Commit Graph

22 Commits

Author SHA1 Message Date
Dan Williams a4683487f9 [SCSI] async: make async_synchronize_full() flush all work regardless of domain
In response to an async related regression James noted:

  "My theory is that this is an init problem: The assumption in a lot of
   our code is that async_synchronize_full() waits for everything ... even
   the domain specific async schedules, which isn't true."

...so make this assumption true.

Each domain, including the default one, registers itself on a global domain
list when work is scheduled.  Once all entries complete it exits that
list.  Waiting for the list to be empty syncs all in-flight work across
all domains.

Domains can opt-out of global syncing if they are declared as exclusive
ASYNC_DOMAIN_EXCLUSIVE().  All stack-based domains have been declared
exclusive since the domain may go out of scope as soon as the last work
item completes.

Statically declared domains are mostly ok, but async_unregister_domain()
is there to close any theoretical races with pending
async_synchronize_full waiters at module removal time.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Reported-by: Meelis Roos <mroos@linux.ee>
Reported-by: Eldad Zack <eldadzack@gmail.com>
Tested-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-07-20 09:07:37 +01:00
Dan Williams 2955b47d2c [SCSI] async: introduce 'async_domain' type
This is in preparation for teaching async_synchronize_full() to sync all
pending async work, and not just on the async_running domain.  This
conversion is functionally equivalent, just embedding the existing list
in a new async_domain type.

The .registered attribute is used in a later patch to distinguish
between domains that want to be flushed by async_synchronize_full()
versus those that only expect async_synchronize_{full|cookie}_domain to
be used for flushing.

[jejb: add async.h to scsi_priv.h for struct async_domain]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Tested-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-07-20 09:05:54 +01:00
Rusty Russell 6d6a55ec08 kernel/async: remove redundant declaration.
It's in linux/init.h, and I'm about to change it to a bool.

Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-13 09:32:18 +10:30
Paul Gortmaker 9984de1a5a kernel: Map most files to use export.h instead of module.h
The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else.  Revector them
onto the isolated export header for faster compile times.

Nothing to see here but a whole lot of instances of:

  -#include <linux/module.h>
  +#include <linux/export.h>

This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 09:20:12 -04:00
Vitaliy Ivanov 124ff4e53a async: uninitialized warning corrections
The variables here are really not used uninitialized.

kernel/async.c: In function 'async_synchronize_cookie_domain':
kernel/async.c:270:10: warning: 'starttime.tv64' may be used uninitialized in this function
kernel/async.c: In function 'async_run_entry_fn':
kernel/async.c:122:10: warning: 'calltime.tv64' may be used uninitialized in this function

Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-09-15 14:22:28 +02:00
Paul McQuade 84c15027a7 async: Fixed an include coding style issue
Added <linux/atomic.h>,<linux/ktime.h> and Removed <asm/atomic.h>.
Added KERN_DEBUG to printk() functions.

Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Paul McQuade <tungstentide@gmail.com>
Link: http://lkml.kernel.org/r/4DE596B4.7030904@gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14 22:48:46 -04:00
Tejun Heo 083b804c4d async: use workqueue for worker pool
Replace private worker pool with system_unbound_wq.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Arjan van de Ven <arjan@infradead.org>
2010-07-14 11:29:46 +02:00
Tejun Heo 5a0e3ad6af 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>
2010-03-30 22:02:32 +09:00
Linus Torvalds 3af968e066 async: Fix lack of boot-time console due to insufficient synchronization
Our async work synchronization was broken by "async: make sure
independent async domains can't accidentally entangle" (commit
d5a877e8dd), because it would report
the wrong lowest active async ID when there was both running and
pending async work.

This caused things like no being able to read the root filesystem,
resulting in missing console devices and inability to run 'init',
causing a boot-time panic.

This fixes it by properly returning the lowest pending async ID: if
there is any running async work, that will have a lower ID than any
pending work, and we should _not_ look at the pending work list.

There were alternative patches from Jaswinder and James, but this one
also cleans up the code by removing the pointless 'ret' variable and
the unnecesary testing for an empty list around 'for_each_entry()' (if
the list is empty, the for_each_entry() thing just won't execute).

