linux-toradex.git/kernel/taskstats.c, branch v2.6.25-rc2

kernel/taskstats.c: fix bogus nlmsg_free()

2007-11-15T02:45:44+00:00

We'd better not nlmsg_free on a pointer containing an undefined value
(and without having anything allocated).

Spotted by the Coverity checker.

Signed-off-by: Adrian Bunk 
Acked-by: Balbir Singh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix misspellings of "system", "controller", "interrupt" and "necessary".

2007-10-19T21:10:43+00:00

Fix the various misspellings of "system", controller", "interrupt" and
"[un]necessary".

Signed-off-by: Robert P. J. Day 
Signed-off-by: Adrian Bunk

Add cgroupstats

2007-10-19T18:53:36+00:00

This patch is inspired by the discussion at
http://lkml.org/lkml/2007/4/11/187 and implements per cgroup statistics
as suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263.  The
patch is on top of 2.6.21-mm1 with Paul's cgroups v9 patches (forward
ported)

This patch implements per cgroup statistics infrastructure and re-uses
code from the taskstats interface.  A new set of cgroup operations are
registered with commands and attributes.  It should be very easy to
*extend* per cgroup statistics, by adding members to the cgroupstats
structure.

The current model for cgroupstats is a pull, a push model (to post
statistics on interesting events), should be very easy to add.  Currently
user space requests for statistics by passing the cgroup file
descriptor.  Statistics about the state of all the tasks in the cgroup
is returned to user space.

TODO's/NOTE:

This patch provides an infrastructure for implementing cgroup statistics.
Based on the needs of each controller, we can incrementally add more statistics,
event based support for notification of statistics, accumulation of taskstats
into cgroup statistics in the future.

Sample output

# ./cgroupstats -C /cgroup/a
sleeping 2, blocked 0, running 1, stopped 0, uninterruptible 0

# ./cgroupstats -C /cgroup/
sleeping 154, blocked 0, running 0, stopped 0, uninterruptible 0

If the approach looks good, I'll enhance and post the user space utility for
the same

Feedback, comments, test results are always welcome!

[akpm@linux-foundation.org: build fix]
Signed-off-by: Balbir Singh 
Cc: Paul Menage 
Cc: Jay Lan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Clean up duplicate includes in kernel/

2007-10-17T15:42:48+00:00

This patch cleans up duplicate includes in
	kernel/

Signed-off-by: Jesper Juhl 
Acked-by: Paul E. McKenney 
Reviewed-by: Satyam Sharma 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

taskstats: add context-switch counters

2007-07-16T16:05:46+00:00

Make available to the user the following task and process performance
statistics:

	* Involuntary Context Switches (task_struct->nivcsw)
	* Voluntary Context Switches (task_struct->nvcsw)

Statistics information is available from:
	1. taskstats interface (Documentation/accounting/)
	2. /proc/PID/status (task only).

This data is useful for detecting hyperactivity patterns between processes.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Maxim Uvarov 
Cc: Shailabh Nagar 
Cc: Balbir Singh 
Cc: Jay Lan 
Cc: Jonathan Lim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

KMEM_CACHE(): simplify slab cache creation

2007-05-07T19:12:55+00:00

This patch provides a new macro

KMEM_CACHE(, )

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: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[NETLINK]: Introduce nlmsg_hdr() helper

2007-04-26T05:26:34+00:00

For the common "(struct nlmsghdr *)skb->data" sequence, so that we reduce the
number of direct accesses to skb->data and for consistency with all the other
cast skb member helpers.

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: David S. Miller

[PATCH] taskstats: cleanup reply assembling

2006-12-07T16:39:34+00:00

Thomas Graf wrote:
>
> nla_nest_start() may return NULL, either rely on prepare_reply() to be
> correct and BUG() on failure or do proper error handling for all
> functions.

nla_put() in taskstat.c can fail only if the 'size' argument of alloc_skb()
was not right. This is a kernel bug, we should not hide it. So add 'BUG()'
on error path and check for 'na == NULL'.

> genlmsg_cancel() is only required in error paths for dumping
> procedures.

So we can remove 'genlmsg_cancel()' calls and 'void *reply' (saves 227 bytes).

Signed-off-by: Oleg Nesterov 
Cc: Thomas Graf 
Cc: Shailabh Nagar 
Cc: Balbir Singh 
Cc: Jay Lan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] taskstats: use nla_reserve() for reply assembling

2006-12-07T16:39:34+00:00

Currently taskstats_user_cmd()/taskstats_exit() do:

	1) allocate stats
	2) fill stats
	3) make a temporary copy on stack (236 bytes)
	4) copy that copy to skb
	5) free stats

With the help of nla_reserve() we can operate on skb->data directly,
thus avoiding all these steps except 2).

So, before this patch:

	// copy *stats to skb->data
	int mk_reply(skb, ..., struct taskstats *stats);

	fill_pid(stats);
	mk_reply(skb, ..., stats);

After:
	// return a pointer to skb->data
	struct taskstats *mk_reply(skb, ...);

	stat = mk_reply(skb, ...);
	fill_pid(stats);

Shrinks taskatsks.o by 162 bytes.

A stupid benchmark (send one million TASKSTATS_CMD_ATTR_PID) shows the

		real user sys
	before:
		4.02 0.06 3.96
		4.02 0.04 3.98
		4.02 0.04 3.97
	after:
		3.86 0.08 3.78
		3.88 0.10 3.77
		3.89 0.09 3.80

but this looks suspiciously good.

Signed-off-by: Oleg Nesterov 
Acked-by: Shailabh Nagar 
Cc: Balbir Singh 
Cc: Jay Lan 
Cc: Thomas Graf 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] taskstats: factor out reply assembling

2006-12-07T16:39:34+00:00

Introduce mk_reply() helper which does all nla_put()s on reply.

Saves 453 bytes and a preparation for the next patch.

Signed-off-by: Oleg Nesterov 
Acked-by: Shailabh Nagar 
Cc: Balbir Singh 
Cc: Jay Lan 
Cc: Thomas Graf 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds