taskstats: fill_stats_for_tgid: use for_each_thread()

do/while_each_thread should be avoided when possible.

Plus I _think_ this change allows to avoid lock_task_sighand() but I am
not sure, I forgot everything about taskstats. In any case, this code
does not look right in that the same thread can be accounted twice:
taskstats_exit() can account the exiting thread in signal->stats and drop
->siglock but this thread is still on the thread-group list, so
lock_task_sighand() can't help.

Link: https://lkml.kernel.org/r/20230909214951.GA24274@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

genetlink: start to validate reserved header bytes

We had historically not checked that genlmsghdr.reserved
is 0 on input which prevents us from using those precious
bytes in the future.

One use case would be to extend the cmd field, which is
currently just 8 bits wide and 256 is not a lot of commands
for some core families.

To make sure that new families do the right thing by default
put the onus of opting out of validation on existing families.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel)
Signed-off-by: David S. Miller <davem@davemloft.net>

kernel: make taskstats available from all net namespaces

If getdelays runs in a non-init network namespace, it will fail in getting
delayacct stats even if it has privilege of root user, which seems to be
not very reasonable. We can simply reproduce this by executing commands:

unshare -n
getdelays -d -p <pid>

I don't think net namespace should be an obstacle to the normal execution
of getdelay function. So let's make it available from all net namespaces.

Link: https://lkml.kernel.org/r/20220412071946.2532318-1-xu.xin16@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: "Dr. Thomas Orgis" <thomas.orgis@uni-hamburg.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ismael Luceno <ismael@iodev.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

taskstats: version 12 with thread group and exe info

The task exit struct needs some crucial information to be able to provide
an enhanced version of process and thread accounting. This change
provides:

1. ac_tgid in additon to ac_pid
2. thread group execution walltime in ac_tgetime
3. flag AGROUP in ac_flag to indicate the last task
in a thread group / process
4. device ID and inode of task's /proc/self/exe in
ac_exe_dev and ac_exe_inode
5. tools/accounting/procacct as demonstrator

When a task exits, taskstats are reported to userspace including the
task's pid and ppid, but without the id of the thread group this task is
part of. Without the tgid, the stats of single tasks cannot be correlated
to each other as a thread group (process).

The taskstats documentation suggests that on process exit a data set
consisting of accumulated stats for the whole group is produced. But such
an additional set of stats is only produced for actually multithreaded
processes, not groups that had only one thread, and also those stats only
contain data about delay accounting and not the more basic information
about CPU and memory resource usage. Adding the AGROUP flag to be set
when the last task of a group exited enables determination of process end
also for single-threaded processes.

My applicaton basically does enhanced process accounting with summed
cputime, biggest maxrss, tasks per process. The data is not available
with the traditional BSD process accounting (which is not designed to be
extensible) and the taskstats interface allows more efficient on-the-fly
grouping and summing of the stats, anyway, without intermediate disk
writes.

Furthermore, I do carry statistics on which exact program binary is used
how often with associated resources, getting a picture on how important
which parts of a collection of installed scientific software in different
versions are, and how well they put load on the machine. This is enabled
by providing information on /proc/self/exe for each task. I assume the
two 64-bit fields for device ID and inode are more appropriate than the
possibly large resolved path to keep the data volume down.

Add the tgid to the stats to complete task identification, the flag AGROUP
to mark the last task of a group, the group wallclock time, and
inode-based identification of the associated executable file.

Add tools/accounting/procacct.c as a simplified fork of getdelays.c to
demonstrate process and thread accounting.

[thomas.orgis@uni-hamburg.de: fix version number in comment]
Link: https://lkml.kernel.org/r/20220405003601.7a5f6008@plasteblaster
Link: https://lkml.kernel.org/r/20220331004106.64e5616b@plasteblaster
Signed-off-by: Dr. Thomas Orgis <thomas.orgis@uni-hamburg.de>
Reviewed-by: Ismael Luceno <ismael@iodev.co.uk>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

taskstats: remove unneeded dead assignment

make clang-analyzer on x86_64 defconfig caught my attention with:

kernel/taskstats.c:120:2: warning: Value stored to 'rc' is never read \
[clang-analyzer-deadcode.DeadStores]
rc = 0;
^

Commit d94a041519f3 ("taskstats: free skb, avoid returns in
send_cpu_listeners") made send_cpu_listeners() not return a value and
hence, the rc variable remained only to be used within the loop where
it is always assigned before read and it does not need any other
initialisation.

So, simply remove this unneeded dead initializing assignment.

As compilers will detect this unneeded assignment and optimize this anyway,
the resulting object code is identical before and after this change.

No functional change. No change to object code.

