1. 14 Jul, 2012 2 commits
    • Tejun Heo's avatar
      workqueue: reimplement WQ_HIGHPRI using a separate worker_pool · 3270476a
      Tejun Heo authored
      WQ_HIGHPRI was implemented by queueing highpri work items at the head
      of the global worklist.  Other than queueing at the head, they weren't
      handled differently; unfortunately, this could lead to execution
      latency of a few seconds on heavily loaded systems.
      
      Now that workqueue code has been updated to deal with multiple
      worker_pools per global_cwq, this patch reimplements WQ_HIGHPRI using
      a separate worker_pool.  NR_WORKER_POOLS is bumped to two and
      gcwq->pools[0] is used for normal pri work items and ->pools[1] for
      highpri.  Highpri workers get -20 nice level and has 'H' suffix in
      their names.  Note that this change increases the number of kworkers
      per cpu.
      
      POOL_HIGHPRI_PENDING, pool_determine_ins_pos() and highpri chain
      wakeup code in process_one_work() are no longer used and removed.
      
      This allows proper prioritization of highpri work items and removes
      high execution latency of highpri work items.
      
      v2: nr_running indexing bug in get_pool_nr_running() fixed.
      
      v3: Refreshed for the get_pool_nr_running() update in the previous
          patch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarJosh Hunt <joshhunt00@gmail.com>
      LKML-Reference: <CAKA=qzaHqwZ8eqpLNFjxnO2fX-tgAOjmpvxgBFjv6dJeQaOW1w@mail.gmail.com>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      3270476a
    • Tejun Heo's avatar
      workqueue: introduce NR_WORKER_POOLS and for_each_worker_pool() · 4ce62e9e
      Tejun Heo authored
      Introduce NR_WORKER_POOLS and for_each_worker_pool() and convert code
      paths which need to manipulate all pools in a gcwq to use them.
      NR_WORKER_POOLS is currently one and for_each_worker_pool() iterates
      over only @gcwq->pool.
      
      Note that nr_running is per-pool property and converted to an array
      with NR_WORKER_POOLS elements and renamed to pool_nr_running.  Note
      that get_pool_nr_running() currently assumes 0 index.  The next patch
      will make use of non-zero index.
      
      The changes in this patch are mechanical and don't caues any
      functional difference.  This is to prepare for multiple pools per
      gcwq.
      
      v2: nr_running indexing bug in get_pool_nr_running() fixed.
      
      v3: Pointer to array is stupid.  Don't use it in get_pool_nr_running()
          as suggested by Linus.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      4ce62e9e
  2. 12 Jul, 2012 4 commits
    • Tejun Heo's avatar
      workqueue: separate out worker_pool flags · 11ebea50
      Tejun Heo authored
      GCWQ_MANAGE_WORKERS, GCWQ_MANAGING_WORKERS and GCWQ_HIGHPRI_PENDING
      are per-pool properties.  Add worker_pool->flags and make the above
      three flags per-pool flags.
      
      The changes in this patch are mechanical and don't caues any
      functional difference.  This is to prepare for multiple pools per
      gcwq.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      11ebea50
    • Tejun Heo's avatar
      workqueue: use @pool instead of @gcwq or @cpu where applicable · 63d95a91
      Tejun Heo authored
      Modify all functions which deal with per-pool properties to pass
      around @pool instead of @gcwq or @cpu.
      
      The changes in this patch are mechanical and don't caues any
      functional difference.  This is to prepare for multiple pools per
      gcwq.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      63d95a91
    • Tejun Heo's avatar
      workqueue: factor out worker_pool from global_cwq · bd7bdd43
      Tejun Heo authored
      Move worklist and all worker management fields from global_cwq into
      the new struct worker_pool.  worker_pool points back to the containing
      gcwq.  worker and cpu_workqueue_struct are updated to point to
      worker_pool instead of gcwq too.
      
      This change is mechanical and doesn't introduce any functional
      difference other than rearranging of fields and an added level of
      indirection in some places.  This is to prepare for multiple pools per
      gcwq.
      
      v2: Comment typo fixes as suggested by Namhyung.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      bd7bdd43
    • Tejun Heo's avatar
      workqueue: don't use WQ_HIGHPRI for unbound workqueues · 974271c4
      Tejun Heo authored
      Unbound wqs aren't concurrency-managed and try to execute work items
      as soon as possible.  This is currently achieved by implicitly setting
      %WQ_HIGHPRI on all unbound workqueues; however, WQ_HIGHPRI
      implementation is about to be restructured and this usage won't be
      valid anymore.
      
      Add an explicit chain-wakeup path for unbound workqueues in
      process_one_work() instead of piggy backing on %WQ_HIGHPRI.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      974271c4
  3. 11 Jul, 2012 34 commits