:14:0:
include/linux/mm.h: In function 'pte_lockptr':
include/linux/mm.h:1392:2: error: implicit declaration of function 'pmd_page' [-Werror=implicit-function-declaration]
include/linux/mm.h:1392:2: warning: passing argument 1 of 'ptlock_ptr' makes pointer from integer without a cast [enabled by default]
include/linux/mm.h:1384:27: note: expected 'struct page *' but argument is of type 'int'Signed-off-by: Kirill A. Shutemov
Reported-by: Uwe Kleine-König
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
load_elf_binary() sets current->mm->def_flags = def_flags and def_flags
is always zero. Not only this looks strange, this is unnecessary
because mm_init() has already set ->def_flags = 0.Signed-off-by: Alex Thorlton
Suggested-by: Oleg Nesterov
Cc: Gerald Schaefer
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Christian Borntraeger
Cc: Paolo Bonzini
Cc: "Kirill A. Shutemov"
Cc: Mel Gorman
Acked-by: Rik van Riel
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Oleg Nesterov
Cc: "Eric W. Biederman"
Cc: Alexander Viro
Cc: Johannes Weiner
Cc: David Rientjes
Cc: Paolo Bonzini
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add VM_INIT_DEF_MASK, to allow us to set the default flags for VMs. It
also adds a prctl control which allows us to set the THP disable bit in
mm->def_flags so that VMs will pick up the setting as they are created.Signed-off-by: Alex Thorlton
Suggested-by: Oleg Nesterov
Cc: Gerald Schaefer
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Christian Borntraeger
Cc: Paolo Bonzini
Cc: "Kirill A. Shutemov"
Cc: Mel Gorman
Acked-by: Rik van Riel
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Oleg Nesterov
Cc: "Eric W. Biederman"
Cc: Alexander Viro
Cc: Johannes Weiner
Cc: David Rientjes
Cc: Paolo Bonzini
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The main motivation behind this patch is to provide a way to disable THP
for jobs where the code cannot be modified, and using a malloc hook with
madvise is not an option (i.e. statically allocated data). This patch
allows us to do just that, without affecting other jobs running on the
system.We need to do this sort of thing for jobs where THP hurts performance,
due to the possibility of increased remote memory accesses that can be
created by situations such as the following:When you touch 1 byte of an untouched, contiguous 2MB chunk, a THP will
be handed out, and the THP will be stuck on whatever node the chunk was
originally referenced from. If many remote nodes need to do work on
that same chunk, they'll be making remote accesses.With THP disabled, 4K pages can be handed out to separate nodes as
they're needed, greatly reducing the amount of remote accesses to
memory.This patch is based on some of my work combined with some
suggestions/patches given by Oleg Nesterov. The main goal here is to
add a prctl switch to allow us to disable to THP on a per mm_struct
basis.Here's a bit of test data with the new patch in place...
First with the flag unset:
# perf stat -a ./prctl_wrapper_mmv3 0 ./thp_pthread -C 0 -m 0 -c 512 -b 256g
Setting thp_disabled for this task...
thp_disable: 0
Set thp_disabled state to 0
Process pid = 18027PF/
MAX MIN TOTCPU/ TOT_PF/ TOT_PF/ WSEC/
TYPE: CPUS WALL WALL SYS USER TOTCPU CPU WALL_SEC SYS_SEC CPU NODES
512 1.120 0.060 0.000 0.110 0.110 0.000 28571428864 -9223372036854775808 55803572 23Performance counter stats for './prctl_wrapper_mmv3_hack 0 ./thp_pthread -C 0 -m 0 -c 512 -b 256g':
273719072.841402 task-clock # 641.026 CPUs utilized [100.00%]
1,008,986 context-switches # 0.000 M/sec [100.00%]
7,717 CPU-migrations # 0.000 M/sec [100.00%]
1,698,932 page-faults # 0.000 M/sec
355,222,544,890,379 cycles # 1.298 GHz [100.00%]
536,445,412,234,588 stalled-cycles-frontend # 151.02% frontend cycles idle [100.00%]
409,110,531,310,223 stalled-cycles-backend # 115.17% backend cycles idle [100.00%]
148,286,797,266,411 instructions # 0.42 insns per cycle
# 3.62 stalled cycles per insn [100.00%]
27,061,793,159,503 branches # 98.867 M/sec [100.00%]
1,188,655,196 branch-misses # 0.00% of all branches427.001706337 seconds time elapsed
Now with the flag set:
# perf stat -a ./prctl_wrapper_mmv3 1 ./thp_pthread -C 0 -m 0 -c 512 -b 256g
Setting thp_disabled for this task...
