The debug functions in spin_lock debugging pollute the output of the
function tracer. This patch adds the debug files in the lib director
to those that should not be compiled with mcount tracing.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Most archs define the string and memory compare functions in assembly.
Some do not. But these functions may be used in some archs at early
boot up.

Since most archs define this code in assembly and they are not usually
traced, there's no need to trace them when they are not defined in
assembly.

This patch removes the -pg from the CFLAGS for lib/string.o.
This prevents the string functions use in either vdso or early bootup
from crashing the system.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The debug smp_processor_id caused a recursive fault in debugging
the irqsoff tracer. The tracer used a smp_processor_id in the
ftrace callback, and this function called preempt_disable which
also is traced. This caused a recursive fault (stack overload).

Since using smp_processor_id without debugging on does not cause
faults with the tracer (even when the tracer is wrong), the
debug version should not cause a system reboot.

This changes the debug_smp_processor_id to use the notrace versions
of preempt_disable and enable.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

If CONFIG_FTRACE is selected and /proc/sys/kernel/ftrace_enabled is
set to a non-zero value the ftrace routine will be called everytime
we enter a kernel function that is not marked with the "notrace"
attribute.

The ftrace routine will then call a registered function if a function
happens to be registered.

[ This code has been highly hacked by Steven Rostedt and Ingo Molnar,
  so don't blame Arnaldo for all of this ;-) ]

Update:
  It is now possible to register more than one ftrace function.
  If only one ftrace function is registered, that will be the
  function that ftrace calls directly. If more than one function
  is registered, then ftrace will call a function that will loop
  through the functions to call.
Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Mark with "notrace" functions in core code that should not be
traced.  The "notrace" attribute will prevent gcc from adding
a call to ftrace on the annotated funtions.
Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

lib/lmb.c: In function 'lmb_dump_all':
lib/lmb.c:51: warning: format '%lx' expects type 'long unsigned int', but argument 2 has type 'u64'
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Add a common hex array in hexdump.c so everyone can use it.

Add a common hi/lo helper to avoid the shifting masking that is
done to get the upper and lower nibbles of a byte value.

Pull the pack_hex_byte helper from kgdb as it is opencoded many
places in the tree that will be consolidated.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

match_strcpy() is a somewhat creepy function: the caller needs to make sure
that the destination buffer is big enough, and when he screws up or
forgets, match_strcpy() happily overruns the buffer.

There's exactly one customer: v9fs_parse_options().  I believe it currently
can't overflow its buffer, but that's not exactly obvious.

The source string is a substing of the mount options.  The kernel silently
truncates those to PAGE_SIZE bytes, including the terminating zero.  See
compat_sys_mount() and do_mount().

The destination buffer is obtained from __getname(), which allocates from
name_cachep, which is initialized by vfs_caches_init() for size PATH_MAX.

We're safe as long as PATH_MAX <= PAGE_SIZE.  PATH_MAX is 4096.  As far as
I know, the smallest PAGE_SIZE is also 4096.

Here's a patch that makes the code a bit more obviously correct.  It
doesn't depend on PATH_MAX <= PAGE_SIZE.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Jim Meyering <meyering@redhat.com>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

They aren't used.  They were briefly used as part of some other patches to
provide an alternative format for displaying some /proc and /sys cpumasks.
They probably should have been removed when those other patches were dropped,
in favor of a different solution.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Cc: "Mike Travis" <travis@sgi.com>
Cc: "Bert Wesarg" <bert.wesarg@googlemail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Having to muck with the build and set DEBUG just to
get lmb_dump_all() to print things isn't very useful.

So use pr_info() and use an early boot param
"lmb=debug" so we can simply ask users to reboot
with this option when we need some debugging from
them.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When allocating, if we will align up the size when making
the reservation, we should also align the size for the
check that the space is actually available.

The simplest thing is to just aling the size up from
the beginning, then we can use plain 'size' throughout.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The generic semaphore rewrite had a huge performance regression on AIM7
(and potentially other BKL-heavy benchmarks) because the generic
semaphores had been rewritten to be simple to understand and fair.  The
latter, in particular, turns a semaphore-based BKL implementation into a
mess of scheduling.

The attempt to fix the performance regression failed miserably (see the
previous commit 00b41ec2 'Revert
"semaphore: fix"'), and so for now the simple and sane approach is to
instead just go back to the old spinlock-based BKL implementation that
never had any issues like this.

This patch also has the advantage of being reported to fix the
regression completely according to Yanmin Zhang, unlike the semaphore
hack which still left a couple percentage point regression.

