A swappiness of 0 has a slightly different meaning for global reclaim
(may swap if file cache really low) and memory cgroup reclaim (never
swap, ever).
In addition, global reclaim at highest priority will scan all LRU lists
equal to their size and ignore other balancing heuristics. UNLESS
swappiness forbids swapping, then the lists are balanced based on recent
reclaim effectiveness. UNLESS file cache is running low, then anonymous
pages are force-scanned.
This (total mess of a) behaviour is implicit and not obvious from the
way the code is organized. At least make it apparent in the code flow
and document the conditions. It will be it easier to come up with sane
semantics later.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Satoru Moriya <satoru.moriya@hds.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Simon Jeons <simon.jeons@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In certain cases (kswapd reclaim, memcg target reclaim), a fixed minimum
amount of pages is scanned from the LRU lists on each iteration, to make
progress.
Do not make this minimum bigger than the respective LRU list size,
however, and save some busy work trying to isolate and reclaim pages
that are not there.
Empty LRU lists are quite common with memory cgroups in NUMA
environments because there exists a set of LRU lists for each zone for
each memory cgroup, while the memory of a single cgroup is expected to
stay on just one node. The number of expected empty LRU lists is thus
memcgs * (nodes - 1) * lru types
Each attempt to reclaim from an empty LRU list does expensive size
comparisons between lists, acquires the zone's lru lock etc. Avoid
that.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Satoru Moriya <satoru.moriya@hds.com>
Cc: Simon Jeons <simon.jeons@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e986850598 ("mm, vmscan: only evict file pages when we have
plenty") makes a point of not going for anonymous memory while there is
still enough inactive cache around.
The check was added only for global reclaim, but it is just as useful to
reduce swapping in memory cgroup reclaim:
200M-memcg-defconfig-j2
vanilla patched
Real time 454.06 ( +0.00%) 453.71 ( -0.08%)
User time 668.57 ( +0.00%) 668.73 ( +0.02%)
System time 128.92 ( +0.00%) 129.53 ( +0.46%)
Swap in 1246.80 ( +0.00%) 814.40 ( -34.65%)
Swap out 1198.90 ( +0.00%) 827.00 ( -30.99%)
Pages allocated 16431288.10 ( +0.00%) 16434035.30 ( +0.02%)
Major faults 681.50 ( +0.00%) 593.70 ( -12.86%)
THP faults 237.20 ( +0.00%) 242.40 ( +2.18%)
THP collapse 241.20 ( +0.00%) 248.50 ( +3.01%)
THP splits 157.30 ( +0.00%) 161.40 ( +2.59%)
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Satoru Moriya <satoru.moriya@hds.com>
Cc: Simon Jeons <simon.jeons@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As per documentation and other places calling putback_lru_pages(),
putback_lru_pages() is called on error only. Make the CMA code behave
consistently.
[akpm@linux-foundation.org: remove a test-n-branch in the wrapup code]
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.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>
Pull x86 mm changes from Peter Anvin:
"This is a huge set of several partly interrelated (and concurrently
developed) changes, which is why the branch history is messier than
one would like.
The *really* big items are two humonguous patchsets mostly developed
by Yinghai Lu at my request, which completely revamps the way we
create initial page tables. In particular, rather than estimating how
much memory we will need for page tables and then build them into that
memory -- a calculation that has shown to be incredibly fragile -- we
now build them (on 64 bits) with the aid of a "pseudo-linear mode" --
a #PF handler which creates temporary page tables on demand.
This has several advantages:
1. It makes it much easier to support things that need access to data
very early (a followon patchset uses this to load microcode way
early in the kernel startup).
2. It allows the kernel and all the kernel data objects to be invoked
from above the 4 GB limit. This allows kdump to work on very large
systems.
3. It greatly reduces the difference between Xen and native (Xen's
equivalent of the #PF handler are the temporary page tables created
by the domain builder), eliminating a bunch of fragile hooks.
The patch series also gets us a bit closer to W^X.
Additional work in this pull is the 64-bit get_user() work which you
were also involved with, and a bunch of cleanups/speedups to
__phys_addr()/__pa()."
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (105 commits)
x86, mm: Move reserving low memory later in initialization
x86, doc: Clarify the use of asm("%edx") in uaccess.h
x86, mm: Redesign get_user with a __builtin_choose_expr hack
x86: Be consistent with data size in getuser.S
x86, mm: Use a bitfield to mask nuisance get_user() warnings
x86/kvm: Fix compile warning in kvm_register_steal_time()
x86-32: Add support for 64bit get_user()
x86-32, mm: Remove reference to alloc_remap()
x86-32, mm: Remove reference to resume_map_numa_kva()
x86-32, mm: Rip out x86_32 NUMA remapping code
x86/numa: Use __pa_nodebug() instead
x86: Don't panic if can not alloc buffer for swiotlb
mm: Add alloc_bootmem_low_pages_nopanic()
x86, 64bit, mm: hibernate use generic mapping_init
x86, 64bit, mm: Mark data/bss/brk to nx
x86: Merge early kernel reserve for 32bit and 64bit
x86: Add Crash kernel low reservation
x86, kdump: Remove crashkernel range find limit for 64bit
memblock: Add memblock_mem_size()
x86, boot: Not need to check setup_header version for setup_data
...
Pull s390 update from Martin Schwidefsky:
"The most prominent change in this patch set is the software dirty bit
patch for s390. It removes __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY and
the page_test_and_clear_dirty primitive which makes the common memory
management code a bit less obscure.
Heiko fixed most of the PCI related fallout, more often than not
missing GENERIC_HARDIRQS dependencies. Notable is one of the 3270
patches which adds an export to tty_io to be able to resize a tty.
