Memory control groups are currently bolted onto the side of
traditional memory management in places where better integration would
be preferrable. To reclaim memory, for example, memory control groups
maintain their own LRU list and reclaim strategy aside from the global
per-zone LRU list reclaim. But an extra list head for each existing
page frame is expensive and maintaining it requires additional code.
This patchset disables the global per-zone LRU lists on memory cgroup
configurations and converts all its users to operate on the per-memory
cgroup lists instead. As LRU pages are then exclusively on one list,
this saves two list pointers for each page frame in the system:
page_cgroup array size with 4G physical memory
vanilla: [ 0.000000] allocated 31457280 bytes of page_cgroup
patched: [ 0.000000] allocated 15728640 bytes of page_cgroup
At the same time, system performance for various workloads is
unaffected:
100G sparse file cat, 4G physical memory, 10 runs, to test for code
bloat in the traditional LRU handling and kswapd & direct reclaim
paths, without/with the memory controller configured in
4 unlimited memcgs running kbuild -j32 each, 4G physical memory, 500M
swap on SSD, 10 runs, to test for regressions in kswapd & direct
reclaim using per-memcg LRU lists with multiple memcgs and multiple
allocators within each memcg
The task counter subsystem has been written assuming that
can_attach_task/attach_task/cancel_attach_task calls are serialized per
task. This is true when we attach only one task but not when we attach a
whole thread group, in which case the sequence is:
for each thread
if (can_attach_task() < 0)
goto rollback
for each_thread
attach_task()
rollback:
for each thread
cancel_attach_task()
The common ancestor, searched on task_counter_attach_task(), can thus
change between each of these calls for a given task. This breaks if some
tasks in the thread group are not in the same cgroup origin. The uncharge
made in attach_task() or the rollback in cancel_attach_task() there would
have an erroneous propagation.
This can even break seriously is some scenario. For example there
with $PID beeing the pid of a multithread process:
On the last move, attach_task() is called on the thread leader with
the wrong common_ancestor, leading to a crash because we uncharge
a res_counter that doesn't exist:
To solve this, keep the original cgroup of each thread in the thread
group cached in the flex array and pass it to can_attach_task()/attach_task()
and cancel_attach_task() so that the correct common ancestor between the old
and new cgroup can be safely retrieved for each task.
This is inspired by a previous patch from Li Zefan:
"[PATCH] cgroups: don't cache common ancestor in task counter subsys".
Reported-by: Ben Blum <bblum@andrew.cmu.edu> Reported-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a new subsystem to limit the number of running tasks, similar to the
NR_PROC rlimit but in the scope of a cgroup.
The user can set an upper bound limit that is checked every time a task
forks in a cgroup or is moved into a cgroup with that subsystem binded.
The primary goal is to protect against forkbombs that explode inside a
container. The traditional NR_PROC rlimit is not efficient in that case
because if we run containers in parallel under the same user, one of these
could starve all the others by spawning a high number of tasks close to
the user wide limit.
This is a prevention against forkbombs, so it's not deemed to cure the
effects of a forkbomb when the system is in a state where it's not
responsive. It's aimed at preventing from ever reaching that state and
stop the spreading of tasks early. While defining the limit on the
allowed number of tasks, it's up to the user to find the right balance
between the resource its containers may need and what it can afford to
provide.
As it's totally dissociated from the rlimit NR_PROC, both can be
complementary: the cgroup task counter can set an upper bound per
container and the rlmit can be an upper bound on the overall set of
containers.
Also this subsystem can be used to kill all the tasks in a cgroup without
races against concurrent forks, by setting the limit of tasks to 0, any
further forks can be rejected. This is a good way to kill a forkbomb in a
container, or simply kill any container without the need to retry an
unbound number of times.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Menage <paul@paulmenage.org> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let the subsystem's fork callback return an error value so that they can
cancel a fork. This is going to be used by the task counter subsystem to
implement the limit.
Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cgroups: pull up res counter charge failure interpretation to caller
res_counter_charge() always returns -ENOMEM when the limit is reached and
the charge thus can't happen.
However it's up to the caller to interpret this failure and return the
appropriate error value. The task counter subsystem will need to report
the user that a fork() has been cancelled because of some limit reached,
not because we are too short on memory.
Fix this by returning -1 when res_counter_charge() fails.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cgroups: ability to stop res charge propagation on bounded ancestor
Moving a task from a cgroup to another may require to substract its
resource charge from the old cgroup and add it to the new one.
For this to happen, the uncharge/charge propagation can just stop when we
reach the common ancestor for the two cgroups. Further the performance
reasons, we also want to avoid to temporarily overload the common
ancestors with a non-accurate resource counter usage if we charge first
the new cgroup and uncharge the old one thereafter. This is going to be a
requirement for the coming max number of task subsystem.
To solve this, provide a pair of new API that can charge/uncharge a
resource counter until we reach a given ancestor.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cgroups: new cancel_attach_task() subsystem callback
To cancel a process attachment on a subsystem, we only call the
cancel_attach() callback once on the leader but we have no way to cancel
the attachment individually for each member of the process group.
This is going to be needed for the max number of tasks susbystem that is
coming.
To prepare for this integration, call a new cancel_attach_task() callback
on each task of the group until we reach the member that failed to attach.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Provide an API to inherit a counter value from a parent. This can be
useful to implement cgroup.clone_children on a resource counter.
Still the resources of the children are limited by those of the parent, so
this is only to provide a default setting behaviour when clone_children is
set.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Extend the resource counter API with a mirror of res_counter_read_u64() to
make it handy to update a resource counter value from a cgroup subsystem
u64 value file.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nothing requires that we lock the filesystem until the root inode is
provided.
Also iget5_locked() triggers a warning because we are holding the
filesystem lock while allocating the inode, which result in a lockdep
suspicion that we have a lock inversion against the reclaim path:
The deadlock shouldn't happen since we are doing that allocation in the
mount path, the filesystem is not available for any reclaim. Still the
warning is annoying.
To solve this, acquire the lock later only where we need it, right before
calling reiserfs_read_locked_inode() that wants to lock to walk the tree.
