2005-04-16 15:20:36 -07:00
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2006-09-04 15:41:16 +02:00
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2005-04-16 15:20:36 -07:00
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2013-05-07 16:19:08 -07:00
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2012-03-05 13:15:27 -08:00
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2005-04-16 15:20:36 -07:00
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2011-11-16 23:57:37 -05:00
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2005-04-16 15:20:36 -07:00
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2012-03-05 13:15:27 -08:00
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2005-04-16 15:20:36 -07:00
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tracing/events: convert block trace points to TRACE_EVENT()
TRACE_EVENT is a more generic way to define tracepoints. Doing so adds
these new capabilities to this tracepoint:
- zero-copy and per-cpu splice() tracing
- binary tracing without printf overhead
- structured logging records exposed under /debug/tracing/events
- trace events embedded in function tracer output and other plugins
- user-defined, per tracepoint filter expressions
...
Cons:
- no dev_t info for the output of plug, unplug_timer and unplug_io events.
no dev_t info for getrq and sleeprq events if bio == NULL.
no dev_t info for rq_abort,...,rq_requeue events if rq->rq_disk == NULL.
This is mainly because we can't get the deivce from a request queue.
But this may change in the future.
- A packet command is converted to a string in TP_assign, not TP_print.
While blktrace do the convertion just before output.
Since pc requests should be rather rare, this is not a big issue.
- In blktrace, an event can have 2 different print formats, but a TRACE_EVENT
has a unique format, which means we have some unused data in a trace entry.
The overhead is minimized by using __dynamic_array() instead of __array().
I've benchmarked the ioctl blktrace vs the splice based TRACE_EVENT tracing:
dd dd + ioctl blktrace dd + TRACE_EVENT (splice)
1 7.36s, 42.7 MB/s 7.50s, 42.0 MB/s 7.41s, 42.5 MB/s
2 7.43s, 42.3 MB/s 7.48s, 42.1 MB/s 7.43s, 42.4 MB/s
3 7.38s, 42.6 MB/s 7.45s, 42.2 MB/s 7.41s, 42.5 MB/s
So the overhead of tracing is very small, and no regression when using
those trace events vs blktrace.
And the binary output of TRACE_EVENT is much smaller than blktrace:
# ls -l -h
-rw-r--r-- 1 root root 8.8M 06-09 13:24 sda.blktrace.0
-rw-r--r-- 1 root root 195K 06-09 13:24 sda.blktrace.1
-rw-r--r-- 1 root root 2.7M 06-09 13:25 trace_splice.out
Following are some comparisons between TRACE_EVENT and blktrace:
plug:
kjournald-480 [000] 303.084981: block_plug: [kjournald]
kjournald-480 [000] 303.084981: 8,0 P N [kjournald]
unplug_io:
kblockd/0-118 [000] 300.052973: block_unplug_io: [kblockd/0] 1
kblockd/0-118 [000] 300.052974: 8,0 U N [kblockd/0] 1
remap:
kjournald-480 [000] 303.085042: block_remap: 8,0 W 102736992 + 8 <- (8,8) 33384
kjournald-480 [000] 303.085043: 8,0 A W 102736992 + 8 <- (8,8) 33384
bio_backmerge:
kjournald-480 [000] 303.085086: block_bio_backmerge: 8,0 W 102737032 + 8 [kjournald]
kjournald-480 [000] 303.085086: 8,0 M W 102737032 + 8 [kjournald]
getrq:
kjournald-480 [000] 303.084974: block_getrq: 8,0 W 102736984 + 8 [kjournald]
kjournald-480 [000] 303.084975: 8,0 G W 102736984 + 8 [kjournald]
bash-2066 [001] 1072.953770: 8,0 G N [bash]
bash-2066 [001] 1072.953773: block_getrq: 0,0 N 0 + 0 [bash]
rq_complete:
konsole-2065 [001] 300.053184: block_rq_complete: 8,0 W () 103669040 + 16 [0]
konsole-2065 [001] 300.053191: 8,0 C W 103669040 + 16 [0]
ksoftirqd/1-7 [001] 1072.953811: 8,0 C N (5a 00 08 00 00 00 00 00 24 00) [0]
ksoftirqd/1-7 [001] 1072.953813: block_rq_complete: 0,0 N (5a 00 08 00 00 00 00 00 24 00) 0 + 0 [0]
rq_insert:
kjournald-480 [000] 303.084985: block_rq_insert: 8,0 W 0 () 102736984 + 8 [kjournald]
kjournald-480 [000] 303.084986: 8,0 I W 102736984 + 8 [kjournald]
Changelog from v2 -> v3:
- use the newly introduced __dynamic_array().
Changelog from v1 -> v2:
- use __string() instead of __array() to minimize the memory required
to store hex dump of rq->cmd().
- support large pc requests.
- add missing blk_fill_rwbs_rq() in block_rq_requeue TRACE_EVENT.
