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  1. 08 May, 2012 6 commits
  3. 07 May, 2012 4 commits
    • Kay Sievers's avatar
      printk: convert byte-buffer to variable-length record buffer · 7ff9554b
      Kay Sievers authored 
      - Record-based stream instead of the traditional byte stream
  buffer. All records carry a 64 bit timestamp, the syslog facility
  and priority in the record header.

- Records consume almost the same amount, sometimes less memory than
  the traditional byte stream buffer (if printk_time is enabled). The record
  header is 16 bytes long, plus some padding bytes at the end if needed.
  The byte-stream buffer needed 3 chars for the syslog prefix, 15 char for
  the timestamp and a newline.

- Buffer management is based on message sequence numbers. When records
  need to be discarded, the reading heads move on to the next full
  record. Unlike the byte-stream buffer, no old logged lines get
  truncated or partly overwritten by new ones. Sequence numbers also
  allow consumers of the log stream to get notified if any message in
  the stream they are about to read gets discarded during the time
  of reading.

- Better buffered IO support for KERN_CONT continuation lines, when printk()
  is called multiple times for a single line. The use of KERN_CONT is now
  mandatory to use continuation; a few places in the kernel need trivial fixes
  here. The buffering could possibly be extended to per-cpu variables to allow
  better thread-safety for multiple printk() invocations for a single line.

- Full-featured syslog facility value support. Different facilities
  can tag their messages. All userspace-injected messages enforce a
  facility value > 0 now, to be able to reliably distinguish them from
  the kernel-generated messages. Independent subsystems like a
  baseband processor running its own firmware, or a kernel-related
  userspace process can use their own unique facility values. Multiple
  independent log streams can co-exist that way in the same
  buffer. All share the same global sequence number counter to ensure
  proper ordering (and interleaving) and to allow the consumers of the
  log to reliably correlate the events from different facilities.
Tested-by: default avatarWilliam Douglas <william.douglas@intel.com>
Signed-off-by: default avatarKay Sievers <kay@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7ff9554b
    • Paul Gortmaker's avatar
      powerpc: fix compile fail in hugetlb cmdline parsing · 89528127
      Paul Gortmaker authored 
      Commit 9fb48c74

    "params: add 3rd arg to option handler callback signature"

added an extra arg to the function, but didn't catch all the use
cases needing it, causing this compile fail in mpc85xx_defconfig:

 arch/powerpc/mm/hugetlbpage.c:316:4: error: passing argument 7 of
 'parse_args' from incompatible pointer type [-Werror]

 include/linux/moduleparam.h:317:12: note: expected
	 'int (*)(char *, char *, const char *)' but argument is of type
	 'int (*)(char *, char *)'

This function has no need to printk out the "doing" value, so
just add the arg as an "unused".

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jim Cromie <jim.cromie@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Becky Bruce <beckyb@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      89528127
    • Zhi Yong Wu's avatar
      kobject: fix the uncorrect comment · 9ff1f838
      Zhi Yong Wu authored 
      Signed-off-by: default avatarZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9ff1f838
    • Greg Kroah-Hartman's avatar
      Revert "dynamic_debug: remove unneeded includes" · fef15d2f
      Greg Kroah-Hartman authored 
      This reverts commit 04db6e5f.

Odds are, we really don't want to revert all of these, and need to be
more careful in the future to make sure we don't break the build of
other arches.
Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Cc: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      fef15d2f
  5. 05 May, 2012 3 commits
  7. 04 May, 2012 7 commits
  9. 02 May, 2012 10 commits
  11. 01 May, 2012 1 commit
  13. 30 Apr, 2012 9 commits
    • Jim Cromie's avatar
      dynamic_debug: init with early_initcall, not arch_initcall · 3ec5652a
      Jim Cromie authored 
      1- Call dynamic_debug_init() from early_initcall, not arch_initcall.
2- Call dynamic_debug_init_debugfs() from fs_initcall, not module_init.

