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
     

13 Mar, 2010

1 commit


19 Sep, 2009

1 commit


08 Dec, 2006

4 commits

  • Allocate ->signal->stats on demand in taskstats_exit(), this allows us to
    remove taskstats_tgid_alloc() (the last non-trivial inline) from taskstat's
    public interface.

    Signed-off-by: Oleg Nesterov
    Cc: Balbir Singh
    Cc: Shailabh Nagar
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • do_exit:
    taskstats_exit_alloc()
    ...
    taskstats_exit_send()
    taskstats_exit_free()

    I think this is not good, let it be a single function exported to the core
    kernel, taskstats_exit(), which does alloc + send + free itself.

    Signed-off-by: Oleg Nesterov
    Cc: Balbir Singh
    Cc: Shailabh Nagar
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • Replace all uses of kmem_cache_t with struct kmem_cache.

    The patch was generated using the following script:

    #!/bin/sh
    #
    # Replace one string by another in all the kernel sources.
    #

    set -e

    for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
    quilt add $file
    sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
    mv /tmp/$$ $file
    quilt refresh
    done

    The script was run like this

    sh replace kmem_cache_t "struct kmem_cache"

    Signed-off-by: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     
  • SLAB_KERNEL is an alias of GFP_KERNEL.

    Signed-off-by: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Christoph Lameter
     

29 Oct, 2006

3 commits

  • signal_struct is (mostly) protected by ->sighand->siglock, I think we don't
    need ->taskstats_lock to protect ->stats. This also allows us to simplify the
    locking in fill_tgid().

    Signed-off-by: Oleg Nesterov
    Cc: Shailabh Nagar
    Cc: Balbir Singh
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • Every subthread (except first) does unneeded kmem_cache_alloc/kmem_cache_free.

    Signed-off-by: Oleg Nesterov
    Cc: Shailabh Nagar
    Cc: Balbir Singh
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • taskstats_tgid_free() is called on copy_process's error path. This is wrong.

    IF (clone_flags & CLONE_THREAD)
    We should not clear ->signal->taskstats, current uses it,
    it probably has a valid accumulated info.
    ELSE
    taskstats_tgid_init() set ->signal->taskstats = NULL,
    there is nothing to free.

    Move the callsite to __exit_signal(). We don't need any locking, entire
    thread group is exiting, nobody should have a reference to soon to be
    released ->signal.

    Signed-off-by: Oleg Nesterov
    Cc: Shailabh Nagar
    Cc: Balbir Singh
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     

15 Jul, 2006

5 commits

  • On systems with a large number of cpus, with even a modest rate of tasks
    exiting per cpu, the volume of taskstats data sent on thread exit can
    overflow a userspace listener's buffers.

    One approach to avoiding overflow is to allow listeners to get data for a
    limited and specific set of cpus. By scaling the number of listeners
    and/or the cpus they monitor, userspace can handle the statistical data
    overload more gracefully.

    In this patch, each listener registers to listen to a specific set of cpus
    by specifying a cpumask. The interest is recorded per-cpu. When a task
    exits on a cpu, its taskstats data is unicast to each listener interested
    in that cpu.

    Thanks to Andrew Morton for pointing out the various scalability and
    general concerns of previous attempts and for suggesting this design.

    [akpm@osdl.org: build fix]
    Signed-off-by: Shailabh Nagar
    Signed-off-by: Balbir Singh
    Signed-off-by: Chandra Seetharaman
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Shailabh Nagar
     
  • Don't send taskstats (per-pid or per-tgid) on thread exit when no one is
    listening for such data.

    Currently the taskstats interface allocates a structure, fills it in and
    calls netlink to send out per-pid and per-tgid stats regardless of whether
    a userspace listener for the data exists (netlink layer would check for
    that and avoid the multicast).

    As a result of this patch, the check for the no-listener case is performed
    early, avoiding the redundant allocation and filling up of the taskstats
    structures.

    Signed-off-by: Balbir Singh
    Signed-off-by: Shailabh Nagar
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Shailabh Nagar
     
  • Send per-tgid data only once during exit of a thread group instead of once
    with each member thread exit.

    Currently, when a thread exits, besides its per-tid data, the per-tgid data
    of its thread group is also sent out, if its thread group is non-empty.
    The per-tgid data sent consists of the sum of per-tid stats for all
    *remaining* threads of the thread group.

    This patch modifies this sending in two ways:

    - the per-tgid data is sent only when the last thread of a thread group
    exits. This cuts down heavily on the overhead of sending/receiving
    per-tgid data, especially when other exploiters of the taskstats
    interface aren't interested in per-tgid stats

    - the semantics of the per-tgid data sent are changed. Instead of being
    the sum of per-tid data for remaining threads, the value now sent is the
    true total accumalated statistics for all threads that are/were part of
    the thread group.

    The patch also addresses a minor issue where failure of one accounting
    subsystem to fill in the taskstats structure was causing the send of
    taskstats to not be sent at all.

    The patch has been tested for stability and run cerberus for over 4 hours
    on an SMP.

    [akpm@osdl.org: bugfixes]
    Signed-off-by: Shailabh Nagar
    Signed-off-by: Balbir Singh
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Shailabh Nagar
     
  • Usage of taskstats interface by delay accounting.

    Signed-off-by: Shailabh Nagar
    Signed-off-by: Balbir Singh
    Cc: Jes Sorensen
    Cc: Peter Chubb
    Cc: Erich Focht
    Cc: Levent Serinol
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Shailabh Nagar
     
  • Create a "taskstats" interface based on generic netlink (NETLINK_GENERIC
    family), for getting statistics of tasks and thread groups during their
    lifetime and when they exit. The interface is intended for use by multiple
    accounting packages though it is being created in the context of delay
    accounting.

    This patch creates the interface without populating the fields of the data
    that is sent to the user in response to a command or upon the exit of a task.
    Each accounting package interested in using taskstats has to provide an
    additional patch to add its stats to the common structure.

    [akpm@osdl.org: cleanups, Kconfig fix]
    Signed-off-by: Shailabh Nagar
    Signed-off-by: Balbir Singh
    Cc: Jes Sorensen
    Cc: Peter Chubb
    Cc: Erich Focht
    Cc: Levent Serinol
    Cc: Jay Lan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Shailabh Nagar