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Conflicts:
block/blktrace.c
Semantic merge:
kernel/trace/blktrace.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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blk_abort_queue() iterates the timeout list and aborts each request on the
list, but if the driver error handling readds a request to the timeout list
during this processing, we could be looping forever. Fix this by splicing
current entries to a local list and run over that list instead.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Hi Tejun,
it looks like your commit:
block: don't depend on consecutive minor space
f331c0296f2a9fee0d396a70598b954062603015
broke a particular case for booting from partitioned md/raid devices.
That is the second time this has been broken recently. The previous
time was fixed by
block: do_mounts - accept root=<non-existant partition>
30f2f0eb4bd2c43d10a8b0d872c6e5ad8f31c9a0
Because the data isn't available when an md device is first created
(we add disks and set it up after creation), the initial partition
scan finds nothing. It is not until the device is opened that
another partition scan happens and finds something.
So at the point where the kernel parameter "root=/dev/md_d0p1" is
being parsed, md_d0 exists, but md_d0p1 does not.
However if we let blk_lookup_devt return the correct device number
even though the device doesn't exist, then the attempt to mount it
will successfully find the partition.
I have tried in the past to find a way to get the partition table to
be read as soon as the array is assembled but that proved impossible
(at the time). I don't remember the details, and could possibly
revisit it. However it would be really nice if blk_lookup_devt
could be adjusted to again accept non existant partitions.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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We can't OR shift values, so get rid of BIO_RW_SYNC and use BIO_RW_SYNCIO
and BIO_RW_UNPLUG explicitly. This brings back the behaviour from before
213d9417fec62ef4c3675621b9364a667954d4dd.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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When submitting requests via SG_IO, which does a sync io, a
bsg_command is not allocated. So an in-Kernel sense_buffer was not
set. However when calling blk_execute_rq() with no sense buffer
one is provided from the stack. Now bsg at blk_complete_sgv4_hdr_rq()
would check if rq->sense_len and a sense was requested by sg_io_v4
the rq->sense was copy_user() back, but by now it is already mangled
stack memory.
I have fixed that by forcing a sense_buffer when calling bsg_map_hdr().
The bsg_command->sense is provided in the write/read path like before,
and on-the-stack buffer is provided when doing SG_IO.
I have also fixed a dprintk message to print rq->errors in hex because
of the scsi bit-field use of this member. For other block devices it
does not matter anyway.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Impact: cleanup
Move blktrace.c to kernel/trace, also move its config entry.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: cleanup
To make it easy for ftrace plugin writers, as this was open coded in
the existing plugins
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: new API
These new functions do what previously was being open coded, reducing
the number of details ftrace plugin writers have to worry about.
It also standardizes the handling of stacktrace, userstacktrace and
other trace options we may introduce in the future.
With this patch, for instance, the blk tracer (and some others already
in the tree) can use the "userstacktrace" /d/tracing/trace_options
facility.
$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
trace_vprintk | -5
trace_graph_return | -22
trace_graph_entry | -26
trace_function | -45
__ftrace_trace_stack | -27
ftrace_trace_userstack | -29
tracing_sched_switch_trace | -66
tracing_stop | +1
trace_seq_to_user | -1
ftrace_trace_special | -63
ftrace_special | +1
tracing_sched_wakeup_trace | -70
tracing_reset_online_cpus | -1
13 functions changed, 2 bytes added, 355 bytes removed, diff: -353
linux-2.6-tip/block/blktrace.c:
__blk_add_trace | -58
1 function changed, 58 bytes removed, diff: -58
linux-2.6-tip/kernel/trace/trace.c:
trace_buffer_lock_reserve | +88
trace_buffer_unlock_commit | +86
2 functions changed, 174 bytes added, diff: +174
/tmp/vmlinux.after:
16 functions changed, 176 bytes added, 413 bytes removed, diff: -237
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: API change, cleanup
>From ring_buffer_{lock_reserve,unlock_commit}.
$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
trace_vprintk | -14
trace_graph_return | -14
trace_graph_entry | -10
trace_function | -8
__ftrace_trace_stack | -8
ftrace_trace_userstack | -8
tracing_sched_switch_trace | -8
ftrace_trace_special | -12
tracing_sched_wakeup_trace | -8
9 functions changed, 90 bytes removed, diff: -90
linux-2.6-tip/block/blktrace.c:
__blk_add_trace | -1
1 function changed, 1 bytes removed, diff: -1
/tmp/vmlinux.after:
10 functions changed, 91 bytes removed, diff: -91
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: cleanup
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: simplification of tracers
As all tracers are doing this we might as well do it in
register_ftrace_event and save one branch each time we call these
callbacks.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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As they actually all return these enumerators.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: bugfix and cleanup
Some callsites were returning either TRACE_ITER_PARTIAL_LINE if the
trace_seq routines (trace_seq_printf, etc) returned 0 meaning its buffer
was full, or zero otherwise.