The rest is the usual bunch of cleanups and bug fixes."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (42 commits)
s390/module: Add missing R_390_NONE relocation type
drivers/gpio: add missing GENERIC_HARDIRQ dependency
drivers/input: add couple of missing GENERIC_HARDIRQS dependencies
s390/cleanup: rename SPP to LPP
s390/mm: implement software dirty bits
s390/mm: Fix crst upgrade of mmap with MAP_FIXED
s390/linker skript: discard exit.data at runtime
drivers/media: add missing GENERIC_HARDIRQS dependency
s390/bpf,jit: add vlan tag support
drivers/net,AT91RM9200: add missing GENERIC_HARDIRQS dependency
iucv: fix kernel panic at reboot
s390/Kconfig: sort list of arch selected config options
phylib: remove !S390 dependeny from Kconfig
uio: remove !S390 dependency from Kconfig
dasd: fix sysfs cleanup in dasd_generic_remove
s390/pci: fix hotplug module init
s390/pci: cleanup clp page allocation
s390/pci: cleanup clp inline assembly
s390/perf: cpum_cf: fallback to software sampling events
s390/mm: provide PAGE_SHARED define
...
Merge misc patches from Andrew Morton:
- Florian has vanished so I appear to have become fbdev maintainer
again :(
- Joel and Mark are distracted to welcome to the new OCFS2 maintainer
- The backlight queue
- Small core kernel changes
- lib/ updates
- The rtc queue
- Various random bits
* akpm: (164 commits)
rtc: rtc-davinci: use devm_*() functions
rtc: rtc-max8997: use devm_request_threaded_irq()
rtc: rtc-max8907: use devm_request_threaded_irq()
rtc: rtc-da9052: use devm_request_threaded_irq()
rtc: rtc-wm831x: use devm_request_threaded_irq()
rtc: rtc-tps80031: use devm_request_threaded_irq()
rtc: rtc-lp8788: use devm_request_threaded_irq()
rtc: rtc-coh901331: use devm_clk_get()
rtc: rtc-vt8500: use devm_*() functions
rtc: rtc-tps6586x: use devm_request_threaded_irq()
rtc: rtc-imxdi: use devm_clk_get()
rtc: rtc-cmos: use dev_warn()/dev_dbg() instead of printk()/pr_debug()
rtc: rtc-pcf8583: use dev_warn() instead of printk()
rtc: rtc-sun4v: use pr_warn() instead of printk()
rtc: rtc-vr41xx: use dev_info() instead of printk()
rtc: rtc-rs5c313: use pr_err() instead of printk()
rtc: rtc-at91rm9200: use dev_dbg()/dev_err() instead of printk()/pr_debug()
rtc: rtc-rs5c372: use dev_dbg()/dev_warn() instead of printk()/pr_debug()
rtc: rtc-ds2404: use dev_err() instead of printk()
rtc: rtc-efi: use dev_err()/dev_warn()/pr_err() instead of printk()
...
This provides a band-aid to provide stable page writes on jbd without
needing to backport the fixed locking and page writeback bit handling
schemes of jbd2. The band-aid works by using bounce buffers to snapshot
page contents instead of waiting.
For those wondering about the ext3 bandage -- fixing the jbd locking
(which was done as part of ext4dev years ago) is a lot of surgery, and
setting PG_writeback on data pages when we actually hold the page lock
dropped ext3 performance by nearly an order of magnitude. If we're
going to migrate iscsi and raid to use stable page writes, the
complaints about high latency will likely return. We might as well
centralize their page snapshotting thing to one place.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Tested-by: Andy Lutomirski <luto@amacapital.net>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Create a helper function to check if a backing device requires stable
page writes and, if so, performs the necessary wait. Then, make it so
that all points in the memory manager that handle making pages writable
use the helper function. This should provide stable page write support
to most filesystems, while eliminating unnecessary waiting for devices
that don't require the feature.
Before this patchset, all filesystems would block, regardless of whether
or not it was necessary. ext3 would wait, but still generate occasional
checksum errors. The network filesystems were left to do their own
thing, so they'd wait too.
After this patchset, all the disk filesystems except ext3 and btrfs will
wait only if the hardware requires it. ext3 (if necessary) snapshots
pages instead of blocking, and btrfs provides its own bdi so the mm will
never wait. Network filesystems haven't been touched, so either they
provide their own stable page guarantees or they don't block at all.
The blocking behavior is back to what it was before 3.0 if you don't
have a disk requiring stable page writes.
Here's the result of using dbench to test latency on ext2:
3.8.0-rc3:
Operation Count AvgLat MaxLat
----------------------------------------
WriteX 109347 0.028 59.817
ReadX 347180 0.004 3.391
Flush 15514 29.828 287.283
Throughput 57.429 MB/sec 4 clients 4 procs max_latency=287.290 ms
3.8.0-rc3 + patches:
WriteX 105556 0.029 4.273
ReadX 335004 0.005 4.112
Flush 14982 30.540 298.634
Throughput 55.4496 MB/sec 4 clients 4 procs max_latency=298.650 ms
As you can see, the maximum write latency drops considerably with this
patch enabled. The other filesystems (ext3/ext4/xfs/btrfs) behave
similarly, but see the cover letter for those results.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patchset ("stable page writes, part 2") makes some key
modifications to the original 'stable page writes' patchset. First, it
provides creators (devices and filesystems) of a backing_dev_info a flag
that declares whether or not it is necessary to ensure that page
contents cannot change during writeout. It is no longer assumed that
this is true of all devices (which was never true anyway). Second, the
flag is used to relaxed the wait_on_page_writeback calls so that wait
only occurs if the device needs it. Third, it fixes up the remaining
disk-backed filesystems to use this improved conditional-wait logic to
provide stable page writes on those filesystems.
It is hoped that (for people not using checksumming devices, anyway)
this patchset will give back unnecessary performance decreases since the
original stable page write patchset went into 3.0. Sorry about not
fixing it sooner.
Complaints were registered by several people about the long write
latencies introduced by the original stable page write patchset.
Generally speaking, the kernel ought to allocate as little extra memory
as possible to facilitate writeout, but for people who simply cannot
wait, a second page stability strategy is (re)introduced: snapshotting
page contents. The waiting behavior is still the default strategy; to
enable page snapshotting, a superblock flag (MS_SNAP_STABLE) must be
set. This flag is used to bandaid^Henable stable page writeback on
ext3[1], and is not used anywhere else.
Given that there are already a few storage devices and network FSes that
have rolled their own page stability wait/page snapshot code, it would
be nice to move towards consolidating all of these. It seems possible
that iscsi and raid5 may wish to use the new stable page write support
to enable zero-copy writeout.
Thank you to Jan Kara for helping fix a couple more filesystems.
