Constify struct sysfs_ops.
This is part of the ops structure constification
effort started by Arjan van de Ven et al.
Benefits of this constification:
* prevents modification of data that is shared
(referenced) by many other structure instances
at runtime
* detects/prevents accidental (but not intentional)
modification attempts on archs that enforce
read-only kernel data at runtime
* potentially better optimized code as the compiler
can assume that the const data cannot be changed
* the compiler/linker move const data into .rodata
and therefore exclude them from false sharing
Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: David Teigland <teigland@redhat.com>
Acked-by: Matt Domsch <Matt_Domsch@dell.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: Hans J. Koch <hjk@linutronix.de>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Constify struct kset_uevent_ops.
This is part of the ops structure constification
effort started by Arjan van de Ven et al.
Benefits of this constification:
* prevents modification of data that is shared
(referenced) by many other structure instances
at runtime
* detects/prevents accidental (but not intentional)
modification attempts on archs that enforce
read-only kernel data at runtime
* potentially better optimized code as the compiler
can assume that the const data cannot be changed
* the compiler/linker move const data into .rodata
and therefore exclude them from false sharing
Signed-off-by: Emese Revfy <re.emese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts commit a069c266ae.
It turns ou that not only was it missing a case (XFS) that needed it,
but perhaps more importantly, people sometimes want to enable new
modules that they hadn't had enabled before, and if such a module uses
list_sort(), it can't easily be inserted any more.
So rather than add a "select LIST_SORT" to the XFS case, just leave it
compiled in. It's not all _that_ big, after all, and the inconvenience
isn't worth it.
Requested-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Don Mullis <don.mullis@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds separate I/O and memory specs, so we don't have to change the
field width in a shared spec, which then lets us make all the specs const
and static, since they never change.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reducing the size of struct printf_spec is a good thing because multiple
instances are commonly passed on stack.
It's possible for type to be u8 and field_width to be s8, but this is
likely small enough for now.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs:
[LogFS] Change magic number
[LogFS] Remove h_version field
[LogFS] Check feature flags
[LogFS] Only write journal if dirty
[LogFS] Fix bdev erases
[LogFS] Silence gcc
[LogFS] Prevent 64bit divisions in hash_index
[LogFS] Plug memory leak on error paths
[LogFS] Add MAINTAINERS entry
[LogFS] add new flash file system
Fixed up trivial conflict in lib/Kconfig, and a semantic conflict in
fs/logfs/inode.c introduced by write_inode() being changed to use
writeback_control' by commit a9185b41a4
("pass writeback_control to ->write_inode")
XFS and UBIFS can pass long lists to list_sort(); this alternative
implementation scales better, reaching ~3x performance gain when list
length exceeds the L2 cache size.
Stand-alone program timings were run on a Core 2 duo L1=32KB L2=4MB,
gcc-4.4, with flags extracted from an Ubuntu kernel build. Object size is
581 bytes compared to 455 for Mark J. Roberts' code.
Worst case for either implementation is a list length just over a power of
two, and to roughly the same degree, so here are timing results for a
range of 2^N+1 lengths. List elements were 16 bytes each including malloc
overhead; initial order was random.
time (msec)
Tatham-Roberts
| generic-Mullis-v2
loop_count length | | ratio
4000000 2 206 294 1.427
2000000 3 176 227 1.289
1000000 5 199 172 0.864
500000 9 235 178 0.757
250000 17 243 182 0.748
125000 33 261 196 0.750
62500 65 277 209 0.754
31250 129 292 219 0.75
15625 257 317 235 0.741
7812 513 340 252 0.741
3906 1025 362 267 0.737
1953 2049 388 283 0.729 ~ L1 size
976 4097 556 323 0.580
488 8193 678 361 0.532
244 16385 773 395 0.510
122 32769 844 418 0.495
61 65537 917 454 0.495
30 131073 1128 543 0.481
15 262145 2355 869 0.369 ~ L2 size
7 524289 5597 1714 0.306
3 1048577 6218 2022 0.325
Mark's code does not actually implement the usual or generic mergesort,
but rather a variant from Simon Tatham described here:
http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html
Simon's algorithm performs O(log N) passes over the entire input list,
doing merges of sublists that double in size on each pass. The generic
algorithm instead merges pairs of equal length lists as early as possible,
in recursive order. For either algorithm, the elements that extend the
list beyond power-of-two length are a special case, handled as nearly as
possible as a "rounding-up" to a full POT.
Some intuition for the locality of reference implications of merge order
may be gotten by watching this animation:
http://www.sorting-algorithms.com/merge-sort
Simon's algorithm requires only O(1) extra space rather than the generic
algorithm's O(log N), but in my non-recursive implementation the actual
O(log N) data is merely a vector of ~20 pointers, which I've put on the
stack.
Long-running list_sort() calls: If the list passed in may be long, or the
client's cmp() callback function is slow, the client's cmp() may
periodically invoke cond_resched() to voluntarily yield the CPU. All
inner loops of list_sort() call back to cmp().
