path: root/fs/nilfs2/mdt.c
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authorJens Axboe <jaxboe@fusionio.com>2011-03-08 13:19:51 +0100
committerJens Axboe <jaxboe@fusionio.com>2011-03-10 08:45:54 +0100
commit73c101011926c5832e6e141682180c4debe2cf45 (patch)
treeb8eeb521a7833cb198d6f39d5a931d820e2a663f /fs/nilfs2/mdt.c
parenta488e74976bf0a9bccecdd094378394942dacef1 (diff)
block: initial patch for on-stack per-task plugging
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 <jaxboe@fusionio.com>
Diffstat (limited to 'fs/nilfs2/mdt.c')
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