[akpm@linux-foundation.org: reduce scope of `rc']

Link: https://lkml.kernel.org/r/20220307093942.21310-1-lukas.bulwahn@gmail.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Tom Rix <trix@redhat.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

treewide: rename nla_strlcpy to nla_strscpy.

Calls to nla_strlcpy are now replaced by calls to nla_strscpy which is the new
name of this function.

Signed-off-by: Francis Laniel <laniel_francis@privacyrequired.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

taskstats: move specifying netlink policy back to ops

commit 3b0f31f2b8c9 ("genetlink: make policy common to family")
had to work around removal of policy from ops by parsing in
the pre_doit callback. Now that policy is back in full ops
we can switch again. Set maxattr to actual size of the policies
- both commands set GENL_DONT_VALIDATE_STRICT so out of range
attributes will be silently ignored, anyway.

v2:
- remove stale comment

Suggested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

genetlink: move to smaller ops wherever possible

Bulk of the genetlink users can use smaller ops, move them.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

taskstats: fix data-race

When assiging and testing taskstats in taskstats_exit() there's a race
when setting up and reading sig->stats when a thread-group with more
than one thread exits:

write to 0xffff8881157bbe10 of 8 bytes by task 7951 on cpu 0:
taskstats_tgid_alloc kernel/taskstats.c:567 [inline]
taskstats_exit+0x6b7/0x717 kernel/taskstats.c:596
do_exit+0x2c2/0x18e0 kernel/exit.c:864
do_group_exit+0xb4/0x1c0 kernel/exit.c:983
get_signal+0x2a2/0x1320 kernel/signal.c:2734
do_signal+0x3b/0xc00 arch/x86/kernel/signal.c:815
exit_to_usermode_loop+0x250/0x2c0 arch/x86/entry/common.c:159
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
do_syscall_64+0x2d7/0x2f0 arch/x86/entry/common.c:299
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881157bbe10 of 8 bytes by task 7949 on cpu 1:
taskstats_tgid_alloc kernel/taskstats.c:559 [inline]
taskstats_exit+0xb2/0x717 kernel/taskstats.c:596
do_exit+0x2c2/0x18e0 kernel/exit.c:864
do_group_exit+0xb4/0x1c0 kernel/exit.c:983
__do_sys_exit_group kernel/exit.c:994 [inline]
__se_sys_exit_group kernel/exit.c:992 [inline]
__x64_sys_exit_group+0x2e/0x30 kernel/exit.c:992
do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by using smp_load_acquire() and smp_store_release().

Reported-by: syzbot+c5d03165a1bd1dead0c1@syzkaller.appspotmail.com
Fixes: 34ec12349c8a ("taskstats: cleanup ->signal->stats allocation")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Will Deacon <will@kernel.org>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/r/20191009114809.8643-1-christian.brauner@ubuntu.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

Based on 3 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [kishon] [vijay] [abraham]
[i] [kishon]@[ti] [com] this program is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [graeme] [gregory]
[gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
[kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
[hk] [hemahk]@[ti] [com] this program is distributed in the hope
that it will be useful but without any warranty without even the
implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

genetlink: optionally validate strictly/dumps

Add options to strictly validate messages and dump messages,
sometimes perhaps validating dump messages non-strictly may
be required, so add an option for that as well.

Since none of this can really be applied to existing commands,
set the options everwhere using the following spatch:

@@
identifier ops;
expression X;
@@
struct genl_ops ops[] = {
...,
{
.cmd = X,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
...
},
...
};

For new commands one should just not copy the .validate 'opt-out'
flags and thus get strict validation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: make validation more configurable for future strictness

We currently have two levels of strict validation:

1) liberal (default)
- undefined (type >= max) & NLA_UNSPEC attributes accepted
- attribute length >= expected accepted
- garbage at end of message accepted
2) strict (opt-in)
- NLA_UNSPEC attributes accepted
- attribute length >= expected accepted

Split out parsing strictness into four different options:
* TRAILING - check that there's no trailing data after parsing
attributes (in message or nested)
* MAXTYPE - reject attrs > max known type
* UNSPEC - reject attributes with NLA_UNSPEC policy entries
* STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
* nla_parse -> nla_parse_deprecated
* nla_parse_strict -> nla_parse_deprecated_strict
* nlmsg_parse -> nlmsg_parse_deprecated
* nlmsg_parse_strict -> nlmsg_parse_deprecated_strict
* nla_parse_nested -> nla_parse_nested_deprecated
* nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
@@
expression TB, MAX, HEAD, LEN, POL, EXT;
@@
-nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
+nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

@@
expression TB, MAX, NLA, POL, EXT;
@@
-nla_parse_nested(TB, MAX, NLA, POL, EXT)
+nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

@@
expression START, MAX, POL, EXT;
@@
-nla_validate_nested(START, MAX, POL, EXT)
+nla_validate_nested_deprecated(START, MAX, POL, EXT)

@@
expression NLH, HDRLEN, MAX, POL, EXT;
@@
-nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
+nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: make nla_nest_start() add NLA_F_NESTED flag

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

genetlink: make policy common to family

Since maxattr is common, the policy can't really differ sanely,
so make it common as well.