Per Andrew Morton's request, here are the result of using dbench to measure
latencies on ext2:
3.8.0-rc3:
Operation Count AvgLat MaxLat
----------------------------------------
WriteX 109347 0.028 59.817
ReadX 347180 0.004 3.391
Flush 15514 29.828 287.283
Throughput 57.429 MB/sec 4 clients 4 procs max_latency=287.290 ms
3.8.0-rc3 + patches:
WriteX 105556 0.029 4.273
ReadX 335004 0.005 4.112
Flush 14982 30.540 298.634
Throughput 55.4496 MB/sec 4 clients 4 procs max_latency=298.650 ms
As you can see, for ext2 the maximum write latency decreases from ~60ms
on a laptop hard disk to ~4ms. I'm not sure why the flush latencies
increase, though I suspect that being able to dirty pages faster gives
the flusher more work to do.
On ext4, the average write latency decreases as well as all the maximum
latencies:
3.8.0-rc3:
WriteX 85624 0.152 33.078
ReadX 272090 0.010 61.210
Flush 12129 36.219 168.260
Throughput 44.8618 MB/sec 4 clients 4 procs max_latency=168.276 ms
3.8.0-rc3 + patches:
WriteX 86082 0.141 30.928
ReadX 273358 0.010 36.124
Flush 12214 34.800 165.689
Throughput 44.9941 MB/sec 4 clients 4 procs max_latency=165.722 ms
XFS seems to exhibit similar latency improvements as ext2:
3.8.0-rc3:
WriteX 125739 0.028 104.343
ReadX 399070 0.005 4.115
Flush 17851 25.004 131.390
Throughput 66.0024 MB/sec 4 clients 4 procs max_latency=131.406 ms
3.8.0-rc3 + patches:
WriteX 123529 0.028 6.299
ReadX 392434 0.005 4.287
Flush 17549 25.120 188.687
Throughput 64.9113 MB/sec 4 clients 4 procs max_latency=188.704 ms
...and btrfs, just to round things out, also shows some latency
decreases:
3.8.0-rc3:
WriteX 67122 0.083 82.355
ReadX 212719 0.005 2.828
Flush 9547 47.561 147.418
Throughput 35.3391 MB/sec 4 clients 4 procs max_latency=147.433 ms
3.8.0-rc3 + patches:
WriteX 64898 0.101 71.631
ReadX 206673 0.005 7.123
Flush 9190 47.963 219.034
Throughput 34.0795 MB/sec 4 clients 4 procs max_latency=219.044 ms
Before this patchset, all filesystems would block, regardless of whether
or not it was necessary. ext3 would wait, but still generate occasional
checksum errors. The network filesystems were left to do their own
thing, so they'd wait too.
After this patchset, all the disk filesystems except ext3 and btrfs will
wait only if the hardware requires it. ext3 (if necessary) snapshots
pages instead of blocking, and btrfs provides its own bdi so the mm will
never wait. Network filesystems haven't been touched, so either they
provide their own wait code, or they don't block at all. The blocking
behavior is back to what it was before 3.0 if you don't have a disk
requiring stable page writes.
This patchset has been tested on 3.8.0-rc3 on x64 with ext3, ext4, and
xfs. I've spot-checked 3.8.0-rc4 and seem to be getting the same
results as -rc3.
[1] The alternative fixes to ext3 include fixing the locking order and
page bit handling like we did for ext4 (but then why not just use
ext4?), or setting PG_writeback so early that ext3 becomes extremely
slow. I tried that, but the number of write()s I could initiate dropped
by nearly an order of magnitude. That was a bit much even for the
author of the stable page series! :)
This patch:
Creates a per-backing-device flag that tracks whether or not pages must
be held immutable during writeout. Eventually it will be used to waive
wait_for_page_writeback() if nothing requires stable pages.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here is the big driver core merge for 3.9-rc1
There are two major series here, both of which touch lots of drivers all
over the kernel, and will cause you some merge conflicts:
- add a new function called devm_ioremap_resource() to properly be
able to check return values.
- remove CONFIG_EXPERIMENTAL
If you need me to provide a merged tree to handle these resolutions,
please let me know.
Other than those patches, there's not much here, some minor fixes and
updates.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core patches from Greg Kroah-Hartman:
"Here is the big driver core merge for 3.9-rc1
There are two major series here, both of which touch lots of drivers
all over the kernel, and will cause you some merge conflicts:
- add a new function called devm_ioremap_resource() to properly be
able to check return values.
- remove CONFIG_EXPERIMENTAL
Other than those patches, there's not much here, some minor fixes and
updates"
Fix up trivial conflicts
* tag 'driver-core-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (221 commits)
base: memory: fix soft/hard_offline_page permissions
drivercore: Fix ordering between deferred_probe and exiting initcalls
backlight: fix class_find_device() arguments
TTY: mark tty_get_device call with the proper const values
driver-core: constify data for class_find_device()
firmware: Ignore abort check when no user-helper is used
firmware: Reduce ifdef CONFIG_FW_LOADER_USER_HELPER
firmware: Make user-mode helper optional
firmware: Refactoring for splitting user-mode helper code
Driver core: treat unregistered bus_types as having no devices
watchdog: Convert to devm_ioremap_resource()
thermal: Convert to devm_ioremap_resource()
spi: Convert to devm_ioremap_resource()
power: Convert to devm_ioremap_resource()
mtd: Convert to devm_ioremap_resource()
mmc: Convert to devm_ioremap_resource()
mfd: Convert to devm_ioremap_resource()
media: Convert to devm_ioremap_resource()
iommu: Convert to devm_ioremap_resource()
drm: Convert to devm_ioremap_resource()
...
Pull fuse updates from Miklos Szeredi:
"The biggest part of this pull request is a patch series from Maxim
Patlasov to optimize scatter-gather direct IO. There's also the
addition of a "readdirplus" API, poll events and various fixes and
cleanups.
