linux-toradex.git/include/linux/aio.h, branch v2.6.20.21

[PATCH] optimize o_direct on block devices

2006-12-13T17:05:50+00:00

Implement block device specific .direct_IO method instead of going through
generic direct_io_worker for block device.

direct_io_worker() is fairly complex because it needs to handle O_DIRECT on
file system, where it needs to perform block allocation, hole detection,
extents file on write, and tons of other corner cases.  The end result is
that it takes tons of CPU time to submit an I/O.

For block device, the block allocation is much simpler and a tight triple
loop can be written to iterate each iovec and each page within the iovec in
order to construct/prepare bio structure and then subsequently submit it to
the block layer.  This significantly speeds up O_D on block device.

[akpm@osdl.org: small speedup]
Signed-off-by: Ken Chen 
Cc: Christoph Hellwig 
Cc: Zach Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] aio: remove ki_retried debugging member

2006-12-07T16:39:46+00:00

Remove the ki_retried member from struct kiocb.  I think the idea was
bounced around a while back, but Arnaldo pointed out another reason that we
should dig it up when he pointed out that the last cacheline of struct
kiocb only contains 4 bytes.  By removing the debugging member, we save
more than the 8 byte on 64 bit machines.

Signed-off-by: Benjamin LaHaise 
Acked-by: Ken Chen 
Acked-by: Zach Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

WorkStruct: Separate delayable and non-delayable events.

2006-11-22T14:54:01+00:00

Separate delayable work items from non-delayable work items be splitting them
into a separate structure (delayed_work), which incorporates a work_struct and
the timer_list removed from work_struct.

The work_struct struct is huge, and this limits it's usefulness.  On a 64-bit
architecture it's nearly 100 bytes in size.  This reduces that by half for the
non-delayable type of event.

Signed-Off-By: David Howells

[PATCH] clean up unused kiocb variables

2006-10-01T07:39:29+00:00

Signed-off-by: Ken Chen 
Acked-by: Zach Brown 
Cc: Suparna Bhattacharya 
Cc: Benjamin LaHaise 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Add vector AIO support

2006-10-01T07:39:29+00:00

This work is initially done by Zach Brown to add support for vectored aio.
These are the core changes for AIO to support
IOCB_CMD_PREADV/IOCB_CMD_PWRITEV.

[akpm@osdl.org: huge build fix]
Signed-off-by: Zach Brown 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Badari Pulavarty 
Acked-by: Benjamin LaHaise 
Acked-by: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Vectorize aio_read/aio_write fileop methods

2006-10-01T07:39:28+00:00

This patch vectorizes aio_read() and aio_write() methods to prepare for
collapsing all aio & vectored operations into one interface - which is
aio_read()/aio_write().

Signed-off-by: Badari Pulavarty 
Signed-off-by: Christoph Hellwig 
Cc: Michael Holzheu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Remove BUG_ON(unlikely) in include/linux/aio.h

2006-10-01T07:39:24+00:00

BUG_ON() does this unlikely check itself, as bugs in Linux are unlikely
anyway :)

Signed-off-by: Rolf Eike Beer 
Acked-by: Zach Brown 
Acked-by: Benjamin LaHaise 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] aio: reorder kiocb structure elements to make sync iocb setup faster

2006-01-09T04:14:03+00:00

Reorder members of the kiocb structure to make sync kiocb setup faster.  By
setting the elements sequentially, the write combining buffers on the CPU
are able to combine the writes into a single burst, which results in fewer
cache cycles being consumed, freeing them up for other code.  This results
in a 10-20KB/s[*] increase on the bw_unix part of LMbench on my test
system.

* The improvement varies based on what other patches are in the system,
  as there are a number of bottlenecks, so this number is not absolutely
  accurate.

Signed-off-by: Benjamin LaHaise 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] aio: don't ref kioctx after decref in put_ioctx

2005-11-14T02:14:16+00:00

put_ioctx's refcount debugging was doing an atomic_read after dropping its
reference when it wasn't the last ref, leaving a tiny race for another freeing
thread to sneak into.  This shifts the debugging before the ops, uses BUG_ON,
and reformats the defines a little.  Sadly, moving to inlines increased the
code size but this change decreases the code size by a whole 9 bytes :)

Signed-off-by: Zach Brown 
Cc: Benjamin LaHaise 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] aio: remove kioctx from mm_struct

2005-11-14T02:14:16+00:00

Sync iocbs have a life cycle that don't need a kioctx.  Their retrying, if
any, is done in the context of their owner who has allocated them on the
stack.

The sole user of a sync iocb's ctx reference was aio_complete() checking for
an elevated iocb ref count that could never happen.  No path which grabs an
iocb ref has access to sync iocbs.

If we were to implement sync iocb cancelation it would be done by the owner of
the iocb using its on-stack reference.

Removing this chunk from aio_complete allows us to remove the entire kioctx
instance from mm_struct, reducing its size by a third.  On a i386 testing box
the slab size went from 768 to 504 bytes and from 5 to 8 per page.

Signed-off-by: Zach Brown 
Acked-by: Benjamin LaHaise 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds