1. 16 Nov, 2015 1 commit
  2. 03 Jul, 2013 1 commit
    • Jianpeng Ma's avatar
      elevator: Fix a race in elevator switching · d50235b7
      Jianpeng Ma authored
      There's a race between elevator switching and normal io operation.
          Because the allocation of struct elevator_queue and struct elevator_data
          don't in a atomic operation.So there are have chance to use NULL
          For example:
              Thread A:                               Thread B
              blk_queu_bio                            elevator_switch
              spin_lock_irq(q->queue_block)           elevator_alloc
              elv_merge                               elevator_init_fn
          Because call elevator_alloc, it can't hold queue_lock and the
          ->elevator_data is NULL.So at the same time, threadA call elv_merge and
          nedd some info of elevator_data.So the crash happened.
          Move the elevator_alloc into func elevator_init_fn, it make the
          operations in a atomic operation.
          Using the follow method can easy reproduce this bug
          1:dd if=/dev/sdb of=/dev/null
          2:while true;do echo noop > scheduler;echo deadline > scheduler;done
          The test method also use this method.
      Signed-off-by: default avatarJianpeng Ma <majianpeng@gmail.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
  3. 06 Mar, 2012 1 commit
    • Tejun Heo's avatar
      elevator: make elevator_init_fn() return 0/-errno · b2fab5ac
      Tejun Heo authored
      elevator_ops->elevator_init_fn() has a weird return value.  It returns
      a void * which the caller should assign to q->elevator->elevator_data
      and %NULL return denotes init failure.
      Update such that it returns integer 0/-errno and sets elevator_data
      directly as necessary.
      This makes the interface more conventional and eases further cleanup.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
  4. 13 Dec, 2011 1 commit
    • Tejun Heo's avatar
      block, cfq: move icq cache management to block core · 3d3c2379
      Tejun Heo authored
      Let elevators set ->icq_size and ->icq_align in elevator_type and
      elv_register() and elv_unregister() respectively create and destroy
      kmem_cache for icq.
      * elv_register() now can return failure.  All callers updated.
      * icq caches are automatically named "ELVNAME_io_cq".
      * cfq_slab_setup/kill() are collapsed into cfq_init/exit().
      * While at it, minor indentation change for iosched_cfq.elevator_name
        for consistency.
      This will help moving icq management to block core.  This doesn't
      introduce any functional change.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
  5. 10 Mar, 2011 1 commit
  6. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      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
      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
      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
      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: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
  7. 29 Dec, 2008 1 commit
  8. 18 Dec, 2007 1 commit
  9. 24 Jul, 2007 1 commit
  10. 01 Dec, 2006 1 commit
  11. 30 Sep, 2006 1 commit
  12. 08 Jun, 2006 1 commit
    • Jens Axboe's avatar
      [PATCH] elevator switching race · bc1c1169
      Jens Axboe authored
      There's a race between shutting down one io scheduler and firing up the
      next, in which a new io could enter and cause the io scheduler to be
      invoked with bad or NULL data.
      To fix this, we need to maintain the queue lock for a bit longer.
      Unfortunately we cannot do that, since the elevator init requires to be
      run without the lock held.  This isn't easily fixable, without also
      changing the mempool API.  So split the initialization into two parts,
      and alloc-init operation and an attach operation.  Then we can
      preallocate the io scheduler and related structures, and run the attach
      inside the lock after we detach the old one.
      This patch has survived 30 minutes of 1 second io scheduler switching
      with a very busy io load.
      Signed-off-by: default avatarJens Axboe <axboe@suse.de>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
  13. 12 Nov, 2005 1 commit
    • Tejun Heo's avatar
      [BLOCK] noop-iosched: reimplementation of request dispatching · 5a7c47ee
      Tejun Heo authored
      The original implementation directly used dispatch queue.  As new
      generic dispatch queue imposes stricter rules over ioscheds and
      dispatch queue usage, this direct use becomes somewhat problematic.
      This patch reimplements noop-iosched such that it complies to generic
      iosched model better.  Request merging with q->last_merge and
      rq->queuelist.prev/next work again now.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
      Signed-off-by: Jens Axboe <axboe@suse.de
  14. 04 Nov, 2005 1 commit
  15. 31 Oct, 2005 1 commit
    • Jens Axboe's avatar
      [PATCH] noop-iosched: avoid corrupted request merging · 581c1b14
      Jens Axboe authored
      Tejun Heo notes:
         "I'm currently debugging this.  The problem is that we are using the
          generic dispatch queue directly in the noop sched and merging is NOT
          allowed on dispatch queues but generic handling of last_merge tries
          to merge requests.  I'm still trying to verify this, so I'll be back
          with results soon."
      In the meantime, disable merging for noop by setting REQ_NOMERGE in
      Eventually, we should add a noop_list and do the dispatching like in the
      other io schedulers.  Merging is still beneficial for noop (and it has
      always done it).
      Signed-off-by: default avatarJens Axboe <axboe@suse.de>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
  16. 28 Oct, 2005 2 commits
    • Tejun Heo's avatar
      [PATCH] 04/05 remove last_merge handling from ioscheds · 98b11471
      Tejun Heo authored
      Remove last_merge handling from all ioscheds.  This patch
      removes merging capability of noop iosched.
      Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
    • Jens Axboe's avatar
      [PATCH] 02/05: update ioscheds to use generic dispatch queue · b4878f24
      Jens Axboe authored
      This patch updates all four ioscheds to use generic dispatch
      queue.  There's one behavior change in as-iosched.
      * In as-iosched, when force dispatching
        (ELEVATOR_INSERT_BACK), batch_data_dir is reset to REQ_SYNC
        and changed_batch and new_batch are cleared to zero.  This
        prevernts AS from doing incorrect update_write_batch after
        the forced dispatched requests are finished.
      * In cfq-iosched, cfqd->rq_in_driver currently counts the
        number of activated (removed) requests to determine
        whether queue-kicking is needed and cfq_max_depth has been
        reached.  With generic dispatch queue, I think counting
        the number of dispatched requests would be more appropriate.
      * cfq_max_depth can be lowered to 1 again.
      Original from Tejun Heo, modified version applied.
      Signed-off-by: default avatarJens Axboe <axboe@suse.de>
  17. 01 May, 2005 1 commit
  18. 16 Apr, 2005 1 commit
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      Let it rip!