The only user that did in fact manage to make a non-common policy
is taskstats, which has to be really careful about it (since it's
still using a common maxattr!). This is no longer supported, but
we can fake it using pre_doit.

This reduces the size of e.g. nl80211.o (which has lots of commands):

text data bss dec hex filename
398745 14323 2240 415308 6564c net/wireless/nl80211.o (before)
397913 14331 2240 414484 65314 net/wireless/nl80211.o (after)
--------------------------------
-832 +8 0 -824

Which is obviously just 8 bytes for each command, and an added 8
bytes for the new policy pointer. I'm not sure why the ops list is
counted as .text though.

Most of the code transformations were done using the following spatch:
@ops@
identifier OPS;
expression POLICY;
@@
struct genl_ops OPS[] = {
...,
{
- .policy = POLICY,
},
...
};

@@
identifier ops.OPS;
expression ops.POLICY;
identifier fam;
expression M;
@@
struct genl_family fam = {
.ops = OPS,
.maxattr = M,
+ .policy = POLICY,
...
};

This also gets rid of devlink_nl_cmd_region_read_dumpit() accessing
the cb->data as ops, which we want to change in a later genl patch.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

pids: introduce find_get_task_by_vpid() helper

There are several functions that do find_task_by_vpid() followed by
get_task_struct(). We can use a helper function instead.

Link: http://lkml.kernel.org/r/1509602027-11337-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: add e/u/stime for TGID command

The elapsed time, user CPU time and system CPU time for the thread group
status request are presently left at zero. Fill these in.

[akpm@linux-foundation.org: run ktime_get_ns() a single time]
[akpm@linux-foundation.org: include linux/sched/cputime.h for task_cputime()]
Link: http://lkml.kernel.org/r/1488508424-12322-1-git-send-email-xiao.zhang@windriver.com
Signed-off-by: Zhang Xiao <xiao.zhang@windriver.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: fix the length of cgroupstats_cmd_get_policy

cgroupstats_cmd_get_policy is [CGROUPSTATS_CMD_ATTR_MAX+1],
taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1],
but their family.maxattr is TASKSTATS_CMD_ATTR_MAX.
CGROUPSTATS_CMD_ATTR_MAX is less than TASKSTATS_CMD_ATTR_MAX,
so we could end up accessing out-of-bound.

Change cgroupstats_cmd_get_policy to TASKSTATS_CMD_ATTR_MAX+1,
this is safe because the rest are initialized to 0's.

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

genetlink: mark families as __ro_after_init

Now genl_register_family() is the only thing (other than the
users themselves, perhaps, but I didn't find any doing that)
writing to the family struct.

In all families that I found, genl_register_family() is only
called from __init functions (some indirectly, in which case
I've add __init annotations to clarifly things), so all can
actually be marked __ro_after_init.

This protects the data structure from accidental corruption.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

genetlink: statically initialize families

Instead of providing macros/inline functions to initialize
the families, make all users initialize them statically and
get rid of the macros.

This reduces the kernel code size by about 1.6k on x86-64
(with allyesconfig).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

genetlink: no longer support using static family IDs

Static family IDs have never really been used, the only
use case was the workaround I introduced for those users
that assumed their family ID was also their multicast
group ID.

Additionally, because static family IDs would never be
reserved by the generic netlink code, using a relatively
low ID would only work for built-in families that can be
registered immediately after generic netlink is started,
which is basically only the control family (apart from
the workaround code, which I also had to add code for so
it would reserve those IDs)

Thus, anything other than GENL_ID_GENERATE is flawed and
luckily not used except in the cases I mentioned. Move
those workarounds into a few lines of code, and then get
rid of GENL_ID_GENERATE entirely, making it more robust.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

taskstats: use the libnl API to align nlattr on 64-bit

Goal of this patch is to use the new libnl API to align netlink attribute
when needed.
The layout of the netlink message will be a bit different after the patch,
because the padattr (TASKSTATS_TYPE_STATS) will be inside the nested
attribute instead of before it.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

netlink: make nlmsg_end() and genlmsg_end() void

Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.

This makes the very common pattern of

if (genlmsg_end(...) < 0) { ... }

be a whole bunch of dead code. Many places also simply do

return nlmsg_end(...);

and the caller is expected to deal with it.