As a spinlock, the BKL obviously has the potential to be a latency
issue, but it's not really any different from any other spinlock in that
respect.  We do want to get rid of the BKL asap, but that has been the
plan for several years.

These days, the biggest users are in the tty layer (open/release in
particular) and Alan holds out some hope:

  "tty release is probably a few months away from getting cured - I'm
   afraid it will almost certainly be the very last user of the BKL in
   tty to get fixed as it depends on everything else being sanely locked."

so while we're not there yet, we do have a plan of action.
Tested-by: NYanmin Zhang <yanmin_zhang@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Alexander Viro <viro@ftp.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kconfig.kgdb: fix menuconfig element
Signed-off-by: NJan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

We provide an ioremap_flags, so this provides a corresponding
devm_ioremap_prot.  The slight name difference is at Ben
Herrenschmidt's request as he plans on changing ioremap_flags to
ioremap_prot in the future.
Signed-off-by: NEmil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Acked-by: NTejun Heo <htejun@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The return inside the loop makes us free only a single layer.
Signed-off-by: NNadia Derbey <Nadia.Derbey@bull.net>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Jim Houston <jim.houston@comcast.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a new sysfs_streq() string comparison function, which ignores
the trailing newlines found in sysfs inputs.  By example:

	sysfs_streq("a", "b")	==> false
	sysfs_streq("a", "a")	==> true
	sysfs_streq("a", "a\n")	==> true
	sysfs_streq("a\n", "a")	==> true

This is intended to simplify parsing of sysfs inputs, letting them
avoid the need to manually strip off newlines from inputs.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NGreg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rename div64_64 to div64_u64 to make it consistent with the other divide
functions, so it clearly includes the type of the divide.  Move its definition
to math64.h as currently no architecture overrides the generic implementation.
 They can still override it of course, but the duplicated declarations are
avoided.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current do_div doesn't explicitly say that it's unsigned and the signed
counterpart is missing, which is e.g.  needed when dealing with time values.

This introduces 64bit signed/unsigned divide functions which also attempts to
cleanup the somewhat awkward calling API, which often requires the use of
temporary variables for the dividend.  To avoid the need for temporary
variables everywhere for the remainder, each divide variant also provides a
version which doesn't return the remainder.

Each architecture can now provide optimized versions of these function,
otherwise generic fallback implementations will be used.

As an example I provided an alternative for the current x86 divide, which
avoids the asm casts and using an union allows gcc to generate better code.
It also avoids the upper divde in a few more cases, where the result is known
(i.e.  upper quotient is zero).
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Finally clean up the odd spacing in these files.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Use a resource_size_t instead of unsigned long since some arch's are
capable of having ioremap deal with addresses greater than the size of a
unsigned long.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This prevents a few unneeded copies.
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add klist_add_after() and klist_add_before() which puts a new node
after and before an existing node, respectively.  This is useful for
callers which need to keep klist ordered.  Note that synchronizing
between simultaneous additions for ordering is the caller's
responsibility.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

__FUNCTION__ is gcc specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add calls to the generic object debugging infrastructure and provide fixup
functions which allow to keep the system alive when recoverable problems have
been detected by the object debugging core code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: Greg KH <greg@kroah.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We can see an ever repeating problem pattern with objects of any kind in the
kernel:

1) freeing of active objects
2) reinitialization of active objects

Both problems can be hard to debug because the crash happens at a point where
we have no chance to decode the root cause anymore.  One problem spot are
kernel timers, where the detection of the problem often happens in interrupt
context and usually causes the machine to panic.

While working on a timer related bug report I had to hack specialized code
into the timer subsystem to get a reasonable hint for the root cause.  This
debug hack was fine for temporary use, but far from a mergeable solution due
to the intrusiveness into the timer code.

The code further lacked the ability to detect and report the root cause
instantly and keep the system operational.

Keeping the system operational is important to get hold of the debug
information without special debugging aids like serial consoles and special
knowledge of the bug reporter.

The problems described above are not restricted to timers, but timers tend to
expose it usually in a full system crash.  Other objects are less explosive,
but the symptoms caused by such mistakes can be even harder to debug.

Instead of creating specialized debugging code for the timer subsystem a
generic infrastructure is created which allows developers to verify their code
and provides an easy to enable debug facility for users in case of trouble.

The debugobjects core code keeps track of operations on static and dynamic
objects by inserting them into a hashed list and sanity checking them on
object operations and provides additional checks whenever kernel memory is
freed.

The tracked object operations are:
- initializing an object
- adding an object to a subsystem list
- deleting an object from a subsystem list

Each operation is sanity checked before the operation is executed and the
subsystem specific code can provide a fixup function which allows to prevent
the damage of the operation.  When the sanity check triggers a warning message
and a stack trace is printed.

The list of operations can be extended if the need arises.  For now it's
limited to the requirements of the first user (timers).

The core code enqueues the objects into hash buckets.  The hash index is
generated from the address of the object to simplify the lookup for the check
on kfree/vfree.  Each bucket has it's own spinlock to avoid contention on a
global lock.

The debug code can be compiled in without being active.  The runtime overhead
is minimal and could be optimized by asm alternatives.  A kernel command line
option enables the debugging code.

Thanks to Ingo Molnar for review, suggestions and cleanup patches.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Greg KH <greg@kroah.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add "max_ratio" to /sys/class/bdi.  This indicates the maximum percentage of
the global dirty threshold allocated to this bdi.

[mszeredi@suse.cz]

 - fix parsing in max_ratio_store().
 - export bdi_set_max_ratio() to modules
 - limit bdi_dirty with bdi->max_ratio
 - document new sysfs attribute
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object.
This allows us to see and set the various BDI specific variables.

In particular this properly exposes the read-ahead window for all relevant
users and /sys/block/<block>/queue/read_ahead_kb should be deprecated.

With patient help from Kay Sievers and Greg KH

[mszeredi@suse.cz]

 - split off NFS and FUSE changes into separate patches
 - document new sysfs attributes under Documentation/ABI
 - do bdi_class_init as a core_initcall, otherwise the "default" BDI
   won't be initialized
 - remove bdi_init_fmt macro, it's not used very much

[akpm@linux-foundation.org: fix ia64 warning]
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: NGreg KH <greg@kroah.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The mapsize optimizations which were moved from x86 to the generic
code in commit 64970b68 increased the
binary size on non x86 architectures.

Looking into the real effects of the "optimizations" it turned out
that they are not used in find_next_bit() and find_next_zero_bit().

The ones in find_first_bit() and find_first_zero_bit() are used in a
couple of places but none of them is a real hot path.

Remove the "optimizations" all together and call the library functions
unconditionally.

Boot-tested on x86 and compile tested on every cross compiler I have.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Avoid a possible kmem_cache_create() failure by creating idr_layer_cache
unconditionary at boot time rather than creating it on-demand when idr_init()
is called the first time.

This change also enables us to eliminate the check every time idr_init() is
called.

[akpm@linux-foundation.org: rename init_id_cache() to idr_init_cache()]
[akpm@linux-foundation.org: fix alpha build]
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change all ia64 machvecs to use the new dma_*map*_attrs() interfaces.
Implement the old dma_*map_*() interfaces in terms of the corresponding new
interfaces.  For ia64/sn, make use of one dma attribute,
DMA_ATTR_WRITE_BARRIER.  Introduce swiotlb_*map*_attrs() functions.
Signed-off-by: NArthur Kepner <akepner@sgi.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Due to the rcupreempt.h WARN_ON trigged, I got 2G syslog file.  For some
serious complaining of kernel, we need repeat the warnings, so here I isolate
the ratelimit part of printk.c to a standalone file.
Signed-off-by: NDave Young <hidave.darkstar@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

iommu_is_span_boundary in lib/iommu-helper.c was exported for PARISC IOMMUs
(commit 3715863a).  SWIOTLB can use it instead
of the homegrown function.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's a pointlessly braced block of code in there.  Remove the braces and
save a tabstop.

Cc: Andi Kleen <ak@suse.de>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Almost all implementations of pci_iomap() in the kernel, including the generic
lib/iomap.c one, copies the content of a struct resource into unsigned long's
which will break on 32 bits platforms with 64 bits resources.

This fixes all definitions of pci_iomap() to use resource_size_t.  I also
"fixed" the 64bits arch for consistency.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

lib/inflate.c (inflate_dynamic): Don't deref NULL upon failed malloc.
Signed-off-by: NJim Meyering <meyering@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provide walk_memory_resource() for 64-bit powerpc.  PowerPC maintains
logical memory region mapping in the lmb.memory structure.  Walk
through these structures and do the callbacks for the contiguous
chunks.
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The powerpc kernel maintains information about logical memory blocks
in the lmb.memory structure, which is initialized and updated at boot
time, but not when memory is added or removed while the kernel is
running.

This adds a hotplug memory notifier which updates lmb.memory when
memory is added or removed.  This information is useful for eHEA
driver to find out the memory layout and holes.