- some cleanups.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A2DF669.5070905@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-09 13:43:05 +08:00
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2008-11-26 11:59:56 +01:00
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2008-12-23 12:42:54 +01:00
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2005-04-16 15:20:36 -07:00
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2011-03-08 08:28:01 +01:00
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2005-04-16 15:20:36 -07:00
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2008-06-17 18:59:56 +02:00
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2012-09-06 15:35:01 -07:00
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2005-04-16 15:20:36 -07:00
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2008-12-10 15:35:05 +01:00
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2012-08-09 15:19:25 +02:00
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2012-10-22 21:53:36 +02:00
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2008-12-10 15:35:05 +01:00
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2010-01-19 14:07:09 +01:00
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2008-12-10 15:35:05 +01:00
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2012-10-22 21:53:36 +02:00
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2012-08-09 15:19:25 +02:00
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2012-10-22 21:53:36 +02:00
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2012-08-09 15:19:25 +02:00
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2008-12-10 15:35:05 +01:00
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2012-10-22 21:53:36 +02:00
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2012-08-09 15:19:25 +02:00
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2008-12-10 15:35:05 +01:00
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2014-03-28 15:51:55 -04:00
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2008-12-10 15:35:05 +01:00
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2008-06-30 20:04:41 +02:00
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2012-10-12 15:29:33 -07:00
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2008-12-10 15:35:05 +01:00
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2012-10-12 15:29:33 -07:00
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2008-12-10 15:35:05 +01:00
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2012-10-12 15:29:33 -07:00
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2005-04-16 15:20:36 -07:00
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2008-12-11 11:53:43 +01:00
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2012-10-12 15:29:33 -07:00
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2008-12-11 11:53:43 +01:00
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2015-11-06 16:28:21 -08:00
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2008-12-11 11:53:43 +01:00
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2008-09-11 13:17:37 +02:00
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2008-12-11 11:53:43 +01:00
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2008-09-11 13:17:37 +02:00
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2008-12-11 11:53:43 +01:00
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2005-04-16 15:20:36 -07:00
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2008-09-11 13:17:37 +02:00
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2015-11-06 16:28:21 -08:00
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2008-12-11 11:53:43 +01:00
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2008-09-11 13:17:37 +02:00
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2008-12-11 11:53:43 +01:00
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2015-11-06 16:28:21 -08:00
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2008-12-11 11:53:43 +01:00
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2005-04-16 15:20:36 -07:00
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2012-09-06 15:35:00 -07:00
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2005-04-16 15:20:36 -07:00
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2012-09-06 15:35:00 -07:00
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2005-04-16 15:20:36 -07:00
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2008-06-30 20:04:41 +02:00
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2012-09-06 15:34:56 -07:00
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2012-09-06 15:35:00 -07:00
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2008-06-30 20:04:41 +02:00
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2012-09-06 15:35:00 -07:00
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2012-05-25 13:03:11 -07:00
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2012-10-12 15:29:33 -07:00
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2012-09-06 15:35:00 -07:00
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2008-12-10 15:35:05 +01:00
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2012-09-06 15:35:00 -07:00
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2005-09-06 15:16:42 -07:00
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2006-01-14 13:20:43 -08:00
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2005-04-16 15:20:36 -07:00
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2007-07-18 13:14:03 +02:00
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2015-04-17 16:15:18 -06:00
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2015-04-17 16:23:59 -06:00
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
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2005-04-16 15:20:36 -07:00
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2012-09-06 15:34:58 -07:00
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2012-09-06 15:35:00 -07:00
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2012-09-06 15:34:58 -07:00
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2015-07-20 15:29:37 +02:00
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2015-04-17 16:15:18 -06:00
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2012-09-06 15:34:58 -07:00
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2016-03-11 17:34:51 +01:00
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2013-11-23 18:34:15 -08:00
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2015-07-20 15:29:37 +02:00
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2016-03-11 17:34:50 +01:00
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2013-11-23 18:34:15 -08:00
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2016-03-11 17:34:51 +01:00
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2013-11-23 18:34:15 -08:00
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2015-05-22 09:14:03 -04:00
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2015-07-24 12:37:59 -06:00
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2015-05-22 09:14:03 -04:00
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2013-11-23 18:34:15 -08:00
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2014-04-20 16:03:31 -07:00
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2013-11-23 18:34:15 -08:00
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2015-04-17 16:15:18 -06:00
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2013-11-23 18:34:15 -08:00
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block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
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2005-04-16 15:20:36 -07:00
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2010-01-15 12:05:07 +02:00
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2005-04-16 15:20:36 -07:00
