Add CRC7 routines, used for example in MMC over SPI communication.
Kerneldoc updates
[akpm@linux-foundation.org: fix funny mix of const and non-const]
Signed-off-by: Jan Nikitenko <jan.nikitenko@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kmalloc_node() and kmem_cache_alloc_node() were not available in a zeroing
variant in the past. But with __GFP_ZERO it is possible now to do zeroing
while allocating.
Use __GFP_ZERO to remove the explicit clearing of memory via memset whereever
we can.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Optimize integer-to-string conversion in vsprintf.c for base 10. This is
by far the most used conversion, and in some use cases it impacts
performance. For example, top reads /proc/$PID/stat for every process, and
with 4000 processes decimal conversion alone takes noticeable time.
Using code from
http://www.cs.uiowa.edu/~jones/bcd/decimal.html
(with permission from the author, Douglas W. Jones)
binary-to-decimal-string conversion is done in groups of five digits at
once, using only additions/subtractions/shifts (with -O2; -Os throws in
some multiply instructions).
On i386 arch gcc 4.1.2 -O2 generates ~500 bytes of code.
This patch is run tested. Userspace benchmark/test is also attached.
I tested it on PIII and AMD64 and new code is generally ~2.5 times
faster. On AMD64:
# ./vsprintf_verify-O2
Original decimal conv: .......... 151 ns per iteration
Patched decimal conv: .......... 62 ns per iteration
Testing correctness
12895992590592 ok... [Ctrl-C]
# ./vsprintf_verify-O2
Original decimal conv: .......... 151 ns per iteration
Patched decimal conv: .......... 62 ns per iteration
Testing correctness
26025406464 ok... [Ctrl-C]
More realistic test: top from busybox project was modified to
report how many us it took to scan /proc (this does not account
any processing done after that, like sorting process list),
and then I test it with 4000 processes:
#!/bin/sh
i=4000
while test $i != 0; do
sleep 30 &
let i--
done
busybox top -b -n3 >/dev/null
on unpatched kernel:
top: 4120 processes took 102864 microseconds to scan
top: 4120 processes took 91757 microseconds to scan
top: 4120 processes took 92517 microseconds to scan
top: 4120 processes took 92581 microseconds to scan
on patched kernel:
top: 4120 processes took 75460 microseconds to scan
top: 4120 processes took 66451 microseconds to scan
top: 4120 processes took 67267 microseconds to scan
top: 4120 processes took 67618 microseconds to scan
The speedup comes from much faster generation of /proc/PID/stat
by sprintf() calls inside the kernel.
Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* There is no point in having full "0...9a...z" constant vector,
if we use only "0...9a...f" (and "x" for "0x").
* Post-decrement usually needs a few more instructions, so use
pre decrement instead where makes sense:
- while (i < precision--) {
+ while (i <= --precision) {
* if base != 10 (=> base 8 or 16), we can avoid using division
in a loop and use mask/shift, obtaining much faster conversion.
(More complex optimization for base 10 case is in the second patch).
Overall, size vsprintf.o shows ~80 bytes smaller text section
with this patch applied.
Signed-off-by: Douglas W Jones <jones@cs.uiowa.edu>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current generic bug implementation has a call to dump_stack() in case a
WARN_ON(whatever) gets hit. Since report_bug(), which calls dump_stack(),
gets called from an exception handler we can do better: just pass the
pt_regs structure to report_bug() and pass it to show_regs() in case of a
warning. This will give more debug informations like register contents,
etc... In addition this avoids some pointless lines that dump_stack()
emits, since it includes a stack backtrace of the exception handler which
is of no interest in case of a warning. E.g. on s390 the following lines
are currently always present in a stack backtrace if dump_stack() gets
called from report_bug():
[<000000000001517a>] show_trace+0x92/0xe8)
[<0000000000015270>] show_stack+0xa0/0xd0
[<00000000000152ce>] dump_stack+0x2e/0x3c
[<0000000000195450>] report_bug+0x98/0xf8
[<0000000000016cc8>] illegal_op+0x1fc/0x21c
[<00000000000227d6>] sysc_return+0x0/0x10
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a rather bizarre thing to have inlined in io.h. Stick it in lib/
instead.