NOTE: No special locking is needed for lmb_add() and lmb_remove().
Calls to these are serialized by caller. (pSeries_reconfig_chain).
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The following adds two more bitmap operators, bitmap_onto() and bitmap_fold(),
with the usual cpumask and nodemask wrappers.

The bitmap_onto() operator computes one bitmap relative to another.  If the
n-th bit in the origin mask is set, then the m-th bit of the destination mask
will be set, where m is the position of the n-th set bit in the relative mask.

The bitmap_fold() operator folds a bitmap into a second that has bit m set iff
the input bitmap has some bit n set, where m == n mod sz, for the specified sz
value.

There are two substantive changes between this patch and its
predecessor bitmap_relative:
 1) Renamed bitmap_relative() to be bitmap_onto().
 2) Added bitmap_fold().

The essential motivation for bitmap_onto() is to provide a mechanism for
converting a cpuset-relative CPU or Node mask to an absolute mask.  Cpuset
relative masks are written as if the current task were in a cpuset whose CPUs
or Nodes were just the consecutive ones numbered 0..N-1, for some N.  The
bitmap_onto() operator is provided in anticipation of adding support for the
first such cpuset relative mask, by the mbind() and set_mempolicy() system
calls, using a planned flag of MPOL_F_RELATIVE_NODES.  These bitmap operators
(and their nodemask wrappers, in particular) will be used in code that
converts the user specified cpuset relative memory policy to a specific system
node numbered policy, given the current mems_allowed of the tasks cpuset.

Such cpuset relative mempolicies will address two deficiencies
of the existing interface between cpusets and mempolicies:
 1) A task cannot at present reliably establish a cpuset
    relative mempolicy because there is an essential race
    condition, in that the tasks cpuset may be changed in
    between the time the task can query its cpuset placement,
    and the time the task can issue the applicable mbind or
    set_memplicy system call.
 2) A task cannot at present establish what cpuset relative
    mempolicy it would like to have, if it is in a smaller
    cpuset than it might have mempolicy preferences for,
    because the existing interface only allows specifying
    mempolicies for nodes currently allowed by the cpuset.

Cpuset relative mempolicies are useful for tasks that don't distinguish
particularly between one CPU or Node and another, but only between how many of
each are allowed, and the proper placement of threads and memory pages on the
various CPUs and Nodes available.

The motivation for the added bitmap_fold() can be seen in the following
example.

Let's say an application has specified some mempolicies that presume 16 memory
nodes, including say a mempolicy that specified MPOL_F_RELATIVE_NODES (cpuset
relative) nodes 12-15.  Then lets say that application is crammed into a
cpuset that only has 8 memory nodes, 0-7.  If one just uses bitmap_onto(),
this mempolicy, mapped to that cpuset, would ignore the requested relative
nodes above 7, leaving it empty of nodes.  That's not good; better to fold the
higher nodes down, so that some nodes are included in the resulting mapped
mempolicy.  In this case, the mempolicy nodes 12-15 are taken modulo 8 (the
weight of the mems_allowed of the confining cpuset), resulting in a mempolicy
specifying nodes 4-7.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: <kosaki.motohiro@jp.fujitsu.com>
Cc: <ray-lk@madrabbit.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Migrate flags must be set on slab creation as agreed upon when the antifrag
logic was reviewed.  Otherwise some slabs of a slabcache will end up in the
unmovable and others in the reclaimable section depending on which flag was
active when a new slab page was allocated.

This likely slid in somehow when antifrag was merged. Remove it.

The buffer_heads are always allocated with __GFP_RECLAIMABLE because the
SLAB_RECLAIM_ACCOUNT option is set.  The set_migrateflags() never had any
effect there.

Radix tree allocations are not directly reclaimable but they are allocated
with __GFP_RECLAIMABLE set on each allocation.  We now set
SLAB_RECLAIM_ACCOUNT on radix tree slab creation making sure that radix
tree slabs are consistently placed in the reclaimable section.  Radix tree
slabs will also be accounted as such.

There is then no user left of set_migratepages. So remove it.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce GENERIC_FIND_FIRST_BIT and GENERIC_FIND_NEXT_BIT in
lib/Kconfig, defaulting to off. An arch that wants to use the
generic implementation now only has to use a select statement
to include them.

I added an always-y option (X86_CPU) to arch/x86/Kconfig.cpu
and used that to select the generic search functions. This
way ARCH=um SUBARCH=i386 automatically picks up the change
too, and arch/um/Kconfig.i386 can therefore be simplified a
bit. ARCH=um SUBARCH=x86_64 does things differently, but
still compiles fine. It seems that a "def_bool y" always
wins over a "def_bool n"?
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>