This also commonly (at least for me) causes errors, because it is very
common to write

if (my_function(...))
/* error condition */

and if my_function() does "return nlmsg_end()" this is of course wrong.

Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.

Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did

- return nlmsg_end(...);
+ nlmsg_end(...);
+ return 0;

I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.

One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

kill f_dentry uses

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

scheduler: Replace __get_cpu_var with this_cpu_ptr

Convert all uses of __get_cpu_var for address calculation to use
this_cpu_ptr instead.

[Uses of __get_cpu_var with cpumask_var_t are no longer
handled by this patch]

Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

genetlink: only pass array to genl_register_family_with_ops()

As suggested by David Miller, make genl_register_family_with_ops()
a macro and pass only the array, evaluating ARRAY_SIZE() in the
macro, this is a little safer.

The openvswitch has some indirection, assing ops/n_ops directly in
that code. This might ultimately just assign the pointers in the
family initializations, saving the struct genl_family_and_ops and
code (once mcast groups are handled differently.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

genetlink: make all genl_ops users const

Now that genl_ops are no longer modified in place when
registering, they can be made const. This patch was done
mostly with spatch:

@@
identifier ops;
@@
+const
struct genl_ops ops[] = {
...
};

(except the struct thing in net/openvswitch/datapath.c)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

taskstats: use genl_register_family_with_ops()

This simplifies the code since there's no longer a
need to have error handling in the registration.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

kernel/taskstats.c: return -ENOMEM when alloc memory fails in add_del_listener()

For registering in add_del_listener(), when kmalloc_node() fails, need
return -ENOMEM instead of success code, and cmd_attr_register_cpumask()
wants to know about it.

After modification, give a simple common test "build -> boot up ->
kernel/controllers/cgroup/getdelays by LTP tools".

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/taskstats.c: add nla_nest_cancel() for failure processing between nla_nest_start() and nla_nest_end()

When failure occurs between nla_nest_start() and nla_nest_end(), we should
call nla_nest_cancel() to clean up related things.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: cgroupstats_user_cmd() may leak on error

If prepare_reply() succeeds we have allocated memory for 'rep_skb'. If
nla_reserve() then subsequently fails and returns NULL we fail to release
the memory we allocated, thus causing a leak.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

switch simple cases of fget_light to fdget

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

userns: Convert taskstats to handle the user and pid namespaces.

- Explicitly limit exit task stat broadcast to the initial user and
pid namespaces, as it is already limited to the initial network
namespace.

- For broadcast task stats explicitly generate all of the idenitiers
in terms of the initial user namespace and the initial pid
namespace.

- For request stats report them in terms of the current user namespace
and the current pid namespace. Netlink messages are delivered
syncrhonously to the kernel allowing us to get the user namespace
and the pid namespace from the current task.

- Pass the namespaces for representing pids and uids and gids
into bacct_add_task.

Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

netlink: Rename pid to portid to avoid confusion

It is a frequent mistake to confuse the netlink port identifier with a
process identifier. Try to reduce this confusion by renaming fields
that hold port identifiers portid instead of pid.

I have carefully avoided changing the structures exported to
userspace to avoid changing the userspace API.

I have successfully built an allyesconfig kernel with this change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

taskstats: check nla_reserve() return

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=44621

Reported-by: <rucsoftsec@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Make TASKSTATS require root access

Ok, this isn't optimal, since it means that 'iotop' needs admin
capabilities, and we may have to work on this some more. But at the
same time it is very much not acceptable to let anybody just read
anybody elses IO statistics quite at this level.

Use of the GENL_ADMIN_PERM suggested by Johannes Berg as an alternative
to checking the capabilities by hand.

Reported-by: Vasiliy Kulikov <segoon@openwall.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: add_del_listener() should ignore !valid listeners

When send_cpu_listeners() finds the orphaned listener it marks it as
!valid and drops listeners->sem. Before it takes this sem for writing,
s->pid can be reused and add_del_listener() can wrongly try to re-use
this entry.

Change add_del_listener() to check ->valid = T.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: add_del_listener() shouldn't use the wrong node

1. Commit 26c4caea9d69 "don't allow duplicate entries in listener mode"
changed add_del_listener(REGISTER) so that "next_cpu:" can reuse the
listener allocated for the previous cpu, this doesn't look exactly
right even if minor.

Change the code to kfree() in the already-registered case, this case
is unlikely anyway so the extra kmalloc_node() shouldn't hurt but
looke more correct and clean.

2. use the plain list_for_each_entry() instead of _safe() to scan
listeners->list.

3. Remove the unneeded INIT_LIST_HEAD(&s->list), we are going to
list_add(&s->list).

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Vasiliy Kulikov <segoon@openwall.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

atomic: use <linux/atomic.h>

This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: don't allow duplicate entries in listener mode

Currently a single process may register exit handlers unlimited times.
It may lead to a bloated listeners chain and very slow process
terminations.