While we're there, despaghetti it a bit, and fix its off-by-one behaviour when
passed a zero length.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
per-cpu counters presently must iterate over all possible CPUs in the
exhaustive percpu_counter_sum().
But it can be much better to only iterate over the presently-online CPUs. To
do this, we must arrange for an offlined CPU's count to be spilled into the
counter's central count.
We can do this for all percpu_counters in the machine by linking them into a
single global list and walking that list at CPU_DEAD time.
(I hope. Might have race windows in which the percpu_counter_sum() count is
inaccurate?)
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new configuration variable
CONFIG_SLUB_DEBUG_ON
If set then the kernel will be booted by default with slab debugging
switched on. Similar to CONFIG_SLAB_DEBUG. By default slab debugging
is available but must be enabled by specifying "slub_debug" as a
kernel parameter.
Also add support to switch off slab debugging for a kernel that was
built with CONFIG_SLUB_DEBUG_ON. This works by specifying
slub_debug=-
as a kernel parameter.
Dave Jones wanted this feature.
http://marc.info/?l=linux-kernel&m=118072189913045&w=2
[akpm@linux-foundation.org: clean up switch statement]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove all ids from the given idr tree. idr_destroy() only frees up
unused, cached idp_layers, but this function will remove all id mappings
and leave all idp_layers unused.
A typical clean-up sequence for objects stored in an idr tree, will use
idr_for_each() to free all objects, if necessay, then idr_remove_all() to
remove all ids, and idr_destroy() to free up the cached idr_layers.
Signed-off-by: Kristian Hoegsberg <krh@redhat.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds an iterator function for the idr data structure. Compared
to just iterating through the idr with an integer and idr_find, this
iterator is (almost, but not quite) linear in the number of elements, as
opposed to the number of integers in the range covered by the idr. This
makes a difference for sparse idrs, but more importantly, it's a nicer way
to iterate through the elements.
The drm subsystem is moving to idr for tracking contexts and drawables, and
with this change, we can use the idr exclusively for tracking these
resources.
[akpm@linux-foundation.org: fix comment]
Signed-off-by: Kristian Hoegsberg <krh@redhat.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6: (37 commits)
[XFS] Fix lockdep annotations for xfs_lock_inodes
[LIB]: export radix_tree_preload()
[XFS] Fix XFS_IOC_FSBULKSTAT{,_SINGLE} & XFS_IOC_FSINUMBERS in compat mode
[XFS] Compat ioctl handler for handle operations
[XFS] Compat ioctl handler for XFS_IOC_FSGEOMETRY_V1.
[XFS] Clean up function name handling in tracing code
[XFS] Quota inode has no parent.
[XFS] Concurrent Multi-File Data Streams
[XFS] Use uninitialized_var macro to stop warning about rtx
[XFS] XFS should not be looking at filp reference counts
[XFS] Use is_power_of_2 instead of open coding checks
[XFS] Reduce shouting by removing unnecessary macros from dir2 code.
[XFS] Simplify XFS min/max macros.
[XFS] Kill off xfs_count_bits
[XFS] Cancel transactions on xfs_itruncate_start error.
[XFS] Use do_div() on 64 bit types.
[XFS] Fix remount,readonly path to flush everything correctly.
[XFS] Cleanup inode extent size hint extraction
[XFS] Prevent ENOSPC from aborting transactions that need to succeed
[XFS] Prevent deadlock when flushing inodes on unmount
...
XFS filestreams functionality uses radix trees and the preload
functions. XFS can be built as a module and hence we need
radix_tree_preload() exported. radix_tree_preload_end() is a
static inline, so it doesn't need exporting.