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2012-09-06 15:35:01 -07:00
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2015-11-06 16:28:21 -08:00
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2012-09-06 15:35:01 -07:00
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block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
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2012-09-06 15:35:01 -07:00
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2005-10-07 07:46:04 +01:00
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2005-04-16 15:20:36 -07:00
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|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
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|
2012-09-06 15:35:01 -07:00
|
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|
2009-04-15 19:50:51 +02:00
|
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|
2009-02-21 11:16:36 +01:00
|
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|
2009-04-15 19:50:51 +02:00
|
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2012-09-06 15:35:01 -07:00
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2014-10-03 17:27:12 -04:00
|
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|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
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2015-11-06 16:28:21 -08:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2015-11-06 16:28:21 -08:00
|
|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
|
|
|
2012-09-06 15:35:01 -07:00
|
|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
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|
2012-09-06 15:35:01 -07:00
|
|
|
|
|
|
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|
|
|
|
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|
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|
|
|
2009-04-15 19:50:51 +02:00
|
|
|
|
|
|
|
|
|
2005-04-16 15:20:36 -07:00
|
|
|
|
2012-09-06 15:35:01 -07:00
|
|
|
|
2009-02-21 11:16:36 +01:00
|
|
|
|
|
|
|
|
|
2012-09-06 15:35:01 -07:00
|
|
|
|
2012-10-12 15:29:33 -07:00
|
|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2012-10-12 15:29:33 -07:00
|
|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
|
|
|
|
|
|
|
|
2009-02-21 11:16:36 +01:00
|
|
|
|
|
|
|
|
|
2012-05-25 13:03:11 -07:00
|
|
|
|
2015-07-24 12:37:59 -06:00
|
|
|
|
2012-09-06 15:35:01 -07:00
|
|
|
|
|
|
|
|
|
2005-04-16 15:20:36 -07:00
|
|
|
|
2012-09-06 15:35:01 -07:00
|
|
|
|
|
|
|
|
|
2009-02-21 11:16:36 +01:00
|
|
|
|
|
|
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|
|
|
2005-04-16 15:20:36 -07:00
|
|
|
|
2009-02-21 11:16:36 +01:00
|
|
|
|
|
|
|
|
|
2009-04-15 19:50:51 +02:00
|
|
|
|
2009-02-21 11:16:36 +01:00
|
|
|
|
2005-04-16 15:20:36 -07:00
|
|
|
|
2009-09-26 16:19:21 +02:00
|
|
|
|
2005-04-16 15:20:36 -07:00
|
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|
2013-11-23 17:19:00 -08:00
|
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|
2005-04-16 15:20:36 -07:00
|
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|
|
2013-11-23 17:19:00 -08:00
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2005-04-16 15:20:36 -07:00
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2009-11-02 11:39:22 +01:00
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2005-04-16 15:20:36 -07:00
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2015-04-17 16:23:59 -06:00
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2012-09-06 15:35:00 -07:00
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2015-04-17 16:23:59 -06:00
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
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2005-04-16 15:20:36 -07:00
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2007-07-24 09:28:11 +02:00
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 18:19:27 -08:00
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2015-07-24 12:37:59 -06:00
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2013-11-23 18:19:27 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 17:26:46 -08:00
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2005-04-16 15:20:36 -07:00
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2012-09-06 15:35:02 -07:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 17:26:46 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 17:26:46 -08:00
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2012-09-06 15:35:02 -07:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 17:26:46 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 17:26:46 -08:00
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2014-02-10 17:45:50 -08:00
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2013-11-23 17:26:46 -08:00
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2008-06-30 20:04:41 +02:00
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2013-11-23 17:26:46 -08:00
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2008-06-30 20:04:41 +02:00
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2014-02-10 17:45:50 -08:00
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2013-11-23 17:26:46 -08:00
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2008-06-30 20:04:41 +02:00
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2014-02-10 17:45:50 -08:00
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2013-11-23 17:26:46 -08:00
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2008-06-30 20:04:41 +02:00
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2013-11-23 17:26:46 -08:00
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2009-03-09 10:42:45 +01:00
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2013-11-23 17:26:46 -08:00
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2008-06-30 20:04:41 +02:00
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2009-03-09 10:42:45 +01:00
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2005-09-06 15:16:42 -07:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 17:26:46 -08:00
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2005-04-16 15:20:36 -07:00
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2012-09-06 15:35:02 -07:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 22:30:22 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 22:30:22 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 22:30:22 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 22:30:22 -08:00
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2005-04-16 15:20:36 -07:00
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2006-01-06 09:43:28 +01:00
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2014-12-10 14:16:53 -08:00
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2006-01-06 09:43:28 +01:00
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2014-06-24 16:22:24 -06:00
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2015-08-19 14:24:05 -07:00
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2014-06-24 16:22:24 -06:00
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2006-01-06 09:43:28 +01:00
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2005-04-16 15:20:36 -07:00
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2014-12-10 14:16:53 -08:00
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2005-04-16 15:20:36 -07:00
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2014-12-10 14:16:53 -08:00
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2005-04-16 15:20:36 -07:00
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2014-12-10 14:16:53 -08:00
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2005-04-16 15:20:36 -07:00
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2014-12-10 14:16:53 -08:00
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2015-07-24 12:37:59 -06:00