Eg after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of
kernel memory is stolen for the handlers chain and "time id" shows 2-7
seconds instead of normal 0.003. It makes it possible to exhaust all
kernel memory and to eat much of CPU time by triggerring numerous exits
on a single CPU.

The patch limits the number of times a single process may register
itself on a single CPU to one.

One little issue is kept unfixed - as taskstats_exit() is called before
exit_files() in do_exit(), the orphaned listener entry (if it was not
explicitly deregistered) is kept until the next someone's exit() and
implicit deregistration in send_cpu_listeners(). So, if a process
registered itself as a listener exits and the next spawned process gets
the same pid, it would inherit taskstats attributes.

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: use appropriate printk priority level

printk()s without a priority level default to KERN_WARNING. To reduce
noise at KERN_WARNING, this patch set the priority level appriopriately
for unleveled printks()s. This should be useful to folks that look at
dmesg warnings closely.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: use better ifdef for alignment

Commit 4be2c95d ("taskstats: pad taskstats netlink response for aligment
issues on ia64") added a null field to align the taskstats structure but
the discussion centered around ia64. The issue exists on other platforms
with inefficient unaligned access and adding them piecemeal would be an
unmaintainable mess.

This patch uses Dave Miller's suggestion of using a combination of
CONFIG_64BIT && !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to determine
whether alignment is needed.

Note that this will cause breakage on those platforms with applications
like iotop which had hard-coded offsets into the packet to access the
taskstats structure.

The message seen on systems without the alignment fixes looks like: kernel
unaligned access to 0xe000023879dca9bc, ip=0xa000000100133d10

The addresses may vary but resolve to locations inside __delayacct_add_tsk.

iotop makes what I'd call unreasonable assumptions about the contents of a
netlink genetlink packet containing generic attributes. They're typed and
have headers that specify value lengths, so the client can (should)
identify and skip the ones the client doesn't understand.

The kernel, as of version 2.6.36, presented a packet like so:
+--------------------------------+
| genlmsghdr - 4 bytes |
+--------------------------------+
| NLA header - 4 bytes | /* Aggregate header */
+-+------------------------------+
| | NLA header - 4 bytes | /* PID header */
| +------------------------------+
| | pid/tgid - 4 bytes |
| +------------------------------+
| | NLA header - 4 bytes | /* stats header */
| + -----------------------------+ <- oops. aligned on 4 byte boundary
| | struct taskstats - 328 bytes |
+-+------------------------------+

The iotop code expects that the kernel will behave as it did then,
assuming that the packet format is set in stone. The format is set in
stone, but the packet offsets are not. There's nothing in the packet
format that guarantees that the packet will be sent in exactly the same
way. The attribute contents are set (or versioned) and the aggregate
contents are set but they can be anywhere in the packet.

The issue here isn't that an unaligned structure gets passed to userspace,
it's that the NLA infrastructure has something of a weakness: The 4 byte
attribute header may force the payload to be unaligned. The taskstats
structure is created at an unaligned location and then 64-bit values are
operated on inside the kernel, so the unaligned access warnings gets
spewed everywhere.

It's possible to use the unaligned access API to operate on the structure
in the kernel but it seems like a wasted effort to work around userspace
code that isn't following the packet format. Any new additions would also
need the be worked around. It's a maintenance nightmare.

The conclusion of the earlier discussion seemed to be "ok fine, if we have
to break it, don't break it on arches that don't have the problem." Dave
pointed out that the unaligned access problem doesn't only exist on ia64,
but also on other 64-bit arches that don't have efficient unaligned access
and it should be fixed there as well. The committed version of the patch
and this addition keep with the conclusion of that discussion not to break
it unnecessarily, which the pid padding and the packet padding fixes did
do. x86_64 and powerpc don't suffer this problem so they shouldn't suffer
the solution. Other 64-bit architectures do and will, though.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reported-by: David S. Miller <davem@davemloft.net>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Florian Mickler <florian@mickler.org>
Cc: Guillaume Chazarain <guichaz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: pad taskstats netlink response for aligment issues on ia64

The taskstats structure is internally aligned on 8 byte boundaries but the
layout of the aggregrate reply, with two NLA headers and the pid (each 4
bytes), actually force the entire structure to be unaligned. This causes
the kernel to issue unaligned access warnings on some architectures like
ia64. Unfortunately, some software out there doesn't properly unroll the
NLA packet and assumes that the start of the taskstats structure will
always be 20 bytes from the start of the netlink payload. Aligning the
start of the taskstats structure breaks this software, which we don't
want. So, for now the alignment only happens on architectures that
require it and those users will have to update to fixed versions of those
packages. Space is reserved in the packet only when needed. This ifdef
should be removed in several years e.g. 2012 once we can be confident
that fixed versions are installed on most systems. We add the padding
before the aggregate since the aggregate is already a defined type.