Reported-by: Knut Petersen <Knut_Petersen@t-online.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
journal_init() doesn't need the lock since no operation on the filesystem
is involved there. journal_read() and get_list_bitmap() have yet to be
reviewed carefully though before removing the lock there. Just keep the
it around these two calls for safety.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
reiserfs: delay reiserfs lock until journal initialization
In the mount path, transactions that are made before journal
initialization don't involve the filesystem. We can delay the reiserfs
lock until we play with the journal.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
WARNING: line over 80 characters
#48: FILE: drivers/rtc/rtc-ab8500.c:268:
+ * Check that the calibration value (which is in units of 0.5 parts-per-million)
ERROR: need consistent spacing around '-' (ctx:WxV)
#64: FILE: drivers/rtc/rtc-ab8500.c:284:
+ rtccal = ~(calibration -1) | 0x80;
^
total: 1 errors, 1 warnings, 139 lines checked
./patches/rtc-ab8500-add-calibration-attribute-to-ab8500-rtc.patch has style problems, please review.
If any of these errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
Please run checkpatch prior to sending patches
Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Linus Walleij <linus.walleij@stericsson.com> Cc: Mark Godfrey <mark.godfrey@stericsson.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mark Godfrey [Wed, 30 Nov 2011 04:11:46 +0000 (15:11 +1100)]
rtc/ab8500: Add calibration attribute to AB8500 RTC
The rtc_calibration attribute allows user-space to get and set the
AB8500's RtcCalibration register. The AB8500 will then use the value in
this register to compensate for RTC drift every 60 seconds.
Signed-off-by: Mark Godfrey <mark.godfrey@stericsson.com> Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jonas Aaberg [Wed, 30 Nov 2011 04:11:46 +0000 (15:11 +1100)]
rtc/ab8500: change to mdelay
The resolution of msleep is related to HZ, so with HZ set to 100 any
msleep of less than 10ms will become ~10ms. This does not work for us, so
stick to mdelay(1).
Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yauhen Kharuzhy [Wed, 30 Nov 2011 04:11:44 +0000 (15:11 +1100)]
drivers/rtc/rtc-mxc.c: fix setting time for MX1 SoC
There is no way to track year in the i.MX1 RTC: Days Counter register is
9-bit wide only. Attempt to save date after 1970-01-01 plus 512 days
causes endless loop in mxc_rtc_set_mmss(). Fix this by resetting year to
1970.
Signed-off-by: Yauhen Kharuzhy <jekhor@gmail.com> Cc: Daniel Mack <daniel@caiaq.de> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Daney [Wed, 30 Nov 2011 04:11:43 +0000 (15:11 +1100)]
MIPS: randomize PIE load address
... by selecting ARCH_BINFMT_ELF_RANDOMIZE_PIE
Signed-off-by: David Daney <david.daney@cavium.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Daney [Wed, 30 Nov 2011 04:11:43 +0000 (15:11 +1100)]
fs: binfmt_elf: create Kconfig variable for PIE randomization
Randomization of PIE load address is hard coded in binfmt_elf.c for X86
and ARM. Create a new Kconfig variable
(CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE) for this and use it instead. Thus
architecture specific policy is pushed out of the generic binfmt_elf.c and
into the architecture Kconfig files.
X86 and ARM Kconfigs are modified to select the new variable so there is
no change in behavior. A follow on patch will select it for MIPS too.
Signed-off-by: David Daney <david.daney@cavium.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Acked-by: H. Peter Anvin <hpa@zytor.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jason Baron [Wed, 30 Nov 2011 04:11:43 +0000 (15:11 +1100)]
epoll: limit paths
The current epoll code can be tickled to run basically indefinitely in
both loop detection path check (on ep_insert()), and in the wakeup paths.
The programs that tickle this behavior set up deeply linked networks of
epoll file descriptors that cause the epoll algorithms to traverse them
indefinitely. A couple of these sample programs have been previously
posted in this thread: https://lkml.org/lkml/2011/2/25/297.
To fix the loop detection path check algorithms, I simply keep track of
the epoll nodes that have been already visited. Thus, the loop detection
becomes proportional to the number of epoll file descriptor and links.
This dramatically decreases the run-time of the loop check algorithm. In
one diabolical case I tried it reduced the run-time from 15 mintues (all
in kernel time) to .3 seconds.
Fixing the wakeup paths could be done at wakeup time in a similar manner
by keeping track of nodes that have already been visited, but the
complexity is harder, since there can be multiple wakeups on different
cpus...Thus, I've opted to limit the number of possible wakeup paths when
the paths are created.
This is accomplished, by noting that the end file descriptor points that
are found during the loop detection pass (from the newly added link), are
actually the sources for wakeup events. I keep a list of these file
descriptors and limit the number and length of these paths that emanate
from these 'source file descriptors'. In the current implemetation I
allow 1000 paths of length 1, 500 of length 2, 100 of length 3, 50 of
length 4 and 10 of length 5. Note that it is sufficient to check the
'source file descriptors' reachable from the newly added link, since no
other 'source file descriptors' will have newly added links. This allows
us to check only the wakeup paths that may have gotten too long, and not
re-check all possible wakeup paths on the system.
In terms of the path limit selection, I think its first worth noting that
the most common case for epoll, is probably the model where you have 1
epoll file descriptor that is monitoring n number of 'source file
descriptors'. In this case, each 'source file descriptor' has a 1 path of
length 1. Thus, I believe that the limits I'm proposing are quite
reasonable and in fact may be too generous. Thus, I'm hoping that the
proposed limits will not prevent any workloads that currently work to
fail.
In terms of locking, I have extended the use of the 'epmutex' to all
epoll_ctl add and remove operations. Currently its only used in a subset
of the add paths. I need to hold the epmutex, so that we can correctly
traverse a coherent graph, to check the number of paths. I believe that
this additional locking is probably ok, since its in the setup/teardown
paths, and doesn't affect the running paths, but it certainly is going to
add some extra overhead. Also, worth noting is that the epmuex was
recently added to the ep_ctl add operations in the initial path loop
detection code using the argument that it was not on a critical path.
