linux-toradex.git/kernel/taskstats.c, branch v2.6.20.21

[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

[PATCH] taskstats: cleanup ->signal->stats allocation

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

Allocate ->signal->stats on demand in taskstats_exit(), this allows us to
remove taskstats_tgid_alloc() (the last non-trivial inline) from taskstat's
public interface.

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

[PATCH] taskstats: cleanup do_exit() path

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

do_exit:
	taskstats_exit_alloc()
	...
	taskstats_exit_send()
	taskstats_exit_free()

I think this is not good, let it be a single function exported to the core
kernel, taskstats_exit(), which does alloc + send + free itself.

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

[PATCH] taskstats_exit_alloc: optimize/simplify

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

If there are no listeners, every task does unneeded kmem_cache alloc/free on
exit. We don't need listeners->sem for 'if (!list_empty())' check. Yes, we may
have a false positive, but this doesn't differ from the case when the listener
is unregistered after we drop the semaphore. So we don't need to do allocation
beforehand.

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

[PATCH] slab: remove kmem_cache_t

2006-12-07T16:39:25+00:00

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

[PATCH] slab: remove SLAB_KERNEL

2006-12-07T16:39:24+00:00

SLAB_KERNEL is an alias of GFP_KERNEL.

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

[GENL]: Add genlmsg_put_reply() to simplify building reply headers

2006-12-03T05:22:42+00:00

By modyfing genlmsg_put() to take a genl_family and by adding
genlmsg_put_reply() the process of constructing the netlink
and generic netlink headers is simplified.

Signed-off-by: Thomas Graf 
Acked-by: Paul Moore 
Signed-off-by: David S. Miller

[GENL]: Add genlmsg_new() to allocate generic netlink messages

2006-12-03T05:22:40+00:00

Signed-off-by: Thomas Graf 
Acked-by: Paul Moore 
Signed-off-by: David S. Miller