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2005-04-16 15:20:36 -07:00
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2006-01-06 09:43:28 +01:00
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2005-04-16 15:20:36 -07:00
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2014-12-10 14:16:53 -08:00
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
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2005-11-11 05:30:27 -06:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 22:30:22 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 22:30:22 -08:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 22:30:22 -08:00
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2014-06-05 13:38:39 -06:00
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2013-11-23 22:30:22 -08:00
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2014-06-10 12:53:56 -06:00
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2013-11-23 22:30:22 -08:00
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
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2005-04-16 15:20:36 -07:00
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2012-09-10 14:41:12 -07:00
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2015-07-20 15:29:37 +02:00
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2012-09-10 14:41:12 -07:00
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2015-07-20 15:29:37 +02:00
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2012-09-10 14:41:12 -07:00
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2016-02-09 17:07:38 +01:00
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2012-09-10 14:41:12 -07:00
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2012-09-28 13:17:55 -07:00
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2013-08-07 14:26:21 -07:00
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2012-09-28 13:17:55 -07:00
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2012-09-10 14:03:28 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2013-08-07 14:26:39 -07:00
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2012-09-10 13:57:51 -07:00
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2005-04-16 15:20:36 -07:00
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2008-08-28 16:17:06 +09:00
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2015-01-18 16:16:31 +01:00
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2005-04-16 15:20:36 -07:00
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2014-04-22 15:09:07 -06:00
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2008-08-25 20:36:08 +02:00
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2005-04-16 15:20:36 -07:00
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2010-10-29 11:46:56 -06:00
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2005-04-16 15:20:36 -07:00
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2013-11-22 19:39:06 -08:00
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2015-01-18 16:16:31 +01:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:34 +01:00
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2008-04-11 12:56:49 +02:00
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2015-01-18 16:16:34 +01:00
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2008-04-11 12:56:49 +02:00
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2013-02-06 12:23:11 -08:00
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2015-01-18 16:16:34 +01:00
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2008-04-11 12:56:49 +02:00
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2015-01-18 16:16:34 +01:00
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2008-04-11 12:56:49 +02:00
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2015-01-18 16:16:34 +01:00
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2008-04-11 12:56:49 +02:00
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2015-01-18 16:16:30 +01:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:29 +01:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:30 +01:00
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2005-04-16 15:20:36 -07:00
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[SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
There is a nasty bug in the SCSI SG_IO ioctl that in some circumstances
leads to one process writing data into the address space of some other
random unrelated process if the ioctl is interrupted by a signal.
What happens is the following:
- A process issues an SG_IO ioctl with direction DXFER_FROM_DEV (ie the
underlying SCSI command will transfer data from the SCSI device to
the buffer provided in the ioctl)
- Before the command finishes, a signal is sent to the process waiting
in the ioctl. This will end up waking up the sg_ioctl() code:
result = wait_event_interruptible(sfp->read_wait,
(srp_done(sfp, srp) || sdp->detached));
but neither srp_done() nor sdp->detached is true, so we end up just
setting srp->orphan and returning to userspace:
srp->orphan = 1;
write_unlock_irq(&sfp->rq_list_lock);
return result; /* -ERESTARTSYS because signal hit process */
At this point the original process is done with the ioctl and
blithely goes ahead handling the signal, reissuing the ioctl, etc.
- Eventually, the SCSI command issued by the first ioctl finishes and
ends up in sg_rq_end_io(). At the end of that function, we run through:
write_lock_irqsave(&sfp->rq_list_lock, iflags);
if (unlikely(srp->orphan)) {
if (sfp->keep_orphan)
srp->sg_io_owned = 0;
else
done = 0;
}
srp->done = done;
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
if (likely(done)) {
/* Now wake up any sg_read() that is waiting for this
* packet.
*/
wake_up_interruptible(&sfp->read_wait);
kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
kref_put(&sfp->f_ref, sg_remove_sfp);
} else {
INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
schedule_work(&srp->ew.work);
}
Since srp->orphan *is* set, we set done to 0 (assuming the
userspace app has not set keep_orphan via an SG_SET_KEEP_ORPHAN
ioctl), and therefore we end up scheduling sg_rq_end_io_usercontext()
to run in a workqueue.
- In workqueue context we go through sg_rq_end_io_usercontext() ->
sg_finish_rem_req() -> blk_rq_unmap_user() -> ... ->
bio_uncopy_user() -> __bio_copy_iov() -> copy_to_user().
The key point here is that we are doing copy_to_user() on a
workqueue -- that is, we're on a kernel thread with current->mm
equal to whatever random previous user process was scheduled before
this kernel thread. So we end up copying whatever data the SCSI
command returned to the virtual address of the buffer passed into
the original ioctl, but it's quite likely we do this copying into a
different address space!
As suggested by James Bottomley <James.Bottomley@hansenpartnership.com>,
add a check for current->mm (which is NULL if we're on a kernel thread
without a real userspace address space) in bio_uncopy_user(), and skip
the copy if we're on a kernel thread.
There's no reason that I can think of for any caller of bio_uncopy_user()
to want to do copying on a kernel thread with a random active userspace
address space.
Huge thanks to Costa Sapuntzakis <costa@purestorage.com> for the
original pointer to this bug in the sg code.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Tested-by: David Milburn <dmilburn@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-08-05 17:55:01 -07:00
|
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|
|
2016-02-12 09:39:15 +01:00
|
|
|
|
|
|
|
|
|
[SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
There is a nasty bug in the SCSI SG_IO ioctl that in some circumstances
leads to one process writing data into the address space of some other
random unrelated process if the ioctl is interrupted by a signal.