But...
/* Return values for print_line callback */
enum print_line_t {
TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
TRACE_TYPE_HANDLED = 1,
TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */
};
In other cases the return value was not being relayed at all.
Most of the time it didn't hurt because the page wasn't get filled, but
for correctness sake, handle the return values everywhere.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: cleanup
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: new feature
With this and a blkrawverify modified not to verify the sequence numbers
we can start using the userspace tools to verify that the data produced
with the ftrace plugin works as expected.
Example:
[root@f10-1 ~]# echo 1 > /sys/block/sda/sda1/trace/enable
[root@f10-1 ~]# echo bin > /d/tracing/trace_options
[root@f10-1 ~]# echo blk > /d/tracing/current_tracer
[root@f10-1 ~]# cat /d/tracing/trace_pipe > sda1.blktrace.0
^C
[root@f10-1 ~]# ./blkrawverify --noseq sda1
Verifying sda1
CPU 0
Wrote output to sda1.verify.out
[root@f10-1 ~]# cat sda1.verify.out
---------------
Verifying sda1
---------------------
Summary for cpu 0:
1349 valid + 0 invalid (100.0%) processed
[root@f10-1 ~]#
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: API change
The trace_seq and trace_entry are in trace_iterator, where there are
more fields that may be needed by tracers, so just pass the
tracer_iterator as is already the case for struct tracer->print_line.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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tracing/core
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Some initial probe requests don't have disk->queue mapped yet, so we
can't rely on a non-NULL queue in blk_queue_io_stat(). Wrap it in
blk_do_io_stat().
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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This patch adds the ability to pre-empt an ongoing BE timeslice when a RT
request is waiting for the current timeslice to complete. This reduces the
wait time to disk for RT requests from an upper bound of 4 (current value
of cfq_quantum) to 1 disk request.
Applied Jens' suggeested changes to avoid the rb lookup and use !cfq_class_rt()
and retested.
Latency(secs) for the RT task when doing sequential reads from 10G file.
| only RT | RT + BE | RT + BE + this patch
small (512 byte) reads | 143 | 163 | 145
large (1Mb) reads | 142 | 158 | 146
Signed-off-by: Divyesh Shah <dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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This allows us to turn off disk stat accounting completely, for the cases
where the 0.5-1% reduction in system time is important.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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This fixes a "regression" from 2.6.28, where the barrier probes that file
systems may do would trigger additional end request warnings in dmesg.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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For some devices (i.e. CFA ATA) we can't reliably detect whether
the device is of rotational or non-rotational type so we need to
leave the final decision about this setting to the user-space.
As a bonus do a minor CodingStyle fixup in queue_nomerges_store().
Suggested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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It can result in a stuck blktrace system, if --kill is used.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Allow a block device to allocate and register an integrity profile
without providing a template. This allows DM to preallocate a profile
to avoid deadlocks during table reconfiguration.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Impact: cleanup
Use tracing_reset_online_cpus instead of open coding it.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: build fix
Also mention in the help text that blktrace now can be used using
the ftrace interface.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Also make sure sparse (make C=2 block/blktrace.o) is happy too.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: New way of using the blktrace infrastructure
This drops the requirement of userspace utilities to use the blktrace
facility.
Configuration is done thru sysfs, adding a "trace" directory to the
partition directory where blktrace can be enabled for the associated
request_queue.
The same filters present in the IOCTL interface are present as sysfs
device attributes.
The /sys/block/sdX/sdXN/trace/enable file allows tracing without any
filters.
The other files in this directory: pid, act_mask, start_lba and end_lba
can be used with the same meaning as with the IOCTL interface.
Using the sysfs interface will only setup the request_queue->blk_trace
fields, tracing will only take place when the "blk" tracer is selected
via the ftrace interface, as in the following example:
To see the trace, one can use the /d/tracing/trace file or the
/d/tracign/trace_pipe file, with semantics defined in the ftrace
documentation in Documentation/ftrace.txt.
[root@f10-1 ~]# cat /t/trace
kjournald-305 [000] 3046.491224: 8,1 A WBS 6367 + 8 <- (8,1) 6304
kjournald-305 [000] 3046.491227: 8,1 Q R 6367 + 8 [kjournald]
kjournald-305 [000] 3046.491236: 8,1 G RB 6367 + 8 [kjournald]
kjournald-305 [000] 3046.491239: 8,1 P NS [kjournald]
kjournald-305 [000] 3046.491242: 8,1 I RBS 6367 + 8 [kjournald]
kjournald-305 [000] 3046.491251: 8,1 D WB 6367 + 8 [kjournald]
kjournald-305 [000] 3046.491610: 8,1 U WS [kjournald] 1
<idle>-0 [000] 3046.511914: 8,1 C RS 6367 + 8 [6367]
[root@f10-1 ~]#
The default line context (prefix) format is the one described in the ftrace
documentation, with the blktrace specific bits using its existing format,
described in blkparse(8).