thp_disable: 1
Set thp_disabled state to 1
Process pid = 144957PF/
MAX MIN TOTCPU/ TOT_PF/ TOT_PF/ WSEC/
TYPE: CPUS WALL WALL SYS USER TOTCPU CPU WALL_SEC SYS_SEC CPU NODES
512 0.620 0.260 0.250 0.320 0.570 0.001 51612901376 128000000000 100806448 23Performance counter stats for './prctl_wrapper_mmv3_hack 1 ./thp_pthread -C 0 -m 0 -c 512 -b 256g':
138789390.540183 task-clock # 641.959 CPUs utilized [100.00%]
534,205 context-switches # 0.000 M/sec [100.00%]
4,595 CPU-migrations # 0.000 M/sec [100.00%]
63,133,119 page-faults # 0.000 M/sec
147,977,747,269,768 cycles # 1.066 GHz [100.00%]
200,524,196,493,108 stalled-cycles-frontend # 135.51% frontend cycles idle [100.00%]
105,175,163,716,388 stalled-cycles-backend # 71.07% backend cycles idle [100.00%]
180,916,213,503,160 instructions # 1.22 insns per cycle
# 1.11 stalled cycles per insn [100.00%]
26,999,511,005,868 branches # 194.536 M/sec [100.00%]
714,066,351 branch-misses # 0.00% of all branches216.196778807 seconds time elapsed
As with previous versions of the patch, We're getting about a 2x
performance increase here. Here's a link to the test case I used, along
with the little wrapper to activate the flag:http://oss.sgi.com/projects/memtests/thp_pthread_mmprctlv3.tar.gz
This patch (of 3):
Revert commit 8e72033f2a48 and add in code to fix up any issues caused
by the revert.The revert is necessary because hugepage_madvise would return -EINVAL
when VM_NOHUGEPAGE is set, which will break subsequent chunks of this
patch set.Here's a snip of an e-mail from Gerald detailing the original purpose of
this code, and providing justification for the revert:"The intent of commit 8e72033f2a48 was to guard against any future
programming errors that may result in an madvice(MADV_HUGEPAGE) on
guest mappings, which would crash the kernel.Martin suggested adding the bit to arch/s390/mm/pgtable.c, if
8e72033f2a48 was to be reverted, because that check will also prevent
a kernel crash in the case described above, it will now send a
SIGSEGV instead.This would now also allow to do the madvise on other parts, if
needed, so it is a more flexible approach. One could also say that
it would have been better to do it this way right from the
beginning..."Signed-off-by: Alex Thorlton
Suggested-by: Oleg Nesterov
Tested-by: Christian Borntraeger
Cc: Gerald Schaefer
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Paolo Bonzini
Cc: "Kirill A. Shutemov"
Cc: Mel Gorman
Cc: Rik van Riel
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Andrea Arcangeli
Cc: Oleg Nesterov
Cc: "Eric W. Biederman"
Cc: Johannes Weiner
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It is just for clean-up to reduce code size and improve readability.
There is no functional change.Signed-off-by: Joonsoo Kim
Acked-by: Vlastimil Babka
Cc: Mel Gorman
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
isolation_suitable() and migrate_async_suitable() is used to be sure
that this pageblock range is fine to be migragted. It isn't needed to
call it on every page. Current code do well if not suitable, but, don't
do well when suitable.1) It re-checks isolation_suitable() on each page of a pageblock that was
already estabilished as suitable.
2) It re-checks migrate_async_suitable() on each page of a pageblock that
was not entered through the next_pageblock: label, because
last_pageblock_nr is not otherwise updated.This patch fixes situation by 1) calling isolation_suitable() only once
per pageblock and 2) always updating last_pageblock_nr to the pageblock
that was just checked.Additionally, move PageBuddy() check after pageblock unit check, since
pageblock check is the first thing we should do and makes things more
simple.[vbabka@suse.cz: rephrase commit description]
Signed-off-by: Joonsoo Kim
Acked-by: Vlastimil Babka
Cc: Mel Gorman
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It is odd to drop the spinlock when we scan (SWAP_CLUSTER_MAX - 1) th
pfn page. This may results in below situation while isolating
migratepage.1. try isolate 0x0 ~ 0x200 pfn pages.
2. When low_pfn is 0x1ff, ((low_pfn+1) % SWAP_CLUSTER_MAX) == 0, so drop
the spinlock.
3. Then, to complete isolating, retry to aquire the lock.I think that it is better to use SWAP_CLUSTER_MAX th pfn for checking the
criteria about dropping the lock. This has no harm 0x0 pfn, because, at
this time, locked variable would be false.Signed-off-by: Joonsoo Kim
Acked-by: Vlastimil Babka
Cc: Mel Gorman
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
suitable_migration_target() checks that pageblock is suitable for
migration target. In isolate_freepages_block(), it is called on every
page and this is inefficient. So make it called once per pageblock.suitable_migration_target() also checks if page is highorder or not, but
it's criteria for highorder is pageblock order. So calling it once
within pageblock range has no problem.Signed-off-by: Joonsoo Kim
Acked-by: Vlastimil Babka
Cc: Mel Gorman
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Purpose of compaction is to get a high order page. Currently, if we
find high-order page while searching migration target page, we break it
to order-0 pages and use them as migration target. It is contrary to
purpose of compaction, so disallow high-order page to be used for
migration target.Additionally, clean-up logic in suitable_migration_target() to simplify
the code. There is no functional changes from this clean-up.Signed-off-by: Joonsoo Kim
Acked-by: Vlastimil Babka
Cc: Mel Gorman
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We had a report about strange OOM killer strikes on a PPC machine
although there was a lot of swap free and a tons of anonymous memory
which could be swapped out. In the end it turned out that the OOM was a
side effect of zone reclaim which wasn't unmapping and swapping out and
so the system was pushed to the OOM. Although this sounds like a bug
somewhere in the kswapd vs. zone reclaim vs. direct reclaim
interaction numactl on the said hardware suggests that the zone reclaim
should not have been set in the first place:node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
node 0 size: 0 MB
node 0 free: 0 MB
node 2 cpus:
node 2 size: 7168 MB
node 2 free: 6019 MB
node distances:
node 0 2
0: 10 40
2: 40 10So all the CPUs are associated with Node0 which doesn't have any memory
while Node2 contains all the available memory. Node distances cause an
automatic zone_reclaim_mode enabling.Zone reclaim is intended to keep the allocations local but this doesn't
make any sense on the memoryless nodes. So let's exclude such nodes for
init_zone_allows_reclaim which evaluates zone reclaim behavior and
suitable reclaim_nodes.Signed-off-by: Michal Hocko
Acked-by: David Rientjes
Acked-by: Nishanth Aravamudan
Tested-by: Nishanth Aravamudan
Acked-by: Mel Gorman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