What happens is the following:
- A process issues an SG_IO ioctl with direction DXFER_FROM_DEV (ie the
underlying SCSI command will transfer data from the SCSI device to
the buffer provided in the ioctl)
- Before the command finishes, a signal is sent to the process waiting
in the ioctl. This will end up waking up the sg_ioctl() code:
result = wait_event_interruptible(sfp->read_wait,
(srp_done(sfp, srp) || sdp->detached));
but neither srp_done() nor sdp->detached is true, so we end up just
setting srp->orphan and returning to userspace:
srp->orphan = 1;
write_unlock_irq(&sfp->rq_list_lock);
return result; /* -ERESTARTSYS because signal hit process */
At this point the original process is done with the ioctl and
blithely goes ahead handling the signal, reissuing the ioctl, etc.
- Eventually, the SCSI command issued by the first ioctl finishes and
ends up in sg_rq_end_io(). At the end of that function, we run through:
write_lock_irqsave(&sfp->rq_list_lock, iflags);
if (unlikely(srp->orphan)) {
if (sfp->keep_orphan)
srp->sg_io_owned = 0;
else
done = 0;
}
srp->done = done;
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
if (likely(done)) {
/* Now wake up any sg_read() that is waiting for this
* packet.
*/
wake_up_interruptible(&sfp->read_wait);
kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
kref_put(&sfp->f_ref, sg_remove_sfp);
} else {
INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
schedule_work(&srp->ew.work);
}
Since srp->orphan *is* set, we set done to 0 (assuming the
userspace app has not set keep_orphan via an SG_SET_KEEP_ORPHAN
ioctl), and therefore we end up scheduling sg_rq_end_io_usercontext()
to run in a workqueue.
- In workqueue context we go through sg_rq_end_io_usercontext() ->
sg_finish_rem_req() -> blk_rq_unmap_user() -> ... ->
bio_uncopy_user() -> __bio_copy_iov() -> copy_to_user().
The key point here is that we are doing copy_to_user() on a
workqueue -- that is, we're on a kernel thread with current->mm
equal to whatever random previous user process was scheduled before
this kernel thread. So we end up copying whatever data the SCSI
command returned to the virtual address of the buffer passed into
the original ioctl, but it's quite likely we do this copying into a
different address space!
As suggested by James Bottomley <James.Bottomley@hansenpartnership.com>,
add a check for current->mm (which is NULL if we're on a kernel thread
without a real userspace address space) in bio_uncopy_user(), and skip
the copy if we're on a kernel thread.
There's no reason that I can think of for any caller of bio_uncopy_user()
to want to do copying on a kernel thread with a random active userspace
address space.
Huge thanks to Costa Sapuntzakis <costa@purestorage.com> for the
original pointer to this bug in the sg code.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Tested-by: David Milburn <dmilburn@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-08-05 17:55:01 -07:00
|
|
|
|
2016-02-12 09:39:15 +01:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2015-01-18 16:16:34 +01:00
|
|
|
|
2015-01-18 16:16:30 +01:00
|
|
|
|
|
|
|
|
|
[SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal
There is a nasty bug in the SCSI SG_IO ioctl that in some circumstances
leads to one process writing data into the address space of some other
random unrelated process if the ioctl is interrupted by a signal.
What happens is the following:
- A process issues an SG_IO ioctl with direction DXFER_FROM_DEV (ie the
underlying SCSI command will transfer data from the SCSI device to
the buffer provided in the ioctl)
- Before the command finishes, a signal is sent to the process waiting
in the ioctl. This will end up waking up the sg_ioctl() code:
result = wait_event_interruptible(sfp->read_wait,
(srp_done(sfp, srp) || sdp->detached));
but neither srp_done() nor sdp->detached is true, so we end up just
setting srp->orphan and returning to userspace:
srp->orphan = 1;
write_unlock_irq(&sfp->rq_list_lock);
return result; /* -ERESTARTSYS because signal hit process */
At this point the original process is done with the ioctl and
blithely goes ahead handling the signal, reissuing the ioctl, etc.
- Eventually, the SCSI command issued by the first ioctl finishes and
ends up in sg_rq_end_io(). At the end of that function, we run through:
write_lock_irqsave(&sfp->rq_list_lock, iflags);
if (unlikely(srp->orphan)) {
if (sfp->keep_orphan)
srp->sg_io_owned = 0;
else
done = 0;
}
srp->done = done;
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
if (likely(done)) {
/* Now wake up any sg_read() that is waiting for this
* packet.
*/
wake_up_interruptible(&sfp->read_wait);
kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
kref_put(&sfp->f_ref, sg_remove_sfp);
} else {
INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
schedule_work(&srp->ew.work);
}
Since srp->orphan *is* set, we set done to 0 (assuming the
userspace app has not set keep_orphan via an SG_SET_KEEP_ORPHAN
ioctl), and therefore we end up scheduling sg_rq_end_io_usercontext()
to run in a workqueue.
- In workqueue context we go through sg_rq_end_io_usercontext() ->
sg_finish_rem_req() -> blk_rq_unmap_user() -> ... ->
bio_uncopy_user() -> __bio_copy_iov() -> copy_to_user().