There's a one line change outside of fuse to mm/filemap.c which makes
the argument of iov_iter_single_seg_count() const, required by Maxim's
patches."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (22 commits)
fuse: allow control of adaptive readdirplus use
Synchronize fuse header with one used in library
fuse: send poll events
fuse: don't WARN when nlink is zero
fuse: avoid out-of-scope stack access
fuse: bump version for READDIRPLUS
FUSE: Adapt readdirplus to application usage patterns
Do not use RCU for current process credentials
fuse: cleanup fuse_direct_io()
fuse: optimize __fuse_direct_io()
fuse: optimize fuse_get_user_pages()
fuse: pass iov[] to fuse_get_user_pages()
mm: minor cleanup of iov_iter_single_seg_count()
fuse: use req->page_descs[] for argpages cases
fuse: add per-page descriptor <offset, length> to fuse_req
fuse: rework fuse_do_ioctl()
fuse: rework fuse_perform_write()
fuse: rework fuse_readpages()
fuse: rework fuse_retrieve()
fuse: categorize fuse_get_req()
...
Pull scheduler changes from Ingo Molnar:
"Main changes:
- scheduler side full-dynticks (user-space execution is undisturbed
and receives no timer IRQs) preparation changes that convert the
cputime accounting code to be full-dynticks ready, from Frederic
Weisbecker.
- Initial sched.h split-up changes, by Clark Williams
- select_idle_sibling() performance improvement by Mike Galbraith:
" 1 tbench pair (worst case) in a 10 core + SMT package:
pre 15.22 MB/sec 1 procs
post 252.01 MB/sec 1 procs "
- sched_rr_get_interval() ABI fix/change. We think this detail is not
used by apps (so it's not an ABI in practice), but lets keep it
under observation.
- misc RT scheduling cleanups, optimizations"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
sched/rt: Add <linux/sched/rt.h> header to <linux/init_task.h>
cputime: Remove irqsave from seqlock readers
sched, powerpc: Fix sched.h split-up build failure
cputime: Restore CPU_ACCOUNTING config defaults for PPC64
sched/rt: Move rt specific bits into new header file
sched/rt: Add a tuning knob to allow changing SCHED_RR timeslice
sched: Move sched.h sysctl bits into separate header
sched: Fix signedness bug in yield_to()
sched: Fix select_idle_sibling() bouncing cow syndrome
sched/rt: Further simplify pick_rt_task()
sched/rt: Do not account zero delta_exec in update_curr_rt()
cputime: Safely read cputime of full dynticks CPUs
kvm: Prepare to add generic guest entry/exit callbacks
cputime: Use accessors to read task cputime stats
cputime: Allow dynamic switch between tick/virtual based cputime accounting
cputime: Generic on-demand virtual cputime accounting
cputime: Move default nsecs_to_cputime() to jiffies based cputime file
cputime: Librarize per nsecs resolution cputime definitions
cputime: Avoid multiplication overflow on utime scaling
context_tracking: Export context state for generic vtime
...
Fix up conflict in kernel/context_tracking.c due to comment additions.
Commit c060f943d0 ("mm: use aligned zone start for pfn_to_bitidx
calculation") fixed out calculation of the index into the pageblock
bitmap when a !SPARSEMEM zome was not aligned to pageblock_nr_pages.
However, the _allocation_ of that bitmap had never taken this alignment
requirement into accout, so depending on the exact size and alignment of
the zone, the use of that index could then access past the allocation,
resulting in some very subtle memory corruption.
This was reported (and bisected) by Ingo Molnar: one of his random
config builds would hang with certain very specific kernel command line
options.
In the meantime, commit c060f943d0 has been marked for stable, so this
fix needs to be back-ported to the stable kernels that backported the
commit to use the right alignment.
Bisected-and-tested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The s390 architecture is unique in respect to dirty page detection,
it uses the change bit in the per-page storage key to track page
modifications. All other architectures track dirty bits by means
of page table entries. This property of s390 has caused numerous
problems in the past, e.g. see git commit ef5d437f71
"mm: fix XFS oops due to dirty pages without buffers on s390".
To avoid future issues in regard to per-page dirty bits convert
s390 to a fault based software dirty bit detection mechanism. All
user page table entries which are marked as clean will be hardware
read-only, even if the pte is supposed to be writable. A write by
the user process will trigger a protection fault which will cause
the user pte to be marked as dirty and the hardware read-only bit
is removed.
With this change the dirty bit in the storage key is irrelevant
for Linux as a host, but the storage key is still required for
KVM guests. The effect is that page_test_and_clear_dirty and the
related code can be removed. The referenced bit in the storage
key is still used by the page_test_and_clear_young primitive to
provide page age information.
For page cache pages of mappings with mapping_cap_account_dirty
there will not be any change in behavior as the dirty bit tracking
already uses read-only ptes to control the amount of dirty pages.
Only for swap cache pages and pages of mappings without
mapping_cap_account_dirty there can be additional protection faults.
To avoid an excessive number of additional faults the mk_pte
primitive checks for PageDirty if the pgprot value allows for writes
and pre-dirties the pte. That avoids all additional faults for
tmpfs and shmem pages until these pages are added to the swap cache.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The total number of low memory pages is determined as totalram_pages -
totalhigh_pages, so without this patch all CMA pageblocks placed in
highmem were accounted to low memory.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The designed workflow for the caches in kmemcg is: register it with
memcg_register_cache() if kmemcg is already available or later on when a
new kmemcg appears at memcg_update_cache_sizes() which will handle all
caches in the system. The caches created at boot time will be handled
by the later, and the memcg-caches as well as any system caches that are
registered later on by the former.
There is a bug, however, in memcg_register_cache: we correctly set up
the array size, but do not mark the cache as a root cache.
This means that allocations for any cache appearing late in the game
will see memcg->memcg_params->is_root_cache == false, and in particular,
trigger VM_BUG_ON(!cachep->memcg_params->is_root_cache) in
__memcg_kmem_cache_get.
The obvious fix is to include the missing assignment.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With commit 8e72033f2a ("thp: make MADV_HUGEPAGE check for
mm->def_flags") the VM_NOHUGEPAGE flag may be set on s390 in
mm->def_flags for certain processes, to prevent future thp mappings.
This would be overwritten by do_mlockall(), which sets it back to 0 with
an optional VM_LOCKED flag set.
To fix this, instead of overwriting mm->def_flags in do_mlockall(), only
the VM_LOCKED flag should be set or cleared.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move rt scheduler definitions out of include/linux/sched.h into
new file include/linux/sched/rt.h
Signed-off-by: Clark Williams <williams@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20130207094707.7b9f825f@riff.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move the sysctl-related bits from include/linux/sched.h into
a new file: include/linux/sched/sysctl.h. Then update source
files requiring access to those bits by including the new
header file.
Signed-off-by: Clark Williams <williams@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20130207094659.06dced96@riff.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We use rwsem since commit 5a505085f0 ("mm/rmap: Convert the struct
anon_vma::mutex to an rwsem"). And most of comments are converted to
the new rwsem lock; while just 2 more missed from:
$ git grep 'anon_vma->mutex'
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
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>
When setting a huge PTE, besides calling pte_mkhuge(), we also need to
call arch_make_huge_pte(), which we indeed do in make_huge_pte(), but we
forget to do in hugetlb_change_protection() and remove_migration_pte().
Signed-off-by: Zhigang Lu <zlu@tilera.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Hillf Danton <dhillf@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No reason to preserve the huge zero page in core dumps.
Reported-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use it to get mem size under the limit_pfn.
to replace local version in x86 reserved_initrd.
-v2: remove not needed cast that is pointed out by HPA.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-29-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Coming patches to x86/mm2 require the changes and advanced baseline in
x86/boot.
Resolved Conflicts:
arch/x86/kernel/setup.c
mm/nobootmem.c
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The function does not modify iov_iter which 'i' points to.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This is to fix up a build problem with a wireless driver due to the
dynamic-debug patches in this branch.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Jan Beulich <JBeulich@novell.com>
CC: Mel Gorman <mel@csn.ul.ie>
CC: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Eric Wong reported on 3.7 and 3.8-rc2 that ppoll() got stuck when
waiting for POLLIN on a local TCP socket. It was easier to trigger if
there was disk IO and dirty pages at the same time and he bisected it to
commit 1fb3f8ca0e ("mm: compaction: capture a suitable high-order page
immediately when it is made available").
The intention of that patch was to improve high-order allocations under
memory pressure after changes made to reclaim in 3.6 drastically hurt
THP allocations but the approach was flawed. For Eric, the problem was
that page->pfmemalloc was not being cleared for captured pages leading
to a poor interaction with swap-over-NFS support causing the packets to
be dropped. However, I identified a few more problems with the patch
including the fact that it can increase contention on zone->lock in some
cases which could result in async direct compaction being aborted early.
In retrospect the capture patch took the wrong approach. What it should
have done is mark the pageblock being migrated as MIGRATE_ISOLATE if it
was allocating for THP and avoided races that way. While the patch was
showing to improve allocation success rates at the time, the benefit is
marginal given the relative complexity and it should be revisited from
scratch in the context of the other reclaim-related changes that have
taken place since the patch was first written and tested. This patch
partially reverts commit 1fb3f8ca0e ("mm: compaction: capture a
suitable high-order page immediately when it is made available").
Reported-and-tested-by: Eric Wong <normalperson@yhbt.net>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Zhouping Liu reported the following against 3.8-rc1 when running a mmap
testcase from LTP.
mapcount 0 page_mapcount 3
------------[ cut here ]------------
kernel BUG at mm/huge_memory.c:1798!
invalid opcode: 0000 [#1] SMP
Modules linked in: ip6table_filter ip6_tables ebtable_nat ebtables bnep bluetooth rfkill iptable_mangle ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack iptable_filter ip_tables be2iscsi iscsi_boot_sysfs bnx2i cnic uio cxgb4i cxgb4 cxgb3i cxgb3 mdio libcxgbi ib_iser rdma_cm ib_addr iw_cm ib_cm ib_sa ib_mad ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi vfat fat dm_mirror dm_region_hash dm_log dm_mod cdc_ether iTCO_wdt i7core_edac coretemp usbnet iTCO_vendor_support mii crc32c_intel edac_core lpc_ich shpchp ioatdma mfd_core i2c_i801 pcspkr serio_raw bnx2 microcode dca vhost_net tun macvtap macvlan kvm_intel kvm uinput mgag200 sr_mod cdrom i2c_algo_bit sd_mod drm_kms_helper crc_t10dif ata_generic pata_acpi ttm ata_piix drm libata i2c_core megaraid_sas
CPU 1
Pid: 23217, comm: mmap10 Not tainted 3.8.0-rc1mainline+ #17 IBM IBM System x3400 M3 Server -[7379I08]-/69Y4356
RIP: __split_huge_page+0x677/0x6d0
RSP: 0000:ffff88017a03fc08 EFLAGS: 00010293
RAX: 0000000000000003 RBX: ffff88027a6c22e0 RCX: 00000000000034d2
RDX: 000000000000748b RSI: 0000000000000046 RDI: 0000000000000246
RBP: ffff88017a03fcb8 R08: ffffffff819d2440 R09: 000000000000054a
R10: 0000000000aaaaaa R11: 00000000ffffffff R12: 0000000000000000
R13: 00007f4f11a00000 R14: ffff880179e96e00 R15: ffffea0005c08000
FS: 00007f4f11f4a740(0000) GS:ffff88017bc20000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000037e9ebb404 CR3: 000000017a436000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process mmap10 (pid: 23217, threadinfo ffff88017a03e000, task ffff880172dd32e0)
Stack:
ffff88017a540ec8 ffff88017a03fc20 ffffffff816017b5 ffff88017a03fc88
ffffffff812fa014 0000000000000000 ffff880279ebd5c0 00000000f4f11a4c
00000007f4f11f49 00000007f4f11a00 ffff88017a540ef0 ffff88017a540ee8
Call Trace:
split_huge_page+0x68/0xb0
__split_huge_page_pmd+0x134/0x330
split_huge_page_pmd_mm+0x51/0x60
split_huge_page_address+0x3b/0x50
__vma_adjust_trans_huge+0x9c/0xf0
vma_adjust+0x684/0x750
__split_vma.isra.28+0x1fa/0x220
do_munmap+0xf9/0x420
vm_munmap+0x4e/0x70
sys_munmap+0x2b/0x40
system_call_fastpath+0x16/0x1b
Alexander Beregalov and Alex Xu reported similar bugs and Hillf Danton
identified that commit 5a505085f0 ("mm/rmap: Convert the struct
anon_vma::mutex to an rwsem") and commit 4fc3f1d66b ("mm/rmap,
migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable")
were likely the problem. Reverting these commits was reported to solve
the problem for Alexander.
