linux/block/elevator.c, branch v2.6.39

elevator: check for ELEVATOR_INSERT_SORT_MERGE in !elvpriv case too

2011-04-21T17:28:35Z

The sort insert is the one that goes to the IO scheduler. With the SORT_MERGE addition, we could bypass IO scheduler setup but still ask the IO scheduler to insert the request. This would cause an oops on switching IO schedulers through the sysfs interface, unless the disk just happened to be idle while it occured. Signed-off-by: Jens Axboe

block: add blk_run_queue_async

2011-04-18T09:41:33Z

Instead of overloading __blk_run_queue to force an offload to kblockd add a new blk_run_queue_async helper to do it explicitly. I've kept the blk_queue_stopped check for now, but I suspect it's not needed as the check we do when the workqueue items runs should be enough. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: get rid of elv_insert() interface

2011-04-05T21:51:37Z

Merge it with __elv_add_request(), it's pretty pointless to have a function with only two callers. The main interface is elv_add_request()/__elv_add_request(). Signed-off-by: Jens Axboe

block: attempt to merge with existing requests on plug flush

2011-03-21T09:14:27Z

One of the disadvantages of on-stack plugging is that we potentially lose out on merging since all pending IO isn't always visible to everybody. When we flush the on-stack plugs, right now we don't do any checks to see if potential merge candidates could be utilized. Correct this by adding a new insert variant, ELEVATOR_INSERT_SORT_MERGE. It works just ELEVATOR_INSERT_SORT, but first checks whether we can merge with an existing request before doing the insertion (if we fail merging). This fixes a regression with multiple processes issuing IO that can be merged. Thanks to Shaohua Li for testing and fixing an accounting bug. Signed-off-by: Jens Axboe

Merge branch 'for-2.6.39/stack-plug' into for-2.6.39/core

2011-03-10T07:58:35Z

Conflicts: block/blk-core.c block/blk-flush.c drivers/md/raid1.c drivers/md/raid10.c drivers/md/raid5.c fs/nilfs2/btnode.c fs/nilfs2/mdt.c Signed-off-by: Jens Axboe

block: remove per-queue plugging

2011-03-10T07:52:07Z

Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe

block: initial patch for on-stack per-task plugging

2011-03-10T07:45:54Z

This patch adds support for creating a queuing context outside of the queue itself. This enables us to batch up pieces of IO before grabbing the block device queue lock and submitting them to the IO scheduler. The context is created on the stack of the process and assigned in the task structure, so that we can auto-unplug it if we hit a schedule event. The current queue plugging happens implicitly if IO is submitted to an empty device, yet callers have to remember to unplug that IO when they are going to wait for it. This is an ugly API and has caused bugs in the past. Additionally, it requires hacks in the vm (->sync_page() callback) to handle that logic. By switching to an explicit plugging scheme we make the API a lot nicer and can get rid of the ->sync_page() hack in the vm. Signed-off-by: Jens Axboe

Merge branch 'for-linus' of ../linux-2.6-block into block-for-2.6.39/core

2011-03-04T18:09:02Z

This merge creates two set of conflicts. One is simple context conflicts caused by removal of throtl_scheduled_delayed_work() in for-linus and removal of throtl_shutdown_timer_wq() in for-2.6.39/core. The other is caused by commit 255bb490c8 (block: blk-flush shouldn't call directly into q->request_fn() __blk_run_queue()) in for-linus crashing with FLUSH reimplementation in for-2.6.39/core. The conflict isn't trivial but the resolution is straight-forward. * __blk_run_queue() calls in flush_end_io() and flush_data_end_io() should be called with @force_kblockd set to %true. * elv_insert() in blk_kick_flush() should use %ELEVATOR_INSERT_REQUEUE. Both changes are to avoid invoking ->request_fn() directly from request completion path and closely match the changes in the commit 255bb490c8. Signed-off-by: Tejun Heo

block: add @force_kblockd to __blk_run_queue()

2011-03-02T13:48:05Z

__blk_run_queue() automatically either calls q->request_fn() directly or schedules kblockd depending on whether the function is recursed. blk-flush implementation needs to be able to explicitly choose kblockd. Add @force_kblockd. All the current users are converted to specify %false for the parameter and this patch doesn't introduce any behavior change. stable: This is prerequisite for fixing ide oops caused by the new blk-flush implementation. Signed-off-by: Tejun Heo Cc: Jan Beulich Cc: James Bottomley Cc: stable@kernel.org Signed-off-by: Jens Axboe

block: share request flush fields with elevator_private

2011-02-11T10:08:00Z

Flush requests are never put on the IO scheduler. Convert request structure's elevator_private* into an array and have the flush fields share a union with it. Reclaim the space lost in 'struct request' by moving 'completion_data' back in the union with 'rb_node'. Signed-off-by: Mike Snitzer Acked-by: Vivek Goyal Acked-by: Tejun Heo Signed-off-by: Jens Axboe