The key point here is that we are doing copy_to_user() on a
workqueue -- that is, we're on a kernel thread with current->mm
equal to whatever random previous user process was scheduled before
this kernel thread. So we end up copying whatever data the SCSI
command returned to the virtual address of the buffer passed into
the original ioctl, but it's quite likely we do this copying into a
different address space!
As suggested by James Bottomley <James.Bottomley@hansenpartnership.com>,
add a check for current->mm (which is NULL if we're on a kernel thread
without a real userspace address space) in bio_uncopy_user(), and skip
the copy if we're on a kernel thread.
There's no reason that I can think of for any caller of bio_uncopy_user()
to want to do copying on a kernel thread with a random active userspace
address space.
Huge thanks to Costa Sapuntzakis <costa@purestorage.com> for the
original pointer to this bug in the sg code.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Tested-by: David Milburn <dmilburn@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-08-05 17:55:01 -07:00
|
|
|
|
2013-11-22 19:39:06 -08:00
|
|
|
|
2005-04-16 15:20:36 -07:00
|
|
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|
2009-09-26 16:19:21 +02:00
|
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|
2005-04-16 15:20:36 -07:00
|
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|
2008-04-11 12:56:49 +02:00
|
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2015-01-18 16:16:31 +01:00
|
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2005-04-16 15:20:36 -07:00
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2008-08-28 16:17:06 +09:00
|
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2015-01-18 16:16:31 +01:00
|
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2005-04-16 15:20:36 -07:00
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2008-04-11 12:56:49 +02:00
|
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|
2015-01-18 16:16:31 +01:00
|
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|
2015-11-21 17:27:31 +08:00
|
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|
2005-04-16 15:20:36 -07:00
|
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2015-01-18 16:16:31 +01:00
|
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|
2008-04-11 12:56:49 +02:00
|
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2015-01-18 16:16:31 +01:00
|
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2008-04-11 12:56:49 +02:00
|
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2010-11-10 14:36:25 +01:00
|
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2008-04-11 12:56:49 +02:00
|
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2009-04-28 20:24:29 +02:00
|
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2015-01-18 16:16:31 +01:00
|
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2005-04-16 15:20:36 -07:00
|
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2015-01-18 16:16:31 +01:00
|
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2005-04-16 15:20:36 -07:00
|
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2009-04-15 22:10:27 +09:00
|
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2005-04-16 15:20:36 -07:00
|
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2015-01-18 16:16:31 +01:00
|
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|
|
2010-08-07 18:20:39 +02:00
|
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2005-04-16 15:20:36 -07:00
|
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2008-12-18 14:49:37 +09:00
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2008-12-18 14:49:36 +09:00
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2008-12-18 14:49:37 +09:00
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2005-04-16 15:20:36 -07:00
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2008-12-18 14:49:36 +09:00
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2005-04-16 15:20:36 -07:00
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2008-12-18 14:49:37 +09:00
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2005-04-16 15:20:36 -07:00
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2008-08-28 16:17:06 +09:00
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2008-12-18 14:49:36 +09:00
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2008-08-28 16:17:06 +09:00
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2008-12-18 14:49:36 +09:00
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2008-08-28 16:17:06 +09:00
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2008-12-18 14:49:36 +09:00
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2005-04-16 15:20:36 -07:00
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2008-12-18 14:49:37 +09:00
|
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2005-04-16 15:20:36 -07:00
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2008-12-18 14:49:37 +09:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:31 +01:00
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2009-07-09 14:46:53 +02:00
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2015-01-18 16:16:34 +01:00
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2008-04-11 12:56:49 +02:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:31 +01:00
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2005-04-16 15:20:36 -07:00
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2008-08-28 16:17:06 +09:00
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2015-01-18 16:16:30 +01:00
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2005-04-16 15:20:36 -07:00
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2013-11-22 19:39:06 -08:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:33 +01:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:31 +01:00
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2005-06-20 14:06:52 +02:00
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2005-04-16 15:20:36 -07:00
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2005-06-20 14:06:52 +02:00
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2015-01-18 16:16:31 +01:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:31 +01:00
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2005-06-20 14:06:52 +02:00
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2010-11-10 14:36:25 +01:00
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2005-06-20 14:06:52 +02:00
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2006-12-01 10:40:20 +01:00
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2005-06-20 14:06:52 +02:00
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2006-12-01 10:40:20 +01:00
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2005-06-20 14:06:52 +02:00
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2005-04-16 15:20:36 -07:00
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2009-04-15 22:10:27 +09:00
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2005-04-16 15:20:36 -07:00
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2008-08-28 16:17:05 +09:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:31 +01:00
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2005-06-20 14:06:52 +02:00
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2010-11-10 14:36:25 +01:00
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2008-07-25 19:45:25 -07:00
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2015-01-18 16:16:31 +01:00
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2006-06-16 13:02:29 +02:00
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2005-06-20 14:06:52 +02:00
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2006-06-16 13:02:29 +02:00
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2005-06-20 14:06:52 +02:00
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2015-11-21 17:27:31 +08:00
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2005-06-20 14:06:52 +02:00
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2005-12-05 02:37:06 -06:00
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2005-06-20 14:06:52 +02:00
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2005-04-16 15:20:36 -07:00
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2005-06-20 14:06:52 +02:00