Another thing to note here, is the length of epoll chains that is allowed.
Currently, eventpoll.c defines:
/* Maximum number of nesting allowed inside epoll sets */
#define EP_MAX_NESTS 4
This basically means that I am limited to a graph depth of 5 (EP_MAX_NESTS
+ 1). However, this limit is currently only enforced during the loop
check detection code, and only when the epoll file descriptors are added
in a certain order. Thus, this limit is currently easily bypassed. The
newly added check for wakeup paths, stricly limits the wakeup paths to a
length of 5, regardless of the order in which ep's are linked together.
Thus, a side-effect of the new code is a more consistent enforcement of
the graph depth.
Thus far, I've tested this, using the sample programs previously
mentioned, which now either return quickly or return -EINVAL. I've also
testing using the piptest.c epoll tester, which showed no difference in
performance. I've also created a number of different epoll networks and
tested that they behave as expectded.
I believe this solves the original diabolical test cases, while still
preserving the sane epoll nesting.
Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Nelson Elhage <nelhage@ksplice.com> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joakim Tjernlund [Wed, 30 Nov 2011 04:11:42 +0000 (15:11 +1100)]
crc32: optimize inner loop
Taking a pointer reference to each row in the crc table matrix, one can
reduce the inner loop with a few insn's
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Cc: Bob Pearson <rpearson@systemfabricworks.com> Cc: Frank Zago <fzago@systemfabricworks.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joe Perches [Wed, 30 Nov 2011 04:11:42 +0000 (15:11 +1100)]
checkpatch: update signature "might be better as" warning
email header lines can look like signature tags. It's valid to have
multiple email recipients on a single line but not valid to have multiple
signatures on a single line.
Validate signatures only when not in the email headers.
Clear the $in_commit_log flag when the patch filename appears.
Add '-' to the valid chars in a message header for headers
like "Message-Id:" and "In-Reply-To:".
Signed-off-by: Joe Perches <joe@perches.com> Reported-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Changes from v1:
minor tweaks to address comments by Stephen Rothwell
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Lin [Wed, 30 Nov 2011 04:11:41 +0000 (15:11 +1100)]
leds: convert leds-dac124s085 to module_spi_driver
Factor out some boilerplate code for spi driver registration into
module_spi_driver.
Signed-off-by: Axel Lin <axel.lin@gmail.com> Cc: Haojian Zhuang <hzhuang1@marvell.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Michael Hennerich <hennerich@blackfin.uclinux.org> Cc: Mike Rapoport <mike@compulab.co.il> Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Lin [Wed, 30 Nov 2011 04:11:40 +0000 (15:11 +1100)]
leds: convert led i2c drivers to module_i2c_driver
Factor out some boilerplate code for i2c driver registration
into module_i2c_driver.
Signed-off-by: Axel Lin <axel.lin@gmail.com> Cc: Haojian Zhuang <hzhuang1@marvell.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Michael Hennerich <hennerich@blackfin.uclinux.org> Cc: Mike Rapoport <mike@compulab.co.il> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Axel Lin [Wed, 30 Nov 2011 04:11:40 +0000 (15:11 +1100)]
leds: convert led platform drivers to module_platform_driver
Factor out some boilerplate code for platform driver registration into
module_platform_driver.
Signed-off-by: Axel Lin <axel.lin@gmail.com> Acked-by: Haojian Zhuang <hzhuang1@marvell.com> [led-88pm860x.c] Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Michael Hennerich <hennerich@blackfin.uclinux.org> Cc: Mike Rapoport <mike@compulab.co.il> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Paul Bolle [Wed, 30 Nov 2011 04:11:40 +0000 (15:11 +1100)]
backlight: remove ADX backlight device support
Support for the Avionic Design Xanthos backlight device got added in
commit 3b96ea9ef8 ("backlight: Add support for the Avionic Design Xanthos
backlight device."). That support depends on ARCH_PXA_ADX. The code that
should have provided that Kconfig symbol never got submitted. It has
never been possible to even build this driver. Remove it.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: Thierry Reding <thierry.reding@avionic-design.de> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Wim Van Sebroeck <wim@iguana.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ian Campbell [Wed, 30 Nov 2011 04:11:39 +0000 (15:11 +1100)]
get_maintainers.pl: follow renames when looking up commit signers
I happen to have had a commit to various network drivers since the big
renaming/reorg which happened to drivers/net recently. This means that I
now appear to be in the top few commit signers (by %age) for many of them
so am getting sent all sorts of stuff and people who are involved with the
driver are not. e.g. (to pick one at random):
$ ./scripts/get_maintainer.pl -f drivers/net/ethernet/nvidia/forcedeth.c
"David S. Miller" <davem@davemloft.net> (commit_signer:5/7=71%)
Ian Campbell <ian.campbell@citrix.com> (commit_signer:2/7=29%)
Eric Dumazet <eric.dumazet@gmail.com> (commit_signer:1/7=14%)
Jeff Kirsher <jeffrey.t.kirsher@intel.com> (commit_signer:1/7=14%)
Jiri Pirko <jpirko@redhat.com> (commit_signer:1/7=14%)
netdev@vger.kernel.org (open list:NETWORKING DRIVERS)
linux-kernel@vger.kernel.org (open list)
With the following patch the renames are followed and the result appears
much more sensible:
Andrei Warkentin [Wed, 30 Nov 2011 04:11:39 +0000 (15:11 +1100)]
include/log2.h: fix rounddown_pow_of_two(1)
1 is a power of two, therefore rounddown_pow_of_two(1) should return 1.
It does in case the argument is a variable but in case it's a constant it
behaves wrong and returns 0. Probably nobody ever did it so this was
never noticed, however net/drivers/vmxnet3 with latest GCC does and breaks
on unicpu systems.
This is similar to Rolf's patch to roundup_pow_of_two(1).
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de> Reviewed-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Andrei Warkentin <andreiw@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andi Kleen [Wed, 30 Nov 2011 04:11:38 +0000 (15:11 +1100)]
brlocks/lglocks: clean up code
lglocks and brlocks are currently generated with some complicated macros
in lglock.h. But there's no reason I can see to not just use common
utility functions that get pointers to the lglock.