Signed-Off-By: Dave Chinner <dgc@sgi.com>
Signed-Off-By: Tim Shimmin <tes@sgi.com>
As kobj sysfs dentries and inodes are gonna be made reclaimable,
dentry can't be used as naming token for sysfs file/directory, replace
kobj->dentry with kobj->sd. The only external interface change is
shadow directory handling. All other changes are contained in kobj
and sysfs.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Implement idr based id allocator. ida is used the same way idr is
used but lacks id -> ptr translation and thus consumes much less
memory. struct ida_bitmap is attached as leaf nodes to idr tree which
is managed by the idr code. Each ida_bitmap is 128bytes long and
contains slightly less than a thousand slots.
ida is more aggressive with releasing extra resources acquired using
ida_pre_get(). After every successful id allocation, ida frees one
reserved idr_layer if possible. Reserved ida_bitmap is not freed
automatically but only one ida_bitmap is reserved and it's almost
always used right away. Under most circumstances, ida won't hold on
to memory for too long which isn't actively used.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Separate out idr_mark_full() from sub_alloc() and make marking the
allocated slot full the responsibility of idr_get_new_above_int().
Allocation part of idr_get_new_above_int() is renamed to
idr_get_empty_slot(). New idr_get_new_above_int() allocates a slot
using the function, install the user pointer and marks it full using
idr_mark_full().
This change doesn't introduce any behavior change. This will be
used by ida.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In sub_alloc(), when bitmap search fails, it goes up one level to
continue search. This is done by updating the id cursor and searching
the upper level again. If the cursor was at the end of the upper
level, we need to go further than that.
This wasn't implemented and when that happens the part of the cursor
which indexes into the upper level wraps and sub_alloc() ends up
searching the wrong bitmap. It allocates id which doesn't match the
actual slot.
This patch fixes this by restarting from the top if the search needs
to go higher than one level.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We get uevents for a bus/class going away, but not one registering.
Add the missing uevent in kset_register(), which will send an
event for a new bus/class. Suppress all unwanted uevents for bus
subdirectories like /bus/*/devices/, /bus/*/drivers/.
Now we get for module usbcore:
add /module/usbcore (module)
add /bus/usb (bus)
add /class/usb_host (class)
add /bus/usb/drivers/hub (drivers)
add /bus/usb/drivers/usb (drivers)
remove /bus/usb/drivers/usb (drivers)
remove /bus/usb/drivers/hub (drivers)
remove /class/usb_host (class)
remove /bus/usb (bus)
remove /module/usbcore (module)
instead of:
add /module/usbcore (module)
add /bus/usb/drivers/hub (drivers)
add /bus/usb/drivers/usb (drivers)
remove /bus/usb/drivers/usb (drivers)
remove /bus/usb/drivers/hub (drivers)
remove /class/usb_host (class)
remove /bus/usb/drivers (bus)
remove /bus/usb/devices (bus)
remove /bus/usb (bus)
remove /module/usbcore (module)
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This is a hybrid version of the patch to add the LZO1X compression
algorithm to the kernel. Nitin and myself have merged the best parts of
the various patches to form this version which we're both happy with (and
are jointly signing off).
The performance of this version is equivalent to the original minilzo code
it was based on. Bytecode comparisons have also been made on ARM, i386 and
x86_64 with favourable results.
There are several users of LZO lined up including jffs2, crypto and reiser4
since its much faster than zlib.
Signed-off-by: Nitin Gupta <nitingupta910@gmail.com>
Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a prefix string parameter. Callers are responsible for any string
length/alignment that they want to see in the output. I.e., callers should
pad strings to achieve alignment if they want that.
Add rowsize parameter. This is the number of raw data bytes to be printed
per line. Must be 16 or 32.
Add a groupsize parameter. This allows callers to dump values as 1-byte,
2-byte, 4-byte, or 8-byte numbers. Default is 1-byte numbers. If the
total length is not an even multiple of groupsize, 1-byte numbers are
printed.
Add an "ascii" output parameter. This causes ASCII data output following
the hex data output.
Clean up some doc examples.
Align the ASCII output on all lines that are produced by one call.
Add a new interface, print_hex_dump_bytes(), that is a shortcut to
print_hex_dump(), using default parameter values to print 16 bytes in
byte-size chunks of hex + ASCII output, using printk level KERN_DEBUG.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make timer-stats have almost zero overhead when enabled in the config but
not used. (this way distros can enable it more easily)
Also update the documentation about overhead of timer_stats - it was
written for the first version which had a global lock and a linear list
walk based lookup ;-)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
