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author | netchild <netchild@FreeBSD.org> | 2006-10-15 14:22:14 +0000 |
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committer | netchild <netchild@FreeBSD.org> | 2006-10-15 14:22:14 +0000 |
commit | 183bd5a34bb7e6bdd1231cfafcc185bc5eb27d7f (patch) | |
tree | 37b5d24e960676debab482dc664dda0e3c7ec546 /sys/amd64/linux32/linux.h | |
parent | 7b28cc9b2faecf0b23e4e115f9cd784767065ea8 (diff) | |
download | FreeBSD-src-183bd5a34bb7e6bdd1231cfafcc185bc5eb27d7f.zip FreeBSD-src-183bd5a34bb7e6bdd1231cfafcc185bc5eb27d7f.tar.gz |
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>
Diffstat (limited to 'sys/amd64/linux32/linux.h')
-rw-r--r-- | sys/amd64/linux32/linux.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/sys/amd64/linux32/linux.h b/sys/amd64/linux32/linux.h index 9c8ed5c..cf4f471 100644 --- a/sys/amd64/linux32/linux.h +++ b/sys/amd64/linux32/linux.h @@ -840,4 +840,6 @@ typedef int l_mqd_t; #define THREADING_FLAGS (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND) +#include <compat/linux/linux_aio.h> + #endif /* !_AMD64_LINUX_LINUX_H_ */ |