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2005-04-16 15:20:36 -07:00
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2005-06-20 14:06:52 +02:00
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2005-04-16 15:20:36 -07:00
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2005-06-20 14:06:52 +02:00
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2005-04-16 15:20:36 -07:00
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2015-01-18 16:16:31 +01:00
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2010-08-07 18:20:39 +02:00
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2005-04-16 15:20:36 -07:00
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2015-07-24 12:37:59 -06:00
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2015-01-18 16:16:33 +01:00
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2005-04-16 15:20:36 -07:00
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2005-06-20 14:06:52 +02:00
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2015-01-18 16:16:31 +01:00
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2005-06-20 14:06:52 +02:00
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2015-01-18 16:16:31 +01:00
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2005-06-20 14:06:52 +02:00
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2005-04-16 15:20:36 -07:00
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2013-02-06 12:23:11 -08:00
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
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2005-04-16 15:20:36 -07:00
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2015-07-20 15:29:37 +02:00
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2005-06-20 14:05:27 +02:00
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2015-01-18 16:16:32 +01:00
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2005-06-20 14:04:44 +02:00
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2009-04-15 22:10:27 +09:00
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2005-06-20 14:04:44 +02:00
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2005-12-05 02:37:06 -06:00
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2015-01-18 16:16:32 +01:00
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2005-06-20 14:04:44 +02:00
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2005-06-20 14:05:27 +02:00
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2005-06-20 14:04:44 +02:00
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2009-09-26 16:19:21 +02:00
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2005-06-20 14:04:44 +02:00
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2015-07-20 15:29:37 +02:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:30 +01:00
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2015-07-20 15:29:37 +02:00
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2015-01-18 16:16:30 +01:00
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2015-01-18 16:16:28 +01:00
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2015-01-18 16:16:30 +01:00
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2008-04-25 12:47:50 +02:00
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2013-02-06 12:23:11 -08:00
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2015-01-18 16:16:30 +01:00
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2013-11-22 19:39:06 -08:00
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2008-04-25 12:47:50 +02:00
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2015-07-20 15:29:37 +02:00
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2008-04-25 12:47:50 +02:00
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2008-04-30 09:08:54 +02:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:28 +01:00
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2015-01-18 16:16:30 +01:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:28 +01:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:28 +01:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:28 +01:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:28 +01:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:30 +01:00
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2015-01-18 16:16:28 +01:00
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2015-01-18 16:16:30 +01:00
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|
2008-08-25 20:36:08 +02:00
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2008-04-25 12:47:50 +02:00
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2015-01-18 16:16:28 +01:00
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2015-01-18 16:16:30 +01:00
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2015-01-18 16:16:28 +01:00
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|
2008-04-25 12:47:50 +02:00
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2009-09-26 16:19:21 +02:00
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2008-04-25 12:47:50 +02:00
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2005-04-16 15:20:36 -07:00
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2012-07-25 18:12:08 +03:00
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2005-04-16 15:20:36 -07:00
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2012-09-05 15:22:02 -07:00
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2005-04-16 15:20:36 -07:00
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2012-09-05 15:22:02 -07:00
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2005-04-16 15:20:36 -07:00
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2008-02-18 13:48:32 +01:00
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2005-04-16 15:20:36 -07:00
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2012-09-05 15:22:02 -07:00
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2005-04-16 15:20:36 -07:00
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2012-09-05 15:22:02 -07:00
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2005-04-16 15:20:36 -07:00
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2006-11-22 14:55:48 +00:00
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2005-04-16 15:20:36 -07:00
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2006-11-22 14:55:48 +00:00
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2005-04-16 15:20:36 -07:00
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2006-11-22 14:55:48 +00:00
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2005-04-16 15:20:36 -07:00
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2012-09-05 15:22:02 -07:00
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2005-04-16 15:20:36 -07:00
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2012-09-05 15:22:02 -07:00
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2005-04-16 15:20:36 -07:00
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2012-09-05 15:22:02 -07:00
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2005-04-16 15:20:36 -07:00
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2014-11-24 11:05:22 +08:00
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2009-11-26 09:16:19 +01:00
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2013-11-23 17:19:00 -08:00
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2009-11-26 09:16:19 +01:00
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2013-11-23 17:19:00 -08:00
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2009-11-26 09:16:19 +01:00
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2015-04-17 16:15:18 -06:00
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2015-05-22 09:14:03 -04:00
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2015-07-24 12:37:59 -06:00
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2015-04-17 16:15:18 -06:00
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2015-05-22 09:14:03 -04:00
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2015-04-17 16:15:18 -06:00
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2005-04-16 15:20:36 -07:00
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2015-07-20 15:29:37 +02:00
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2005-04-16 15:20:36 -07:00
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2015-07-20 15:29:37 +02:00