Commit 85893120 ("delayacct: align to 8 byte boundary on 64-bit systems")
previously addressed the alignment issues by padding out the pid field.
This was supposed to be a compatible change but the circumstances
described above mean that it wasn't. This patch backs out that change,
since it was a hack, and introduces a new NULL attribute type to provide
the padding. Padding the response with 4 bytes avoids allocating an
aligned taskstats structure and copying it back. Since the structure
weighs in at 328 bytes, it's too big to do it on the stack.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reported-by: Brian Rogers <brian@xyzw.org>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Guillaume Chazarain <guichaz@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: Use this_cpu_ops

Use this_cpu_inc_return in one place and avoid ugly __raw_get_cpu in
another.

V3->V4:
- Fix off by one.

V4-V4f:
- Use &listener_array

Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

taskstats: split fill_pid function

Separate the finding of a task_struct by pid or tgid from filling the
taskstats data. This makes the code more readable.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: separate taskstats commands

Move each taskstats command into a single function. This makes the code
more readable and makes it easier to add new commands.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

delayacct: align to 8 byte boundary on 64-bit systems

prepare_reply() sets up an skb for the response. The payload contains:

+--------------------------------+
| genlmsghdr - 4 bytes |
+--------------------------------+
| NLA header - 4 bytes | /* Aggregate header */
+-+------------------------------+
| | NLA header - 4 bytes | /* PID header */
| +------------------------------+
| | pid/tgid - 4 bytes |
| +------------------------------+
| | NLA header - 4 bytes | /* stats header */
| + -----------------------------+ <- oops. aligned on 4 byte boundary
| | struct taskstats - 328 bytes |
+-+------------------------------+

The start of the taskstats struct must be 8 byte aligned on IA64 (and
other systems with 8 byte alignment rules for 64-bit types) or runtime
alignment warnings will be issued.

This patch pads the pid/tgid field out to sizeof(long), which forces the
alignment of taskstats. The getdelays userspace code is ok with this
since it assumes 32-bit pid/tgid and then honors that header's length
field.

An array is used to avoid exposing kernel memory contents to userspace in
the response.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

const: struct nla_policy

Make remaining netlink policies as const.
Fixup coding style where needed.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

genetlink: make netns aware

This makes generic netlink network namespace aware. No
generic netlink families except for the controller family
are made namespace aware, they need to be checked one by
one and then set the family->netnsok member to true.

A new function genlmsg_multicast_netns() is introduced to
allow sending a multicast message in a given namespace,
for example when it applies to an object that lives in
that namespace, a new function genlmsg_multicast_allns()
to send a message to all network namespaces (for objects
that do not have an associated netns).

The function genlmsg_multicast() is changed to multicast
the message in just init_net, which is currently correct
for all generic netlink families since they only work in
init_net right now. Some will later want to work in all
net namespaces because they do not care about the netns
at all -- those will have to be converted to use one of
the new functions genlmsg_multicast_allns() or
genlmsg_multicast_netns() whenever they are made netns
aware in some way.

After this patch families can easily decide whether or
not they should be available in all net namespaces. Many
genl families us it for objects not related to networking
and should therefore be available in all namespaces, but
that will have to be done on a per family basis.

Note that this doesn't touch on the checkpoint/restart
problem where network namespaces could be used, genl
families and multicast groups are numbered globally and
I see no easy way of changing that, especially since it
must be possible to multicast to all network namespaces
for those families that do not care about netns.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

cpumask: convert rest of files in kernel/

Impact: Reduce stack usage, use new cpumask API.

Mainly changing cpumask_t to 'struct cpumask' and similar simple API
conversion. Two conversions worth mentioning:

1) we use cpumask_any_but to avoid a temporary in kernel/softlockup.c,
2) Use cpumask_var_t in taskstats_user_cmd().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>

cpumask: change cpumask_scnprintf, cpumask_parse_user, cpulist_parse, and cpulist_scnprintf to take pointers.

Impact: change calling convention of existing cpumask APIs

Most cpumask functions started with cpus_: these have been replaced by
cpumask_ ones which take struct cpumask pointers as expected.

These four functions don't have good replacement names; fortunately
they're rarely used, so we just change them over.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: paulus@samba.org
Cc: mingo@redhat.com
Cc: tony.luck@intel.com
Cc: ralf@linux-mips.org
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: cl@linux-foundation.org
Cc: srostedt@redhat.com

taskstats: remove initialization of static per-cpu variable

Cc: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

core: use performance variant for_each_cpu_mask_nr

Change references from for_each_cpu_mask to for_each_cpu_mask_nr
where appropriate

Reviewed-by: Paul Jackson <pj@sgi.com>
Reviewed-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Use find_task_by_vpid in taskstats

The pid to lookup a task by is passed inside taskstats code via genetlink
message.