Fixes-bug: http://bugzilla.kernel.org/show_bug.cgi?id=13474
Reported-and-tested-by: Chris Clayton <chris2553@googlemail.com>
Cc: Jaswinder Singh Rajput <jaswinder@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-08 12:31:53 -07:00
James Bottomley d5a877e8dd async: make sure independent async domains can't accidentally entangle
The problem occurs when async_synchronize_full_domain() is called when
the async_pending list is not empty.  This will cause lowest_running()
to return the cookie of the first entry on the async_pending list, which
might be nothing at all to do with the domain being asked for and thus
cause the domain synchronization to wait for an unrelated domain.   This
can cause a deadlock if domain synchronization is used from one domain
to wait for another.

Fix by running over the async_pending list to see if any pending items
actually belong to our domain (and return their cookies if they do).

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-24 13:38:41 -07:00
Arjan van de Ven 9710794383 async: remove the temporary (2.6.29) "async is off by default" code
Now that everyone has been able to test the async code (and it's being used
in the Moblin betas by default), we can enable it by default.
The various fixes needed have gone into 2.6.29 already.

[With an important bugfix from Stefan Richter]

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-03-28 13:05:30 -07:00
Stefan Richter f7de7621f0 async: use list_move_tail
list.h provides a dedicated primitive for
"list_del followed by list_add_tail"... list_move_tail.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2009-02-08 10:00:26 -08:00
Cornelia Huck 766ccb9ed4 async: Rename _special -> _domain for clarity.
Rename the async_*_special() functions to async_*_domain(), which
describes the purpose of these functions much better.
[Broke up long lines to silence checkpatch]

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:11 -08:00
Cornelia Huck f30d5b307c async: Add some documentation.
Add some kerneldoc to the async interface.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:11 -08:00
Cornelia Huck 86532d8b16 async: Handle kthread_run() return codes.
If we fail to create the manager thread, fall back to non-fastboot.
If we fail to create an async thread, try again after waiting for
a bit.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:10 -08:00
Cornelia Huck 7a89bbc749 async: Fix running list handling.
async_schedule() should pass in async_running as the running
list, and run_one_entry() should put the entry to be run on
the provided running list instead of always on the generic one.

Reported-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:10 -08:00
Andrew Morton 58763a2974 kernel/async.c: fix printk warnings
alpha:

kernel/async.c: In function 'run_one_entry':
kernel/async.c:141: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t'
kernel/async.c:149: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t'
kernel/async.c:149: warning: format '%lld' expects type 'long long int', but argument 4 has type 's64'
kernel/async.c: In function 'async_synchronize_cookie_special':
kernel/async.c:250: warning: format '%lli' expects type 'long long int', but argument 3 has type 's64'

Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-05 12:56:46 -08:00
Arjan van de Ven 37a76bd4f1 async: fix __lowest_in_progress()
At 37000 feet somewhere near Greenland I woke up from a half-sleep with the
realisation that __lowest_in_progress() is buggy. After landing I checked
and there were indeed 2 problems with it; this patch fixes both:
* The order of the list checks was wrong
* The locking was not correct.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-12 16:39:58 -08:00
Arjan van de Ven cdb80f630b async: make async a command line option for now
... and have it default off.
This does allow people to work with it for testing.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-01-09 13:23:45 -08:00
Arjan van de Ven 33b04b9308 async: make async_synchronize_full() more serializing
turns out that there are real problems with allowing async
tasks that are scheduled from async tasks to run after
the async_synchronize_full() returns.

This patch makes the _full more strict and a complete
synchronization. Later I might need to add back a lighter
form of synchronization for other uses.. but not right now.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 12:58:09 -08:00
Arjan van de Ven ad160d2319 async: don't do the initcall stuff post boot
while tracking the asynchronous calls during boot using the initcall_debug
convention is useful, doing it once the kernel is done is actually
bad now that we use asynchronous operations post boot as well...

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-01-07 09:31:49 -08:00
Arjan van de Ven 22a9d64567 async: Asynchronous function calls to speed up kernel boot
Right now, most of the kernel boot is strictly synchronous, such that
various hardware delays are done sequentially.

In order to make the kernel boot faster, this patch introduces
infrastructure to allow doing some of the initialization steps
asynchronously, which will hide significant portions of the hardware delays
in practice.

In order to not change device order and other similar observables, this
patch does NOT do full parallel initialization.

Rather, it operates more in the way an out of order CPU does; the work may
be done out of order and asynchronous, but the observable effects
(instruction retiring for the CPU) are still done in the original sequence.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-01-07 08:45:46 -08:00