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2005-04-16 15:20:36 -07:00
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2016-03-11 17:34:52 +01:00
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2016-03-11 17:34:53 +01:00
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2016-03-11 17:34:52 +01:00
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2005-04-16 15:20:36 -07:00
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2016-03-11 17:34:52 +01:00
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2013-11-23 18:34:15 -08:00
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2016-03-11 17:34:52 +01:00
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
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2005-04-16 15:20:36 -07:00
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2013-11-23 18:21:01 -08:00
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2015-07-22 07:57:12 -04:00
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2013-11-23 18:21:01 -08:00
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2015-07-22 07:57:12 -04:00
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2013-11-23 18:21:01 -08:00
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2013-08-07 11:14:32 -07:00
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2013-10-11 15:44:27 -07:00
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2013-08-07 11:14:32 -07:00
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2015-07-24 12:37:59 -06:00
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2013-08-07 11:14:32 -07:00
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2013-10-11 15:44:27 -07:00
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2013-08-07 11:14:32 -07:00
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2005-04-16 15:20:36 -07:00
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2014-04-22 15:09:05 -06:00
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2005-04-16 15:20:36 -07:00
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2008-12-11 11:53:43 +01:00
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2005-04-16 15:20:36 -07:00
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2012-10-12 15:29:33 -07:00
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2005-04-16 15:20:36 -07:00
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block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
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2005-04-16 15:20:36 -07:00
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2012-10-12 15:29:33 -07:00
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2009-06-26 15:37:49 +02:00
|
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2008-12-10 15:35:05 +01:00
|
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2005-04-16 15:20:36 -07:00
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2009-09-26 16:19:21 +02:00
|
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2005-04-16 15:20:36 -07:00
|
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2014-10-03 17:27:12 -04:00
|
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2005-04-16 15:20:36 -07:00
|
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2008-12-23 12:42:54 +01:00
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2008-10-22 20:32:58 +02:00
|
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2005-04-16 15:20:36 -07:00
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2008-10-22 20:32:58 +02:00
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2005-04-16 15:20:36 -07:00
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2008-12-10 15:35:05 +01:00
|
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|
2008-10-22 20:32:58 +02:00
|
|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
|
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|
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|
|
|
2008-12-23 12:42:54 +01:00
|
|
|
|
2008-12-10 15:35:05 +01:00
|
|
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2005-04-16 15:20:36 -07:00
|
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|
2014-10-03 17:27:12 -04:00
|
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|
|
|
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|
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|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2005-04-16 15:20:36 -07:00
|
|
|
|
block: Avoid deadlocks with bio allocation by stacking drivers
Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
2012-09-10 14:33:46 -07:00
|
|
|
|
2005-04-16 15:20:36 -07:00
|
|
|
|
|
|
|
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|
|
2014-10-03 17:27:12 -04:00
|
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|
2009-09-26 16:19:21 +02:00
|
|
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|
2005-04-16 15:20:36 -07:00
|
|
|
|
2014-10-03 17:27:12 -04:00
|
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|
2012-03-05 13:15:27 -08:00
|
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|
2015-05-22 17:13:24 -04:00
|
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2015-07-23 14:27:09 -04:00
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2015-05-22 17:13:24 -04:00
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2012-03-05 13:15:27 -08:00
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2015-05-22 17:13:24 -04:00
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2012-03-05 13:15:27 -08:00
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blkcg: rename subsystem name from blkio to io
blkio interface has become messy over time and is currently the
largest. In addition to the inconsistent naming scheme, it has
multiple stat files which report more or less the same thing, a number
of debug stat files which expose internal details which shouldn't have
been part of the public interface in the first place, recursive and
non-recursive stats and leaf and non-leaf knobs.
Both recursive vs. non-recursive and leaf vs. non-leaf distinctions
don't make any sense on the unified hierarchy as only leaf cgroups can
contain processes. cgroups is going through a major interface
revision with the unified hierarchy involving significant fundamental
usage changes and given that a significant portion of the interface
doesn't make sense anymore, it's a good time to reorganize the
interface.
As the first step, this patch renames the external visible subsystem
name from "blkio" to "io". This is more concise, matches the other
two major subsystem names, "cpu" and "memory", and better suited as
blkcg will be involved in anything writeback related too whether an
actual block device is involved or not.
As the subsystem legacy_name is set to "blkio", the only userland
visible change outside the unified hierarchy is that blkcg is reported
as "io" instead of "blkio" in the subsystem initialized message during
boot. On the unified hierarchy, blkcg now appears as "io".
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 14:55:29 -07:00
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2012-03-05 13:15:27 -08:00
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2015-07-23 14:27:09 -04:00
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2012-03-05 13:15:27 -08:00
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2005-04-16 15:20:36 -07:00
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2008-12-05 16:10:29 +01:00
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2005-04-16 15:20:36 -07:00
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2007-07-20 10:11:58 +09:00
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2005-04-16 15:20:36 -07:00
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2008-12-10 15:35:05 +01:00
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2005-04-16 15:20:36 -07:00
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2009-06-26 15:37:49 +02:00
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2005-04-16 15:20:36 -07:00
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2008-12-10 15:35:05 +01:00
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2005-04-16 15:20:36 -07:00
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2011-03-17 11:11:05 +01:00
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2005-04-16 15:20:36 -07:00
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