Despite the reason for these commits, NUMA balancing is not the direct
source of the problem. split_huge_page() expects the anon_vma lock to
be exclusive to serialise the whole split operation. Ordinarily it is
expected that the anon_vma lock would only be required when updating the
avcs but THP also uses the anon_vma rwsem for collapse and split
operations where the page lock or compound lock cannot be used (as the
page is changing from base to THP or vice versa) and the page table
locks are insufficient.
This patch takes the anon_vma lock for write to serialise against parallel
split_huge_page as THP expected before the conversion to rwsem.
Reported-and-tested-by: Zhouping Liu <zliu@redhat.com>
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Reported-by: Alex Xu <alex_y_xu@yahoo.ca>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 5a505085f0 ("mm/rmap: Convert the struct anon_vma::mutex to an
rwsem") turned anon_vma mutex to rwsem.
However, the properly annotated nested locking in mm_take_all_locks()
has been converted from
mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem);
to
down_write(&anon_vma->root->rwsem);
which is incomplete, and causes the false positive report from lockdep
below.
Annotate the fact that mmap_sem is used as an outter lock to serialize
taking of all the anon_vma rwsems at once no matter the order, using the
down_write_nest_lock() primitive.
This patch fixes this lockdep report:
=============================================
[ INFO: possible recursive locking detected ]
3.8.0-rc2-00036-g5f73896 #171 Not tainted
---------------------------------------------
qemu-kvm/2315 is trying to acquire lock:
(&anon_vma->rwsem){+.+...}, at: mm_take_all_locks+0x149/0x1b0
but task is already holding lock:
(&anon_vma->rwsem){+.+...}, at: mm_take_all_locks+0x149/0x1b0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&anon_vma->rwsem);
lock(&anon_vma->rwsem);
*** DEADLOCK ***
May be due to missing lock nesting notation
4 locks held by qemu-kvm/2315:
#0: (&mm->mmap_sem){++++++}, at: do_mmu_notifier_register+0xfc/0x170
#1: (mm_all_locks_mutex){+.+...}, at: mm_take_all_locks+0x36/0x1b0
#2: (&mapping->i_mmap_mutex){+.+...}, at: mm_take_all_locks+0xc9/0x1b0
#3: (&anon_vma->rwsem){+.+...}, at: mm_take_all_locks+0x149/0x1b0
stack backtrace:
Pid: 2315, comm: qemu-kvm Not tainted 3.8.0-rc2-00036-g5f73896 #171
Call Trace:
print_deadlock_bug+0xf2/0x100
validate_chain+0x4f6/0x720
__lock_acquire+0x359/0x580
lock_acquire+0x121/0x190
down_write+0x3f/0x70
mm_take_all_locks+0x149/0x1b0
do_mmu_notifier_register+0x68/0x170
mmu_notifier_register+0xe/0x10
kvm_create_vm+0x22b/0x330 [kvm]
kvm_dev_ioctl+0xf8/0x1a0 [kvm]
do_vfs_ioctl+0x9d/0x350
sys_ioctl+0x91/0xb0
system_call_fastpath+0x16/0x1b
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently free_all_bootmem_core ignores that node_min_pfn may be not
multiple of BITS_PER_LONG. Eg commit 6dccdcbe2c ("mm: bootmem: fix
checking the bitmap when finally freeing bootmem") shifts vec by lower
bits of start instead of lower bits of idx. Also
if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL)
assumes that vec bit 0 corresponds to start pfn, which is only true when
node_min_pfn is a multiple of BITS_PER_LONG. Also loop in the else
clause can double-free pages (e.g. with node_min_pfn == start == 1,
map[0] == ~0 on 32-bit machine page 32 will be double-freed).
This bug causes the following message during xtensa kernel boot:
bootmem::free_all_bootmem_core nid=0 start=1 end=8000
BUG: Bad page state in process swapper pfn:00001
page:d04bd020 count:0 mapcount:-127 mapping: (null) index:0x2
page flags: 0x0()
Call Trace:
bad_page+0x8c/0x9c
free_pages_prepare+0x5e/0x88
free_hot_cold_page+0xc/0xa0
__free_pages+0x24/0x38
__free_pages_bootmem+0x54/0x56
free_all_bootmem_core$part$11+0xeb/0x138
free_all_bootmem+0x46/0x58
mem_init+0x25/0xa4
start_kernel+0x11e/0x25c
should_never_return+0x0/0x3be7
The fix is the following:
- always align vec so that its bit 0 corresponds to start
- provide BITS_PER_LONG bits in vec, if those bits are available in the
map
- don't free pages past next start position in the else clause.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Cc: Gavin Shan <shangw@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Prasad Koya <prasad.koya@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current calculation in pfn_to_bitidx assumes that (pfn -
zone->zone_start_pfn) >> pageblock_order will return the same bit for
all pfn in a pageblock. If zone_start_pfn is not aligned to
pageblock_nr_pages, this may not always be correct.
Consider the following with pageblock order = 10, zone start 2MB:
pfn | pfn - zone start | (pfn - zone start) >> page block order
----------------------------------------------------------------
0x26000 | 0x25e00 | 0x97
0x26100 | 0x25f00 | 0x97
0x26200 | 0x26000 | 0x98
0x26300 | 0x26100 | 0x98
This means that calling {get,set}_pageblock_migratetype on a single page
will not set the migratetype for the full block. Fix this by rounding
down zone_start_pfn when doing the bitidx calculation.
For our use case, the effects of this bug were mostly tied to the fact
that CMA allocations would either take a long time or fail to happen.
Depending on the driver using CMA, this could result in anything from
visual glitches to application failures.
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
when run the folloing command under shell, it will return error
sh/$ echo 1 > /proc/sys/vm/compact_memory
sh/$ sh: write error: Bad address
After strace, I found the following log:
...
write(1, "1\n", 2) = 3
write(1, "", 4294967295) = -1 EFAULT (Bad address)
write(2, "echo: write error: Bad address\n", 31echo: write error: Bad address
) = 31
This tells system return 3(COMPACT_COMPLETE) after write data to
compact_memory.