Since there are at least two users it makes sense to share this code in a
library.
This will also make it later possible to dynamically allocate lglocks.
In general the users now look more like normal function calls with
pointers, not magic macros.
The patch is rather large because I move over all users in one go to keep
it bisectable. This impacts the VFS somewhat in terms of lines changed.
But no actual behaviour change.
Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jesper Juhl [Wed, 30 Nov 2011 04:11:38 +0000 (15:11 +1100)]
audit: always follow va_copy() with va_end()
A call to va_copy() should always be followed by a call to va_end() in the
same function. In kernel/autit.c::audit_log_vformat() this is not always
done. This patch makes sure va_end() is always called.
Signed-off-by: Jesper Juhl <jj@chaosbits.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Heiko Carstens [Wed, 30 Nov 2011 04:11:37 +0000 (15:11 +1100)]
mm,slub,x86: decouple size of struct page from CONFIG_CMPXCHG_LOCAL
While implementing cmpxchg_double() on s390 I realized that we don't set
CONFIG_CMPXCHG_LOCAL besides the fact that we have support for it.
However setting that option will increase the size of struct page by eight
bytes on 64 bit, which we certainly do not want. Also, it doesn't make
sense that a present cpu feature should increase the size of struct page.
Besides that it looks like the dependency to CMPXCHG_LOCAL is wrong and
that it should depend on CMPXCHG_DOUBLE instead.
This patch:
If an architecture supports CMPXCHG_LOCAL this shouldn't result
automatically in larger struct pages if the SLUB allocator is used.
Instead introduce a new config option "HAVE_ALIGNED_STRUCT_PAGE" which can
be selected if a double word aligned struct page is required. Also update
x86 Kconfig so that it should work as before.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
WARNING: please, no spaces at the start of a line
#57: FILE: arch/m68k/amiga/config.c:515:
+ __noreturn;$
total: 0 errors, 1 warnings, 106 lines checked
./patches/treewide-convert-uses-of-attrib_noreturn-to-__noreturn.patch has style problems, please review.
If any of these errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
Please run checkpatch prior to sending patches
Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Shaohua Li [Wed, 30 Nov 2011 04:11:34 +0000 (15:11 +1100)]
intel_idle: fix API misuse
smp_call_function() only lets all other CPUs execute a specific function,
while we expect all CPUs do in intel_idle. Without the fix, we could have
one cpu which has auto_demotion enabled or has no boradcast timer setup.
Usually we don't see impact because auto demotion just harms power and the
intel_idle init is called in CPU 0, where boradcast timer delivers
interrupt, but this still could be a problem.
Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Magnus Lynch [Wed, 30 Nov 2011 04:11:34 +0000 (15:11 +1100)]
hpet: factor timer allocate from open
The current implementation of the /dev/hpet driver couples opening the
device with allocating one of the (scarce) timers (aka comparators). This
is a limitation in that the main counter may be valuable to applications
seeking a high-resolution timer who have no use for the interrupt
generating functionality of the comparators.
This patch alters the open semantics so that when the device is opened, no
timer is allocated. Operations that depend on a timer being in context
implicitly attempt allocating a timer, to maintain backward compatibility.
There is also an IOCTL (HPET_ALLOC_TIMER _IO) added so that the
allocation may be done explicitly. (I prefer the explicit open then
allocate pattern but don't know how practical it would be to require all
existing code to be changed.)
/dev/hpet is accessed via mmap(). This is the only interface of /dev/hpet
that is actually used in practice.
[akpm@linux-foundation.org: coding-style tweaks]
[arnd@arndb.de: fix build] Signed-off-by: Magnus Lynch <maglyx@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Acked-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hillf Danton [Wed, 30 Nov 2011 04:11:33 +0000 (15:11 +1100)]
mm: compaction: push isolate search base of compact control one pfn ahead
After isolated the current pfn will no longer be scanned and isolated if
the next round is necessary, so push the isolate_migratepages search base
of the given compact_control one step ahead.
Signed-off-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Wed, 30 Nov 2011 04:11:33 +0000 (15:11 +1100)]
Btrfs: pass __GFP_WRITE for buffered write page allocations
Tell the page allocator that pages allocated for a buffered write are
expected to become dirty soon.
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Wed, 30 Nov 2011 04:11:33 +0000 (15:11 +1100)]
mm: filemap: pass __GFP_WRITE from grab_cache_page_write_begin()
Tell the page allocator that pages allocated through
grab_cache_page_write_begin() are expected to become dirty soon.
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Wed, 30 Nov 2011 04:11:32 +0000 (15:11 +1100)]
mm: try to distribute dirty pages fairly across zones
The maximum number of dirty pages that exist in the system at any time is
determined by a number of pages considered dirtyable and a user-configured
percentage of those, or an absolute number in bytes.
This number of dirtyable pages is the sum of memory provided by all the
zones in the system minus their lowmem reserves and high watermarks, so
that the system can retain a healthy number of free pages without having
to reclaim dirty pages.
But there is a flaw in that we have a zoned page allocator which does not
care about the global state but rather the state of individual memory
zones. And right now there is nothing that prevents one zone from filling
up with dirty pages while other zones are spared, which frequently leads
to situations where kswapd, in order to restore the watermark of free
pages, does indeed have to write pages from that zone's LRU list. This
can interfere so badly with IO from the flusher threads that major
filesystems (btrfs, xfs, ext4) mostly ignore write requests from reclaim
already, taking away the VM's only possibility to keep such a zone
balanced, aside from hoping the flushers will soon clean pages from that
zone.
Enter per-zone dirty limits. They are to a zone's dirtyable memory what
the global limit is to the global amount of dirtyable memory, and try to
make sure that no single zone receives more than its fair share of the
globally allowed dirty pages in the first place. As the number of pages
considered dirtyable excludes the zones' lowmem reserves and high
watermarks, the maximum number of dirty pages in a zone is such that the
zone can always be balanced without requiring page cleaning.
As this is a placement decision in the page allocator and pages are
dirtied only after the allocation, this patch allows allocators to pass
__GFP_WRITE when they know in advance that the page will be written to and
become dirty soon. The page allocator will then attempt to allocate from
the first zone of the zonelist - which on NUMA is determined by the task's
NUMA memory policy - that has not exceeded its dirty limit.
At first glance, it would appear that the diversion to lower zones can
increase pressure on them, but this is not the case. With a full high
zone, allocations will be diverted to lower zones eventually, so it is
more of a shift in timing of the lower zone allocations. Workloads that
previously could fit their dirty pages completely in the higher zone may
be forced to allocate from lower zones, but the amount of pages that
"spill over" are limited themselves by the lower zones' dirty constraints,
and thus unlikely to become a problem.
For now, the problem of unfair dirty page distribution remains for NUMA
configurations where the zones allowed for allocation are in sum not big
enough to trigger the global dirty limits, wake up the flusher threads and
remedy the situation. Because of this, an allocation that could not
succeed on any of the considered zones is allowed to ignore the dirty
limits before going into direct reclaim or even failing the allocation,
until a future patch changes the global dirty throttling and flusher
thread activation so that they take individual zone states into account.
Test results
15M DMA + 3246M DMA32 + 504 Normal = 3765M memory
40% dirty ratio
16G USB thumb drive
10 runs of dd if=/dev/zero of=disk/zeroes bs=32k count=$((10 << 15))
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Tested-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Wed, 30 Nov 2011 04:11:32 +0000 (15:11 +1100)]
mm: writeback: cleanups in preparation for per-zone dirty limits
The next patch will introduce per-zone dirty limiting functions in
addition to the traditional global dirty limiting.
Rename determine_dirtyable_memory() to global_dirtyable_memory() before
adding the zone-specific version, and fix up its documentation.
Also, move the functions to determine the dirtyable memory and the
function to calculate the dirty limit based on that together so that their
relationship is more apparent and that they can be commented on as a
group.
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Mel Gorman <mel@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Mason <chris.mason@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <jweiner@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Wed, 30 Nov 2011 04:11:31 +0000 (15:11 +1100)]
mm: exclude reserved pages from dirtyable memory
Per-zone dirty limits try to distribute page cache pages allocated for
writing across zones in proportion to the individual zone sizes, to reduce
the likelihood of reclaim having to write back individual pages from the
LRU lists in order to make progress.
This patch:
The amount of dirtyable pages should not include the full number of free
pages: there is a number of reserved pages that the page allocator and
kswapd always try to keep free.
The closer (reclaimable pages - dirty pages) is to the number of reserved
pages, the more likely it becomes for reclaim to run into dirty pages:
This patch introduces a per-zone dirty reserve that takes both the lowmem
reserve as well as the high watermark of the zone into account, and a
global sum of those per-zone values that is subtracted from the global
amount of dirtyable pages. The lowmem reserve is unavailable to page
cache allocations and kswapd tries to keep the high watermark free. We
don't want to end up in a situation where reclaim has to clean pages in
order to balance zones.
Not treating reserved pages as dirtyable on a global level is only a
conceptual fix. In reality, dirty pages are not distributed equally
across zones and reclaim runs into dirty pages on a regular basis.
But it is important to get this right before tackling the problem on a
per-zone level, where the distance between reclaim and the dirty pages is
mostly much smaller in absolute numbers.
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Rientjes [Wed, 30 Nov 2011 04:11:31 +0000 (15:11 +1100)]
mm, debug: test for online nid when allocating on single node
Calling alloc_pages_exact_node() means the allocation only passes the
zonelist of a single node into the page allocator. If that node isn't
online, it's zonelist may never have been initialized causing a strange
oops that may not immediately be clear.
I recently debugged an issue where node 0 wasn't online and an allocator
was passing 0 to alloc_pages_exact_node() and it resulted in a NULL
pointer on zonelist->_zoneref. If CONFIG_DEBUG_VM is enabled, though, it
would be nice to catch this a bit earlier.
Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Shawn Bohrer [Wed, 30 Nov 2011 04:11:30 +0000 (15:11 +1100)]
fadvise: only initiate writeback for specified range with FADV_DONTNEED
Previously POSIX_FADV_DONTNEED would start writeback for the entire file
when the bdi was not write congested. This negatively impacts performance
if the file contians dirty pages outside of the requested range. This
change uses __filemap_fdatawrite_range() to only initiate writeback for
the requested range.
Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Disable slub debug facilities and allocate slabs at minimal order when
debug_guardpage_minorder > 0 to increase probability to catch random
memory corruption by cpu exception.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When debugging with CONFIG_DEBUG_PAGEALLOC and debug_guardpage_minorder >
0, we have lot of free pages that are not marked so. Snapshot code
account them as savable, what cause hibernate memory preallocation
failure.
It is pretty hard to make hibernate allocation succeed with
debug_guardpage_minorder=1. This change at least make it possible when
system has relatively big amount of RAM.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With CONFIG_DEBUG_PAGEALLOC configured, the CPU will generate an exception
on access (read,write) to an unallocated page, which permits us to catch
code which corrupts memory. However the kernel is trying to maximise
memory usage, hence there are usually few free pages in the system and
buggy code usually corrupts some crucial data.
This patch changes the buddy allocator to keep more free/protected pages
and to interlace free/protected and allocated pages to increase the
probability of catching corruption.
When the kernel is compiled with CONFIG_DEBUG_PAGEALLOC,
debug_guardpage_minorder defines the minimum order used by the page
allocator to grant a request. The requested size will be returned with
the remaining pages used as guard pages.
The default value of debug_guardpage_minorder is zero: no change from
current behaviour.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Daney [Wed, 30 Nov 2011 04:11:28 +0000 (15:11 +1100)]
hugetlb: replace BUG() with BUILD_BUG() for dummy definitions
The file linux/hugetlb.h has many places where dummy symbols were defined
so that the main source code would contain fewer:
#ifdef CONFIG_HUGETLBFS
or
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
If there were any misuse of these symbols, the only symptom would be an
OOPS at runtime. Change the BUG() to BUILD_BUG() to catch any such abuse
at compile time instead.
