linux-toradex.git/kernel/tsacct.c, branch v2.6.36-rc5

mm: clean up mm_counter

2010-03-06T19:26:23+00:00

Presently, per-mm statistics counter is defined by macro in sched.h

This patch modifies it to
  - defined in mm.h as inlinf functions
  - use array instead of macro's name creation.

This patch is for reducing patch size in future patch to modify
implementation of per-mm counter.

Signed-off-by: KAMEZAWA Hiroyuki 
Reviewed-by: Minchan Kim 
Cc: Christoph Lameter 
Cc: Lee Schermerhorn 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix fixpoint divide exception in acct_update_integrals

2009-03-09T15:13:35+00:00

Frans Pop reported the crash below when running an s390 kernel under Hercules:

  Kernel BUG at 000738b4  verbose debug info unavailable!
  fixpoint divide exception: 0009  #1! SMP
  Modules linked in: nfs lockd nfs_acl sunrpc ctcm fsm tape_34xx
     cu3088 tape ccwgroup tape_class ext3 jbd mbcache dm_mirror dm_log dm_snapshot
     dm_mod dasd_eckd_mod dasd_mod
  CPU: 0 Not tainted 2.6.27.19 #13
  Process awk (pid: 2069, task: 0f9ed9b8, ksp: 0f4f7d18)
  Krnl PSW : 070c1000 800738b4 (acct_update_integrals+0x4c/0x118)
             R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0
  Krnl GPRS: 00000000 000007d0 7fffffff fffff830
             00000000 ffffffff 00000002 0f9ed9b8
             00000000 00008ca0 00000000 0f9ed9b8
             0f9edda4 8007386e 0f4f7ec8 0f4f7e98
  Krnl Code: 800738aa: a71807d0         lhi     %r1,2000
             800738ae: 8c200001         srdl    %r2,1
             800738b2: 1d21             dr      %r2,%r1
            >800738b4: 5810d10e         l       %r1,270(%r13)
             800738b8: 1823             lr      %r2,%r3
             800738ba: 4130f060         la      %r3,96(%r15)
             800738be: 0de1             basr    %r14,%r1
             800738c0: 5800f060         l       %r0,96(%r15)
  Call Trace:
  ( <000000000004fdea>! blocking_notifier_call_chain+0x1e/0x2c)
    <0000000000038502>! do_exit+0x106/0x7c0
    <0000000000038c36>! do_group_exit+0x7a/0xb4
    <0000000000038c8e>! SyS_exit_group+0x1e/0x30
    <0000000000021c28>! sysc_do_restart+0x12/0x16
    <0000000077e7e924>! 0x77e7e924

Reason for this is that cpu time accounting usually only happens from
interrupt context, but acct_update_integrals gets also called from
process context with interrupts enabled.

So in acct_update_integrals we may end up with the following scenario:

Between reading tsk->stime/tsk->utime and tsk->acct_timexpd an interrupt
happens which updates accouting values.  This causes acct_timexpd to be
greater than the former stime + utime.  The subsequent calculation of

	dtime = cputime_sub(time, tsk->acct_timexpd);

will be negative and the division performed by

	cputime_to_jiffies(dtime)

will generate an exception since the result won't fit into a 32 bit
register.

In order to fix this just always disable interrupts while accessing any
of the accounting values.

Reported by: Frans Pop 
Tested by: Frans Pop 
Cc: stable@kernel.org
Cc: Martin Schwidefsky 
Signed-off-by: Heiko Carstens 
Signed-off-by: Linus Torvalds

mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting

2009-01-06T23:59:09+00:00

xacct_add_tsk() relies on do_exit()->update_hiwater_xxx() and uses
mm->hiwater_xxx directly, this leads to 2 problems:

- taskstats_user_cmd() can call fill_pid()->xacct_add_tsk() at any
  moment before the task exits, so we should check the current values of
  rss/vm anyway.

- do_exit()->update_hiwater_xxx() calls are racy.  An exiting thread can
  be preempted right before mm->hiwater_xxx = new_val, and another thread
  can use A_LOT of memory and exit in between.  When the first thread
  resumes it can be the last thread in the thread group, in that case we
  report the wrong hiwater_xxx values which do not take A_LOT into
  account.

Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() helpers and change
xacct_add_tsk() to use them.  The first helper will also be used by
rusage->ru_maxrss accounting.

Kill do_exit()->update_hiwater_xxx() calls.  Unless we are going to
decrease rss/vm there is no point to update mm->hiwater_xxx, and nobody
can look at this mm_struct when exit_mmap() actually unmaps the memory.

Signed-off-by: Oleg Nesterov 
Acked-by: Hugh Dickins 
Reviewed-by: KOSAKI Motohiro 
Acked-by: Balbir Singh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

CRED: Use RCU to access another task's creds and to release a task's own creds

2008-11-13T23:39:19+00:00

Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells 
Acked-by: James Morris 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris

CRED: Separate task security context from task_struct

2008-11-13T23:39:16+00:00

Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne 

Signed-off-by: David Howells 
Acked-by: James Morris 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris

task IO accounting: move all IO statistics in struct task_io_accounting

2008-07-27T23:12:28+00:00

Simplify the code of include/linux/task_io_accounting.h.

It is also more reasonable to have all the task i/o-related statistics in a
single struct (task_io_accounting).

Signed-off-by: Andrea Righi 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Linus Torvalds

task IO accounting: improve code readability

2008-07-27T16:58:20+00:00

Put all i/o statistics in struct proc_io_accounting and use inline functions to
initialize and increment statistics, removing a lot of single variable
assignments.

This also reduces the kernel size as following (with CONFIG_TASK_XACCT=y and
CONFIG_TASK_IO_ACCOUNTING=y).

    text    data     bss     dec     hex filename
   11651       0       0   11651    2d83 kernel/exit.o.before
   11619       0       0   11619    2d63 kernel/exit.o.after
   10886     132     136   11154    2b92 kernel/fork.o.before
   10758     132     136   11026    2b12 kernel/fork.o.after

 3082029  807968 4818600 8708597  84e1f5 vmlinux.o.before
 3081869  807968 4818600 8708437  84e155 vmlinux.o.after

Signed-off-by: Andrea Righi 
Acked-by: Oleg Nesterov 
Signed-off-by: Linus Torvalds

tsacct: fix bacct_add_tsk()'s use of do_div()

2008-07-25T17:53:47+00:00

Fix bacct_add_tsk()'s use of do_div() on an s64 by making ac_etime a u64
instead and dividing that.

Possibly this should be guarded lest the interval calculation turn up
negative, but the possible negativity of the result of the division is
cast away, and it shouldn't end up negative anyway.

This was introduced by patch f3cef7a99469afc159fec3a61b42dc7ca5b6824f.

Signed-off-by: David Howells 
Cc: Jay Lan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

accounting: account for user time when updating memory integrals

2008-07-25T17:53:46+00:00

Adapt acct_update_integrals() to include user time when calculating the time
difference.  The units of acct_rss_mem1 and acct_vm_mem1 are also changed from
pages-jiffies to pages-usecs to avoid calling jiffies_to_usecs() in
xacct_add_tsk() which might overflow.

Signed-off-by: Jonathan Lim 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Add scaled time to taskstats based process accounting

2007-10-18T21:37:28+00:00

This adds items to the taststats struct to account for user and system
time based on scaling the CPU frequency and instruction issue rates.

Adds account_(user|system)_time_scaled callbacks which architectures
can use to account for time using this mechanism.

Signed-off-by: Michael Neuling 
Cc: Balbir Singh 
Cc: Jay Lan 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds