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| author |   Christoph Hellwig <hch@infradead.org> | 2013-09-04 15:04:39 +0200 |
|---|---|---|
| committer |   Al Viro <viro@zeniv.linux.org.uk> | 2013-09-04 09:23:46 -0400 |
| commit | 7b7a8665edd8db733980389b098530f9e4f630b2 (patch) | |
| tree | 968d570a9f0c4d861226aefed2f5f97a131c8d53 /include/linux/buffer_head.h | |
| parent | add formats for dentry/file pathnames (diff) | |
| download | wireguard-linux-7b7a8665edd8db733980389b098530f9e4f630b2.tar.xz wireguard-linux-7b7a8665edd8db733980389b098530f9e4f630b2.zip | |
direct-io: Implement generic deferred AIO completions
Add support to the core direct-io code to defer AIO completions to user
context using a workqueue. This replaces opencoded and less efficient
code in XFS and ext4 (we save a memory allocation for each direct IO)
and will be needed to properly support O_(D)SYNC for AIO.
The communication between the filesystem and the direct I/O code requires
a new buffer head flag, which is a bit ugly but not avoidable until the
direct I/O code stops abusing the buffer_head structure for communicating
with the filesystems.
Currently this creates a per-superblock unbound workqueue for these
completions, which is taken from an earlier patch by Jan Kara. I'm
not really convinced about this use and would prefer a "normal" global
workqueue with a high concurrency limit, but this needs further discussion.
JK: Fixed ext4 part, dynamic allocation of the workqueue.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/buffer_head.h')
| -rw-r--r-- | include/linux/buffer_head.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 91fa9a94ae92..d77797a52b7b 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -36,6 +36,7 @@ enum bh_state_bits { BH_Quiet, /* Buffer Error Prinks to be quiet */ BH_Meta, /* Buffer contains metadata */ BH_Prio, /* Buffer should be submitted with REQ_PRIO */ + BH_Defer_Completion, /* Defer AIO completion to workqueue */ BH_PrivateStart,/* not a state bit, but the first bit available * for private allocation by other entities @@ -128,6 +129,7 @@ BUFFER_FNS(Write_EIO, write_io_error) BUFFER_FNS(Unwritten, unwritten) BUFFER_FNS(Meta, meta) BUFFER_FNS(Prio, prio) +BUFFER_FNS(Defer_Completion, defer_completion) #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) |