Signed-off-by: David Daney <david.daney@cavium.com> Cc: David Rientjes <rientjes@google.com> Cc: DM <dm.n9107@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Daney [Wed, 30 Nov 2011 04:11:28 +0000 (15:11 +1100)]
kernel.h: Add BUILD_BUG() macro.
We can place this in definitions that we expect the compiler to remove
by dead code elimination. If this assertion fails, we get a nice
error message at build time.
The GCC function attribute error("message") was added in version 4.3,
so we define a new macro __linktime_error(message) to expand to this
for GCC-4.3 and later. This will give us an error diagnostic from the
compiler on the line that fails. For other compilers
__linktime_error(message) expands to nothing, and we have to be
content with a link time error, but at least we will still get a build
error.
BUILD_BUG() expands to the undefined function __build_bug_failed() and
will fail at link time if the compiler ever emits code for it. On
GCC-4.3 and later, attribute((error())) is used so that the failure
will be noted at compile time instead.
Acked-by: David Howells <dhowells@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: David Daney <david.daney@cavium.com> Cc: David Rientjes <rientjes@google.com> Cc: DM <dm.n9107@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Daney [Wed, 30 Nov 2011 04:11:28 +0000 (15:11 +1100)]
kernel.h: add BUILD_BUG() macro
We can place this in definitions that we expect the compiler to remove by
dead code elimination. If this assertion fails, we get a nice error
message at build time.
The GCC function attribute error("message") was added in version 4.3, so
we define a new macro __linktime_error(message) to expand to this for
GCC-4.3 and later. This will give us an error diagnostic from the
compiler on the line that fails. For other compilers
__linktime_error(message) expands to nothing, and we have to be content
with a link time error, but at least we will still get a build error.
BUILD_BUG() expands to the undefined function __build_bug_failed() and
will fail at link time if the compiler ever emits code for it. On GCC-4.3
and later, attribute((error())) is used so that the failure will be noted
at compile time instead.
Signed-off-by: David Daney <david.daney@cavium.com> Acked-by: David Rientjes <rientjes@google.com> Cc: DM <dm.n9107@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/hugetlb.c: fix virtual address handling in hugetlb fault
handle_mm_fault() passes 'faulted' address to hugetlb_fault(). This
address is not aligned to a hugepage boundary.
Most of the functions for hugetlb pages are aware of that and calculate an
alignment themselves. However some functions such as
copy_user_huge_page() and clear_huge_page() don't handle alignment by
themselves.
This patch make hugeltb_fault() fix the alignment and pass an aligned
addresss (to address of a faulted hugepage) to functions.
Let's make it clear that we cannot race with other fault handlers due to
hugetlb (global) mutex. Also make it clear that we want to keep pte_same
checks anayway to have a transition from the global mutex easier.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Hillf Danton <dhillf@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hillf Danton [Wed, 30 Nov 2011 04:11:26 +0000 (15:11 +1100)]
hugetlb: detect race upon page allocation failure during COW
Currently we are not rechecking pte_same in hugetlb_cow after we take ptl
lock again in the page allocation failure code path and simply retry
again. This is not an issue at the moment because hugetlb fault path is
protected by hugetlb_instantiation_mutex so we cannot race.
The original page is locked and so we cannot race even with the page
migration.
Let's add the pte_same check anyway as we want to be consistent with the
other check later in this function and be safe if we ever remove the
mutex.
[mhocko@suse.cz: reworded the changelog] Signed-off-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm: account reaped page cache on inode cache pruning
Inode cache pruning indirectly reclaims page-cache by invalidating mapping
pages. Let's account them into reclaim-state to notice this progress in
memory reclaimer.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Wed, 30 Nov 2011 04:11:07 +0000 (15:11 +1100)]
mm: avoid livelock on !__GFP_FS allocations
Colin Cross reported;
Under the following conditions, __alloc_pages_slowpath can loop forever:
gfp_mask & __GFP_WAIT is true
gfp_mask & __GFP_FS is false
reclaim and compaction make no progress
order <= PAGE_ALLOC_COSTLY_ORDER
These conditions happen very often during suspend and resume,
when pm_restrict_gfp_mask() effectively converts all GFP_KERNEL
allocations into __GFP_WAIT.
The oom killer is not run because gfp_mask & __GFP_FS is false,
but should_alloc_retry will always return true when order is less
than PAGE_ALLOC_COSTLY_ORDER.
In his fix, he avoided retrying the allocation if reclaim made no progress
and __GFP_FS was not set. The problem is that this would result in
GFP_NOIO allocations failing that previously succeeded which would be very
unfortunate.
The big difference between GFP_NOIO and suspend converting GFP_KERNEL to
behave like GFP_NOIO is that normally flushers will be cleaning pages and
kswapd reclaims pages allowing GFP_NOIO to succeed after a short delay.
The same does not necessarily apply during suspend as the storage device
may be suspended.
This patch special cases the suspend case to fail the page allocation if
reclaim cannot make progress and adds some documentation on how
gfp_allowed_mask is currently used. Failing allocations like this may
cause suspend to abort but that is better than a livelock.
[mgorman@suse.de: Rework fix to be suspend specific]
[rientjes@google.com: Move suspended device check to should_alloc_retry] Reported-by: Colin Cross <ccross@android.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
WARNING: line over 80 characters
#42: FILE: mm/page_alloc.c:3464:
+ /* Blocks with reserved pages will never free, skip them. */
WARNING: line over 80 characters
#61: FILE: mm/page_alloc.c:3477:
+ set_pageblock_migratetype(page, MIGRATE_RESERVE);
WARNING: line over 80 characters
#62: FILE: mm/page_alloc.c:3478:
+ move_freepages_block(zone, page, MIGRATE_RESERVE);
total: 0 errors, 3 warnings, 44 lines checked
./patches/mm-reduce-the-amount-of-work-done-when-updating-min_free_kbytes.patch has style problems, please review.