RFC: This works for me on a 64 bit desktop and a i586 SBC, but is
untested on other arches.  I presume there is or was a reason
original code used arch_initcall, maybe the constraints have changed.

This makes facility available as soon as possible.

2nd change has a downside when dynamic_debug.verbose=1; all the
vpr_info()s called in the proc-fs code are activated, causing
voluminous output from dmesg.  TBD: Im unsure of this explanation, but
the output is there.  This could be fixed by changing those callsites
to v2pr_info(if verbose > 1).

1st change is still not early enough to enable pr_debugs in
kernel/params, so parsing of boot-args isnt logged.  The reparse of
those args is however visible after params.dyndbg="+p" is processed.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3ec5652a
    • Jim Cromie's avatar
      dynamic_debug: update Documentation/*, Kconfig.debug · 29e36c9f
      Jim Cromie authored 
      In dynamic-debug-howto.txt:

- add section: Debug Messages at Module Initialization Time
- update flags indicators in example outputs to include '='
- make flags descriptions tabular
- add item on '_' flag-char
- add dyndbg, boot-args examples
- rewrap some paragraphs with long lines

In Kconfig.debug, note that compiling with -DDEBUG enables all
pr_debug()s in that code.

In kernel-parameters.txt, add dyndbg and module.dyndbg items,
and deprecate ddebug_query.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      29e36c9f
    • Jim Cromie's avatar
      dynamic_debug: add modname arg to exec_query callchain · 8e59b5cf
      Jim Cromie authored 
      Pass module name into ddebug_exec_queries(), ddebug_exec_query(), and
ddebug_parse_query() as separate parameter.  In ddebug_parse_query(),
the module name is added into the query struct before the query-string
is parsed.  This allows the query-string to be shorter:

instead of:
   $modname.dyndbg="module $modname +fp"
do this:
   $modname.dyndbg="+fp"

Omitting "module $modname" from the query string is actually required
for $modname.dyndbg rules; the set-only-once check added in a previous
patch will throw an error if its added again.  ddebug_query="..." has
no $modname associated with it, so the query string may include it.

This also fixes redundant "module $modname" otherwise needed to handle
multiple queries per string:

   $modname.dyndbg="func foo +fp; func bar +fp"
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8e59b5cf
    • Jim Cromie's avatar
      dynamic_debug: print ram usage by ddebug tables if verbose · 41076927
      Jim Cromie authored 
      Print ram usage of dynamic-debug tables and verbose section so user
knows cost of enabling CONFIG_DYNAMIC_DEBUG.  This only counts the
size of the _ddebug tables for builtins and the __verbose section that
they refer to, not those used in loadable modules.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      41076927
    • Jim Cromie's avatar
      dynamic_debug: simplify dynamic_debug_init error exit · af442399
      Jim Cromie authored 
      We dont want errors while parsing ddebug_query to unload ddebug
tables, so set success after tables are loaded, and return 0 after
query parsing is done.

Simplify error handling code since its no longer used for success,
and change goto label to out_err to clarify this.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      af442399
    • Jim Cromie's avatar
      dynamic_debug: combine parse_args callbacks together · 6ab676e9
      Jim Cromie authored 
      Refactor ddebug_dyndbg_boot_param_cb and ddebug_dyndbg_module_param_cb
into a common helper function, and call it from both.  The handling of
foo.dyndbg is unneeded by the latter, but harmless.

The 2 callers differ only by pr_info and the return code they pass to
the helper for when an unknown param is handled.  I could slightly
reduce dmesg clutter by putting the vpr_info in the common helper,
after the return on_err, but that loses __func__ context, is overly
silent on module_cb unknown param errors, and the clutter is only when
dynamic_debug.verbose=1 anyway.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6ab676e9
    • Jim Cromie's avatar
      dynamic_debug: deprecate ddebug_query, suggest dyndbg instead · f0b919d9
      Jim Cromie authored 
      With ddebug_dyndbg_boot_params_cb() handling bare dyndbg params, we
dont need ddebug_query param anymore.  Add a warning when processing
ddebug_query= param that it is deprecated, and to change it to dyndbg=

Add a deprecation notice for v3.8 to feature-removal-schedule.txt, and
add a suggested deprecation period of 3 releases to the header.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f0b919d9
    • Jim Cromie's avatar
      dynamic_debug: make dynamic-debug work for module initialization · b48420c1
      Jim Cromie authored 
      This introduces a fake module param $module.dyndbg.  Its based upon
Thomas Renninger's $module.ddebug boot-time debugging patch from
https://lkml.org/lkml/2010/9/15/397

The 'fake' module parameter is provided for all modules, whether or
not they need it.  It is not explicitly added to each module, but is
implemented in callbacks invoked from parse_args.

For builtin modules, dynamic_debug_init() now directly calls
parse_args(..., &ddebug_dyndbg_boot_params_cb), to process the params
undeclared in the modules, just after the ddebug tables are processed.

While its slightly weird to reprocess the boot params, parse_args() is
already called repeatedly by do_initcall_levels().  More importantly,
the dyndbg queries (given in ddebug_query or dyndbg params) cannot be
activated until after the ddebug tables are ready, and reusing
parse_args is cleaner than doing an ad-hoc parse.  This reparse would
break options like inc_verbosity, but they probably should be params,
like verbosity=3.

ddebug_dyndbg_boot_params_cb() handles both bare dyndbg (aka:
ddebug_query) and module-prefixed dyndbg params, and ignores all other
parameters.  For example, the following will enable pr_debug()s in 4
builtin modules, in the order given:

  dyndbg="module params +p; module aio +p" module.dyndbg=+p pci.dyndbg

For loadable modules, parse_args() in load_module() calls
ddebug_dyndbg_module_params_cb().  This handles bare dyndbg params as
passed from modprobe, and errors on other unknown params.

Note that modprobe reads /proc/cmdline, so "modprobe foo" grabs all
foo.params, strips the "foo.", and passes these to the kernel.
ddebug_dyndbg_module_params_cb() is again called for the unknown
params; it handles dyndbg, and errors on others.  The "doing" arg
added previously contains the module name.

For non CONFIG_DYNAMIC_DEBUG builds, the stub function accepts
and ignores $module.dyndbg params, other unknowns get -ENOENT.

If no param value is given (as in pci.dyndbg example above), "+p" is
assumed, which enables all pr_debug callsites in the module.

The dyndbg fake parameter is not shown in /sys/module/*/parameters,
thus it does not use any resources.  Changes to it are made via the
control file.

Also change pr_info in ddebug_exec_queries to vpr_info,
no need to see it all the time.
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
CC: Thomas Renninger <trenn@suse.de>
CC: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b48420c1
    • Jim Cromie's avatar
      params: add 3rd arg to option handler callback signature · 9fb48c74
      Jim Cromie authored 
      Add a 3rd arg, named "doing", to unknown-options callbacks invoked
from parse_args(). The arg is passed as:

  "Booting kernel" from start_kernel(),
  initcall_level_names[i] from do_initcall_level(),
  mod->name from load_module(), via parse_args(), parse_one()

parse_args() already has the "name" parameter, which is renamed to
"doing" to better reflect current uses 1,2 above.  parse_args() passes
it to an altered parse_one(), which now passes it down into the
unknown option handler callbacks.

The mod->name will be needed to handle dyndbg for loadable modules,
since params passed by modprobe are not qualified (they do not have a
"$modname." prefix), and by the time the unknown-param callback is
called, the module name is not otherwise available.

Minor tweaks:

Add param-name to parse_one's pr_debug(), current message doesnt
identify the param being handled, add it.

Add a pr_info to print current level and level_name of the initcall,
and number of registered initcalls at that level.  This adds 7 lines
to dmesg output, like:

   initlevel:6=device, 172 registered initcalls

Drop "parameters" from initcall_level_names[], its unhelpful in the
pr_info() added above.  This array is passed into parse_args() by
do_initcall_level().

CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9fb48c74
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