If one wants to have the classic blktrace formatting, this is possible by
using:
[root@f10-1 ~]# echo blk_classic > /t/trace_options
[root@f10-1 ~]# cat /t/trace
8,1 0 3046.491224 305 A WBS 6367 + 8 <- (8,1) 6304
8,1 0 3046.491227 305 Q R 6367 + 8 [kjournald]
8,1 0 3046.491236 305 G RB 6367 + 8 [kjournald]
8,1 0 3046.491239 305 P NS [kjournald]
8,1 0 3046.491242 305 I RBS 6367 + 8 [kjournald]
8,1 0 3046.491251 305 D WB 6367 + 8 [kjournald]
8,1 0 3046.491610 305 U WS [kjournald] 1
8,1 0 3046.511914 0 C RS 6367 + 8 [6367]
[root@f10-1 ~]#
Using the ftrace standard format allows more flexibility, such
as the ability of asking for backtraces via trace_options:
[root@f10-1 ~]# echo noblk_classic > /t/trace_options
[root@f10-1 ~]# echo stacktrace > /t/trace_options
[root@f10-1 ~]# cat /t/trace
kjournald-305 [000] 3318.826779: 8,1 A WBS 6375 + 8 <- (8,1) 6312
kjournald-305 [000] 3318.826782:
<= submit_bio
<= submit_bh
<= sync_dirty_buffer
<= journal_commit_transaction
<= kjournald
<= kthread
<= child_rip
kjournald-305 [000] 3318.826836: 8,1 Q R 6375 + 8 [kjournald]
kjournald-305 [000] 3318.826837:
<= generic_make_request
<= submit_bio
<= submit_bh
<= sync_dirty_buffer
<= journal_commit_transaction
<= kjournald
<= kthread
Please read the ftrace documentation to use aditional, standardized
tracing filters such as /d/tracing/trace_cpumask, etc.
See also /d/tracing/trace_mark to add comments in the trace stream,
that is equivalent to the /d/block/sdaN/msg interface.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (57 commits)
jbd2: Fix oops in jbd2_journal_init_inode() on corrupted fs
ext4: Remove "extents" mount option
block: Add Kconfig help which notes that ext4 needs CONFIG_LBD
ext4: Make printk's consistently prefixed with "EXT4-fs: "
ext4: Add sanity checks for the superblock before mounting the filesystem
ext4: Add mount option to set kjournald's I/O priority
jbd2: Submit writes to the journal using WRITE_SYNC
jbd2: Add pid and journal device name to the "kjournald2 starting" message
ext4: Add markers for better debuggability
ext4: Remove code to create the journal inode
ext4: provide function to release metadata pages under memory pressure
ext3: provide function to release metadata pages under memory pressure
add releasepage hooks to block devices which can be used by file systems
ext4: Fix s_dirty_blocks_counter if block allocation failed with nodelalloc
ext4: Init the complete page while building buddy cache
ext4: Don't allow new groups to be added during block allocation
ext4: mark the blocks/inode bitmap beyond end of group as used
ext4: Use new buffer_head flag to check uninit group bitmaps initialization
ext4: Fix the race between read_inode_bitmap() and ext4_new_inode()
ext4: code cleanup
...
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* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (45 commits)
[SCSI] qla2xxx: Update version number to 8.03.00-k1.
[SCSI] qla2xxx: Add ISP81XX support.
[SCSI] qla2xxx: Use proper request/response queues with MQ instantiations.
[SCSI] qla2xxx: Correct MQ-chain information retrieval during a firmware dump.
[SCSI] qla2xxx: Collapse EFT/FCE copy procedures during a firmware dump.
[SCSI] qla2xxx: Don't pollute kernel logs with ZIO/RIO status messages.
[SCSI] qla2xxx: Don't fallback to interrupt-polling during re-initialization with MSI-X enabled.
[SCSI] qla2xxx: Remove support for reading/writing HW-event-log.
[SCSI] cxgb3i: add missing include
[SCSI] scsi_lib: fix DID_RESET status problems
[SCSI] fc transport: restore missing dev_loss_tmo callback to LLDD
[SCSI] aha152x_cs: Fix regression that keeps driver from using shared interrupts
[SCSI] sd: Correctly handle 6-byte commands with DIX
[SCSI] sd: DIF: Fix tagging on platforms with signed char
[SCSI] sd: DIF: Show app tag on error
[SCSI] Fix error handling for DIF/DIX
[SCSI] scsi_lib: don't decrement busy counters when inserting commands
[SCSI] libsas: fix test for negative unsigned and typos
[SCSI] a2091, gvp11: kill warn_unused_result warnings
[SCSI] fusion: Move a dereference below a NULL test
...
Fixed up trivial conflict due to moving the async part of sd_probe
around in the async probes vs using dev_set_name() in naming.
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jens Axboe <jens.axboe@oracle.com>
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Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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The commit 818827669d85b84241696ffef2de485db46b0b5e (block: make
blk_rq_map_user take a NULL user-space buffer) extended
blk_rq_map_user to accept a NULL user-space buffer with a READ
command. It was necessary to convert sg to use the block layer mapping
API.
This patch extends blk_rq_map_user again for a WRITE command. It is
necessary to convert st and osst drivers to use the block layer
apping API.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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This fixes bio_copy_user_iov to properly handle the partial mappings
with struct rq_map_data (which only sg uses for now but st and osst
will shortly). It adds the offset member to struct rq_map_data and
changes blk_rq_map_user to update it so that bio_copy_user_iov can add
an appropriate page frame via bio_add_pc_page().
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
arch/x86/kernel/io_apic.c
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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
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Original patch from Nikanth Karthikesan <knikanth@suse.de>
When a queue exits the queue lock is taken and cfq_exit_queue() would free all
the cic's associated with the queue.
But when a task exits, cfq_exit_io_context() gets cic one by one and then
locks the associated queue to call __cfq_exit_single_io_context. It looks like
between getting a cic from the ioc and locking the queue, the queue might have
exited on another cpu.
Fix this by rechecking the cfq_io_context queue key inside the queue lock
again, and not calling into __cfq_exit_single_io_context() if somebody
beat us to it.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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We have two seperate config entries for large devices/files. One
is CONFIG_LBD that guards just the devices, the other is CONFIG_LSF
that handles large files. This doesn't make a lot of sense, you typically
want both or none. So get rid of CONFIG_LSF and change CONFIG_LBD wording
to indicate that it covers both.
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Sparse asked whether these could be static.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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zero is invalid for max_phys_segments, max_hw_segments, and
max_segment_size. It's better to use use min_not_zero instead of
min. min() works though (because the commit 0e435ac makes sure that
these values are set to the default values, non zero, if a queue is
initialized properly).
With this patch, blk_queue_stack_limits does the almost same thing
that dm's combine_restrictions_low() does. I think that it's easy to
remove dm's combine_restrictions_low.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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disk_map_sector_rcu() returns a partition from a sector offset,
which we use for IO statistics on a per-partition basis. The
lookup itself is an O(N) list lookup, where N is the number of
partitions. This actually hurts performance quite a bit, even
on the lower end partitions. On higher numbered partitions,
it can get pretty bad.
Solve this by adding a one-hit cache for partition lookup.
This makes the lookup O(1) for the case where we do most IO to
one partition. Even for mixed partition workloads, amortized cost
is pretty close to O(1) since the natural IO batching makes the
one-hit cache last for lots of IOs.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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This basically limits the hardware queue depth to 4*quantum at any
point in time, which is 16 with the default settings. As CFQ uses
other means to shrink the hardware queue when necessary in the first
place, there's really no need for this extra heuristic. Additionally,
it ends up hurting performance in some cases.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Just use struct elevator_queue everywhere instead.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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We just want to hand the first bits of IO to the device as fast
as possible. Gains a few percent on the IOPS rate.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Empty barrier on write-through (or no cache) w/ ordered tag has no
command to execute and without any command to execute ordered tag is
never issued to the device and the ordering is never achieved. Force
draining for such cases.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Empty barrier required special handling in __elv_next_request() to
complete it without letting the low level driver see it.
With previous changes, barrier code is now flexible enough to skip the
BAR step using the same barrier sequence selection mechanism. Drop
the special handling and mask off q->ordered from start_ordered().
Remove blk_empty_barrier() test which now has no user.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Barrier completion had the following assumptions.
* start_ordered() couldn't finish the whole sequence properly. If all
actions are to be skipped, q->ordseq is set correctly but the actual
completion was never triggered thus hanging the barrier request.
* Drain completion in elv_complete_request() assumed that there's
always at least one request in the queue when drain completes.
Both assumptions are true but these assumptions need to be removed to
improve empty barrier implementation. This patch makes the following
changes.
* Make start_ordered() use blk_ordered_complete_seq() to mark skipped
steps complete and notify __elv_next_request() that it should fetch
the next request if the whole barrier has completed inside
start_ordered().
* Make drain completion path in elv_complete_request() check whether
the queue is empty. Empty queue also indicates drain completion.
* While at it, convert 0/1 return from blk_do_ordered() to false/true.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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In all barrier sequences, the barrier write itself was always assumed
to be issued and thus didn't have corresponding control flag. This
patch adds QUEUE_ORDERED_DO_BAR and unify action mask handling in
start_ordered() such that any barrier action can be skipped.
This patch doesn't introduce any visible behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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