If any of these errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
Please run checkpatch prior to sending patches
Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Wed, 30 Nov 2011 04:11:06 +0000 (15:11 +1100)]
mm: reduce the amount of work done when updating min_free_kbytes
When min_free_kbytes is updated, some pageblocks are marked
MIGRATE_RESERVE. Ordinarily, this work is unnoticable as it happens early
in boot but on large machines with 1TB of memory, this has been reported
to delay boot times, probably due to the NUMA distances involved.
The bulk of the work is due to calling calling pageblock_is_reserved() an
unnecessary amount of times and accessing far more struct page metadata
than is necessary. This patch significantly reduces the amount of work
done by setup_zone_migrate_reserve() improving boot times on 1TB machines.
Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Isaacson <adi@hexapodia.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Wed, 30 Nov 2011 04:11:05 +0000 (15:11 +1100)]
mm: do not stall in synchronous compaction for THP allocations
Occasionally during large file copies to slow storage, there are still
reports of user-visible stalls when THP is enabled. Reports on this have
been intermittent and not reliable to reproduce locally but;
Andy Isaacson reported a problem copying to VFAT on SD Card
https://lkml.org/lkml/2011/11/7/2
In this case, it was stuck in munmap for betwen 20 and 60
seconds in compaction. It is also possible that khugepaged
was holding mmap_sem on this process if CONFIG_NUMA was set.
Johannes Weiner reported stalls on USB
https://lkml.org/lkml/2011/7/25/378
In this case, there is no stack trace but it looks like the
same problem. The USB stick may have been using NTFS as a
filesystem based on other work done related to writing back
to USB around the same time.
Internally in SUSE, I received a bug report related to stalls in firefox
when using Java and Flash heavily while copying from NFS
to VFAT on USB. It has not been confirmed to be the same problem
but if it looks like a duck and quacks like a duck.....
In the past, commit [11bc82d6: mm: compaction: Use async migration for
__GFP_NO_KSWAPD and enforce no writeback] forced that sync compaction
would never be used for THP allocations. This was reverted in commit
[c6a140bf: mm/compaction: reverse the change that forbade sync migraton
with __GFP_NO_KSWAPD] on the grounds that it was uncertain it was
beneficial.
While user-visible stalls do not happen for me when writing to USB, I
setup a test running postmark while short-lived processes created
anonymous mapping. The objective was to exercise the paths that allocate
transparent huge pages. I then logged when processes were stalled for
more than 1 second, recorded a stack strace and did some analysis to
aggregate unique "stall events" which revealed
Time stalled in this event: 47369 ms
Event count: 20
usemem sleep_on_page 3690 ms
usemem sleep_on_page 2148 ms
usemem sleep_on_page 1534 ms
usemem sleep_on_page 1518 ms
usemem sleep_on_page 1225 ms
usemem sleep_on_page 2205 ms
usemem sleep_on_page 2399 ms
usemem sleep_on_page 2398 ms
usemem sleep_on_page 3760 ms
usemem sleep_on_page 1861 ms
usemem sleep_on_page 2948 ms
usemem sleep_on_page 1515 ms
usemem sleep_on_page 1386 ms
usemem sleep_on_page 1882 ms
usemem sleep_on_page 1850 ms
usemem sleep_on_page 3715 ms
usemem sleep_on_page 3716 ms
usemem sleep_on_page 4846 ms
usemem sleep_on_page 1306 ms
usemem sleep_on_page 1467 ms
[<ffffffff810ef30c>] wait_on_page_bit+0x6c/0x80
[<ffffffff8113de9f>] unmap_and_move+0x1bf/0x360
[<ffffffff8113e0e2>] migrate_pages+0xa2/0x1b0
[<ffffffff81134273>] compact_zone+0x1f3/0x2f0
[<ffffffff811345d8>] compact_zone_order+0xa8/0xf0
[<ffffffff811346ff>] try_to_compact_pages+0xdf/0x110
[<ffffffff810f773a>] __alloc_pages_direct_compact+0xda/0x1a0
[<ffffffff810f7d5d>] __alloc_pages_slowpath+0x55d/0x7a0
[<ffffffff810f8151>] __alloc_pages_nodemask+0x1b1/0x1c0
[<ffffffff811331db>] alloc_pages_vma+0x9b/0x160
[<ffffffff81142bb0>] do_huge_pmd_anonymous_page+0x160/0x270
[<ffffffff814410a7>] do_page_fault+0x207/0x4c0
[<ffffffff8143dde5>] page_fault+0x25/0x30
The stall times are approximate at best but the estimates represent 25% of
the worst stalls and even if the estimates are off by a factor of 10, it's
severe.
This patch once again prevents sync migration for transparent hugepage
allocations as it is preferable to fail a THP allocation than stall.
It was suggested that __GFP_NORETRY be used instead of __GFP_NO_KSWAPD to
look less like a special case. This would prevent THP allocation using
sync compaction but it would have other side-effects. There are existing
users of __GFP_NORETRY that are doing high-order allocations and while
they can handle allocation failure, it seems reasonable that they continue
to use sync compaction unless there is a deliberate reason to change that.
To help clarify this for the future, this patch updates the comment for
__GFP_NO_KSWAPD.
If accepted, this is a -stable candidate.
Reported-by: Andy Isaacson <adi@hexapodia.org> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Acked-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jacobo Giralt [Wed, 30 Nov 2011 04:11:05 +0000 (15:11 +1100)]
mm: migrate: one less atomic operation
migrate_page_move_mapping() drops a reference from the old page after
unfreezing its counter. Both operations can be merged into a single
atomic operation by directly unfreezing to one less reference.
The same applies to migrate_huge_page_move_mapping().
Signed-off-by: Jacobo Giralt <jacobo.giralt@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rik van Riel [Wed, 30 Nov 2011 04:11:04 +0000 (15:11 +1100)]
mm-add-extra-free-kbytes-tunable-update
All the fixes suggested by Andrew Morton. Not much of a changelog
since the patch should probably be folded into
mm-add-extra-free-kbytes-tunable.patch
Thank you for pointing these out, Andrew.
Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rik van Riel [Wed, 30 Nov 2011 04:11:04 +0000 (15:11 +1100)]
mm: add extra free kbytes tunable
Add a userspace visible knob to tell the VM to keep an extra amount of
memory free, by increasing the gap between each zone's min and low
watermarks.
This is useful for realtime applications that call system calls and have a
bound on the number of allocations that happen in any short time period.
In this application, extra_free_kbytes would be left at an amount equal to
or larger than than the maximum number of allocations that happen in any
burst.
It may also be useful to reduce the memory use of virtual machines
(temporarily?), in a way that does not cause memory fragmentation like
ballooning does.
Testing results from Satoru Moriya:
: I ran some sample workloads and measure memory allocation latency
: (latency of __alloc_page_nodemask()).
: The test is like following:
:
: - CPU: 1 socket, 4 core
: - Memory: 4GB
:
: - Background load:
: $ dd if=3D/dev/zero of=3D/tmp/tmp1
: $ dd if=3D/dev/zero of=3D/tmp/tmp2
: $ dd if=3D/dev/zero of=3D/tmp/tmp3
:
: - Main load:
: $ mapped-file-stream 1 $((1024 * 1024 * 640)) --(*)
:
: (*) This is made by Johannes Weiner
: https://lkml.org/lkml/2010/8/30/226
:
: It allocates/access 640MByte memory at a burst.
:
: The result is follwoing:
:
: | | extra |
: | default | kbytes |
: --------------------------------------------------------------
: min_free_kbytes | 8113 | 8113 |
: extra_free_kbytes | 0 | 640*1024 | (KB)
: --------------------------------------------------------------
: worst latency | 517.762 | 20.775 | (usec)
: --------------------------------------------------------------
: vmstat result | | |
: nr_vmscan_write | 0 | 0 |
: pgsteal_dma | 0 | 0 |
: pgsteal_dma32 | 143667 | 144882 |
: pgsteal_normal | 31486 | 27001 |
: pgsteal_movable | 0 | 0 |
: pgscan_kswapd_dma | 0 | 0 |
: pgscan_kswapd_dma32 | 138617 | 156351 |
: pgscan_kswapd_normal | 30593 | 27955 |
: pgscan_kswapd_movable | 0 | 0 |
: pgscan_direct_dma | 0 | 0 |
: pgscan_direct_dma32 | 5050 | 0 |
: pgscan_direct_normal | 896 | 0 |
: pgscan_direct_movable | 0 | 0 |
: kswapd_steal | 169207 | 171883 |
: kswapd_inodesteal | 0 | 0 |
: kswapd_low_wmark_hit_quickly | 43 | 45 |
: kswapd_high_wmark_hit_quickly | 1 | 0 |
: allocstall | 32 | 0 |
:
:
: As you can see, in the default case there were 32 direct reclaim
: (allocstal= l) and its worst latency was 517.762 usecs. This value may be
: larger if a process would sleep or issue I/O in the direct reclaim path.
: OTOH, ii the other case where I add extra free bytes, there were no direct
: reclaim and its worst latency was 20.775 usecs.
:
: In this test case, we can avoid direct reclaim and keep a latency low.
Signed-off-by: Rik van Riel<riel@redhat.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Tested-by: Satoru Moriya <satoru.moriya@hds.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After commit v2.6.36-5896-gd065bd8 "mm: retry page fault when blocking on
disk transfer" we usually wait in page-faults without mmap_sem held, so
all swap-token logic was broken, because it based on using
rwsem_is_locked(&mm->mmap_sem) as sign of in progress page-faults.
Add an atomic counter of in progress page-faults for mm to the mm_struct
with swap-token.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename mm_page_free_direct into mm_page_free and mm_pagevec_free into
mm_page_free_batched
Since v2.6.33-5426-gc475dab the kernel triggers mm_page_free_direct for
all freed pages, not only for directly freed. So, let's name it properly.
For pages freed via page-list we also trigger mm_page_free_batched event.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch adds helper free_hot_cold_page_list() to free list of 0-order
pages. It frees pages directly from list without temporary page-vector.
It also calls trace_mm_pagevec_free() to simulate pagevec_free()
behaviour.
vmscan: activate executable pages after first usage
Logic added in commit 8cab4754d24a0 ("vmscan: make mapped executable pages
the first class citizen") was noticeably weakened in commit 645747462435d84 ("vmscan: detect mapped file pages used only once").
Currently these pages can become "first class citizens" only after second
usage. After this patch page_check_references() will activate they after
first usage, and executable code gets yet better chance to stay in memory.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 645747462435 ("vmscan: detect mapped file pages used only once")
greatly decreases lifetime of single-used mapped file pages.
Unfortunately it also decreases life time of all shared mapped file pages.
Because after commit bf3f3bc5e7347 ("mm: don't mark_page_accessed
in fault path") page-fault handler does not mark page active or even
referenced.
Thus page_check_references() activates file page only if it was used twice
while it stays in inactive list, meanwhile it activates anon pages after
first access. Inactive list can be small enough, this way reclaimer can
accidentally throw away any widely used page if it wasn't used twice in
short period.
After this patch page_check_references() also activate file mapped page at
first inactive list scan if this page is already used multiple times via
several ptes.
I found this while trying to fix degragation in rhel6 (~2.6.32) from rhel5
(~2.6.18). There a complete mess with >100 web/mail/spam/ftp containers,
they share all their files but there a lot of anonymous pages: ~500mb
shared file mapped memory and 15-20Gb non-shared anonymous memory. In
this situation major-pagefaults are very costly, because all containers
share the same page. In my load kernel created a disproportionate
pressure on the file memory, compared with the anonymous, they equaled
only if I raise swappiness up to 150 =)
These patches actually wasn't helped a lot in my problem, but I saw
noticable (10-20 times) reduce in count and average time of
major-pagefault in file-mapped areas.
Actually both patches are fixes for commit v2.6.33-5448-g6457474, because
it was aimed at one scenario (singly used pages), but it breaks the logic
in other scenarios (shared and/or executable pages)
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: Pekka Enberg <penberg@kernel.org> Acked-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
projects / karo-tx-linux.git / log