The fix is to make the system just return 0 instead 3(COMPACT_COMPLETE)
from sysctl_compaction_handler after compaction_nodes finished.
Signed-off-by: Jason Liu <r64343@freescale.com>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memmove span covers from (next+1) to the end of the array, and the
index of next is (i+1), so the index of (next+1) is (i+2). So the size
of remaining array elements is (type->cnt - (i + 2)).
Since the remaining elements of the memblock array are move forward by
one element and there is only one additional element caused by this bug.
So there won't be any write overflow here but read overflow. It may
read one more element out of the array address if the array happens to
be full. Commonly it doesn't matter at all but if the array happens to
be located at the end a memblock, it may cause a invalid read operation
for the physical address doesn't exist.
There are 2 *happens to be* here, so I think the probability is quite
low, I don't know if any guy is haunted by this bug before.
Mostly I think it's user-invisible.
Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins pointed out that migrate_misplaced_transhuge_page() does
not check page_count before migrating like base page migration and
khugepage. He could not see why this was safe and he is right.
The potential impact of the bug is avoided due to the limitations of
NUMA balancing. The page_mapcount() check ensures that only a single
address space is using this page and as THPs are typically private it
should not be possible for another address space to fault it in
parallel. If the address space has one associated task then it's
difficult to have both a GUP pin and be referencing the page at the same
time. If there are multiple tasks then a buggy scenario requires that
another thread be accessing the page while the direct IO is in flight.
This is dodgy behaviour as there is a possibility of corruption with or
without THP migration. It would be
While we happen to be safe for the most part it is shoddy to depend on
such "safety" so this patch checks the page count similar to anonymous
pages. Note that this does not mean that the page_mapcount() check can
go away. If we were to remove the page_mapcount() check the the THP
would have to be unmapped from all referencing PTEs, replaced with
migration PTEs and restored properly afterwards.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The check for a pmd being in the process of being split was dropped by
mistake by commit d10e63f294 ("mm: numa: Create basic numa page
hinting infrastructure"). Put it back.
Reported-by: Dave Jones <davej@redhat.com>
Debugged-by: Hillf Danton <dhillf@gmail.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Kirill Shutemov <kirill@shutemov.name>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit e303297e6c ("mm: extended batches for generic
mmu_gather") we are batching pages to be freed until either
tlb_next_batch cannot allocate a new batch or we are done.
This works just fine most of the time but we can get in troubles with
non-preemptible kernel (CONFIG_PREEMPT_NONE or CONFIG_PREEMPT_VOLUNTARY)
on large machines where too aggressive batching might lead to soft
lockups during process exit path (exit_mmap) because there are no
scheduling points down the free_pages_and_swap_cache path and so the
freeing can take long enough to trigger the soft lockup.
The lockup is harmless except when the system is setup to panic on
softlockup which is not that unusual.
The simplest way to work around this issue is to limit the maximum
number of batches in a single mmu_gather. 10k of collected pages should
be safe to prevent from soft lockups (we would have 2ms for one) even if
they are all freed without an explicit scheduling point.
This patch doesn't add any new explicit scheduling points because it
relies on zap_pmd_range during page tables zapping which calls
cond_resched per PMD.
The following lockup has been reported for 3.0 kernel with a huge
process (in order of hundreds gigs but I do know any more details).
BUG: soft lockup - CPU#56 stuck for 22s! [kernel:31053]
Modules linked in: af_packet nfs lockd fscache auth_rpcgss nfs_acl sunrpc mptctl mptbase autofs4 binfmt_misc dm_round_robin dm_multipath bonding cpufreq_conservative cpufreq_userspace cpufreq_powersave pcc_cpufreq mperf microcode fuse loop osst sg sd_mod crc_t10dif st qla2xxx scsi_transport_fc scsi_tgt netxen_nic i7core_edac iTCO_wdt joydev e1000e serio_raw pcspkr edac_core iTCO_vendor_support acpi_power_meter rtc_cmos hpwdt hpilo button container usbhid hid dm_mirror dm_region_hash dm_log linear uhci_hcd ehci_hcd usbcore usb_common scsi_dh_emc scsi_dh_alua scsi_dh_hp_sw scsi_dh_rdac scsi_dh dm_snapshot pcnet32 mii edd dm_mod raid1 ext3 mbcache jbd fan thermal processor thermal_sys hwmon cciss scsi_mod
Supported: Yes
CPU 56
Pid: 31053, comm: kernel Not tainted 3.0.31-0.9-default #1 HP ProLiant DL580 G7
RIP: 0010: _raw_spin_unlock_irqrestore+0x8/0x10
RSP: 0018:ffff883ec1037af0 EFLAGS: 00000206
RAX: 0000000000000e00 RBX: ffffea01a0817e28 RCX: ffff88803ffd9e80
RDX: 0000000000000200 RSI: 0000000000000206 RDI: 0000000000000206
RBP: 0000000000000002 R08: 0000000000000001 R09: ffff887ec724a400
R10: 0000000000000000 R11: dead000000200200 R12: ffffffff8144c26e
R13: 0000000000000030 R14: 0000000000000297 R15: 000000000000000e
FS: 00007ed834282700(0000) GS:ffff88c03f200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 000000000068b240 CR3: 0000003ec13c5000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process kernel (pid: 31053, threadinfo ffff883ec1036000, task ffff883ebd5d4100)
Call Trace:
release_pages+0xc5/0x260
free_pages_and_swap_cache+0x9d/0xc0
tlb_flush_mmu+0x5c/0x80
tlb_finish_mmu+0xe/0x50
exit_mmap+0xbd/0x120
mmput+0x49/0x120
exit_mm+0x122/0x160
do_exit+0x17a/0x430
do_group_exit+0x3d/0xb0
get_signal_to_deliver+0x247/0x480
do_signal+0x71/0x1b0
do_notify_resume+0x98/0xb0
int_signal+0x12/0x17
DWARF2 unwinder stuck at int_signal+0x12/0x17
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org> [3.0+]
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 702d1a6e07 ("memory-hotplug: fix kswapd looping forever
problem") added an isolated pageblocks counter (nr_pageblock_isolate in
struct zone) and used it to adjust free pages counter in
zone_watermark_ok_safe() to prevent kswapd looping forever problem.
