linux-toradex.git/include/linux/ratelimit.h, branch v4.11-rc3

ratelimit: fix WARN_ON_RATELIMIT return value

2016-12-20T17:48:47+00:00

The macro is to be used similarly as WARN_ON as:

  if (WARN_ON_RATELIMIT(condition, state))
	do_something();

One would expect only 'condition' to affect the 'if', but
WARN_ON_RATELIMIT does internally only:

  WARN_ON((condition) && __ratelimit(state))

So the 'if' is affected by the ratelimiting state too.  Fix this by
returning 'condition' in any case.

Note that nobody uses WARN_ON_RATELIMIT yet, so there is nothing to
worry about.  But I was about to use it and was a bit surprised.

Link: http://lkml.kernel.org/r/20161215093224.23126-1-jslaby@suse.cz
Signed-off-by: Jiri Slaby 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ratelimit: extend to print suppressed messages on release

2016-08-02T23:35:06+00:00

Extend the ratelimiting facility to print the amount of suppressed lines
when it is being released.

This use case is aimed at short-termed, burst-like users for which we
want to output the suppressed lines stats only once, after it has been
disposed of.  For an example, see /dev/kmsg usage in a follow-on patch.

Also, change the printk() line we issue on release to not use
"callbacks" as it is misleading: we're not suppressing callbacks but
printk() calls.

This has been separated from a previous patch by Linus.

Link: http://lkml.kernel.org/r/20160716061745.15795-2-bp@alien8.de
Signed-off-by: Borislav Petkov 
Cc: Dave Young 
Cc: Franck Bui 
Cc: Greg Kroah-Hartman 
Cc: Ingo Molnar 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Cc: Uwe Kleine-König 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ratelimit: add initialization macro

2014-12-13T20:42:52+00:00

Signed-off-by: Dmitry Monakhov 
Cc: Akinobu Mita 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tty: Fix bogus "callbacks suppressed" messages

2012-10-05T16:26:01+00:00

On the current git tree one sees messages such as:
 tty_init_dev: 24 callbacks suppressed
 tty_init_dev: 3 callbacks suppressed

To fix this we need to look at condition before calling __ratelimit in
the WARN_RATELIMIT macro. While at it remove the superfluous
__WARN_RATELIMIT macros.

Original patch is from Joe Perches and Jiri Slaby.

Signed-off-by: Markus Trippelsdorf 
Acked-and-tested-by: Borislav Petkov 
Signed-off-by: Greg Kroah-Hartman

locking, printk: Annotate logbuf_lock as raw

2011-09-13T09:11:54+00:00

The logbuf_lock lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner 
[ merged and fixed it ]
Signed-off-by: Ingo Molnar

bug.h: Move ratelimit warn interfaces to ratelimit.h

2011-05-26T19:00:31+00:00

As reported by Ingo Molnar, we still have configuration combinations
where use of the WARN_RATELIMIT interfaces break the build because
dependencies don't get met.

Instead of going down the long road of trying to make it so that
ratelimit.h can get included by kernel.h or asm-generic/bug.h,
just move the interface into ratelimit.h and make users have
to include that.

Reported-by: Ingo Molnar 
Signed-off-by: David S. Miller 
Acked-by: Randy Dunlap

printk: declare printk_ratelimit_state in ratelimit.h

2010-10-26T23:52:16+00:00

Adding declaration of printk_ratelimit_state in ratelimit.h removes
potential build breakage and following sparse warning:

 kernel/printk.c:1426:1: warning: symbol 'printk_ratelimit_state' was not declared. Should it be static?

[akpm@linux-foundation.org: remove unneeded ifdef]
Signed-off-by: Namhyung Kim 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ratelimit: add ratelimit_state_init()

2010-05-25T15:07:03+00:00

For now, all users of ratelimit_state allocates it statically, so
DEFINE_RATELIMIT_STATE() is enough.  But, I want to use ratelimit_state
for fs, i.e.  per super_block to suppress too many error reports.

So, this adds ratelimit_state_init() to initialize ratelimite_state
which is dynamically allocated, instead of opencoding.

Signed-off-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ratelimit: Make suppressed output messages more useful

2009-10-23T15:26:37+00:00

Today I got:

  [39648.224782] Registered led device: iwl-phy0::TX
  [40676.545099] __ratelimit: 246 callbacks suppressed
  [40676.545103] abcdef[23675]: segfault at 0 ...

as you can see the ratelimit message contains a function prefix.
Since this is always __ratelimit, this wont help much.

This patch changes __ratelimit and printk_ratelimit to print the
function name that calls ratelimit.

This will pinpoint the responsible function, as long as not several
different places call ratelimit with the same ratelimit state at
the same time. In that case we catch only one random function that
calls ratelimit after the wait period.

Signed-off-by: Christian Borntraeger 
Cc: Dave Young 
Cc: Linus Torvalds 
CC: Andrew Morton 
LKML-Reference: <200910231458.11832.borntraeger@de.ibm.com>
Signed-off-by: Ingo Molnar

ratelimit: Use per ratelimit context locking

2009-09-22T13:31:34+00:00

I'd like to use printk_ratelimit() in atomic context, but that's
not possible right now due to the spinlock usage this commit
introduced more than a year ago:

  717115e: printk ratelimiting rewrite

As a first step push the lock into the ratelimit state structure.
This allows us to deal with locking failures to be considered as an
event related to that state being too busy.

Also clean up the code a bit (without changing functionality):

 - tidy up the definitions

 - clean up the code flow

This also shrinks the code a tiny bit:

   text	   data	    bss	    dec	    hex	filename
    264	      0	      4	    268	    10c	ratelimit.o.before
    255	      0	      0	    255	     ff	ratelimit.o.after

( Whole-kernel data size got a bit larger, because we have
  two ratelimit-state data structures right now. )

Cc: Peter Zijlstra 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: David S. Miller 
LKML-Reference: 
Signed-off-by: Ingo Molnar