Date: Sun, 15 Oct 2006 14:22:14 +0000 (UTC) From: Alexander Leidinger <netchild@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/amd64/linux32 linux.h syscalls.master src/sys/compat/linux linux_aio.c linux_aio.h src/sys/conf files.amd64 files.i386 src/sys/i386/linux linux.h syscalls.master src/sys/kern vfs_aio.c src/sys/modules/aio Makefile ... Message-ID: <200610151422.k9FEMEnI081495@repoman.freebsd.org>
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netchild 2006-10-15 14:22:14 UTC
FreeBSD src repository
Modified files:
sys/amd64/linux32 linux.h syscalls.master
sys/conf files.amd64 files.i386
sys/i386/linux linux.h syscalls.master
sys/kern vfs_aio.c
sys/modules/aio Makefile
sys/modules/linux Makefile
Added files:
sys/compat/linux linux_aio.c linux_aio.h
Log:
MFP4 (with some minor changes):
Implement the linux_io_* syscalls (AIO). They are only enabled if the native
AIO code is available (either compiled in to the kernel or as a module) at
the time the functions are used. If the AIO stuff is not available there
will be a ENOSYS.
From the submitter:
---snip---
DESIGN NOTES:
1. Linux permits a process to own multiple AIO queues (distinguished by
"context"), but FreeBSD creates only one single AIO queue per process.
My code maintains a request queue (STAILQ of queue(3)) per "context",
and throws all AIO requests of all contexts owned by a process into
the single FreeBSD per-process AIO queue.
When the process calls io_destroy(2), io_getevents(2), io_submit(2) and
io_cancel(2), my code can pick out requests owned by the specified context
from the single FreeBSD per-process AIO queue according to the per-context
request queues maintained by my code.
2. The request queue maintained by my code stores contrast information between
Linux IO control blocks (struct linux_iocb) and FreeBSD IO control blocks
(struct aiocb). FreeBSD IO control block actually exists in userland memory
space, required by FreeBSD native aio_XXXXXX(2).
3. It is quite troubling that the function io_getevents() of libaio-0.3.105
needs to use Linux-specific "struct aio_ring", which is a partial mirror
of context in user space. I would rather take the address of context in
kernel as the context ID, but the io_getevents() of libaio forces me to
take the address of the "ring" in user space as the context ID.
To my surprise, one comment line in the file "io_getevents.c" of
libaio-0.3.105 reads:
Ben will hate me for this
REFERENCE:
1. Linux kernel source code: http://www.kernel.org/pub/linux/kernel/v2.6/
(include/linux/aio_abi.h, fs/aio.c)
2. Linux manual pages: http://www.kernel.org/pub/linux/docs/manpages/
(io_setup(2), io_destroy(2), io_getevents(2), io_submit(2), io_cancel(2))
3. Linux Scalability Effort: http://lse.sourceforge.net/io/aio.html
The design notes: http://lse.sourceforge.net/io/aionotes.txt
4. The package libaio, both source and binary:
http://rpmfind.net/linux/rpm2html/search.php?query=libaio
Simple transparent interface to Linux AIO system calls.
5. Libaio-oracle: http://oss.oracle.com/projects/libaio-oracle/
POSIX AIO implementation based on Linux AIO system calls (depending on
libaio).
---snip---
Submitted by: Li, Xiao <intron@intron.ac>
Revision Changes Path
1.7 +2 -0 src/sys/amd64/linux32/linux.h
1.21 +5 -5 src/sys/amd64/linux32/syscalls.master
1.1 +1349 -0 src/sys/compat/linux/linux_aio.c (new)
1.1 +98 -0 src/sys/compat/linux/linux_aio.h (new)
1.95 +1 -0 src/sys/conf/files.amd64
1.567 +1 -0 src/sys/conf/files.i386
1.70 +2 -0 src/sys/i386/linux/linux.h
1.81 +5 -5 src/sys/i386/linux/syscalls.master
1.228 +4 -4 src/sys/kern/vfs_aio.c
1.2 +2 -0 src/sys/modules/aio/Makefile
1.69 +7 -5 src/sys/modules/linux/Makefile
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