Then later, commit 2139cbe627 ("cma: fix counting of isolated pages")
fixed accounting of isolated pages in global free pages counter. It
made the previous zone_watermark_ok_safe() fix unnecessary and
potentially harmful (cause now isolated pages may be accounted twice
making free pages counter incorrect).
This patch removes the special isolated pageblocks counter altogether
which fixes zone_watermark_ok_safe() free pages check.
Reported-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CONFIG_HOTPLUG is going away as an option. As a result, the __dev*
markings need to be removed.
This change removes the use of __devinit from the file.
Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sasha was fuzzing with trinity and reported the following problem:
BUG: sleeping function called from invalid context at kernel/mutex.c:269
in_atomic(): 1, irqs_disabled(): 0, pid: 6361, name: trinity-main
2 locks held by trinity-main/6361:
#0: (&mm->mmap_sem){++++++}, at: [<ffffffff810aa314>] __do_page_fault+0x1e4/0x4f0
#1: (&(&mm->page_table_lock)->rlock){+.+...}, at: [<ffffffff8122f017>] handle_pte_fault+0x3f7/0x6a0
Pid: 6361, comm: trinity-main Tainted: G W
3.7.0-rc2-next-20121024-sasha-00001-gd95ef01-dirty #74
Call Trace:
__might_sleep+0x1c3/0x1e0
mutex_lock_nested+0x29/0x50
mpol_shared_policy_lookup+0x2e/0x90
shmem_get_policy+0x2e/0x30
get_vma_policy+0x5a/0xa0
mpol_misplaced+0x41/0x1d0
handle_pte_fault+0x465/0x6a0
This was triggered by a different version of automatic NUMA balancing
but in theory the current version is vunerable to the same problem.
do_numa_page
-> numa_migrate_prep
-> mpol_misplaced
-> get_vma_policy
-> shmem_get_policy
It's very unlikely this will happen as shared pages are not marked
pte_numa -- see the page_mapcount() check in change_pte_range() -- but
it is possible.
To address this, this patch restores sp->lock as originally implemented
by Kosaki Motohiro. In the path where get_vma_policy() is called, it
should not be calling sp_alloc() so it is not necessary to treat the PTL
specially.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the unused argument (formerly no_context) from mpol_parse_str()
and from mpol_to_str().
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently I suggested using "mount -o remount,mpol=local /tmp" in NUMA
mempolicy testing. Very nasty. Reading /proc/mounts, /proc/pid/mounts
or /proc/pid/mountinfo may then corrupt one bit of kernel memory, often
in a page table (causing "Bad swap" or "Bad page map" warning or "Bad
pagetable" oops), sometimes in a vm_area_struct or rbnode or somewhere
worse. "mpol=prefer" and "mpol=prefer:Node" are equally toxic.
Recent NUMA enhancements are not to blame: this dates back to 2.6.35,
when commit e17f74af35 "mempolicy: don't call mpol_set_nodemask() when
no_context" skipped mpol_parse_str()'s call to mpol_set_nodemask(),
which used to initialize v.preferred_node, or set MPOL_F_LOCAL in flags.
With slab poisoning, you can then rely on mpol_to_str() to set the bit
for node 0x6b6b, probably in the next page above the caller's stack.
mpol_parse_str() is only called from shmem_parse_options(): no_context
is always true, so call it unused for now, and remove !no_context code.
Set v.nodes or v.preferred_node or MPOL_F_LOCAL as mpol_to_str() might
expect. Then mpol_to_str() can ignore its no_context argument also,
the mpol being appropriately initialized whether contextualized or not.
Rename its no_context unused too, and let subsequent patch remove them
(that's not needed for stable backporting, which would involve rejects).
I don't understand why MPOL_LOCAL is described as a pseudo-policy:
it's a reasonable policy which suffers from a confusing implementation
in terms of MPOL_PREFERRED with MPOL_F_LOCAL. I believe this would be
much more robust if MPOL_LOCAL were recognized in switch statements
throughout, MPOL_F_LOCAL deleted, and MPOL_PREFERRED use the (possibly
empty) nodes mask like everyone else, instead of its preferred_node
variant (I presume an optimization from the days before MPOL_LOCAL).
But that would take me too long to get right and fully tested.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
An unintended consequence of commit 4ae0a48b5e ("mm: modify
pgdat_balanced() so that it also handles order-0") is that
wait_iff_congested() can now be called with NULL 'struct zone *'
producing kernel oops like this:
BUG: unable to handle kernel NULL pointer dereference
IP: [<ffffffff811542d9>] wait_iff_congested+0x59/0x140
This trivial patch fixes it.
Reported-by: Zhouping Liu <zliu@redhat.com>
Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Zlatko Calusic <zlatko.calusic@iskon.hr>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Teach pgdat_balanced() about order-0 allocations so that we can simplify
code in a few places in vmstat.c.
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Zlatko Calusic <zlatko.calusic@iskon.hr>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge the rest of Andrew's patches for -rc1:
"A bunch of fixes and misc missed-out-on things.
That'll do for -rc1. I still have a batch of IPC patches which still
have a possible bug report which I'm chasing down."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (25 commits)
keys: use keyring_alloc() to create module signing keyring
keys: fix unreachable code
sendfile: allows bypassing of notifier events
SGI-XP: handle non-fatal traps
fat: fix incorrect function comment
Documentation: ABI: remove testing/sysfs-devices-node
proc: fix inconsistent lock state
linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors
memcg: don't register hotcpu notifier from ->css_alloc()
checkpatch: warn on uapi #includes that #include <uapi/...
revert "rtc: recycle id when unloading a rtc driver"
mm: clean up transparent hugepage sysfs error messages
hfsplus: add error message for the case of failure of sync fs in delayed_sync_fs() method
hfsplus: rework processing of hfs_btree_write() returned error
hfsplus: rework processing errors in hfsplus_free_extents()
hfsplus: avoid crash on failed block map free
kcmp: include linux/ptrace.h
drivers/rtc/rtc-imxdi.c: must include <linux/spinlock.h>
mm: cma: WARN if freed memory is still in use
exec: do not leave bprm->interp on stack
...