Stability of the sort: distinct elements that compare equal emerge from
the sort in the same order as with Mark's code, for simple test cases. A
boot-time test is provided to verify this and other correctness
requirements.
A kernel that uses drm.ko appears to run normally with this change; I have
no suitable hardware to similarly test the use by UBIFS.
[akpm@linux-foundation.org: style tweaks, fix comment, make list_sort_test __init]
Signed-off-by: Don Mullis <don.mullis@gmail.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add adds a debugfs interface and additional failure modes to LKDTM to
provide similar functionality to the provoke-crash driver submitted here:
http://lwn.net/Articles/371208/
Crashes can now be induced either through module parameters (as before)
or through the debugfs interface as in provoke-crash.
The patch also provides a new "direct" interface, where KPROBES are not
used, i.e., the crash is invoked directly upon write to the debugfs
file. When built without KPROBES configured, only this mode is available.
Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Cc: M. Mohan Kumar <mohan@in.ibm.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the same log level for printk's in show_mem(), so that those messages
can be shown completely when using log level 6.
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (44 commits)
rcu: Fix accelerated GPs for last non-dynticked CPU
rcu: Make non-RCU_PROVE_LOCKING rcu_read_lock_sched_held() understand boot
rcu: Fix accelerated grace periods for last non-dynticked CPU
rcu: Export rcu_scheduler_active
rcu: Make rcu_read_lock_sched_held() take boot time into account
rcu: Make lockdep_rcu_dereference() message less alarmist
sched, cgroups: Fix module export
rcu: Add RCU_CPU_STALL_VERBOSE to dump detailed per-task information
rcu: Fix rcutorture mod_timer argument to delay one jiffy
rcu: Fix deadlock in TREE_PREEMPT_RCU CPU stall detection
rcu: Convert to raw_spinlocks
rcu: Stop overflowing signed integers
rcu: Use canonical URL for Mathieu's dissertation
rcu: Accelerate grace period if last non-dynticked CPU
rcu: Fix citation of Mathieu's dissertation
rcu: Documentation update for CONFIG_PROVE_RCU
security: Apply lockdep-based checking to rcu_dereference() uses
idr: Apply lockdep-based diagnostics to rcu_dereference() uses
radix-tree: Disable RCU lockdep checking in radix tree
vfs: Abstract rcu_dereference_check for files-fdtable use
...
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (88 commits)
powerpc: Fix lwsync feature fixup vs. modules on 64-bit
powerpc: Convert pmc_owner_lock to raw_spinlock
powerpc: Convert die.lock to raw_spinlock
powerpc: Convert tlbivax_lock to raw_spinlock
powerpc: Convert mpic locks to raw_spinlock
powerpc: Convert pmac_pic_lock to raw_spinlock
powerpc: Convert big_irq_lock to raw_spinlock
powerpc: Convert feature_lock to raw_spinlock
powerpc: Convert i8259_lock to raw_spinlock
powerpc: Convert beat_htab_lock to raw_spinlock
powerpc: Convert confirm_error_lock to raw_spinlock
powerpc: Convert ipic_lock to raw_spinlock
powerpc: Convert native_tlbie_lock to raw_spinlock
powerpc: Convert beatic_irq_mask_lock to raw_spinlock
powerpc: Convert nv_lock to raw_spinlock
powerpc: Convert context_lock to raw_spinlock
powerpc/85xx: Add NOR, LEDs and PIB support for MPC8568E-MDS boards
powerpc/86xx: Enable VME driver on the GE SBC610
powerpc/86xx: Enable VME driver on the GE PPC9A
powerpc/86xx: Add MSI section to GE PPC9A DTS
...
I've forgot to add 'perf lock' line to command-list.txt,
so users of perf could not find perf lock when they type 'perf'.
Fixing command-list.txt requires document
(tools/perf/Documentation/perf-lock.txt).
But perf lock is too much "under construction" to write a
stable document, so this is something like pseudo document for now.
And I wrote description of perf lock at help section of
CONFIG_LOCK_STAT, this will navigate users of lock trace events.
Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
LKML-Reference: <1265267295-8388-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (187 commits)
sh: remove dead LED code for migo-r and ms7724se
sh: ecovec build fix for CONFIG_I2C=n
sh: ecovec r-standby support
sh: ms7724se r-standby support
sh: SH-Mobile R-standby register save/restore
clocksource: Fix up a registration/IRQ race in the sh drivers.
sh: ms7724: modify scan_timing for KEYSC
sh: ms7724: Add sh_sir support
sh: mach-ecovec24: Add sh_sir support
sh: wire up SET/GET_UNALIGN_CTL.
sh: allow alignment fault mode to be configured at kernel boot.
sh: sh7724: Update FSI/SPU2 clock
sh: always enable sh7724 vpu_clk and set to 166MHz on Ecovec
sh: add sh7724 kick callback to clk_div4_table
sh: introduce struct clk_div4_table
sh: clock-cpg div4 set_rate() shift fix
sh: Turn on speculative return for SH7785 and SH7786
sh: Merge legacy and dynamic PMB modes.
sh: Use uncached I/O helpers in PMB setup.
sh: Provide uncached I/O helpers.
...
