rename all 'cnt' fields and variables to the less yucky 'count' name.

yuckage noticed by Andrew Morton.

no change in code, other than the /proc/sched_debug bkl_count string got
a bit larger:

   text    data     bss     dec     hex filename
  38236    3506      24   41766    a326 sched.o.before
  38240    3506      24   41770    a32a sched.o.after
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

update delay-accounting to use CFS's precise stats.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch provides a new macro

KMEM_CACHE(<struct>, <flags>)

to simplify slab creation. KMEM_CACHE creates a slab with the name of the
struct, with the size of the struct and with the alignment of the struct.
Additional slab flags may be specified if necessary.

Example

struct test_slab {
	int a,b,c;
	struct list_head;
} __cacheline_aligned_in_smp;

test_slab_cache = KMEM_CACHE(test_slab, SLAB_PANIC)

will create a new slab named "test_slab" of the size sizeof(struct
test_slab) and aligned to the alignment of test slab.  If it fails then we
panic.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

	#!/bin/sh
	#
	# Replace one string by another in all the kernel sources.
	#

	set -e

	for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
		quilt add $file
		sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
		mv /tmp/$$ $file
		quilt refresh
	done

The script was run like this

	sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

SLAB_KERNEL is an alias of GFP_KERNEL.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make the delayacct lock irqsave; this avoids the possible deadlock where
an interrupt is taken while holding the delayacct lock which needs to
take the delayacct lock.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Cleanup allocation and freeing of tsk->delays used by delay accounting.
This solves two problems reported for delay accounting:

1. oops in __delayacct_blkio_ticks
http://www.uwsg.indiana.edu/hypermail/linux/kernel/0608.2/1844.html

Currently tsk->delays is getting freed too early in task exit which can
cause a NULL tsk->delays to get accessed via reading of /proc/<tgid>/stats.
 The patch fixes this problem by freeing tsk->delays closer to when
task_struct itself is freed up.  As a result, it also eliminates the use of
tsk->delays_lock which was only being used (inadequately) to safeguard
access to tsk->delays while a task was exiting.

2. Possible memory leak in kernel/delayacct.c
http://www.uwsg.indiana.edu/hypermail/linux/kernel/0608.2/1389.html

The patch cleans up tsk->delays allocations after a bad fork which was
missing earlier.

The patch has been tested to fix the problems listed above and stress
tested with rapid calls to delay accounting's taskstats command interface
(which is the other path that can access the same data, besides the /proc
interface causing the oops above).
Signed-off-by: NShailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Enable delay accounting by default so that feature gets coverage testing
without requiring special measures.

Earlier, it was off by default and had to be enabled via a boot time param.
 This patch reverses the default behaviour to improve coverage testing.  It
can be removed late in the kernel development cycle if its believed users
shouldn't have to incur any cost if they don't want delay accounting.  Or
it can be retained forever if the utility of the stats is deemed common
enough to warrant keeping the feature on.
Signed-off-by: NShailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Export I/O delays seen by a task through /proc/<tgid>/stats for use in top
etc.

Note that delays for I/O done for swapping in pages (swapin I/O) is clubbed
together with all other I/O here (this is not the case in the netlink
interface where the swapin I/O is kept distinct)

[akpm@osdl.org: printk warning fix]
Signed-off-by: NShailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NBalbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Usage of taskstats interface by delay accounting.
Signed-off-by: NShailabh Nagar <nagar@us.ibm.com>
Signed-off-by: NBalbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Unlike earlier iterations of the delay accounting patches, now delays are only
collected for the actual I/O waits rather than try and cover the delays seen
in I/O submission paths.

Account separately for block I/O delays incurred as a result of swapin page
faults whose frequency can be affected by the task/process' rss limit.  Hence
swapin delays can act as feedback for rss limit changes independent of I/O
priority changes.
Signed-off-by: NShailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NBalbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initialization code related to collection of per-task "delay" statistics which
measure how long it had to wait for cpu, sync block io, swapping etc.  The
collection of statistics and the interface are in other patches.  This patch
sets up the data structures and allows the statistics collection to be
disabled through a kernel boot parameter.
Signed-off-by: NShailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NBalbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>