tree 9750c39119447fb32963448bf1935e1ba22b2f9d
parent 4557398f8cbaf9f254cff747534b4724c7f75c4f
author Zach Brown <zach.brown@oracle.com> 1131926853 -0800
committer Linus Torvalds <torvalds@g5.osdl.org> 1131934456 -0800

[PATCH] aio: remove kioctx from mm_struct

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 <zach.brown@oracle.com>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>