Since netlink packets are now processed in the context of the sending task,
this is correct to lookup the task with find_task_by_vpid() here.

Besides, I fix the call to fill_pid() from taskstats_exit(), since the
tsk->pid is not required in fill_pid() in this case, and the pid field on
task_struct is going to be deprecated as well.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Jonathan Lim <jlim@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/taskstats.c: fix bogus nlmsg_free()

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 <bunk@kernel.org>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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

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

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

Add cgroupstats

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 <balbir@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Clean up duplicate includes in kernel/

This patch cleans up duplicate includes in
kernel/

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

taskstats: add context-switch counters

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 <muvarov@ru.mvista.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Jonathan Lim <jlim@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

KMEM_CACHE(): simplify slab cache creation

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: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[NETLINK]: Introduce nlmsg_hdr() helper

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 <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] taskstats: cleanup reply assembling

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 <oleg@tv-sign.ru>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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

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 <oleg@tv-sign.ru>
Acked-by: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] taskstats: factor out reply assembling

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 <oleg@tv-sign.ru>
Acked-by: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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

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 <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] taskstats: cleanup do_exit() path

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 <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] taskstats_exit_alloc: optimize/simplify

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 <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Acked-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] slab: remove kmem_cache_t

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 <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] slab: remove SLAB_KERNEL

SLAB_KERNEL is an alias of GFP_KERNEL.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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

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 <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETLINK]: Do precise netlink message allocations where possible

Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.

Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] taskstats: fix sub-threads accounting

If there are no listeners, taskstats_exit_send() just returns because
taskstats_exit_alloc() didn't allocate *tidstats. This is wrong, each
sub-thread should do fill_tgid_exit() on exit, otherwise its ->delays is
not recorded in ->signal->stats and lost.

Q: We don't send TASKSTATS_TYPE_AGGR_TGID when single-threaded process
exits. Is it good? How can the listener figure out that it was actually a
process exit, not sub-thread?

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Acked-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] taskstats: fix sk_buff size calculation

prepare_reply() adds GENL_HDRLEN to the payload (genlmsg_total_size()),
but then it does genlmsg_put()->nlmsg_put(). This means we forget to
reserve a room for 'struct nlmsghdr'.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] taskstats: fix sk_buff leak

'return genlmsg_cancel()' in taskstats_user_cmd/taskstats_exit_send
potentially leaks a skb. Unless we pass 'rep_skb' to the netlink layer
we own sk_buff. This means we should always do kfree_skb() on failure.

[ Thomas acked and pointed out missing return value in original version ]

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Thomas Graf <tgraf@suug.ch>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] fill_tgid: cleanup delays accounting

fill_tgid() should skip not only an already exited group leader. If the
task has ->exit_state != 0 it already did exit_notify(), so it also did
fill_tgid_exit()->delayacct_add_tsk(->signal->stats) and we should skip it
to avoid a double accounting.

This patch doesn't close the race completely, but it cleanups the code.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] taskstats: don't use tasklist_lock

Remove tasklist_lock from taskstats.c. find_task_by_pid() is rcu-safe.
->siglock allows us to traverse subthread without tasklist.

Q: delay accounting looks wrong to me. If sub-thread has already called
taskstats_exit_send() but didn't call release_task(self) yet it will be
accounted twice. The window is big. No?

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] taskstats: kill ->taskstats_lock in favor of ->siglock

signal_struct is (mostly) protected by ->sighand->siglock, I think we don't
need ->taskstats_lock to protect ->stats. This also allows us to simplify the
locking in fill_tgid().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] fill_tgid: fix task_struct leak and possible oops

1. fill_tgid() forgets to do put_task_struct(first).

2. release_task(first) can happen after fill_tgid() drops tasklist_lock,
it is unsafe to dereference first->signal.

This is a temporary fix, imho the locking should be reworked.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] csa: Extended system accounting over taskstats

Add extended system accounting handling over taskstats interface. A
CONFIG_TASK_XACCT flag is created to enable the extended accounting code.

Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] csa: basic accounting over taskstats

Add some basic accounting fields to the taskstats struct, add a new
kernel/tsacct.c to handle basic accounting data handling upon exit. A handle
is added to taskstats.c to invoke the basic accounting data handling.

Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Cc: "Michal Piotrowski" <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Fix taskstats size calculation (use the new genetlink utility functions)

The addition of the CSA patch pushed the size of struct taskstats to 256
bytes. This exposed a problem with prepare_reply(), we were not allocating
space for the netlink and genetlink header. It worked earlier because
alloc_skb() would align the skb to SMP_CACHE_BYTES, which added some additonal
bytes.

Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jamal Hadi <hadi@cyberus.ca>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[NETLINK]: Extend netlink messaging interface

Adds:
nlmsg_get_pos() return current position in message
nlmsg_trim() trim part of message
nla_reserve_nohdr(skb, len) reserve room for an attribute w/o hdr
nla_put_nohdr(skb, len, data) add attribute w/o hdr
nla_find_nested() find attribute in nested attributes

Fixes nlmsg_new() to take allocation flags and consider size.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] taskstats: free skb, avoid returns in send_cpu_listeners

Add a missing freeing of skb in the case there are no listeners at all.
Also remove the returning of error values by the function as it is unused
by the sole caller.

Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] make taskstats sending completely independent of delay accounting on/off status

Complete the separation of delay accounting and taskstats by ignoring the
return value of delay accounting functions that fill in parts of taskstats
before it is sent out (either in response to a command or as part of a task
exit).

Also make delayacct_add_tsk return silently when delay accounting is turned
off rather than treat it as an error.

Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Remove down_write() from taskstats code invoked on the exit() path

In send_cpu_listeners(), which is called on the exit path, a down_write()
was protecting operations like skb_clone() and genlmsg_unicast() that do
GFP_KERNEL allocations. If the oom-killer decides to kill tasks to satisfy
the allocations,the exit of those tasks could block on the same semphore.

The down_write() was only needed to allow removal of invalid listeners from
the listener list. The patch converts the down_write to a down_read and
defers the removal to a separate critical region. This ensures that even
if the oom-killer is called, no other task's exit is blocked as it can
still acquire another down_read.

Thanks to Andrew Morton & Herbert Xu for pointing out the oom related
pitfalls, and to Chandra Seetharaman for suggesting this fix instead of
using something more complex like RCU.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] per-task delay accounting taskstats interface: control exit data through cpumasks

On systems with a large number of cpus, with even a modest rate of tasks
exiting per cpu, the volume of taskstats data sent on thread exit can
overflow a userspace listener's buffers.

One approach to avoiding overflow is to allow listeners to get data for a
limited and specific set of cpus. By scaling the number of listeners
and/or the cpus they monitor, userspace can handle the statistical data
overload more gracefully.

In this patch, each listener registers to listen to a specific set of cpus
by specifying a cpumask. The interest is recorded per-cpu. When a task
exits on a cpu, its taskstats data is unicast to each listener interested
in that cpu.

Thanks to Andrew Morton for pointing out the various scalability and
general concerns of previous attempts and for suggesting this design.

[akpm@osdl.org: build fix]
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] delay accounting taskstats interface send tgid once

Send per-tgid data only once during exit of a thread group instead of once
with each member thread exit.

Currently, when a thread exits, besides its per-tid data, the per-tgid data
of its thread group is also sent out, if its thread group is non-empty.
The per-tgid data sent consists of the sum of per-tid stats for all
*remaining* threads of the thread group.

This patch modifies this sending in two ways:

- the per-tgid data is sent only when the last thread of a thread group
exits. This cuts down heavily on the overhead of sending/receiving
per-tgid data, especially when other exploiters of the taskstats
interface aren't interested in per-tgid stats

- the semantics of the per-tgid data sent are changed. Instead of being
the sum of per-tid data for remaining threads, the value now sent is the
true total accumalated statistics for all threads that are/were part of
the thread group.

The patch also addresses a minor issue where failure of one accounting
subsystem to fill in the taskstats structure was causing the send of
taskstats to not be sent at all.

The patch has been tested for stability and run cerberus for over 4 hours
on an SMP.

[akpm@osdl.org: bugfixes]
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] per-task-delay-accounting: delay accounting usage of taskstats interface

Usage of taskstats interface by delay accounting.

Signed-off-by: Shailabh Nagar <nagar@us.ibm.com>
Signed-off-by: Balbir 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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] per-task-delay-accounting: taskstats interface

Create a "taskstats" interface based on generic netlink (NETLINK_GENERIC
family), for getting statistics of tasks and thread groups during their
lifetime and when they exit. The interface is intended for use by multiple
accounting packages though it is being created in the context of delay
accounting.

This patch creates the interface without populating the fields of the data
that is sent to the user in response to a command or upon the exit of a task.
Each accounting package interested in using taskstats has to provide an
additional patch to add its stats to the common structure.

[akpm@osdl.org: cleanups, Kconfig fix]
Signed-off-by: Shailabh Nagar <nagar@us.ibm.com>
Signed-off-by: Balbir 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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>