linux.git/init/Kconfig, branch v3.17-rc2

mm: fix CROSS_MEMORY_ATTACH help text grammar

2014-08-14T16:56:15+00:00

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel: build bin2c based on config option CONFIG_BUILD_BIN2C

2014-08-08T22:57:32+00:00

currently bin2c builds only if CONFIG_IKCONFIG=y. But bin2c will now be
used by kexec too.  So make it compilation dependent on CONFIG_BUILD_BIN2C
and this config option can be selected by CONFIG_KEXEC and CONFIG_IKCONFIG.

Signed-off-by: Vivek Goyal 
Cc: Borislav Petkov 
Cc: Michael Kerrisk 
Cc: Yinghai Lu 
Cc: Eric Biederman 
Cc: H. Peter Anvin 
Cc: Matthew Garrett 
Cc: Greg Kroah-Hartman 
Cc: Dave Young 
Cc: WANG Chao 
Cc: Baoquan He 
Cc: Andy Lutomirski 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

printk: allow increasing the ring buffer depending on the number of CPUs

2014-08-07T01:01:23+00:00

The default size of the ring buffer is too small for machines with a
large amount of CPUs under heavy load.  What ends up happening when
debugging is the ring buffer overlaps and chews up old messages making
debugging impossible unless the size is passed as a kernel parameter.
An idle system upon boot up will on average spew out only about one or
two extra lines but where this really matters is on heavy load and that
will vary widely depending on the system and environment.

There are mechanisms to help increase the kernel ring buffer for tracing
through debugfs, and those interfaces even allow growing the kernel ring
buffer per CPU.  We also have a static value which can be passed upon
boot.  Relying on debugfs however is not ideal for production, and
relying on the value passed upon bootup is can only used *after* an
issue has creeped up.  Instead of being reactive this adds a proactive
measure which lets you scale the amount of contributions you'd expect to
the kernel ring buffer under load by each CPU in the worst case
scenario.

We use num_possible_cpus() to avoid complexities which could be
introduced by dynamically changing the ring buffer size at run time,
num_possible_cpus() lets us use the upper limit on possible number of
CPUs therefore avoiding having to deal with hotplugging CPUs on and off.
This introduces the kernel configuration option LOG_CPU_MAX_BUF_SHIFT
which is used to specify the maximum amount of contributions to the
kernel ring buffer in the worst case before the kernel ring buffer flips
over, the size is specified as a power of 2.  The total amount of
contributions made by each CPU must be greater than half of the default
kernel ring buffer size (1 << LOG_BUF_SHIFT bytes) in order to trigger
an increase upon bootup.  The kernel ring buffer is increased to the
next power of two that would fit the required minimum kernel ring buffer
size plus the additional CPU contribution.  For example if LOG_BUF_SHIFT
is 18 (256 KB) you'd require at least 128 KB contributions by other CPUs
in order to trigger an increase of the kernel ring buffer.  With a
LOG_CPU_BUF_SHIFT of 12 (4 KB) you'd require at least anything over > 64
possible CPUs to trigger an increase.  If you had 128 possible CPUs the
amount of minimum required kernel ring buffer bumps to:

   ((1 << 18) + ((128 - 1) * (1 << 12))) / 1024 = 764 KB

Since we require the ring buffer to be a power of two the new required
size would be 1024 KB.

This CPU contributions are ignored when the "log_buf_len" kernel
parameter is used as it forces the exact size of the ring buffer to an
expected power of two value.

[pmladek@suse.cz: fix build]
Signed-off-by: Luis R. Rodriguez 
Signed-off-by: Petr Mladek 
Tested-by: Davidlohr Bueso 
Tested-by: Petr Mladek 
Reviewed-by: Davidlohr Bueso 
Cc: Andrew Lunn 
Cc: Stephen Warren 
Cc: Michal Hocko 
Cc: Petr Mladek 
Cc: Joe Perches 
Cc: Arun KS 
Cc: Kees Cook 
Cc: Davidlohr Bueso 
Cc: Chris Metcalf 
Cc: Jan Kara 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branches 'doc.2014.07.08a', 'fixes.2014.07.09a', 'maintainers.2014.07.08b', 'nocbs.2014.07.07a' and 'torture.2014.07.07a' into HEAD

2014-07-09T16:16:54+00:00

doc.2014.07.08a: Documentation updates.
fixes.2014.07.09a: Miscellaneous fixes.
maintainers.2014.07.08b: Maintainership updates.
nocbs.2014.07.07a: Callback-offloading fixes.
torture.2014.07.07a: Torture-test updates.

rcu: Handle obsolete references to TINY_PREEMPT_RCU

2014-07-09T16:14:17+00:00

Signed-off-by: Paul E. McKenney 
Reviewed-by: Lai Jiangshan

rcu: Don't offload callbacks unless specifically requested

2014-07-07T22:13:44+00:00

Enabling NO_HZ_FULL currently has the side effect of enabling callback
offloading on all CPUs.  This results in lots of additional rcuo kthreads,
and can also increase context switching and wakeups, even in cases where
callback offloading is neither needed nor particularly desirable.  This
commit therefore enables callback offloading on a given CPU only if
specifically requested at build time or boot time, or if that CPU has
been specifically designated (again, either at build time or boot time)
as a nohz_full CPU.

Signed-off-by: Paul E. McKenney

sys_sgetmask/sys_ssetmask: add CONFIG_SGETMASK_SYSCALL

2014-06-04T23:54:14+00:00

sys_sgetmask and sys_ssetmask are obsolete system calls no longer
supported in libc.

This patch replaces architecture related __ARCH_WANT_SYS_SGETMAX by expert
mode configuration.That option is enabled by default for those
architectures.

Signed-off-by: Fabian Frederick 
Cc: Steven Miao 
Cc: Mikael Starvik 
Cc: Jesper Nilsson 
Cc: David Howells 
Cc: Geert Uytterhoeven 
Cc: Michal Simek 
Cc: Ralf Baechle 
Cc: Koichi Yasutake 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: "David S. Miller" 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Greg Ungerer 
Cc: Heiko Carstens 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/process_vm_access: move config option into init/Kconfig

2014-06-04T23:54:12+00:00

CONFIG_CROSS_MEMORY_ATTACH adds couple syscalls: process_vm_readv and
process_vm_writev, it's a kind of IPC for copying data between processes.
Currently this option is placed inside "Processor type and features".

This patch moves it into "General setup" (where all other arch-independed
syscalls and ipc features are placed) and changes prompt string to less
cryptic.

Signed-off-by: Konstantin Khlebnikov 
Cc: Christopher Yeoh 
Cc: Davidlohr Bueso 
Cc: Hugh Dickins 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: kill CONFIG_MM_OWNER

2014-06-04T23:54:01+00:00

CONFIG_MM_OWNER makes no sense.  It is not user-selectable, it is only
selected by CONFIG_MEMCG automatically.  So we can kill this option in
init/Kconfig and do s/CONFIG_MM_OWNER/CONFIG_MEMCG/ globally.

Signed-off-by: Oleg Nesterov 
Acked-by: Michal Hocko 
Acked-by: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation/memcg: warn about incomplete kmemcg state

2014-06-04T23:54:00+00:00

Kmemcg is currently under development and lacks some important features.
In particular, it does not have support of kmem reclaim on memory pressure
inside cgroup, which practically makes it unusable in real life.  Let's
warn about it in both Kconfig and Documentation to prevent complaints
arising.

Signed-off-by: Vladimir Davydov 
Acked-by: Michal Hocko 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds