30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

16 Jun, 2009

1 commit


12 Jun, 2009

1 commit

  • * 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block: (153 commits)
    block: add request clone interface (v2)
    floppy: fix hibernation
    ramdisk: remove long-deprecated "ramdisk=" boot-time parameter
    fs/bio.c: add missing __user annotation
    block: prevent possible io_context->refcount overflow
    Add serial number support for virtio_blk, V4a
    block: Add missing bounce_pfn stacking and fix comments
    Revert "block: Fix bounce limit setting in DM"
    cciss: decode unit attention in SCSI error handling code
    cciss: Remove no longer needed sendcmd reject processing code
    cciss: change SCSI error handling routines to work with interrupts enabled.
    cciss: separate error processing and command retrying code in sendcmd_withirq_core()
    cciss: factor out fix target status processing code from sendcmd functions
    cciss: simplify interface of sendcmd() and sendcmd_withirq()
    cciss: factor out core of sendcmd_withirq() for use by SCSI error handling code
    cciss: Use schedule_timeout_uninterruptible in SCSI error handling code
    block: needs to set the residual length of a bidi request
    Revert "block: implement blkdev_readpages"
    block: Fix bounce limit setting in DM
    Removed reference to non-existing file Documentation/PCI/PCI-DMA-mapping.txt
    ...

    Manually fix conflicts with tracing updates in:
    block/blk-sysfs.c
    drivers/ide/ide-atapi.c
    drivers/ide/ide-cd.c
    drivers/ide/ide-floppy.c
    drivers/ide/ide-tape.c
    include/trace/events/block.h
    kernel/trace/blktrace.c

    Linus Torvalds
     

10 Jun, 2009

1 commit

  • 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 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
    LKML-Reference:
    Signed-off-by: Steven Rostedt

    Li Zefan
     

23 May, 2009

1 commit


29 Dec, 2008

1 commit


26 Nov, 2008

2 commits

  • Port to the new tracepoints API: split DEFINE_TRACE() and DECLARE_TRACE()
    sites. Spread them out to the usage sites, as suggested by
    Mathieu Desnoyers.

    Signed-off-by: Ingo Molnar
    Acked-by: Mathieu Desnoyers

    Ingo Molnar
     
  • This was a forward port of work done by Mathieu Desnoyers, I changed it to
    encode the 'what' parameter on the tracepoint name, so that one can register
    interest in specific events and not on classes of events to then check the
    'what' parameter.

    Signed-off-by: Arnaldo Carvalho de Melo
    Signed-off-by: Jens Axboe
    Signed-off-by: Ingo Molnar

    Arnaldo Carvalho de Melo
     

09 Oct, 2008

1 commit


16 Oct, 2007

1 commit


10 Oct, 2007

1 commit

  • As bi_end_io is only called once when the reqeust is complete,
    the 'size' argument is now redundant. Remove it.

    Now there is no need for bio_endio to subtract the size completed
    from bi_size. So don't do that either.

    While we are at it, change bi_end_io to return void.

    Signed-off-by: Neil Brown
    Signed-off-by: Jens Axboe

    NeilBrown
     

24 Jul, 2007

1 commit

  • Some of the code has been gradually transitioned to using the proper
    struct request_queue, but there's lots left. So do a full sweet of
    the kernel and get rid of this typedef and replace its uses with
    the proper type.

    Signed-off-by: Jens Axboe

    Jens Axboe
     

27 Mar, 2007

1 commit

  • There is a small problem in handling page bounce.

    At the moment blk_max_pfn equals max_pfn, which is in fact not maximum
    possible _number_ of a page frame, but the _amount_ of page frames. For
    example for the 32bit x86 node with 4Gb RAM, max_pfn = 0x100000, but not
    0xFFFF.

    request_queue structure has a member q->bounce_pfn and queue needs bounce
    pages for the pages _above_ this limit. This routine is handled by
    blk_queue_bounce(), where the following check is produced:

    if (q->bounce_pfn >= blk_max_pfn)
    return;

    Assume, that a driver has set q->bounce_pfn to 0xFFFF, but blk_max_pfn
    equals 0x10000. In such situation the check above fails and for each bio
    we always fall down for iterating over pages tied to the bio.

    I want to notice, that for quite a big range of device drivers (ide, md,
    ...) such problem doesn't happen because they use BLK_BOUNCE_ANY for
    bounce_pfn. BLK_BOUNCE_ANY is defined as blk_max_pfn << PAGE_SHIFT, and
    then the check above doesn't fail. But for other drivers, which obtain
    reuired value from drivers, it fails. For example sata_nv uses
    ATA_DMA_MASK or dev->dma_mask.

    I propose to use (max_pfn - 1) for blk_max_pfn. And the same for
    blk_max_low_pfn. The patch also cleanses some checks related with
    bounce_pfn.

    Signed-off-by: Vasily Tarasov
    Signed-off-by: Andrew Morton
    Signed-off-by: Jens Axboe

    Vasily Tarasov
     

13 Jan, 2007

1 commit

  • Currently we issue a bounce trace when __blk_queue_bounce() is called,
    but that merely means that the device has a lower dma mask than the
    higher pages in the system. The bio itself may still be lower pages. So
    move the bounce trace into __blk_queue_bounce(), when we know there will
    actually be page bouncing.

    Signed-off-by: Jens Axboe
    Signed-off-by: Linus Torvalds

    Jens Axboe
     

01 Oct, 2006

1 commit